TOXICOLOGICAL PROFILE FOR

 WOOD CREOSOTE, COAL TAR CREOSOTE, COAL TAR, 

COAL TAR PITCH, AND COAL TAR PITCH VOLATILES

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

Agency for Toxic Substances and Disease Registry

September 2002
CREOSOTE ii

DISCLAIMER

The use of company or product name(s) is for identification only and does not imply endorsement by the

Agency for Toxic Substances and Disease Registry.
CREOSOTE iii

UPDATE STATEMENT

Toxicological profiles are revised and republished as necessary, but no less than once every three years. 

For information regarding the update status of previously released profiles, contact ATSDR at:

Agency for Toxic Substances and Disease Registry

Division of Toxicology/Toxicology Information Branch

1600 Clifton Road NE, E-29

Atlanta, Georgia 30333

V 

FOREWORD 

This toxicological profile is prepared in accordance with guidelines" developed by the Agency for 

Toxic Substances and Disease Registry (ATSDR) and the Environmental Protection Agency (EPA). The 

original guidelines were published in the Federal Register on April 17, 1987. Each profile will be revised 

and republished as necessary. 

The ATSDR toxicological profile succinctly characterizes the toxicologic and adverse health 

effects information for the hazardous substance described therein. Each peer-reviewed profile identifies 

and reviews the key literature that describes a hazardous substance's toxicologic properties. Other 

pertinent literature is also presented, but is described in less detail than the key studies. The profile is not 

intended to be an exhaustive document; however, more comprehensive sources of specialty information 

are referenced. 

The focus of the profiles is on health and toxicologic information; therefore, each toxicological 

profile begins with a public health statement that describes, in nontechnical language, a substance's 

relevant toxicological properties. Following the public health statement is information concerning levels 

of si,~ficant human exposure and, where known, significant health effects. The adequacy of 

information to determine a substance's health effects is described in a health effects summary. Data 

needs that are of significance to protection of public health are identified by ATSDR and EPA. 

Each profile includes the following: 

The examination, summary, and interpretation of available toxicologic information and 

epidemiologic evaluations on a hazardous substance to ascertain the levels of significant 

human exposure for the substance and the associated acute, subacute, and chronic health 

effects; 

A determination of whether adequate information on the health effects of each substance is 

available or in the process of development to determine levels of exposure that present a 

significant risk to human health of acute, subacute, and chronic health effects; and 

Where appropriate, identification of toxicologic testing needed to identify the types or levels 

of exposure that may present significant risk of adverse health effects in humans. 

The principal audiences for the toxicological profiles are health professionals at the federal, state, 

and local levels; interested private sector organizations and groups; and members of the public. 

This profile reflects ATSDR's assessment of all relevant toxicologic testing and information that 

has been peer-reviewed. Staff of the Centers for Disease Control and Prevention and other federal 

scientists have also reviewed the profile. In addition, this profile has been peer-reviewed by a 

nongovernmental panel and was made available for public review. Final responsibility for the contents 

and views expressed in this toxicological profile resides with ATSDR. 

Administrator 

Agency for Toxic Substances and 

Disease Registry 
vi 

*Legislative Background 

The toxicological profiles are developed in response to the Superfund Amendments and 

Reauthorization Act (SARA) of 1986 (Public Law 99-499) which amended the Comprehensive 

Environmental Response, Compensation, and Liability Act of 1980 (CERCLA or Superfund). This 

public law directed ATSDR to prepare toxicological profiles for hazardous substances most commonly 

found at facilities on the CERCLA National Priorities List and that pose the most significant potential 

threat to human health, as determined by ATSDR and the EPA. The availability of the revised priority 

list of 275 hazardous substances was announced in the FederaZ Register on October 25,2001 

(66 FR 54014). For prior versions of the list of substances, see FederaZ Register notices dated 

April 17, 1987 (52 FR 12866); October 20,1988 (53 FR41280); October 26, 1989 (54 FR 43619); 

October 17,1990 (55 FR 42067); October 17, 1991 (56 FR 52166); October 28, 1992 (57 FR 48801); 

February 28, 1994 (59 FR 9486); April 29,1996 (61 FR 18744); November 17,1997 (62 FR 61332); and 

October 21, 1999 (64 FR 56792). Section 104(i)(3) of CERCLA, as amended, directs the Administrator 

of ATSDR to prepare a toxicological profile for each substance on the list. 
CREOSOTE vii

QUICK REFERENCE FOR HEALTH CARE PROVIDERS

Toxicological Profiles are a unique compilation of toxicological information on a given hazardous

substance. Each profile reflects a comprehensive and extensive evaluation, summary, and interpretation

of available toxicologic and epidemiologic information on a substance. Health care providers treating

patients potentially exposed to hazardous substances will find the following information helpful for fast

answers to often-asked questions.

Primary Chapters/Sections of Interest

Chapter 1: Public Health Statement: The Public Health Statement can be a useful tool for educating

patients about possible exposure to a hazardous substance. It explains a substance’s relevant

toxicologic properties in a nontechnical, question-and-answer format, and it includes a review of

the general health effects observed following exposure.

Chapter 2: Relevance to Public Health: The Relevance to Public Health Section evaluates, interprets,

and assesses the significance of toxicity data to human health.

Chapter 3: Health Effects: Specific health effects of a given hazardous compound are reported by type

of health effect (death, systemic, immunologic, reproductive), by route of exposure, and by length

of exposure (acute, intermediate, and chronic). In addition, both human and animal studies are

reported in this section. 

NOTE: Not all health effects reported in this section are necessarily observed

in the clinical setting. Please refer to the Public Health Statement to identify

general health effects observed following exposure.

Pediatrics: Four new sections have been added to each Toxicological Profile to address child health

issues:

Section 1.6 How Can Creosote Affect Children?

Section 1.7 How Can Families Reduce the Risk of Exposure to Creosote?

Section 3.7 Children’s Susceptibility

Section 6.6 Exposures of Children

Other Sections of Interest:

Section 3.8 Biomarkers of Exposure and Effect

Section 3.11 Methods for Reducing Toxic Effects

ATSDR Information Center 

Phone: 1-888-42-ATSDR or (404) 498-0110 Fax: (404) 498-0057

E-mail: atsdric@cdc.gov Internet: http://www.atsdr.cdc.gov

The following additional material can be ordered through the ATSDR Information Center:

Case Studies in Environmental Medicine: Taking an Exposure History—The importance of taking an

exposure history and how to conduct one are described, and an example of a thorough exposure

history is provided. Other case studies of interest include Reproductive and Developmental

Hazards; Skin Lesions and Environmental Exposures; Cholinesterase-Inhibiting Pesticide

Toxicity; and numerous chemical-specific case studies.
CREOSOTE viii

Managing Hazardous Materials Incidents is a three-volume set of recommendations for on-scene

(prehospital) and hospital medical management of patients exposed during a hazardous materials incident. 

Volumes I and II are planning guides to assist first responders and hospital emergency department

personnel in planning for incidents that involve hazardous materials. Volume III—Medical Management

Guidelines for Acute Chemical Exposures—is a guide for health care professionals treating patients

exposed to hazardous materials.

Fact Sheets (ToxFAQs) provide answers to frequently asked questions about toxic substances.

Other Agencies and Organizations

The National Center for Environmental Health (NCEH) focuses on preventing or controlling disease,

injury, and disability related to the interactions between people and their environment outside the

workplace. Contact: NCEH, Mailstop F-29, 4770 Buford Highway, NE, Atlanta, GA 30341-

3724 • Phone: 770-488-7000 • FAX: 770-488-7015.

The National Institute for Occupational Safety and Health (NIOSH) conducts research on occupational

diseases and injuries, responds to requests for assistance by investigating problems of health and

safety in the workplace, recommends standards to the Occupational Safety and Health

Administration (OSHA) and the Mine Safety and Health Administration (MSHA), and trains

professionals in occupational safety and health. Contact: NIOSH, 200 Independence Avenue,

SW, Washington, DC 20201 • Phone: 800-356-4674 or NIOSH Technical Information Branch,

Robert A. Taft Laboratory, Mailstop C-19, 4676 Columbia Parkway, Cincinnati, OH 45226-1998

• Phone: 800-35-NIOSH.

 The National Institute of Environmental Health Sciences (NIEHS) is the principal federal agency for

biomedical research on the effects of chemical, physical, and biologic environmental agents on

human health and well-being. Contact: NIEHS, PO Box 12233, 104 T.W. Alexander Drive,

Research Triangle Park, NC 27709 • Phone: 919-541-3212.

Referrals

The Association of Occupational and Environmental Clinics (AOEC) has developed a network of clinics

in the United States to provide expertise in occupational and environmental issues. Contact:

AOEC, 1010 Vermont Avenue, NW, #513, Washington, DC 20005 • Phone: 202-347-4976 •

FAX: 202-347-4950 • e-mail: AOEC@AOEC.ORG • Web Page: http://www.aoec.org/.

The American College of Occupational and Environmental Medicine (ACOEM) is an association of

physicians and other health care providers specializing in the field of occupational and

environmental medicine. Contact: ACOEM, 55 West Seegers Road, Arlington Heights, IL

60005 • Phone: 847-818-1800 • FAX: 847-818-9266.
CREOSOTE ix

CONTRIBUTORS

CHEMICAL MANAGER(S)/AUTHORS(S):

Gangadhar Choudhary, Ph.D.

ATSDR, Division of Toxicology, Atlanta, GA

Mario J. Citra, Ph.D.

Syracuse Research Corporation, North Syracuse, NY

A. Rosa McDonald, Ph.D

Syracuse Research Corporation, North Syracuse, NY

Antonio Quiñones-Rivera, M.S.

Syracuse Research Corporation, North Syracuse, NY

THE PROFILE HAS UNDERGONE THE FOLLOWING ATSDR INTERNAL REVIEWS:

1. Health Effects Review. The Health Effects Review Committee examines the health effects

chapter of each profile for consistency and accuracy in interpreting health effects and classifying

end points.

2. Minimal Risk Level Review. The Minimal Risk Level Workgroup considers issues relevant to

substance-specific minimal risk levels (MRLs), reviews the health effects database of each

profile, and makes recommendations for derivation of MRLs.

3. Data Needs Review. The Research Implementation Branch reviews data needs sections to assure

consistency across profiles and adherence to instructions in the Guidance.

CREOSOTE xi

PEER REVIEW

A peer review panel was assembled for creosote. The panel consisted of the following members: 

1. Dr. Gary Pascoe, EA Engineering, Science and Technology Inc., 210 Taylor Street, Room 15, Port

Townsend, Washington 98368;

2. Dr. Norman Trieff, University of North Texas, Health Science Center at Fort Worth, 35 Camp

Bowie Boulevard, Fort Worth, Texas 76107-2699; and

3. Dr. David Warshawsky, University of Cincinnati, Environmental Health, Kettering 137, Cincinnati,

Ohio 45267-0056.

These experts collectively have knowledge of creosote's physical and chemical properties, toxicokinetics,

key health end points, mechanisms of action, human and animal exposure, and quantification of risk to

humans. All reviewers were selected in conformity with the conditions for peer review specified in

Section 104(I)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as

amended.

Scientists from the Agency for Toxic Substances and Disease Registry (ATSDR) have reviewed the peer

reviewers' comments and determined which comments will be included in the profile. A listing of the

peer reviewers' comments not incorporated in the profile, with a brief explanation of the rationale for their

exclusion, exists as part of the administrative record for this compound. A list of databases reviewed and

a list of unpublished documents cited are also included in the administrative record.

The citation of the peer review panel should not be understood to imply its approval of the profile's final

content. The responsibility for the content of this profile lies with the ATSDR.

CREOSOTE xiii

CONTENTS

FOREWORD ....................................................................... v

QUICK REFERENCE FOR HEALTH CARE PROVIDERS ................................. vii

CONTRIBUTORS ................................................................... ix

PEER REVIEW ..................................................................... xi

LIST OF FIGURES ................................................................ xvii

LIST OF TABLES .................................................................. xix

1. PUBLIC HEALTH STATEMENT .................................................... 1

1.1 WHAT IS CREOSOTE? ...................................................... 1

1.2 WHAT HAPPENS TO CREOSOTE WHEN IT ENTERS THE ENVIRONMENT? ........ 3

1.3 HOW MIGHT I BE EXPOSED TO CREOSOTE? .................................. 5

1.4 HOW CAN CREOSOTE ENTER AND LEAVE MY BODY? ......................... 6

1.5 HOW CAN CREOSOTE AFFECT MY HEALTH? ................................. 7

1.6 HOW CAN CREOSOTE AFFECT CHILDREN? ................................... 8

1.7 HOW CAN FAMILIES REDUCE THE RISK OF EXPOSURE TO CREOSOTE? ........ 10

1.8 IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN EXPOSED TO

CREOSOTE? .............................................................. 13

1.9 WHAT RECOMMENDATIONS HAS THE FEDERAL GOVERNMENT MADE TO

PROTECT HUMAN HEALTH? ............................................... 14

1.10 WHERE CAN I GET MORE INFORMATION? .................................. 15

2. RELEVANCE TO PUBLIC HEALTH ............................................... 17

2.1 BACKGROUND AND ENVIRONMENTAL EXPOSURES TO CREOSOTE IN THE

UNITED STATES .......................................................... 17

2.1.1 Wood Creosotes ....................................................... 17

2.1.2 Coal Tar and Coal Tar Products ........................................... 17

2.2 SUMMARY OF HEALTH EFFECTS ........................................... 20

2.2.1 Wood Creosotes ........................................................ 20

2.2.2 Coal Tar and Coal Tar Products ........................................... 21

2.3 MINIMAL RISK LEVELS ................................................... 23

3. HEALTH EFFECTS .............................................................. 27

3.1 INTRODUCTION .......................................................... 27

3.2 DISCUSSION OF HEALTH EFFECTS BY ROUTE OF EXPOSURE ................. 27

3.2.1 Inhalation Exposure .................................................. 30

3.2.1.1 Death ..................................................... 42

3.2.1.2 Systemic Effects ............................................ 45

3.2.1.3 Immunological and Lymphoreticular Effects ...................... 54

3.2.1.4 Neurological Effects ......................................... 55

3.2.1.5 Reproductive Effects ......................................... 55

3.2.1.6 Developmental Effects ....................................... 56

3.2.1.7 Cancer .................................................... 57

3.2.2 Oral Exposure........................................... ....... ..... . 63
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3.2.2.1 Death . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

3.2.2.2 Systemic Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

3.2.2.3 Immunological and Lymphoreticular Effects . . . . . . . . . . . . . . . . . . . . . 101

3.2.2.4 Neurological Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

3.2.2.5 Reproductive Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

3.2.2.6 Developmental Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

3.2.2.7 Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

3.2.3 Dermal Exposure ................................................... 111

3.2.3.1 Death . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

3.2.3.2 Systemic Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

3.2.3.3 Immunological and Lymphoreticular Effects . . . . . . . . . . . . . . . . . . . . . 131

3.2.3.4 Neurological Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

3.2.3.5 Reproductive Effects ........................................ 132

3.2.3.6 Developmental Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

3.2.3.7 Cancer ................................................... 135

3.4 TOXICOKINETICS ........................................................ 154

3.4.1 Absorption ........................................................ 154

3.4.1.1 Inhalation Exposure ......................................... 154

3.4.1.2 Oral Exposure ............................................. 157

3.4.1.3 Dermal Exposure ........................................... 158

3.4.2 Distribution ....................................................... 161

3.4.2.1 Inhalation Exposure ......................................... 162

3.4.2.2 Oral Exposure ............................................. 163

3.4.2.3 Dermal Exposure ........................................... 164

3.4.3 Metabolism ........................................................ 164

3.4.3.1 Inhalation Exposure ......................................... 167

3.4.3.2 Oral Exposure ............................................. 168

3.4.3.3 Dermal Exposure ........................................... 169

3.4.4 Elimination and Excretion ............................................ 172

3.4.4.1 Inhalation Exposure ......................................... 173

3.4.4.2 Oral Exposure ............................................. 175

3.4.4.3 Dermal Exposure ........................................... 177

3.4.5 Physiologically Based Pharmacokinetic (PBPK)/Pharmacodynamic (PD) Models

................................................................. 179

3.5 MECHANISMS OF ACTION ................................................ 181

3.5.1 Pharmacokinetic Mechanisms ......................................... 181

3.5.2 Mechanisms of Toxicity .............................................. 184

3.5.3 Animal-to-Human Extrapolations ...................................... 185

3.6 TOXICITIES MEDIATED THROUGH THE NEUROENDOCRINE AXIS ............ 185

3.7 CHILDREN’S SUSCEPTIBILITY ............................................ 189

3.8 BIOMARKERS OF EXPOSURE AND EFFECT ................................. 193

3.8.1 Biomarkers Used to Identify or Quantify Exposure to Creosote ............... 195

3.8.2 Biomarkers Used to Characterize Effects Caused by Creosote ................ 196

3.9 INTERACTIONS WITH OTHER CHEMICALS ................................. 196

3.10 POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE ...................... 197

3.11 METHODS FOR REDUCING TOXIC EFFECTS ................................ 199

3.11.1 Reducing Peak Absorption Following Exposure ........................... 199

3.11.2 Reducing Body Burden .............................................. 200

3.11.3 Interfering with the Mechanism of Action for Toxic Effects .................. 201

3.12 ADEQUACY OF THE DATABASE ........................................... 201

3.12.1 Existing Information on Health Effects of Creosote ........................ 202
CREOSOTE xv

3.12.2 Identification of Data Needs .......................................... 204

3.12.3 Ongoing Studies .................................................... 213

4. CHEMICAL AND PHYSICAL INFORMATION ...................................... 216

4.1 CHEMICAL IDENTITY .................................................... 216

4.2 PHYSICAL AND CHEMICAL PROPERTIES ................................... 216

4.2.1 Wood Creosote ..................................................... 216

4.2.2 Coal Tar Creosote, Coal Tar, and Coal Tar Pitch .......................... 220

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL ............................ 232

5.1 PRODUCTION ........................................................... 232

5.2 IMPORT/EXPORT ........................................................ 233

5.3 USE ..................................................................... 233

5.4 DISPOSAL ............................................................... 237

6. POTENTIAL FOR HUMAN EXPOSURE ........................................... 240

6.1 OVERVIEW .............................................................. 240

6.2 RELEASES TO THE ENVIRONMENT ........................................ 242

6.2.1 Air .............................................................. 246

6.2.2 Water ............................................................ 247

6.2.3 Soil .............................................................. 248

6.3 ENVIRONMENTAL FATE .................................................. 249

6.3.1 Transport and Partitioning ............................................ 250

6.3.2 Transformation and Degradation ....................................... 252

6.3.2.1 Air ...................................................... 252

6.3.2.2 Water .................................................... 253

6.3.2.3 Sediment and Soil .......................................... 255

6.3.2.4 Other Media............................................... 257

6.4 LEVELS MONITORED OR ESTIMATED IN THE ENVIRONMENT ............... 257

6.4.1 Air .............................................................. 257

6.4.2 Water ............................................................ 257

6.4.3 Sediment and Soil .................................................. 258

6.4.4 Other Environmental Media ........................................... 260

6.5 GENERAL POPULATION AND OCCUPATIONAL EXPOSURE .................. 261

6.6 EXPOSURES OF CHILDREN ............................................... 269

6.7 POPULATIONS WITH POTENTIALLY HIGH EXPOSURES ...................... 272

6.8 ADEQUACY OF THE DATABASE ........................................... 274

6.8.1 Identification of Data Needs .......................................... 274

6.8.2 Ongoing Studies .................................................... 279

7. ANALYTICAL METHODS ....................................................... 282

7.1 BIOLOGICAL MATERIALS ................................................ 282

7.2 ENVIRONMENTAL SAMPLES .............................................. 286

7.3 ADEQUACY OF THE DATABASE ........................................... 294

7.3.1 Identification of Data Needs .......................................... 294

7.3.2 Ongoing Studies .................................................... 296

8. REGULATIONS AND ADVISORIES .............................................. 298

9. REFERENCES ................................................................. 302
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10. GLOSSARY .................................................................. 348

APPENDICES

D. ATSDR MINIMAL RISK LEVELS AND WORKSHEETS . . . . . . . . . . . . . . . . . . . . . . . . . A-1

E. USER’S GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

F. ACRONYMS, ABBREVIATIONS, AND SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

G. INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
CREOSOTE xvii

LIST OF FIGURES

2-1 Origin of Wood Creosotes and Coal Tar Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3-1 Levels of Significant Exposure to Creosote—Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3-2 Levels of Significant Exposure to Creosote—Oral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

3-3 Levels of Significant Exposure to Wood Creosote—Oral ............................... 82

3-4 Proposed Metabolic Scheme for Benzo[a]pyrene ..................................... 165

3-5 Conceptual Representation of a Physiologically Based Pharmacokinetic (PBPK) Model for a

Hypothetical Chemical Substance ................................................ 182

3-6 Existing Information on Health Effects of Creosote ................................... 203

6-1 Frequency of NPL Sites with Creosote Contamination ................................ 241

CREOSOTE xix

LIST OF TABLES

3-1 Levels of Significant Exposure to Creosote—Inhalation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3-2 Levels of Significant Exposure to Creosote—Oral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

3-3 Levels of Significant Exposure to Wood Creosote—Oral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

3-4 Levels of Significant Exposure to Creosote—Dermal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

3-5 Levels of Significant Exposure to Wood Creosote—Dermal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

3-6 Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch, or Coal Tar Pitch 

Volatiles In Vivo .............................................................. 150

3-7 Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch, or Coal Tar Pitch 

Volatiles In Vitro ............................................................. 152

4-1 Chemical Identity of Wood Creosote .............................................. 217

4-2 Chemical Identity of Coal Tar Creosote ............................................ 218

4-3 Chemical Identity of Coal Tar ................................................... 219

4-4 Identity of Major Components of Wood Creosote .................................... 221

4-5 Physical and Chemical Properties of Wood Creosote ................................. 222

4-6 Identity of PAH Components of Coal Tar Pitch ...................................... 224

4-7 Physical and Chemical Properties of Coal Tar Creosote ............................... 225

4-8 Physical and Chemical Properties of Coal Tar ....................................... 230

5-1 Facilities that Produce, Process, or Use Coal Tar Creosote ............................. 234

5-2 Import/Export Volumes for Creosote .............................................. 236

6-1 Releases to the Environment from Facilities that Produce, Process, or Use Coal 

Tar Creosote ................................................................. 244

7-1 Analytical Methods for Determining Creosote/Coal Tar-Derived PAH Components in 

Biological Samples ............................................................ 284

7-2 Analytical Methods for Determining Creosote/Coal Tar-Derived PAH Components in

Environmental Samples ........................................................ 287

8-1 Regulations and Guidelines Applicable to Coal Tar Creosote, Coal Tar, Coal Tar Pitch, and Coal

Tar Pitch Volatiles ............................................................ 299

CREOSOTE 1

1. PUBLIC HEALTH STATEMENT

This public health statement tells you about wood creosote, coal tar creosote, coal tar, coal tar

pitch, and coal tar pitch volatiles and the effects of exposure. 

The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in

the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for

long-term federal cleanup activities. Coal tar creosote, coal tar, and coal tar pitch have been

found in at least 46 of the 1,613 current or former NPL sites. However, the total number of NPL

sites evaluated for these substances is not known. As more sites are evaluated, the sites at which

coal tar creosote, coal tar, and coal tar pitch are found may increase. This information is

important because exposure to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles

may harm you and because these sites may be sources of exposure.

When a substance is released from a large area, such as an industrial plant, or from a container,

such as a drum or bottle, it enters the environment. This release does not always lead to

exposure. You are exposed to a substance only when you come in contact with it. You may be

exposed by breathing, eating, or drinking the substance, or by skin contact.

If you are exposed to wood creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch

volatiles, many factors determine whether you’ll be harmed. These factors include the dose

(how much), the duration (how long), and how you come in contact with them. You must also

consider the other chemicals you’re exposed to and your age, sex, diet, family traits, lifestyle,

and state of health.

1.1 WHAT IS CREOSOTE?

Creosote is the name used for a variety of products that are mixtures of many chemicals. Wood

creosotes are derived from the resin from leaves of the creosote bush (Larrea, referred to herein

as creosote bush resin) and beechwood (Fagus, referred to herein as beechwood creosote). Coal

tars are by-products of the carbonization of coal to produce coke or natural gas. Coal tar
CREOSOTE 2

1. PUBLIC HEALTH STATEMENT

creosotes are distillation products of coal tar, and coal tar pitch is a residue produced during the

distillation of coal tar. Coal tar pitch volatiles are compounds given off from coal tar pitch when

it is heated. Coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles are rarely

formed in nature. Coal tar creosote, coal tar, and coal tar pitch are mixtures of similar

compounds. For this reason, many times throughout the profile, we will refer to coal tar

creosote, coal tar, and coal tar pitch simply as creosote. Creosotes are created by

high-temperature treatment of beech and other woods (beechwood creosote) or coal (coal tar

creosote), or from the resin of the creosote bush (creosote bush resin). Wood creosote is a

colorless to yellowish greasy liquid with a characteristic smoky odor and sharp burned taste. It

is relatively soluble in water. Creosote prepared from coal tar is the most common form of

creosote in the workplace and at hazardous waste sites in the United States. Coal tar creosote is

a thick, oily liquid that is typically amber to black in color. It is easily set on fire and does not

dissolve easily in water. Coal tar and coal tar pitch are the by-products of the high-temperature

treatment of coal to make coke or natural gas. They are usually thick, black or dark brown

liquids or semisolids with a smoky or aromatic odor. Coal tar residues can also be found in the

chimneys of homes heated with coal, especially if insufficient oxygen is present. Chemicals in

the coal tar pitch can be given off into the air as coal tar pitch volatiles when coal tar pitch is

heated. 

Beechwood creosote has been used as a disinfectant, a laxative, and a cough treatment. In the

past, treatments for leprosy, pneumonia, and tuberculosis also involved eating or drinking

beechwood creosote. It is rarely used today in the United States by doctors since it has been

replaced by better medicines, and it is no longer produced by businesses in the United States. It

is still available as an herbal remedy, and is used as an expectorant and a laxative in Japan. The

major chemicals in beechwood creosote are phenol, cresols, and guaiacol. 

Coal tar creosote is the most widely used wood preservative in the United States. It is also a

restricted-use pesticide, so it can be used only by people who have been trained to use it safely. 

Coal tar products are ingredients in medicines used to treat skin diseases such as psoriasis. 

These products are also used as animal and bird repellents, insecticides, animal dips, and

fungicides. Coal tar, coal tar pitch, and coal tar pitch volatiles are used or produced in several
CREOSOTE 3

1. PUBLIC HEALTH STATEMENT

industries, including road paving, roofing, aluminum smelting, rubber producing, and coking. 

The major chemicals in coal tar creosote, coal tar, and coal tar pitch that can cause harmful

health effects are polycyclic aromatic hydrocarbons (PAHs), phenol, and cresols. Coal tar pitch

volatiles vary depending on the makeup of the coal tar product that is being heated. About

300 chemicals have been identified in coal tar creosote, but as many as 10,000 other chemicals

may be in this mixture. Because coal tar creosote is the major type found in the environment and

at hazardous waste sites in the United States, we will emphasize its effects on human health in

this profile. The health effects of coal tar and coal tar pitch will also be described.

This profile is specifically about the toxicity of wood creosote, coal tar creosote, coal tar, coal tar

pitch, and coal tar pitch volatiles, so we will not discuss in detail the health effects of individual

chemicals in them, such as PAHs or phenol. In the chapters describing what happens to creosote

in the environment and exposure to creosote, we will discuss some of the individual chemicals or

groups of chemicals (such as PAHs) because many of the tests done in the scientific laboratories

can tell us which of these chemicals are present in the soil, water, and air.

The Agency for Toxic Substances and Disease Registry (ATSDR) Toxicological Profile for

Polycyclic Aromatic Hydrocarbons (1995), the ATSDR Toxicological Profile for Cresols

(1992), and the ATSDR Toxicological Profile for Phenol (1998) provide more information on

these chemicals. For more information on the chemical and physical properties of creosotes,

coal tar, coal tar pitch, and coal tar pitch volatiles, see Chapter 4. For more information on these

substances in the environment, see Chapters 5 and 6.

1.2 WHAT HAPPENS TO CREOSOTE WHEN IT ENTERS THE ENVIRONMENT?

No information is available on what happens to wood creosote when it enters the environment. 

Coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles do not occur in the

environment naturally, but are by-products produced in coke or gas manufacturing plants using

high-temperature processes. Coal tar creosote is released to water and soil mainly as a result of

its use in the wood preservation industry. In the past, waste water from wood-treatment facilities

was often discharged to unlined lagoons where it formed a sludge. Also, companies that
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1. PUBLIC HEALTH STATEMENT

preserve wood with coal tar creosote may treat their water wastes in treatment plants or release

the waste water to the municipal water treatment system. This is still the largest source of coal

tar creosote in the environment. However, new restrictions from EPA have caused changes in

the treatment methods that have decreased the amount of creosote available to move into soil

from waste water effluents. Coal tar creosote contains some components that dissolve in water

and some that do not. Coal tar creosote components that dissolve in water may move through

the soil to eventually reach and enter the groundwater, where they may persist. Once in the

groundwater, breakdown may take years. Most of the components that are not water soluble will

remain in place in a tar-like mass. Migration from the site of contamination is not extensive. 

Breakdown in soil can take months for some components of coal tar creosote, and much longer

for others. Sometimes, the small amounts of chemical remaining in the soil or water that take a

long time to break down are still toxic to some animals and possibly to humans. Coal tar

creosote components may also be found in the soil as a result of leaking or seeping from treated

timber. More complete information on how creosote enters the environment and what happens

to creosote in the environment can be found in Chapters 5 and 6 of this profile.

Volatile chemicals in coal tar creosote may evaporate and enter the air. About 1–2% of the coal

tar creosote applied to treated wood is released to the air. This is a small amount compared with

the amount of coal tar creosote found in waste water or soil. Volatile chemicals in coal tar and

coal tar pitch are released into the environment in a similar way. They are most often found in

and around coke- or natural gas-producing factories, in industrial plants where coal tar and coal

tar sludges are used, or at abandoned coke or gas factory sites. Water or soil surrounding these

areas may contain detectable levels of coal tar or coal tar pitch.

Once coal tar creosote is in the environment, both plants and animals can absorb parts of the

creosote mixture. Some components of coal tar creosote have been found in plants exposed to

creosote-treated wood in nearby soil. The plants absorb very little (less than 0.5% of the amount

available to the plant). Animals such as voles, crickets, snails, pill bugs, and worms take up coal

tar creosote components from the environment that are passed into the body through skin, lungs,

or stomachs. Animals that live in the water, such as crustacea, shellfish, and worms, also take up

coal tar creosote compounds. For instance, mussels attached to creosote-treated pilings and
CREOSOTE 5

1. PUBLIC HEALTH STATEMENT

snails and oysters living in water near a wood-treatment plant had creosote in their tissues. Coal

tar creosote components are also broken down by microorganisms living in the soil and natural

water. The components of coal tar and coal tar pitch move in the environment in a similar way.

1.3 HOW MIGHT I BE EXPOSED TO CREOSOTE?

Most people are exposed to very low levels of creosote. People who are exposed to higher

concentrations than the general population are those exposed to creosote in their jobs and those

who use products that contain creosote to improve a health problem such as eczema or psoriasis. 

Some people are exposed to creosote by using shampoos for psoriasis that contain creosote. 

Herbal remedies containing the leaves from the creosote bush (chaparral) are available as a

dietary supplement and are a source of exposure to wood creosote. People who drink chaparral

tea could be exposed to wood creosote. Hazardous waste sites are a major source of

contamination with creosote, coal tar, and coal tar pitch. Individuals working in the woodpreserving industry make up the largest part of the population that might be exposed to coal tar

creosote. Individuals who live in areas that used to be sites of wood-preserving facilities may be

exposed if the soil was never cleaned up. The most common way that creosote will enter the

body when it is present in soils is through the skin. In addition, children may also ingest

creosote if they put their unwashed hands in their mouths after touching soil or wood

contaminated with creosote. The most common way that it will enter the body for individuals in

the wood-preserving industry is through the lungs.

Asphalt workers; rubber, aluminum, iron, steel, and tire factory workers; and people working in

the coke-producing industries are also at risk for potential exposure to coal tar pitch and coal tar

pitch volatiles. They may breathe in vapors from or have direct skin contact with woodpreservation solutions, freshly treated wood, asphalt mixtures, or other products of cokeproducing industries. Workers who use creosote-treated wood in building fences, bridges, or

railroad tracks or installing telephone poles may be exposed; those who inspect or maintain these

materials, or apply asphalt or other coal tar pitch-containing materials, may also be exposed. 

Homeowners, farmers, or landscapers who apply coal tar creosote to wood in noncommercial
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1. PUBLIC HEALTH STATEMENT

settings using a brush or dip procedure (which is no longer allowed by law unless you have been

trained to safely use creosote as a wood preservative), or who use railroad ties or telephone poles

in landscaping, or who reclaim scrap lumber from a treated structure may also be exposed. In

addition, people who work or live in treated-wood houses (log cabins) may be exposed through

the air or by direct contact with the wood. Exposure to coal tar products may also occur in the

natural gas and aluminum smelting industries. You can be exposed by any contact with water,

soil, air, or plant and animal tissues that contain creosotes, coal tar, coal tar pitch, or its volatile

components. Intentional or accidental eating of coal tar creosote has resulted in poisoning. If

your activities bring you into contact with these mixtures, such as at hazardous waste sites, in

contaminated groundwater, in wood products treated with creosote, or in contaminated shellfish,

you will be exposed to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles. 

You can also be exposed by drinking water contaminated by a hazardous waste site. For more

information on human exposure to these substances, see Chapter 6.

1.4 HOW CAN CREOSOTE ENTER AND LEAVE MY BODY?

Creosotes and coal tar products can enter your body through the lungs, stomach, intestines, and

skin. No information that describes how fast or how much creosote or its components might

enter the body after one or many exposures is available. The amount that enters the body

depends on how you come in contact with it (via air, food, water, skin), how much of the mixture

is present, and how long you are exposed to it. Many of the parts of the coal tar creosote mixture

(for example, PAHs) are rapidly absorbed through the lungs, stomach, and intestines. Prolonged

exposure through the skin, without washing, may increase the amount of the creosotes or coal tar

products that pass into the bloodstream. Individual components of coal tar creosote, coal tar,

coal tar pitch, and coal tar pitch volatiles may be stored in body fat. In the body, some coal tar

components may be metabolized. For example, pyrene can be metabolized to 1-hydroxypyrene. 

Some studies indicate that creosotes may cross the placenta into the tissue of the developing

fetus. Because coal tar products may be stored in body fat, they may be found in breast milk. 

Creosotes leave the body primarily in the stool; a smaller amount leaves the body in the urine. 

See Chapter 3 for more information on how creosotes and coal tar products enter and leave the

body. 
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1. PUBLIC HEALTH STATEMENT

1.5 HOW CAN CREOSOTE AFFECT MY HEALTH?

To protect the public from the harmful effects of toxic chemicals and to find ways to treat people

who have been harmed, scientists use many tests. 

Exposure to creosotes, coal tar, coal tar pitch, or coal tar pitch volatiles may be harmful to your

health. Eating food or drinking water contaminated with a high level of these compounds may

cause a burning in the mouth and throat as well as stomach pain. Taking herbal remedies

containing creosote bush leaves may result in damage to the liver or kidney. Reports describing

poisoning in workers exposed to coal tar creosote, or in people who accidentally or intentionally

ate coal tar creosote prove that these chemicals can be harmful. These reports indicate that brief

exposure to large amounts of coal tar creosote may result in a rash or severe irritation of the skin,

chemical burns of the surfaces of the eye, convulsions and mental confusion, kidney or liver

problems, unconsciousness, or even death. Longer exposure to lower levels of coal tar creosote,

coal tar, coal tar pitch or coal tar pitch volatiles by direct contact with the skin or by exposure to

the vapors from these mixtures can also result in increased sensitivity to sunlight, damage to the

cornea, and skin damage such as reddening, blistering, or peeling. Longer exposures to the

vapors of the creosotes, coal tar, coal tar pitch, or coal tar pitch volatiles can also cause irritation

of the respiratory tract. Skin cancer and cancer of the scrotum have also resulted from long

exposure to low levels of these chemical mixtures, especially through direct contact with the skin

during wood treatment or manufacture of coal tar creosote-treated products, or in coke or natural

gas factories. Prolonged skin exposure to soot and coal tar creosote has been associated with

cancer of the scrotum in chimney sweeps. These levels are much higher than the levels that you

are likely to be exposed to in groundwater, food, air, or soil.

One way to see if a chemical will hurt people is to learn how the chemical is absorbed, used, and

released by the body; for some chemicals, animal testing may be necessary. Animal testing may

also be used to identify health effects such as cancer or birth defects. Without laboratory

animals, scientists would lose a basic method to get information needed to make wise decisions

to protect public health. Scientists have the responsibility to treat research animals with care and
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1. PUBLIC HEALTH STATEMENT

compassion. Laws today protect the welfare of research animals, and scientists must comply

with strict animal care guidelines.

Rats and mice fed a large amount of wood creosote at one time had convulsions and died. Rats

fed a smaller amount of wood creosote for a long period developed kidney and liver problems,

and died. Exposure to coal tar products through the skin has resulted in skin cancer in animals. 

Laboratory animals that ate food containing coal tar developed cancer of the lungs, liver, and

stomach, and animals exposed to coal tar in the air developed lung and skin cancer.

The International Agency for Research on Cancer (IARC) has determined that coal tar is

carcinogenic to humans and that creosote is probably carcinogenic to humans. EPA has also

determined that coal tar creosote is a probable human carcinogen. 

1.6 HOW CAN CREOSOTE AFFECT CHILDREN?

This section discusses potential health effects from exposures during the period from conception

to maturity at 18 years of age in humans. 

Children are generally exposed to very low levels of creosote, but intentional or accidental eating

of coal tar creosote has resulted in poisoning. Children who live in hazardous waste areas

contaminated with creosote may be exposed by drinking contaminated water or from contact

with soil. The most common way that creosote will enter the body when it is present in soils is

through the skin. However, children may also swallow creosote if they eat dirt or put their

unwashed hands in their mouths after touching soil or wood contaminated with creosote. In

addition, children may be exposed to creosote compounds if they eat fish and shellfish from

contaminated areas. Children may also be exposed to creosote if they use products that contain

creosote to improve a health problem such as dandruff, eczema, or psoriasis, or if they are given

an herbal remedy containing the leaves from the creosote bush (chaparral). 

Children may also be exposed to creosote if they breathe in vapors from or have direct skin

contact with freshly treated wood found in fences, bridges, railroad ties, or telephone poles. In
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1. PUBLIC HEALTH STATEMENT

addition, children who live in treated-wood houses (log cabins) may be exposed through the air

or by direct contact with the wood. The use of creosote to protect wooden playground

equipment or wooden decks for the yard is not recommended, but children may be exposed to

creosote if it has been applied to wood in or around the home in the past. Children could also be

exposed to creosote on their parent’s clothing or shoes if these have been contaminated with

creosote at the workplace. Children are not more likely to be exposed to creosote than adults,

and there is no unique exposure of children to creosote.

Children who played on soil contaminated with creosote had more skin rashes than children who

played in uncontaminated areas. Apart from this, the health effects of creosote have not been

studied in children, but they would likely experience the same health effects seen in adults

exposed to creosote. We do not know whether children differ from adults in their susceptibility

to health effects from creosote. Children could be more susceptible to cancer because they might

have a longer time in which to develop it, but this association has not been studied.

No effects have been reported for children exposed to creosote before birth. Experiments in

laboratory animals have shown birth defects, such as cleft palates, in the young of mothers

exposed to high levels of creosote during pregnancy, but whether creosote could induce such

defects in humans is not known. Some animal studies indicate that creosotes may cross the

placenta into the tissue of the developing fetus. Because chemical components of coal tar may

be stored in body fat, they may be found in breast milk and therefore could be transferred to

newborns and infants. For more information on the effects of creosote on children, see

Section 3.7.
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1. PUBLIC HEALTH STATEMENT

1.7 HOW CAN FAMILIES REDUCE THE RISK OF EXPOSURE TO CREOSOTE?

If your doctor finds that you have been exposed to significant amounts of creosote, coal tar, coal

tar pitch, or coal tar pitch volatiles, ask whether your children might also be exposed. Your

doctor might need to ask your state health department to investigate.

Families may reduce the risk of exposure to coal tar creosote, coal tar, coal tar pitch, and coal tar

pitch volatiles in several ways if they find that they are at risk of such exposures. If you live in a

residential area that used to have a wood preservation facility or gas manufacturing plant located

nearby, you should use precautions to decrease or limit your exposure to creosote that may be

present in the soil or water. This may include wearing long-sleeved shirts and long pants when

working or playing outside and avoiding using water contaminated with creosote. If the soil in

your yard was contaminated by creosote in the past, you should probably not grow food in it. 

You will need to wash your hands and any other exposed skin carefully after you are in contact

with the contaminated soil or water outside. This is especially true for children since they have a

tendency to put their hands in their mouths. Some children eat a lot of dirt. It is not fully

understood how much of the creosote bound to dirt may come off the dirt when it is inside your

body. You should discourage children from eating dirt. Make sure they wash their hands

frequently and before eating. Discourage your children from putting their hands in their mouths

or from engaging in other hand-to-mouth activity.

Children may be exposed to creosote during their outdoor play activities. You should encourage

your children not to play in contaminated areas, particularly in those that may be abandoned

waste sites or waste sites undergoing cleanup. Some children will ignore signs posted at the sites

that alert the public to possible dangers and declare the areas off limits. Encourage your children

to follow the instructions on the signs and to play elsewhere. Children may come into contact

with creosote-treated wood when playing on or near railroad tracks, in ditches close to utility

poles, in old barns or other farm structures, or on bridges or piers. Children may also be exposed

to creosote through ingestion if they chew or place their mouths on creosote-treated objects such

as fence posts or pier railings. You should discourage your children from such behavior and

from putting foreign objects in their mouths. 
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1. PUBLIC HEALTH STATEMENT

Drinking chaparral tea may result in exposure to wood creosote by swallowing. If you drink

chaparral tea you may expose your children. Creosote is also found in coal tar shampoos used

for anti-dandruff therapy, in coal tar ointments used for treatment of eczematous dermatitis and

in mineral coal tar for the treatment of psoriasis. You may expose your children to creosote if

you use any of these products. Ask your doctor to suggest alternative treatments that do not

involve the use of these products.

It is sometimes possible to carry creosote into the home on work clothing or shoes that may have

been exposed to coal tar creosote, coal tar, or coal tar pitch at the workplace. This may be of

more importance for people who work in the wood-preserving industry or in jobs such as

roofing, paving, and chimney cleaning than for people who work in the coking industry, or in

other plants that use coal tar-derived products and for which the main route of exposure is

through breathing in contaminated dust. You can contaminate your car, home, or other locations

outside work where children might be exposed to creosote. You should know about this

possibility if you work with creosote. Long-term exposure to low levels of creosote through

direct contact with skin has resulted in skin cancer. For workers in wood preservation facilities,

the American Wood Preservers Institute (AWPI) recommends washing work clothes separately

from other household clothing if oily creosote residues or sawdust from creosote-treated wood

are present on the clothes. Adults with contaminated work clothes should wash them before

reusing them. If you work in an industry in which creosote is used, your occupational health and

safety officer at work should tell you whether this or other chemicals you work with are

dangerous and likely to be carried home on your clothes, body, or tools and whether you should

be showering and changing clothes before you leave work, storing your street clothes in a

separate area of the workplace, or laundering your work clothes at home separately from other

clothes. Your employer should have Material Safety Data Sheets (MSDSs) for many of the

chemicals used at your place of work, as required by the Occupational Safety and Health

Administration (OSHA). Information on these sheets should include chemical names and

hazardous ingredients, important properties (such as fire and explosion data), potential health

effects, how you get the chemical(s) in your body, how to properly handle the materials, and

what to do in an emergency. Your employer is legally responsible for providing a safe

workplace and should freely answer your questions about hazardous chemicals. Your OSHA-
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1. PUBLIC HEALTH STATEMENT

approved state occupational safety and health program or OSHA can answer any further

questions and help your employer identify and correct problems with hazardous substances. 

Your OSHA-approved state occupational safety and health program or OSHA will listen to your

formal complaints about workplace health hazards and inspect your workplace when necessary. 

Employees have a right to optimal safety and health on the job without fear of punishment.

Your children may be exposed to creosote compounds by eating certain types of fish and

shellfish caught from certain locations. Certain states, American Indian tribes, and U.S.

territories have issued freshwater fish advisories to warn people about creosote-contaminated

fish. Each state, American Indian tribe, or U.S. territory sets its own criteria for issuing fish

advisories. A fish advisory will specify which bodies of water have restrictions. The advisory

will tell you what types and sizes of fish are of concern. The advisory may completely ban

eating fish or tell you to limit your meals of a certain fish type. For example, an advisory may

tell you to eat a certain type of fish no more than once a month. The advisory may tell you to eat

only certain parts of the fish and how to prepare or cook the fish to decrease your exposure to

creosote. The fish advisory may be stricter to protect pregnant women, nursing mothers, and

young children. Chemicals in creosote have been found in breast milk and may cross the

placenta. To reduce your child’s exposure to creosote, obey fish advisories. Information on fish

and wildlife advisories in your home state is available from your state health or natural resources

department. Signs might also be posted in certain fishing areas.

Creosote is a restricted-use pesticide, meaning that it is only supposed to be applied by people

who are trained to use it safely and who have been tested and approved to use it. It is not

available over-the-counter for use in the home or garden. The AWPI does not recommend the

use of creosote to protect wooden playground equipment or wooden decks for the yard. Other

pesticides are generally used for preserving playground equipment and decks. Your children

may be exposed to creosote if an unqualified person applies it to wood in or around your home,

such as to sundecks or to wooden equipment your children play on. In some cases, the improper

use of pesticides banned for use in homes has turned homes into hazardous waste sites. Make

sure that any person you hire is licensed and, if appropriate (as is the case for creosote), certified

to apply pesticides. Your state licenses each person who is qualified to apply pesticides
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1. PUBLIC HEALTH STATEMENT

according to EPA standards and further certifies each person who is qualified to apply restricteduse pesticides. Ask to see the license and certification. Also ask for the brand name of the

pesticide, an MSDS, the name of the product’s active ingredient (the chemical that makes the

pesticide work), and the EPA registration number. Ask whether EPA has designated the

pesticide “for restricted use” and what the approved uses are. This information is important if

you or your family react to the product.

If you feel sick after a pesticide has been used in your home, consult your doctor or local poison

control center.

1.8 IS THERE A MEDICAL TEST TO DETERMINE WHETHER I HAVE BEEN

EXPOSED TO CREOSOTE?

No medical test will determine if you have been exposed to wood creosote, coal tar creosote,

coal tar, coal tar pitch mixtures, or coal tar pitch volatiles. However, chemicals contained in

creosote (such as PAHs or phenol) may be detected and measured in body tissues (organs,

muscle, or fat), urine, or blood after exposure to creosote. Typically, this may be done for

employees in industry who work with coal tar creosote, coal tar, and coal tar pitch to monitor

their exposure. For example, the metabolite 1-hydroxypyrene, which can be detected in urine

after exposure to pyrene, has been used to test for exposure to creosote because pyrene is a

component of creosote. This test would determine only whether you have recently been exposed

to pyrene, but cannot positively identify the source of the pyrene as creosote or accurately

predict whether you will experience any adverse health effects. Moreover, analyses of urine

samples for 1-hydroxypyrene are not normally done in a doctor’s office because they require

special equipment.

For more information on tests to measure coal tar creosote, coal tar, coal tar pitch, or coal tar

pitch volatiles in the body, see Chapters 3 and 7.
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1. PUBLIC HEALTH STATEMENT

1.9 WHAT RECOMMENDATIONS HAS THE FEDERAL GOVERNMENT MADE TO

PROTECT HUMAN HEALTH?

The federal government develops regulations and recommendations to protect public health. 

Regulations can be enforced by law. Federal agencies that develop regulations for toxic

substances include the EPA, the OSHA, and the Food and Drug Administration (FDA). 

Recommendations provide valuable guidelines to protect public health but cannot be enforced by

law. Federal organizations that develop recommendations for toxic substances include the

ATSDR and the National Institute for Occupational Safety and Health (NIOSH).

Regulations and recommendations can be expressed in not-to-be-exceeded levels in air, water,

soil, or food that are usually based on levels that affect animals; then they are adjusted to help

protect people. Sometimes these not-to-be-exceeded levels differ among federal organizations

because of different exposure times (an 8-hour workday or a 24-hour day), the use of different

animal studies, or other factors.

Recommendations and regulations are also periodically updated as more information becomes

available. For the most current information, check with the federal agency or organization that

provides it. Some regulations and recommendations for creosote include the following:

On December 10, 1992, FDA issued a nationwide warning to consumers (FDA Press Release,

P92-38) about chaparral, an herbal product derived from the leaves of the creosote bush, because

of reports of acute toxic hepatitis after its use. The press release can be found at the FDA Web

site, http://www.fda.gov.

Regulatory standards and guidelines for air and water exist for the most important individual

PAHs and phenols contained in wood creosote, coal tar creosote, coal tar, and coal tar pitch. 

EPA has designated coal tar creosote a restricted-use pesticide. This means it can only be

bought and used by certified applicators and only for those uses covered by the applicator's

certification. In addition, coal tar creosote has been identified by EPA as a hazardous waste.
CREOSOTE 15

1. PUBLIC HEALTH STATEMENT

The federal government has developed regulatory standards and guidelines to protect workers

from the potential health effects of other coal tar products in air. OSHA has set a Permissible

Exposure Limit (PEL) of 0.2 milligrams of coal tar pitch volatiles per cubic meter of air

(0.2 mg/m3

) in workroom air to protect workers during an 8-hour shift.

For more information on regulations and advisories for coal tar creosote, coal tar, and coal tar

pitch exposure, see Chapter 8.

1.10 WHERE CAN I GET MORE INFORMATION?

If you have any more questions or concerns, please contact your community or state health or

environmental quality department or

Agency for Toxic Substances and Disease Registry

Division of Toxicology

1600 Clifton Road NE, Mailstop E-29

Atlanta, GA 30333

Web site: http://www.atsdr.cdc.gov

* Information line and technical assistance

Phone: 1-888-42-ATSDR (1-888-422-8737)

Fax: 1-404-498-0057

ATSDR can also tell you the location of occupational and environmental health clinics. These

clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to

hazardous substances.

* To order toxicological profiles, contact

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Phone: (800) 553-6847 or (703) 605-6000
CREOSOTE 16
CREOSOTE 17

2. RELEVANCE TO PUBLIC HEALTH

2. RELEVANCE TO PUBLIC HEALTH

2.1 BACKGROUND AND ENVIRONMENTAL EXPOSURES TO CREOSOTE IN THE

UNITED STATES

This profile addresses several substances: wood creosotes, coal tar creosote, coal tar, coal tar pitch, and

coal tar pitch volatiles. Figure 2-1 shows how these substances are produced.

Creosote has been identified in at least 46 of the 1,613 hazardous waste sites that have been proposed for

inclusion on the EPA National Priorities List (NPL). However, the number of sites evaluated for creosote

is not known. Of these sites, all 46 are located within the United States.

2.1.1 Wood Creosotes

Wood creosotes are derived from the resin from leaves of the creosote bush (Larrea, referred to herein as

creosote bush resin) and beechwood (Fagus, referred to herein as beechwood creosote). Creosote bush

resin consists of phenolic (e.g., flavonoids and nordihydroguaiaretic acid), neutral (e.g., waxes), basic

(e.g., alkaloids), and acidic (e.g., phenolic acids) compounds. The phenolic portion comprises 83–91% of

the total resin, while nordihydroguaiaretic acid accounts for 5–10% of the dry weight of the leaves. 

Extracts of the creosote bush are used in homeopathic medicine, and the leaves are used to make an

infusion called chaparral. Beechwood creosote consists mainly of phenol, cresols, guaiacol, xylenol, and

cresol. It is a colorless or pale yellowish liquid, and has a characteristic smoky odor and burnt taste. It

had therapeutic applications in the past as a disinfectant, laxative, and stimulating expectorant, but it is

not a major pharmaceutical ingredient today in the United States. Exposure to wood creosotes appears to

be confined to dermal contact with the plants and ingestion of plant extracts such as chaparral.

2.1.2 Coal Tar and Coal Tar Products

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Coal tar

creosotes are distillation products of coal tar, while coal tar pitch is a residue produced during the

distillation of coal tar. Coal tar pitch volatiles are compounds given off from coal tar pitch when it is

heated. Coal tar creosotes, coal tar, coal tar pitch, and coal tar pitch volatiles are composed of many 
CREOSOTE 18

2. RELEVANCE TO PUBLIC HEALTH

Coal Tar Creosotes

Coal

Wood Creosotes

Creosote Bush Leaves Resin

Beechwood

Chemical

extraction

Coke of Natural Gas

Coal Tars

Carbonization

Distillation

Coal Tar Pitch Residues

Coal Tar Pitch Volatiles

Heat

Figure 2-1. Origin of Wood Creosotes and Coal Tar Products
CREOSOTE 19

2. RELEVANCE TO PUBLIC HEALTH

individual compounds of varying physical and chemical characteristics. In addition, the composition of

each, although referred to by specific name (e.g., coal tar creosote) is not consistent. For instance, the

components and properties of the mixture depend on the temperature of the destructive distillation

(carbonization) and on the nature of the carbon-containing material used as a feedstock for combustion. 

Usually, coal tars are viscous liquids or semisolids that are black or dark brown with a naphthalene-like

odor. Coal tars are complex combinations of polycyclic aromatic hydrocarbons (PAHs), phenols,

heterocyclic oxygen, sulfur, and nitrogen compounds. PAH composition of coal tars is variable. 

Analyses of PAHs in four coal tar samples revealed 2- to 20-fold differences in concentration of selected

PAHs among the samples. For example, benzo[a]pyrene ranged from nondetectable levels to 1.7, 3.9, and

6.4 g/kg of coal tar. By comparison, coal tar creosotes have an oily liquid consistency and range in color

from yellowish-dark green to brown. The coal tar creosotes consist of PAHs and PAH derivatives. At

least 75% of the coal tar creosote mixture is PAHs. Coal tar pitch is a shiny, dark brown-to-black residue

that contains PAHs and their methyl and polymethyl derivatives, as well as heteronuclear compounds. 

Coal tar creosote, coal tar, and coal tar products are used as wood preservatives, herbicides, fungicides,

insecticides, and disinfectants. Volatile components of the coal tar pitch can be given off during

operations involving coal tar pitch, including transporting, and in the coke, aluminum, and steel

industries. 

There are no known natural sources of coal tar creosote. Coal tar creosote has been widely used as a

wood-treatment pesticide since the turn of the 20th century, and workers in the wood-preserving industry

have been exposed to coal tar creosote by the dermal and inhalation routes. Potential sources of nonoccupational human exposure to coal tar creosote include contact with coal tar creosote-treated wood

products (e.g., railroad ties used for landscaping), incineration of coal tar creosote-treated scrap lumber,

contact with contaminated environmental media at hazardous waste sites (e.g., ingestion of contaminated

groundwater), and the use of pharmaceutical products (e.g., shampoos) containing coal tar creosote. The

EPA canceled all nonwood uses of coal tar creosote and restricted use of coal tar creosote products to

certified applicators in January 1986. No information was found in the available literature regarding

ambient atmospheric or water concentrations of coal tar creosote-derived components (i.e., PAHs) in the

United States. PAHs have been measured in surface and subsurface soils around abandoned coal tar

creosote wood treatment facilities at levels ranging from nondetectable to 1,000 ppm. Since coal tar

creosotes are complex mixtures, techniques for relating apparent bioaccumulation or biomagnification in

food chains to human health concerns are not well defined. Fish or shellfish directly exposed to coal tar

creosote wastes will be tainted by offensive odors and tastes. In addition, fish and shellfish may
CREOSOTE 20

2. RELEVANCE TO PUBLIC HEALTH

accumulate coal tar creosote constituents at concentrations high enough to prompt public health officials

to issue consumption advisories. The potential for human exposure to coal tar creosote is discussed in

detail in Chapter 6 of this profile.

2.2 SUMMARY OF HEALTH EFFECTS

2.2.1 Wood Creosotes

Exposure to wood creosotes appears to be confined to ingestion of plant extracts and dermal contact with

the plants. Most of the toxicity data for oral exposure to wood creosotes comes from reports of

individuals who ingested plant extracts such as chaparral, an herbal extract prepared by grinding leaves of

the creosote bush, or “seirogan”, a Japanese folk remedy made with wood creosote that is typically taken

for stomachaches.

Several reports suggest that repeated exposure to chaparral is associated with adverse liver effects. There

are isolated reports of renal failure, and of cystic renal disease and cystic adenocarcinoma of the kidney in

individuals taking chaparral tea for periods ranging from 3 to 10 months. However, because of the

limited amount of data, it is not possible to attribute the findings of renal effects to ingestion of chaparral

tea. Cases of acute allergic dermatitis from dermal exposure to the creosote bush have been reported.

Information on health effects associated with the use of beechwood creosote is also very limited. It has

been observed that the distribution of cancer cases in Japan coincided with “seirogan” production areas,

but an association between cancer incidence in Japan and the use of “seirogan” cannot be made with the

available data. It should be noted that beechwood creosote doses of up to 394 mg/kg/day in the diet for

96 weeks induced signs of toxicity in rats, but failed to produce treatment-related increases in the

incidence of tumors. Organs examined for tumors include testis, ovary, pancreas, breast, thyroid and

adrenal glands, lungs, and lymph nodes. Similar results were seen in a 52-week study with mice. In

humans, dermal administration of beechwood tar for up to 8 weeks did not impair renal function or

produce other adverse effects; however, animal studies suggest that long-term oral exposure to

beechwood creosote has the potential to induce adverse effects in the kidney. The available data suggest

that hepatic and dermal effects are the main adverse outcomes that result from oral or dermal exposure,

respectively, to wood creosotes.
CREOSOTE 21

2. RELEVANCE TO PUBLIC HEALTH

Hepatic Effects. Icterus, jaundice, abdominal pain, liver failure, acute toxic hepatitis, and elevated

serum liver enzymes were among the effects reported in four individuals who repeatedly ingested

chaparral capsules (160–1,500 mg chaparral/day) over a period ranging from 6 weeks to 10 months. 

Liver transplant was required for one of the patients. Elevated liver enzymes returned to normal levels

3–6 weeks after exposure to chaparral was discontinued. Increased liver-to-body weight ratio has been

observed in rats and mice orally exposed to beechwood creosote for as little as 3 months. The effect was

generally seen at doses >143 mg/kg/day. However, no treatment-related liver histopathological

alterations were observed in these animals. These findings are relevant for individuals in the general

population who ingest chaparral capsules or chaparral tea.

Dermal Effects. There are reports of seven cases of acute allergic dermatitis following contact with

the creosote bush. The patients presented erythematous and vesicular dermatitis of the face, the upper

part of the neck, and the backs of the hands. An allergic component to these reactions was confirmed by

patch tests. Beechwood creosote has been found to irritate the periapical tissue (the connective tissue

surrounding the apex of the tooth) in dogs 7 days after its application. Localized inflammatory changes

and occasional abscess formation were observed in these animals. Application of birch tar to the ear of

rabbits for 3 weeks was associated with the formation of comedones on the ear. These findings show that

members of the general population who come into contact with the creosote bush may develop acute

allergic reactions of the skin.

2.2.2 Coal Tar and Coal Tar Products

Exposures to coal tar and coal tar products may take place in industrial and non-industrial settings and can

occur through a number of different routes of exposure. Information regarding the adverse human health

effects of coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles is available from

occupational surveys and retrospective health studies. Unfortunately, the usefulness of many of the

occupational studies is hampered by incomplete characterization of worker exposure and the difficulty in

ascribing adverse effects to a particular exposure route. Additional health effects information is available

from the use of coal tar products in the medical treatment of psoriasis patients. There are no reports of

adverse reproductive or developmental outcomes in humans exposed to coal tar and coal tar products. 

Sperm counts and sperm characteristics were found to be unaffected in workers exposed to coal tar pitch

volatiles. Women treated with coal tar for psoriasis or dermatitis (ages at treatment were 18–35 years) did

not exhibit an increase in spontaneous abortions or congenital disorders in their offspring. There were no

changes in reproductive outcomes, such as number of pregnancies, live, premature, and still births, or
CREOSOTE 22

2. RELEVANCE TO PUBLIC HEALTH

spontaneous abortions, among women who reside in a housing development built on contaminated land

formerly occupied by a coal tar creosote wood treatment plant. Some studies have found adverse

developmental effects in animals that were administered coal tar orally during gestation. There is,

however, evidence of maternal toxicity in these studies. Estrogenic effects were not seen in mice orally

administered coal tar creosote. The available information suggests that increased carcinogenicity risk and

adverse dermal and respiratory effects are the most important health concerns related to exposure to coal

tar and coal tar products.

Cancer. Studies of workers exposed to coal tar creosote, coal tar, coal tar pitch, and coal tar pitch

volatiles in various industrial environments have found increased cancer risk involving a number of

tissues including the respiratory tract, skin, lung, pancreas, kidney, scrotum, prostate, rectum, bladder,

and central nervous system. Leukemia and lymphoma have also been diagnosed. These adverse effects

are not apparent in patients undergoing coal tar therapy. Animal studies have demonstrated the

carcinogenic potential of dermally-applied coal tar products. Less typical lesions include the

development of cancer of the lip in a group of men involved in fishing net repair. These men typically

held a creosote-laden wooden needle in their mouths during their work. Laboratory studies have found

increases in mortality due to lung tumors in female Wistar rats exposed to coal tar pitch aerosol for 10 or

20 months. These findings are relevant to workers exposed to coal tar and coal tar products and

individuals using coal tar therapeutically.

IARC has classified creosotes as a Group 2A mixture, probable human carcinogen, based on limited

human evidence and sufficient animal evidence of carcinogenicity. IARC classified coal tar and coal tar

pitches as Group 1 mixtures, carcinogenic to humans, based on sufficient evidence of human and animal

carcinogenicity. EPA has classified creosote as a Group B1 probable human carcinogen, based on

sufficient evidence from animal studies and limited evidence from human studies.

Dermal Effects. Dermal effects have been documented in populations occupationally and nonoccupationally exposed to coal tar and coal tar products. In patients medically treated with 5% coal tar,

dermal applications induced a photosensitizing effect in all patients within 30 minutes of treatment. The

Texas Department of Health documented an increased incidence of skin rashes among residents of a

housing development built on contaminated land formerly occupied by a coal tar creosote wood treatment

plant. The rashes were associated with contact with the soil in the housing area. In workers exposed to

coal tar and coal tar products, the observed dermal effects appear to be generally limited to unprotected

areas such as the hands, face, and neck, including the posterior part of the neck. There is also a report of
CREOSOTE 23

2. RELEVANCE TO PUBLIC HEALTH

erythematous, papular, and vesicular eruptions seen in the ankle region of men that came in contact with

coal tar creosote from freshly coated wood. Most of the chemical burns reported in workers who handled

wood treated with coal tar creosote are mild; however, the remainder can lead to subsequent pigmentation

and desquamation. Dermal irritation, burning, erythema, dry peeling skin on the face and neck with

irritation, and folliculitis on the forearms have been reported in workers handling creosote-treated wood. 

The symptoms appeared to worsen on hot sunny days, which suggests a phototoxic effect. Similar effects

were seen in workers exposed to coal tar pitch and coal tar. A skin lesion classified as a benign squamous

cell papilloma was diagnosed in a man who was “heavily exposed” while dipping wood in coal tar

creosote tanks. In laboratory animals, skin irritation and the formation of comedones have been observed

following short-term dermal exposure to coal tar creosote.

Respiratory Effects. Workers using coal tar and coal tar creosote in wood preservative plants

exhibited mild to moderate pulmonary restrictive and obstructive deficits. There did not appear to be

large differences between smokers and nonsmokers in the prevalence of these conditions. Adverse

respiratory symptoms, including increased morbidity from obstructive lung disease, have also been

associated with long-term exposure of workers in an electrode manufacturing plant and in the aluminum

industry. A residential survey conducted by the Texas Department of Health as part of a site surveillance

program did not detect any adverse respiratory effects among residents of a housing development built on

contaminated land formerly occupied by a coal tar creosote wood treatment plant. Studies with animals

exposed to vapors of coal tar creosote or coal tar have shown lesions of the olfactory epithelium,

histiocytosis of the lung tissue, and chronic fibrosing pneumonitis with peribronchial adenomatosis.

2.3 MINIMAL RISK LEVELS

Minimal Risk Levels (MRLs) for wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar

pitch volatiles cannot be determined because available data are insufficient for acute, intermediate, and

chronic exposures via the oral and inhalation routes. In addition, coal tar creosote, coal tar, coal tar pitch,

and coal tar pitch volatiles are extremely complex in their chemical compositions, thereby further

complicating the MRL derivation process. The MRL is an estimate of the daily human exposure to a

substance (noncarcinogenic) that is likely to be without an appreciable adverse risk over a specified

duration of exposure. The primary limitation to deriving the MRL for these agents is that the MRL is,

generally, based on measured biological effects of a single substance and not on the effects produced by

mixtures of chemicals, which is the chemical nature of the wood creosotes, coal tar creosote, coal tar, and

coal tar pitch. As stated in Section 1.1, creosote is a complex mixture originating from high temperature
CREOSOTE 24

2. RELEVANCE TO PUBLIC HEALTH

treatments of coal tar and beechwood or occurring in the resin of the creosote bush. About 300 chemicals

have been identified in coal tar creosote, and there may be 10,000 other chemicals present in the mixture. 

Creosote derived from plants is composed of various organic compounds including phenols, cresols, and

guaiacol. 

The derivation of the MRL is further complicated by the variability of the mixture's composition among

wood creosote and coal tar creosote samples and the differences in mode of action of the individual

components. The mixtures’ composition is dependent on the sources and preparation parameters of wood

creosote and coal tar creosote and, as a result, the creosote components are rarely consistent in their type

and concentration. Hence, toxicological evaluations of one creosote sample, for instance, are most likely

inadequate for extrapolation to other creosote samples, unless their compositions are similar. An example

of the composition variability among creosote samples was presented by Weyand et al. (1991). In that

study, the concentrations of several PAHs were analyzed in four samples of manufactured gas plant

(MGP) residue, a form of coal tar. All of the PAHs identified exhibited 2- to nearly 20-fold differences in

concentration among the four samples. Benzo[a]pyrene, a component whose individual toxicity has been

examined extensively, ranged from nondetectable levels (detection limit 0.3 g/kg) to 1.7, 6.4, and 3.9 g/kg

of coal tar. Other studies that illustrate the variability of samples include Wrench and Britten (1975),

Niemeier et al. (1988), and Emmett et al. (1981). 

The risk assessment of mixtures on human and environmental health is complicated by the paucity of 

approaches to assess environmental exposures and biological effects of chemical mixtures. Furthermore,

the use of single-compound toxicity data to predict the toxicity and health effects of complex mixtures is

highly speculative. The difficulty of using single-compound toxicity data to estimate the toxicity of

complex mixtures is illustrated by the considerable variation in carcinogenicity of PAHs depending on the

components of the mixture (Warshawsky et al. 1993). For instance, when benzo[a]pyrene, a potent

animal carcinogen, is added at noncarcinogenic levels to mixtures of carcinogenic or noncarcinogenic

PAHs, the skin tumorigenicity of the mixture, as well as the latency of tumor incidence, is changed. 

Hence, unless the actual complex mixture is evaluated directly for toxicity, it is unlikely that its toxic

potency can be interpreted from that of its isolated components. 

While there are no MRLs for the mixtures discussed in this profile, the interested reader should refer to

Table 8-1 for some regulations and guidelines applicable to coal tar creosote, coal tar, coal tar pitch, and

coal tar pitch volatiles.

CREOSOTE 26
CREOSOTE 27

3. HEALTH EFFECTS

3. HEALTH EFFECTS

3.1 INTRODUCTION

The primary purpose of this chapter is to provide public health officials, physicians, toxicologists, and

other interested individuals and groups with an overall perspective on the toxicology of creosote. It

contains descriptions and evaluations of toxicological studies and epidemiological investigations and

provides conclusions, where possible, on the relevance of toxicity and toxicokinetic data to public health.

A glossary and list of acronyms, abbreviations, and symbols can be found at the end of this profile.

3.2 DISCUSSION OF HEALTH EFFECTS BY ROUTE OF EXPOSURE

To help public health professionals and others address the needs of persons living or working near

hazardous waste sites, the information in this section is organized first by route of exposure (inhalation,

oral, and dermal) and then by health effect (death, systemic, immunological, neurological, reproductive,

developmental, genotoxic, and carcinogenic effects). These data are discussed in terms of three exposure

periods: acute (14 days or less), intermediate (15–364 days), and chronic (365 days or more).

Levels of significant exposure for each route and duration are presented in tables and illustrated in

figures. The points in the figures showing no-observed-adverse-effect levels (NOAELs) or

lowest-observed-adverse-effect levels (LOAELs) reflect the actual doses (levels of exposure) used in the

studies. LOAELs have been classified into "less serious" or "serious" effects. "Serious" effects are those

that evoke failure in a biological system and can lead to morbidity or mortality (e.g., acute respiratory

distress or death). "Less serious" effects are those that are not expected to cause significant dysfunction

or death, or those whose significance to the organism is not entirely clear. ATSDR acknowledges that a

considerable amount of judgment may be required in establishing whether an end point should be

classified as a NOAEL, "less serious" LOAEL, or "serious" LOAEL, and that in some cases, there will be

insufficient data to decide whether the effect is indicative of significant dysfunction. However, the

Agency has established guidelines and policies that are used to classify these end points. ATSDR

believes that there is sufficient merit in this approach to warrant an attempt at distinguishing between

"less serious" and "serious" effects. The distinction between "less serious" effects and "serious" effects is

considered to be important because it helps the users of the profiles to identify levels of exposure at which

major health effects start to appear. LOAELs or NOAELs should also help in determining whether or not
CREOSOTE 28

3. HEALTH EFFECTS

the effects vary with dose and/or duration, and place into perspective the possible significance of these

effects to human health. 

The significance of the exposure levels shown in the Levels of Significant Exposure (LSE) tables and

figures may differ depending on the user's perspective. Public health officials and others concerned with

appropriate actions to take at hazardous waste sites may want information on levels of exposure

associated with more subtle effects in humans or animals (LOAEL) or exposure levels below which no

adverse effects (NOAELs) have been observed. Estimates of levels posing minimal risk to humans

(Minimal Risk Levels or MRLs) may be of interest to health professionals and citizens alike.

Levels of exposure associated with carcinogenic effects (Cancer Effect Levels, CELs) of creosote are

indicated in Tables 3-1, 3-2, and 3-4 and Figures 3-1 and 3-2.

A User's Guide has been provided at the end of this profile (see Appendix B). This guide should aid in

the interpretation of the tables and figures for Levels of Significant Exposure and the MRLs.

This profile addresses the toxicological and toxicokinetics database for several substances, wood creosote,

coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles, whose production stems from the

incomplete combustion or pyrolysis of carbon-containing materials. Creosotes, coal tar, coal tar pitch,

and coal tar pitch volatiles are composed of many individual compounds of varying physical and

chemical characteristics. In addition, the composition of each, although referred to by specific name (e.g.,

wood creosote or coal tar creosote) is not consistent. For instance, the components and properties of the

mixture depend on the temperature of the destructive distillation (carbonization) and on the nature of the

carbon-containing material used as a feedstock for combustion. 

Wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles differ from each other

with respect to their composition. Wood creosotes are derived from beechwood (Fagus, referred to

herein as beechwood creosote) and the resin from leaves of the creosote bush (Larrea, referred to herein

as creosote bush resin). Beechwood creosote consists mainly of phenol, cresols, guaiacol, xylenol, and

creosol. It is a colorless or pale yellowish liquid, and has a characteristic smoky odor and burnt taste

(Miyazato et al. 1981). It had therapeutic applications in the past as a disinfectant, a laxative, and a

stimulating expectorant, but it is not a major pharmaceutical ingredient today in the United States.
CREOSOTE 29

3. HEALTH EFFECTS

Creosote bush resin consists of phenolic (e.g., flavonoids and nordihydroguaiaretic acid), neutral (e.g.,

waxes), basic (e.g., alkaloids), and acidic (e.g., phenolic acids) compounds. The phenolic portion

comprises 83–91% of the total resin. Nordihydroguaiaretic acid accounts for 5–10% of the dry weight of

the leaves (Leonforte 1986). It is not known whether the health effects associated with creosote bush

resin are attributable to the phenolic components. 

Coal tars are by-products of the carbonization of coal to produce coke or natural gas. Physically, they are

usually viscous liquids or semisolids that are black or dark brown with a naphthalene-like odor. The coal

tars are complex combinations of polycyclic aromatic hydrocarbons (PAHs), phenols, heterocyclic

oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of

coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. At

least 75% of the coal tar creosote mixture is PAHs. Unlike the coal tars and coal tar creosotes, coal tar

pitch is a residue produced during the distillation of coal tar. The pitch is a shiny, dark brown to black

residue which contains PAHs and their methyl and polymethyl derivatives, as well as heteronuclear

compounds (American Wood Preserver's Association 1988). Coal tar creosote, coal tar, and coal tar

products are used as wood preservatives, herbicides, fungicides, insecticides, and disinfectants (EPA

1981a, 1984a). Volatile components of the coal tar pitch can be given off during operations involving

coal tar pitch, including transporting, and in the coke, aluminum, and steel industries (Bender et al. 1988;

Mazumdar et al. 1975; NIOSH 1983; Rönneberg 1995b; Rönneberg and Anderson 1995).

Although beechwood creosote, creosote bush resin, and coal tar creosote have some components in

common, such as phenols, the differences in composition are pronounced enough to assume with

reasonable certainty that they will have different toxicological properties. Furthermore, coal tar creosote

contains PAHs, some of which are carcinogenic to animals, and beechwood creosote does not. Thus, the

relevance of health effects data on beechwood creosote to risk associated with exposure to coal tar

creosote is not known.

Throughout this profile, every attempt is made to specify the characteristics of the creosote, coal tar, coal

tar pitch, or coal tar pitch volatiles under discussion, and to indicate which health effects may be expected

to be common to two or more forms. The intent of this profile is to discuss the creosotes, coal tar, coal tar

pitch, and coal tar pitch volatiles. Therefore, the health effects of the individual components (e.g., PAHs,

phenol, or others) will not be discussed in great detail even though it is likely that the toxicity of wood

creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch volatiles is due largely to these major

individual components. However, it is understood that the toxicity of the individual components may not
CREOSOTE 30

3. HEALTH EFFECTS

be representative of the actual toxicity of the mixtures because of the possibility of synergistic and/or

antagonistic interactions in the mixture. For more information on the health effects of these components,

the reader can refer to the ATSDR Toxicological Profiles for phenol, cresols, and polycyclic aromatic

hydrocarbons (Agency for Toxic Substances and Disease Registry 1992, 1995, 1998).

3.2.1 Inhalation Exposure

This section describes the health effects observed in humans and laboratory animals associated with

inhalation exposure to coal tar pitch or coal tar pitch volatiles, for which reliable exposure levels could be

determined. LSEs by the inhalation route presented in Table 3-1 and Figure 3-1 include studies using

coal tar pitch volatiles or aerosols. All reliable exposure levels have been stated, where possible. No

studies were located regarding the health effects in humans exposed solely by inhalation to wood

creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles. Studies of occupational

exposure of humans (Armstrong et al. 1994; Bender et al. 1988; Bertrand et al. 1987; Bolt and Golka

1993; CEOH 1997; Costantino et al. 1995; Gibbs 1985; Gibbs and Horowitz 1979; Karlehagen et al.

1992; Kromhout et al. 1992; Kunze et al. 1992; Lloyd 1971; Lloyd et al. 1970; Mazumdar et al. 1975;

NIOSH 1982; Park and Mirer 1996; Persson et al. 1989; Petsonk et al. 1988; Redmond 1976; Redmond et

al. 1972, 1976; Rockette and Arena 1983; Romundstad et al. 2000; Rönneberg 1995b; Rönneberg and

Andersen 1995; Sakabe et al. 1975; Schildt et al. 1999; Siemiatycki et al. 1994; Spinelli et al. 1991; Stern

et al. 2000; Swaen and Slangen 1997; TOMA 1979, 1981, 1982; Tremblay et al. 1995; Ward 1988; Wu et

al. 1998; Yadav and Seth 1998) did not distinguish between inhalation, oral, or dermal exposure. Several

studies were found describing health effects in animals of inhalation exposure to aerosols of coal tar or

coal tar pitch (Heinrich et al. 1994a, 1994b; Hueper and Payne 1960; MacEwen et al. 1977; Pfitzer et al.

1965; Springer et al. 1982, 1986b, 1987). Beechwood creosote, creosote bush resin, coal tar creosote,

coal tar, coal tar pitch, and coal tar pitch volatiles have some components in common, however, it is not

known which of these components produce the toxic effects.
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation ~~ ~ 

Exposure/ LOAEL 

Duration/ 

Key to Species Frequency 

figure (Strain) (Specific Route) System (mg/m**3) (mg/m**3) (mg/m**3) Chemical Form 

ACUTE EXPOSURE 

Systemic 

Serious Reference NOAEL Less Serious a 

Ocular 0.18 M (conjunctivitis) 

lmmuno/lyrnphoret 

(CD) 

3 Rat 5 d Gd 12-16 6 hr/d 

Reproductive 

4 Rat 5 d Gd 12-16 6 hr/d 

(CD) 

Developmental 

5 Rat 5 d Gd 12-16 6 hr/d 

(CD) 

INTERMEDIATE EXPOSURE 

Death 

(Wistar) 

6 Rat 10 mo 5 d/wk 17 hr/d 

Hepatic 

Renal 

Endocr 

Bd Wt 

84 F 660 F (significant increase in lung 

weight) 

660 F 

660 F 

660 F 

84 F 660 F (significant decrease in body 

weight) 

84 F 660 F (significant decrease in thymus 

weight and increase in spleen 

weight) 

84 F 660 F (significant increase in the 

incidence of mid- and 

late-gestational resorptions) 

84 660 (reduced fetal size, weight and 

lung size, reduced ossification) 

Emmett 1986 

CTPV 

Springer et al. 1982 

coal tar aerosol 

Springer et al. 1982 

coal tar aerosol 

Springer et al. 1982 

coal tar aerosol 

Springer et al. 1982 

coal tar aerosol 

Heinrich et al. 1994a. b 

coal tar pitch 

2.6 F (increased mortality) 

P 

0 

D 

I 

0 

3 

F 

0 

;D 

m 

a 

0 

-I 

m 
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation (continued) 

Exposure1 LOAEL 

Duration1 

Key to Species Frequency 

figure (Strain) (Specific Route) System (mglm"3) (mg/m**3) (mg/mw3) 

Reference 

Chemical Form 

NOAEL Less Serious Serious a 

Systemic 

6 wk 5 d/wk 6 hld 

Cardio 

7 Rat 

(Fischer-344) 

8 Rat 

(Fischer- 344) 

5 wk 5 d/wk 6 hr/d 

Bd Wt 

Resp 

Cardio 

Gastro 

Hemato 

Hepatic 

Renal 

690 

140 M 

690 F 

30 

140 M 

30 F 

700 M (20% elevation in arterial blood 

pressure) 

700 M (17.5 % decrease in body 

weight) 

30 (histiocytosis of lung) 

690 M (epithelial hyperplasia and 

chronic inflammation in cecum) 

140 (significant decrease in red 

blood cells, hemoglobin, and 

volume of packed red cells, 

significant increase in 

reticulocytes) 

690 M (significant increase in relative 

weight of liver and serum 

cholesterol) 

30 M (significant increase in relative 

weight of kidney) 

690 M (pelvic epithelial hyperplasia) 

140 F 

Sasser et al. 1989 

coal mixture 

Springer et al. 1986b 

coal tar aerosol 

0 

XI 

rn 

0 

$ 

-I 

m 

(J 

0 

I 

rn 

5 

0 

P 

IP 

0 

-u 

I 

0 

3 

F 

0 

z 

z 

D 

-4 

Endocr 

Bd Wt 

690 

30 140 (7% decrease in body weight) 

W 

h) 
Table 3-1 Levels of Significant Exposure to Creosote - inhalation (continued) 

Exposure1 

Duration1 

LOAEL 

Serious Reference NOAEL Less Serious a Key to Species Frequency 

figure (Strain) (Specific Route) System (mg/rn**3) (mg/m**3) (mglm**3) Chemical Form 

Systemic 

(Fischer- 344) 

9 Rat 13 wk 5 d/wk 6 hr/d 

Resp 

Cardio 

Gastro 

Hemato 

Hepatic 

Renal 

Endocr 

Bd Wt 

690 

140 

30 M 

140 F 

30 F 

30 

690 

30 

30 (histiocytosis of lung) Springer et al. 1986b 

coal tar aerosol 

690 (lesions of olfactory epithelium) 

690 (epithelial hyperplasia, ulcers 

and chronic inflammation of 

cecum) 

140 M 

690 F (significant decrease in red 

blood cells, hemoglobin, and 

volume of packed red cells) 

liver weight) 

30 M (significant increase in relative 690 (presence of liver lesions. 

elevated cholesterol, blood urea 

nitrogen and alteration in 

140 F activities of SGPT and LDH) 

140 (significant increase in relative 140 M (pelvic epithelial hyperplasia 

and pigmentation of cortical 

tubules) kidney weight) 

690 F 

140 (10% decrease in body weight) 

0 

z 

rn 

0 

$ 

-I 

rn 

u 

0 

I 

m 

z 

0 

- 

F 

P 

o 

W 

W 
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation (continued) 

Exposure/ LOAEL 

Duration1 

Key to Species Frequency 

figure (Strain) (Specific Route) System (mg/m**3) (mglm**3) (mg/m**3) 

a NOAEL Less Serious Serious Reference 

Chemical Form 

Systemic 

140 

Cardio 690 

Gastro 690 

Hemato 140 

11 Rabbit 9 mo 5 d/wk 6 hr/d 

(New 

Zealand) 

lmmunollymphoret 

(Fischer- 344) 

12 Rat 5 wk 5 hld 6 hr/d 

13 Rat 13 wk 5 d/wk 6 hr/d 

(Fischer- 344) 

Hepatic 

Renal 

Endocr 

Bd Wt 

Bd Wt 

29 M 

140 F 

690 

690 

690 

140 

30 

690 (lesions of olfactory epithelium) 

690 (significant decrease in red 

blood cells, hemoglobin, 

reticulocytes and volume of 

packed red cells) 

140 M (significant decrease in liver 

weight) 

690 F 

690 (decreased number of 

megakaryocytes in spleen) 

Springer et al. 1987 

coal tar aerosol 

MacEwen et al. 1977 

coal tar 

10 F (31% decrease in body weight) 

Springer et al. 1986b 

coal tar aerosol 

Springer et al. 1986b 

140 (significant reduction in weight 690 (atrophy of thymus, hypocellular of thymus) bone marrow. and decreased coal tar aerosol 

number of megakaryocytes in 

marrow and spleen) 

0 

A 

rn 

2 

9 

rn 

u 

0 

I 

m 

5 

0 

F' 

P 

0 

W 

P 
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation (continued) 

Exposure/ LOAEL 

Duration/ a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mg/m**3) (mg/m**3) (mg/m**3) Chemical Form 

lmmunollymphoret 

14 Mouse 13 wk 5 d/wk 6 hr/d 

(CD-1) 

Neurological 

(Fischer- 344) 

15 Rat 5wk 5d/wk 6 hr/d 

16 Rat 13 wk 5 d/wk 6 hr/d 

(Fischer- 344) 

17 Mouse 13 wk 5 d/wk 6 hr/d 

(CD-1) 

Reproductive 

(Fischer- 344) 

18 Rat 5 wk 5 h/d 6 hr/d 

19 Rat 13 wk 5 d/wk 6 hr/d 

(Fischer- 344) 

20 Mouse 13 wk 5 d/wk 6 hrld 

(CD-1) 

140 M 

29 F 

690 M (significant decrease in weight 

140 F 

of thymus) 

140 M 

690 F 

690 M (significant increase in relative 

brain weight) 

30 140 (significant increase in relative 

brain weight) 

690 

690 M 

140 F 

690 F (decreased luteal tissue) 

30 M 

140 F 

140 M (significant increase in relative 

weight of testis) 

690 F (significant decrease in relative 

weight of ovary and amount of 

luteal tissue) 

690 M 

140 F 

690 F (significant decrease in ovary 

weight) 

Springer et al. 1987 

coal tar aerosol 

Springer et al. 1986b 

coal tar aerosol 

Springer et al. 1986b 

coal tar aerosol 

Springer et al. 1987 

coal tar aerosol 

Springer et al. 1986b 

coal tar aerosol 

Springer et al. 1986b 

coal tar aerosol 

Springer et al. 1987 

coal tar 

FJ 

P 

O 

0 

A 

m 

$ 

s 

rn 

W 

cn 
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation (continued) ~~~ 

Exposure1 

Duration1 

LOAEL 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglm"3) (mg/m**3) (mglm**3) Chemical Form 

Cancer 

(Wistar) 

21 Rat 10 rno 5 d/wk 17 hr/d 

22 Mouse 90 d 24 hr/d 

CAFI- JAX 

23 Mouse 90 d 24 hr/d 

ICR CF-1 

CHRONIC EXPOSURE 

Death 

(Wistar) 

Systemic 

25 Monkey 

(Macaca 

rnulatta) 

24 Rat 

26 Rat 

(SpragueDawley) 

Cancer 

(Wistar) 

27 Rat 

20 mo 5 dlwk 17 hr/d 

18 rno 5 d/wk 6 hr/d 

18 rno 5 dlwk 6 hrld 

20 rno 5 d/wk 17 hr/d 

Bd Wt 

Bd Wt 

10 

10 (15% decrease in body weight) 

2.6 F ICEL: 39% incidence 

Heinrich et al. 1994a. b 

broncho-alveolar adenornas & coal tar pitch 

adenocarcinomas) 

MacEwen et al. 1977 

coal tar 

10 F (CEL: 18/43 skin tumor, control 

= 0/225) (CEL: 27/50 lung 

tumor, control = 01225) 

MacEwen et al. 1977 

2 F (CEL: 14/75 skin tumor, 

controls = 31225) coal tar 

Heinrich et al. 1994a 

coal tar pitch 

2.6 F (increased mortality) 

MacEwen et al. 1977 

coal tar 

MacEwen et al. 1977 

coal tar 

Heinrich et al. 1994a, b 

broncho-alveolar adenornas & coal tar pitch 

adenocarcinornas) 

1.1 F (CEL: 33% incidence 

W 

0 

I 

rn 

5 

F 

0 

P 

0 
Table 3-1 Levels of Significant Exposure to Creosote - Inhalation (continued) 

Exposure/ LOAEL 

Duration/ a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mg/m**3) (mg/m*'3) (mglm**3) Chemical Form 

28 Rat 18 mo 5 dlwk 6 hr/d 

(SpragueDawley) 

MacEwen et al. 1977 10 M (CEL: 38/38 squarnous cell 

carcinoma) coal tar 

10 F (CEL: 31/38 squarnous cell 

carcinoma and 3/38 mammary 

fibroadenorna) 

__ ~ 

aThe number corresponds to entries in Figure 3-1. 

Differences in levels of health effects and cancer between males and females are not indicated in figure 3-1 

Bd Wt = body weight; Cardio = cardiovascular; CEL = cancer effect level; CTPV = coal tar pitch volatiles; d = day@); Endocr = endocrine; F = female; Gastro = gastrointestinal; Gd 

= gestation day; Hemato = hematological; hr = hour(s); LDH = lactic dehydrogenase; LOAEL = lowest-observable-adverse-effect level; M = male; mo = rnonth(s); NOAEL = no-observable-adverse-effect level; Resp = respiratory; SGPT = serum glutamic pyruvic transarninase; wk = week(s) 

w 

0 

I 

rn 

0 

s 

F 

P 

0 

-u 

I 

-< 

0 

0, 

P 
mglm3 

1000 

100 

10 

0.1 

c-Cat 

r-Rat 

d-DOg k "p:w 

Figure 3-1 Levels of Significant Exposure to Creosote - Inhalation 

Acute (114 days) 

w 

02r 02r 03r 04r 

Ai 

-Humans f-Ferret n-Mink Cancer Effect Level-Animals 

k-Monkey jPigeon o-Other 0 LOAEL, More Serious-Animals 

m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals 

h-Rabbit s-Hamster 0 NOAEL -Animals 

a-Sheep g-Guinea Pig 

05r 

Cancer Effect Level-Humans LD50/LC50 

; Minimal Risk Level 

: for effects 

NOAEL - Humans A other than 

Cancer 

A LOAEL, More Serious-Humans A LOAEL, Less Serious-Humans 
mg/m3 

1000 

100 

10 

Figure 3-1 Levels of Significant Exposure to Creosote - Inhalation (Continued) 

Intermediate (15-364 days) 

@8r @9r 

O8r 09r 

O8r 09r 

1 

c-Cat -Humans f-Ferret n-Mink + Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other 0 LOAEL, More Serious-Animals A LOAEL, More Serious-Humans 

r-Rat m-Mouse e-Gerbil @ LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans I foreffects 

A other than 

Cancer p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals 

I Minimal Risk Level 

NOAEL - Humans 

q-Cow a-Sheep g-Guinea Pig - -__ - 

w 

(I) 
mglm3 

1000 

100 

10 

Figure 3-1 Levels of Significant Exposure to Creosote - Inhalation (Continued) 

Intermediate (1 5-364 days) 

@8r 08r 09r 

.llh 

01 3r 

*Doses represent the lowest dose tested per study that produced a tumorigenic 

response and do not imply the existence of a threshold for the cancer endpoint. 

016r 

422m 

421 r 

42311-1 

1 

c-Cat -Humans f-Ferret n-Mink Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other LOAEL, More Serious-Animals A LOAEL, More Serious-Humans : Minimal Risk Level 

r-Rat m-Mouse e-Gerbil (3 LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans I foreffects 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals NOAEL - Humans A other than 

q-cow a-Sig __ ~. - -~ - - - - - - - - Cancer 

0 

I 

rn 

3 

0 

9 

IP 

0 
mglm3 

100 

1 

Figure 3-1 Levels of Significant Exposure to Creosote - Inhalation (Continued) 

Chronic (2365 days) 

+27r 

u 

0 

I 

rn 

5 

0 

9 

r 

P 

0 

77 

I 

i2 

0 

F 

*Doses represent the lowest dose tested per study that produced a tumorigenic 

response and do not imply the existence of a threshold for the cancer endpoint. 

P, c-Cat -Humans f-Ferret n-Mink + Cancer Effect Level-Animals V Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other 0 LOAEL, More Serious-Animals A LOAEL. More Serious-Humans ; Minimal Risk Level 

r-Rat m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans : for effects 

p-Pig h-Rabbit s-Hamster 0 NOAEL - Animals A NOAEL - Humans A other than 

q-Cow a-Sheep g-Guinea Pig Cancer- ___. 
CREOSOTE 42

3. HEALTH EFFECTS

3.2.1.1 Death

No reports were located of death in humans attributed to inhalation exposure to wood creosote or the

creosote bush by inhalation. 

Coal Tar Products. No studies were located connecting death in humans following exposure to coal tar

creosote, coal tar, coal tar pitch, or coal tar pitch volatiles solely by inhalation. A mortality study of

human exposure during employment at eight coal tar plants indicated significant increases in cancerrelated deaths, compared to the general population (TOMA 1982). No clear relationship between

inhalation of coal tar and increased mortality could be established since exposure routes in addition to

inhalation (e.g., dermal and oral) were likely and subjects were also exposed to other chemicals and

cigarette smoke. Since the study was retrospective, no attempt was made to estimate occupational

exposure levels from any source (TOMA 1982). Limitations of the study included absence of data on

smoking habits, short cut-off date of 10 days of employment, use of U.S. male mortality rates for

comparison as opposed to regional mortality rates, and mixed chemical exposure. The same study

population was used as the basis for a nested cancer case-control study (CEOH 1997). Fifty lung-cancer

cases were identified and matched with controls from the same cohort. There were three controls per

case, and individuals were matched for plant, gender, race, date of hire, and age at hire. Smoking history,

work and medical history data were gathered by telephone interviews with the subjects or their next of kin

and used to assign workers to various exposure classes. There was no statistically significant increase in

lung cancer risk in persons assessed as highly exposed to coal tar compared with those having low or no

exposure. The risk associated with working for >20 years in production was lower than that of short-term

employees. Controlling for smoking (data analyzed for smokers only) did not change the results, but no

nonsmoking cases were identified and therefore, it was not possible to assess the effects of coal tar

exposure without concurrent cigarette smoking.

In a mortality study of steelworkers employed in a coke oven plant in 1953, increased mortality from

respiratory neoplasms (monitored from 1953 to 1961) was observed in coke oven workers compared to

expected mortality rates (Lloyd 1971). Specifically, 20 deaths from respiratory neoplasms were

observed, compared to the expected 7.5 deaths. The increase in mortality was linked to an increase in

mortality from respiratory neoplasms in nonwhite oven workers who had been employed for $5 years. 

No increase in deaths from respiratory neoplasms was observed in nonoven workers. In a series of follow

up studies of these same coke oven workers in Allegheny County, Pennsylvania, similar associations

between coal tar or coal tar pitch volatile exposure and mortality, primarily from lung cancer, were
CREOSOTE 43

3. HEALTH EFFECTS

observed (Redmond 1976; Redmond et al. 1972, 1976). An increase in death due to kidney cancer was

observed at the plant, although this was not limited to the coke oven workers at the steel plant (Redmond

et al. 1976). Lung cancer mortality was higher in men exposed to coal tar in an aluminum smelter plant

for more than 21 years, with a standardized mortality ratio (SMR) of 2.2–2.4 compared to persons not

exposed to tar (Gibbs 1985; Gibbs and Horowitz 1979). Increased risk of mortality from pancreatic

cancer and leukemia of more than 30% was observed for workers in the potrooms and carbon departments

of 14 aluminum reduction plants, who had worked for >5 years (Rockette and Arena 1983). 

A study of proportionate mortality among the 11,144 members of the United Union of Roofers,

Waterproofers, and Allied Workers (Stern et al. 2000) found a significant excess in mortality due to

cancers of the lung, bladder, esophagus, and larynx, and to pneumoconioses and other nonmalignant

respiratory diseases in these workers compared with U.S. age-, gender-, and race-specific proportional

mortality rates for the years of the study (1950–1996). These workers were occupationally exposed to

asphalt fumes and asbestos as well as coal tar pitch volatiles, and cigarette smoking must also be

considered as a likely confounding factor.

Spinelli et al. (1991) examined mortality and cancer incidence over a 30-year period among a cohort of

4,213 workers exposed to coal tar pitch volatiles emitted during the production of aluminum. A

significant increase in the mortality rate for brain cancer was observed. However, no exposure response

was seen for deaths from any form of cancer in direct relation to cumulative coal tar pitch volatile

exposure. Mortality in a Norwegian aluminum smelter plant was investigated in a cohort of

1,085–1,137 men who worked between 1922 and 1975 (Rönneberg 1995b; Rönneberg and Andersen

1995). An increase in mortality from atherosclerosis and chronic obstructive lung disease were associated

with 40 or more years of exposure or 20–39 years exposure to pot emissions, respectively (Rönneberg

1995b). When cancer incidence was analyzed, associations were found between tar exposure and

increases in bladder, prostatic, and lung cancer (Rönneberg and Andersen 1995). In a study of exposure

to coal tar pitch volatiles in coke oven plants in France, mortality due to lung cancer was 2.5 times higher

in the coke plant workers (534 males) exposed for periods from <5 to >10 years compared to the French

national male population (Bertrand et al. 1987). In another study of coal tar pitch volatile exposure in

coke oven plants, mortality was monitored in coke oven workers in Pennsylvania who had been employed

for >10 years (Mazumdar et al. 1975). An increase in mortality due to lung cancer was positively

correlated with coal tar pitch volatile exposure. In a study of coal tar pitch volatile exposure in the

aluminum industry, four workers from the same area of the plant died of lung cancer (Bolt and Golka

1993). The duration of exposure to coal tar pitch volatiles ranged from 3.5 to 23 years. Costantino et al.
CREOSOTE 44

3. HEALTH EFFECTS

(1995) carried out an epidemiological study of 5,321 coke oven workers and 10,497 non-oven workers. 

Statistically significant excess mortality was present among coke workers for several categories of death. 

The relative risk (RR) for all causes of death was 1.08 (P<0.01; 95% confidence interval [CI]=1.02–1.14). 

The increase in overall mortality was primarily due to increased deaths from cancers. There were highly

significant trends (P<0.001) for increased cancer risk with increasing duration of employment and

increasing exposure. The study did not control for smoking. However, the similar socioeconomic status

of the controls and exposed workers suggests that it is unlikely that there was a substantial difference in

smoking habits between the two groups. Further discussion of retrospective human cancer/mortality

studies can be found in Section 3.2.1.7.

Animal studies were also limited in number for this route of exposure. One study was located in which

rats were exposed for 1 hour to saturated vapors of coal tar creosote (Pfitzer et al. 1965). In this study, no

specific concentration level was stated and no deaths were observed. In a study in Wistar rats, female rats

were exposed to 1.1 or 2.6 mg/m3

 coal tar pitch aerosol for 17 hours/day, 5 days/week for 10 months,

followed by exposure to clean air for 20 months (Heinrich et al. 1994a, 1994b). Increased mortality was

observed in the high-concentration group, due to lung tumors (no mortality data shown). Increased

mortality was also observed in Wistar rats exposed to 1.1 or 2.6 mg/m3

 coal tar pitch aerosol for

17 hours/day, 5 days/week for 20 months, followed by clean air exposure for 10 months (Heinrich et al.

1994a, 1994b). New Zealand white rabbits exposed to 10 mg/m3

 coal tar pitch aerosol in a mixture of

benzene, toluene, and xylene for 6 hours/day, 5 days/week for 18 months, exhibited higher mortality than

the control animals (89 versus 33%), although the authors attributed death to chronic respiratory infection

(MacEwen et al. 1977). Further evaluation of these animals was not provided, so it is not known whether

the inhalation exposure affected the susceptibility of the animals to respiratory infection. More

importantly, the biological effect of benzene, toluene, and xylene (BTX), which were used as carrier

solvents for the coal tar aerosol, was not evaluated in this study. Thus, while these solvents may have

played a part in the development of the adverse effects observed in this study, the actual magnitude of the

effect, if any, cannot be determined. Kock et al. (1994) reported death of 7 of 20 black rhinoceroses that

had been held in creosote-treated holding pens. The animals that died had oral and gastric ulcers,

widespread hemorrhages and hematoma, and uniformly swollen intensely green livers, containing

excessive intrahepatic bilirubin. However, doses and routes of exposure were not established in this

study.

The LOAEL values for death in each species are recorded in Table 3-1 and plotted in Figure 3-1.
CREOSOTE 45

3. HEALTH EFFECTS

3.2.1.2 Systemic Effects

No studies were located regarding the gastrointestinal, musculoskeletal, hepatic, endocrine, or body

weight effects in humans or musculoskeletal effects in animals after inhalation exposure to creosotes, coal

tar, coal tar pitch, or coal tar pitch volatiles. The systemic effects that have been observed in humans and

animals are discussed below. LOAEL and NOAEL values for systemic effects are recorded in Table 3-1

and plotted in Figure 3-1.

Respiratory Effects. 

Coal Tar Products. A single case report describes acute bronchoconstriction in an asthmatic patient

exposed to coal tar vapor while being treated with coal tar occlusive bandages for a skin condition

(Ibbotson et al. 1995). The authors conclude that the effect was probably due to inhalation of coal tar

vapor leading to a nonspecific irritant response. In an industrial health survey of employees in four wood

preservative plants in which coal tar creosote and coal tar were the main treatments used, respiratory

effects, including reduced lung function (forced vital capacity [FVC]), were noted in 17% (44 of 257) of

the employees examined. Most of these respiratory impairments (35/44) were considered to be mild

(reduction in FVC of 66–79%) (TOMA 1979). Reductions in FVC were evident in smoking and

nonsmoking workers in similar proportions. Obstructive deficits were observed in 8% of smoking and

5% of nonsmoking workers; these were also generally mild to moderate (reduction in forced expiratory

volume of 46–69%), but one smoker did show a severe deficit. Workers in nine coal tar plants had a 33%

(150 of 453) incidence of restrictive pulmonary deficits (reduced FVC) (TOMA 1981). The study authors

proposed that the elevated abnormal findings could be attributed to factors related to administration of the

test and not to a disease state. However, other pulmonary function tests were, according to the authors,

within the normal limits. A limitation of this study is that smoking status of the subjects was not reported

(TOMA 1981). Industrial hygiene surveys of coal tar pitch volatiles at the four wood preservative plants

indicated that airborne exposure to benzene-soluble components of the coal tar pitch volatiles was within

the OSHA permissible limit of 0.2 mg/m3

 in 94% of the samples (TOMA 1979). The other 6% of the

samples ranged from 0.21 to 3.6 mg/m3

 (TOMA 1979). Nevertheless, no clear relationship could be

established because exposure routes in addition to inhalation (e.g., dermal and oral) were likely. Also, the

ability to relate respiratory effects to coal tar creosote and coal tar exposure was further confounded by

the possibility that the subjects were also exposed to other chemicals and cigarette smoke (TOMA 1979,

1981). Additional limitations of the studies included geographical variation in plant locations, lack of

past employment history, voluntary participation in the study that could have biased it in favor of healthy
CREOSOTE 46

3. HEALTH EFFECTS

workers, lack of statistical analyses, lack of adequate controls, use of only current employees, and testing

confined to a single season (winter). In an industrial health survey of five workers in an electrode

manufacturing plant, respiratory symptoms were observed, including pneumonoconiosis, respiratory

obstruction, impaired gas exchange, and lung fibrosis with interstitial tissue alveoli filled with black

pigment (Petsonk et al. 1988). These workers had been exposed to coke dust, pitch fumes, pitch dust, and

other dusts for >15 years, which could be associated with the respiratory symptoms. Increased chronic

obstructive lung disease was associated with 20–39 years of exposure to pot emissions in an aluminum

smelter (Rönneberg 1995b). Similar increases in respiratory diseases have been noted in other studies of

the aluminum industry (Gibbs 1985).

A study of proportionate mortality among the 11,144 members of the United Union of Roofers,

Waterproofers, and Allied Workers (Stern et al. 2000) found a significant excess in mortality due to

pneumoconioses and other nonmalignant respiratory diseases in these workers compared with U.S. age-,

gender-, and race-specific proportional mortality rates for the years of the study (1950–1996). These

workers were occupationally exposed to asphalt fumes and asbestos as well as coal tar pitch volatiles. 

Cigarette smoking is a potential confounding factor that, due to the nature of the study, could not be

evaluated.

A site surveillance program was conducted by the Texas Department of Health beginning in 1990 at a

housing development in Texarkana, Texas, that had been built on part of an abandoned Koppers

Company, Inc., creosote wood treatment plant (Agency for Toxic Substances and Disease Registry 1994). 

The plant had ceased creosoting activities in 1961, after operating for 51 years. A sand and gravel

company had operated on part of the abandoned site during the 1970s and 1980s. Because of soil and

groundwater contamination with PAHs and other chemicals, the EPA identified this site and placed it on

the National Priorities List (NPL) in 1984. Several residential lots were observed to have soil

concentrations of benzo[a]pyrene (B[a]P) in excess of 325 mg/kg, or oily-stained areas, and were subject

to emergency resodding by the EPA. Contaminated soils were scheduled to be treated for clean-up. A

total of 214 residents (123 males, 91 females) of the contaminated residential area (Koppers) were

interviewed twice during a period of 2 years, and were compared to 212 residents (122 males, 93 females)

from a nearby town. Since all of the residents from the Koppers area who were participating in the survey

were African American, the chosen regional comparison population was also African American. During

the second year of the surveillance, the responses of the Koppers area residents were compared with the

1990 National Health Interview Survey results. No data were presented in this study regarding the

relative importance of inhalation versus dermal exposure. The residents of the Koppers area showed a
CREOSOTE 47

3. HEALTH EFFECTS

significantly higher risk of chronic bronchitis (RR=2.65, 95% CI=1.26–5.57) relative to the comparison

population during the first year of the study. During the second year of the study, 11 residents from the

Koppers area reported chronic bronchitis, whereas 7 were expected based on the 1990 National Health

Interview Survey rates. These study results are seriously limited by the study’s reliance on self reporting

of health conditions for which diagnosis verification was not always available.

Pfitzer et al. (1965) exposed rats by inhalation to near-saturated vapors generated from coal tar creosote

for 1 day. The rats exhibited dyspnea and slight nasal irritation. The actual exposure level was not

determined (Pfitzer et al. 1965). A significant increase in lung weight was reported for female Fischer

rats exposed to 660 mg/m3

 of a coal tar aerosol for 6 hours/day on gestational days 12–16, but not for

females exposed to 84 mg/m3 (Springer et al. 1982). Lesions of the olfactory epithelium were reported

for Fischer rats and CD-1 mice exposed to 690 mg/m3

 of a coal tar aerosol for 6 hours/day, 5 days/week

for 13 weeks, but not for animals exposed to 140 mg/m3

 (Springer et al. 1986b, 1987). Rats exposed to

concentrations of coal tar $30 mg/m3

 for 5 or 13 weeks also showed histiocytosis of the lung tissue

(Springer et al. 1986b). No lesions of the olfactory epithelium were reported for rats exposed to up to

690 mg/m3

 coal tar aerosol for 5 weeks (Springer et al. 1986b). Respiratory symptoms, consisting of

extensive chronic fibrosing pneumonitis with peribronchial adenomatosis, were observed in female

Bethesda rats and guinea pigs (sex not specified) exposed to coal tar or roofing asphalt vapors (exposure

level not specified) for 4 days/week for a total period of 2 years (Hueper and Payne 1960).

Cardiovascular Effects. 

Coal Tar Products. In an industrial health survey of employees in a wood preservative plant in which

coal tar creosote, coal tar, and pentachlorophenol were the main treatments used, cardiovascular effects,

including increased diastolic blood pressure, were noted in 21% (24 of 113) of the employees examined

(TOMA 1979). Industrial hygiene surveys of coal tar pitch volatiles at this and three other wood

preservative plants indicated that airborne exposure to benzene-soluble components of the coal tar pitch

volatiles was within the OSHA permissible limit of 0.2 mg/m3

 in 94% of the samples (TOMA 1979). The

other 6% of the samples ranged from 0.21 to 3.6 mg/m3

 (TOMA 1979). Nevertheless, no clear

relationship could be established because exposure routes in addition to inhalation (e.g., oral and dermal)

were likely. Also, the ability to relate cardiovascular effects to coal tar creosote and coal tar exposure was

further confounded by the possibility that the subjects were also exposed to other chemicals including

pentachlorophenol and cigarette smoke (TOMA 1979). Additional limitations of the study are noted

above (see "Respiratory Effects"). However, in another industrial study, an increase in mortality from
CREOSOTE 48

3. HEALTH EFFECTS

atherosclerosis was associated with cumulative tar exposure and $40 years of exposure to pot emissions

in the aluminum industry (Rönneberg 1995b).

 

The susceptibility of the rat cardiovascular system to high-boiling coal liquid (heavy distillate, HD)

administered by inhalation (700 mg/m3

, for 6 hours/day, 5 days/week for 6 consecutive weeks) was

studied in male Fischer 344 rats (Sasser et al. 1989). Ten days after treatment was stopped, the

cardiovascular assessments were made. The most striking observation was a 20% increase in arterial

blood pressure of HD-exposed rats over that of sham-exposed rats. Heart rate was also elevated in the

HD-treated animals. The nature of the causal relationship (i.e., direct or secondary) between HD and the

elevation of blood pressure and heart rate is not clear since physiological disturbances of other systems,

whose activity influence pressure and rate parameters (e.g., pulmonary and renal systems) might have

produced the observed changes in cardiovascular activity. No change in heart weight or the histology of

the heart or aorta was found for Fischer rats or CD-1 mice exposed to up to 690 mg/m3

 of a coal tar

aerosol for 6 hours/day, 5 days/week for up to 13 weeks (Springer et al. 1986b, 1987).

Gastrointestinal Effects. 

Coal Tar Products. No change in histology of the gastrointestinal tract was found in female Fischer rats

exposed to up to 690 mg/m3

 of a coal tar aerosol for 6 hours/day, 5 days/week for 5 weeks or in male or

female CD-1 mice exposed to up to 690 mg/m3

 of a coal tar aerosol for 6 hours/day, 5 days/week for

13 weeks (Springer et al. 1986b, 1987). Male rats exposed to exposed to 690 mg/m3

 (but not 140 mg/m3)

coal tar aerosol for 6 hours/day, 5 days/week for 5 weeks and male and female rats exposed to 690 mg/m3

(but not 140 mg/m3) coal tar for 13 weeks showed epithelial hyperplasia and chronic inflammation of the

cecum (Springer et al. 1986b).

Hematological Effects. 

Coal Tar Products. In an industrial health survey of employees in four wood preservative plants in

which coal tar creosote and coal tar were the main treatments used, hematological effects, including

increased number of white blood cells (basophils), were noted in 6% (15 of 257) of the employees

examined (TOMA 1979). Similarly, 8% of the employees in nine coal tar plants surveyed had increased

white blood cells (eosinophils). However, the changes in white blood cell numbers, as well as their

morphology, were apparently related to mild infections and allergies. According to the study authors,

these results do not indicate any adverse hematologic effects directly related to plant hazards (TOMA
CREOSOTE 49

3. HEALTH EFFECTS

1981). Industrial hygiene surveys of coal tar pitch volatiles at the four wood preservative plants indicated

that airborne exposure to benzene-soluble components of the coal tar pitch volatiles was within the OSHA

permissible limit of 0.2 mg/m3

 in 94% of the samples (TOMA 1979). The other 6% of the samples

ranged from 0.21 to 3.6 mg/m3

 (TOMA 1979). No determination of exposure was made at the nine coal

tar plants (TOMA 1981). Nevertheless, no clear relationship could be established because exposure

routes in addition to inhalation (e.g., oral and dermal) were likely. Also, the ability to relate

hematological effects to coal tar creosote and coal tar exposure was further confounded by the possibility

that the subjects were also exposed to other chemicals and cigarette smoke (TOMA 1981). Other

limitations of the studies are noted above (see "Respiratory Effects").

In two studies by Springer et al. (1986b, 1987) Fischer rats appeared to be more sensitive to the effects of

inhaled coal tar aerosol than CD-1 mice. Male rats exposed to 140 mg/m3

, but not to 30 mg/m3, of a coal

tar aerosol for 6 hours/day, 5 days/week for 5 or 13 weeks had decreased red blood cell counts,

hemoglobin concentration, white blood cells, lymphocytes, eosinophils, monocytes, and increased

reticulocytes (Springer et al. 1986b). Female rats also had decreased red blood cell counts, hemoglobin

concentration, white blood cells, lymphocytes, eosinophils, monocytes, and increased reticulocytes when

exposed to 140 mg/m3

 coal tar for 5 weeks or 690 mg/m3 for 13 weeks, but there was no significant

difference from controls for females exposed to 30 mg/m3

 coal tar for 5 weeks or 140 mg/m3 coal tar for

13 weeks. Red blood cell counts, hemoglobin concentration, and the volume of packed red cells were

also significantly decreased in CD-1 mice exposed to 690 mg/m3

 (but not 140 mg/m3) of a coal tar aerosol

for 6 hours/day, 5 days/week for 13 weeks, but other hematologic parameters such as erythrocyte,

leukocyte, and reticulocyte counts were unaffected by exposure (Springer et al. 1987). Kock et al. (1994)

reported death of 7 of 20 black rhinoceroses which had been held in creosote-treated holding pens. The

animals which died had widespread hemorrhages and anemia which may reflect the effects of hemolysis,

but doses and routes of exposure were not established in this study.

Hepatic Effects. 

Coal Tar Products. No significant change in liver weight was reported for female CD rats exposed to up

to 660 mg/m3

 of a coal tar aerosol for 6 hours/day on gestational days 12–16 (Springer et al. 1982). In

two other studies, Fischer rats appeared to be slightly more sensitive to the effects of inhaled coal tar

aerosol than CD-1 mice (Springer et al. 1986b, 1987). Relative liver weights were significantly increased

in male rats exposed to 690 mg/m3

 (but not 140 mg/m3) and female rats exposed to $30 mg/m3 of a coal

tar aerosol for 6 hours/day, 5 days/week for 5 weeks and in male rats exposed to $30 mg/m3

 and female
CREOSOTE 50

3. HEALTH EFFECTS

rats exposed to $140 mg/m3 (but not 30 mg/m3) coal tar aerosol for 13 weeks (Springer et al. 1986b). 

Subtle changes in liver histology were also noted for males and females exposed to 690 mg/m3

 compared

with controls. These included a slight increase in cytoplasmic basophilia, slightly more variability in

hepatocellular size, the presence of hepatomegalocytes, increased variability in nuclear size and minimal

loss of cording and lobular pattern. Minimal scattered focal necrosis was also observed in liver tissue of

some exposed animals, but not in controls. Similar changes in weight and histology were also noted in

mice exposed to 690 mg/m3

 (females) or $140 mg/m3 (males) of a coal tar aerosol for 6 hours/day,

5 days/week for 13 weeks (Springer et al. 1987). No changes in weight or histology were observed for

female mice exposed to 140 mg/m3

 or male mice exposed to 29 mg/m3 for 13 weeks (Springer et al.

1987). Kock et al. (1994) reported death of 7 of 20 black rhinoceroses that had been held in creosotetreated holding pens. The animals that died had uniformly swollen intensely green livers, containing

excessive intrahepatic bilirubin. Serum levels of aspartate transaminase (AST) and bilirubin were also

elevated. However, doses and routes of exposure were not established in this study.

Renal Effects. 

Coal Tar Products. Elevated red and white cell counts in urine were noted in 6–8% (29–34 of 452) of

the employees examined in an industrial health survey in nine coal tar plants in which coal tar creosote

and coal tar were the main treatments used (TOMA 1981). Some of these cell count elevations were

attributed to urinary tract infections resulting from inadequate personal hygiene, and not to industrial

exposure to toxic chemicals. However, some of the workers with elevated red and white cell counts in

urine had cellular and granular casts and traces of protein, suggesting abnormal renal function. These

individuals were referred to their physicians for diagnosis. No determination of exposure was made at the

nine coal tar plants (TOMA 1981). Moreover, no clear relationship could be established because

exposure routes in addition to inhalation (e.g., oral and dermal) were likely. Also, the ability to relate

renal effects to coal tar creosote and coal tar exposure was further confounded by the possibility that the

subjects were also exposed to other chemicals and cigarette smoke. Additional limitations of the study

included seasonal and geographical variation in plant locations, past employment history, voluntary

participation in the study that could have biased it in favor of healthy workers, lack of statistical analyses,

lack of adequate controls, and use of only current employees. 

No change in kidney weight was reported for female CD rats exposed to up to 660 mg/m3

 of a coal tar

aerosol for 6 hours/day on gestational days 12–16 (Springer et al. 1982). In another two studies, Fischer

rats appeared to be more sensitive to the renal effects of inhaled coal tar aerosol than CD-1 mice (Springer
CREOSOTE 51

3. HEALTH EFFECTS

et al. 1986b, 1987). Relative kidney weights were increased in female rats exposed to $140 mg/m3 (but

not 30 mg/m3

) and in male rats exposed to $30 mg/m3 of a coal tar aerosol for 6 hours/day, 5 days/week

for 5 weeks and in male rats and female rats exposed to $140 mg/m3 (but not 30 mg/m3) for 13 weeks

(Springer et al. 1986b). Male rats exposed to 690 mg/m3

 (but not 140 mg/m3) for 5 weeks or 140 mg/m3

(but not 30 mg/m3) for 13 weeks and female rats exposed to 690 mg/m3 (but not 140 mg/m3) for 13 weeks

also showed pelvic epithelial hyperplasia and pigmentation of the cortical tubules (Springer et al. 1986b). 

Relative kidney weights were also increased in mice exposed to 690 mg/m3

 (but not 140 mg/m3) of a coal

tar aerosol for 6 hours/day, 5 days/week for 13 weeks, but the difference between exposed and control

animals was not significant and no histological changes were reported (Springer et al. 1987).

Endocrine Effects. 

Coal Tar Products. No adverse effect on the adrenal glands was reported for female CD rats exposed to

up to 660 mg/m3

 of a coal tar aerosol for 6 hours/day on gestational days 12–16 or on the adrenal,

pancreas, parathyroid, pituitary, or thyroid glands in Fischer rats exposed to up to 690 mg/m3

 for 5 or

13 weeks or in CD-1 mice exposed to up to 690 mg/m3

 for 13 weeks (Springer et al. 1982, 1986b, 1987).

Dermal Effects. 

Coal Tar Products. In an industrial health survey of 251 employees in four wood preservative plants in

which coal tar creosote and coal tar were the main treatments used, 82 instances of dermal effects,

including skin irritation, eczema, folliculitis, and benign growths on the skin were noted (TOMA 1979). 

The incidence of benign growths, eczema, and folliculitis was greater than that observed in the general

U.S. population, but the study authors concluded that only the incidence of folliculitis cases met the

criterion of a significant skin condition such “that the examiner believes should be seen at least once by a

physician for assessment or care”. In another industrial health survey (TOMA 1981), workers in nine

coal tar plants had a 2% incidence of benign skin growth and a 21% incidence of some other skin

condition such as keratosis, eczema, folliculitis, and chloracne, but the study authors concluded that the

incidence of skin conditions was less than that seen in the general population. Industrial hygiene surveys

of coal tar pitch volatiles at the four wood preservative plants indicated that airborne exposure to

benzene-soluble components of the coal tar pitch volatiles was within the OSHA permissible limit of

0.2 mg/m3

 in 94% of the samples (TOMA 1979). The other 6% of the samples ranged from 0.21 to

3.6 mg/m3

 (TOMA 1979). No determination of exposure was made at the nine coal tar plants (TOMA

1981). Moreover, no clear relationship could be established because exposure routes in addition to
CREOSOTE 52

3. HEALTH EFFECTS

inhalation were likely (e.g., dermal contact with coal tar creosote and coal tar vapors and oral exposure). 

Also, the ability to relate dermal effects to coal tar creosote and coal tar exposure was further confounded

by the possibility that the subjects were also exposed to other chemicals (TOMA 1979, 1981). Additional

limitations of the studies are noted above (see "Respiratory Effects"). In other industrial studies, dermal

effects were also noted (Bolt and Golka 1993; NIOSH 1982). Four workers in an aluminum reduction

plant, who had been exposed to coal tar pitch volatiles for a period of 3.5–23 years showed tar-related

skin changes, including hyperkeratosis and telangiectasis (Bolt and Golka 1993). Skin lesions that were

possibly pitch-related were observed in four workers involved in the transfer and transport of coal tar

pitch, who had been exposed to coal tar pitch and asphalt for 2–8 years (NIOSH 1982). Warts and other

lesions on the hands and face were described. Workers transferring coal tar pitch from a river barge to an

ocean barge, or from a railroad car to an ocean barge were observed for 2 days to evaluate exposure

conditions and health complaints after exposure to coal tar pitch volatiles (NIOSH 1982). Skin irritation,

described as redness like a sunburn, lasting 2–3 days, with drying and peeling, and photosensitivity, was

described by the workers. Personal air samples from the workers indicated respirable coal tar pitch

vapors in concentrations up to 0.18 mg/m3

. 

Dermal effects were noted in a site surveillance program conducted by the Texas Department of Health

beginning in 1990 at a housing development in Texarkana, Texas, that had been built on part of an

abandoned Koppers Company, Inc., creosote wood treatment plant (Agency for Toxic Substances and

Disease Registry 1994). Because of soil and groundwater contamination with PAHs and other chemicals,

the EPA identified this site and placed it on the NPL in 1984. A total of 214 residents of the

contaminated residential area (Koppers) were interviewed twice during a period of 2 years, and were

compared to 212 residents from a nearby town. Since all of the residents from the Koppers area who

were participating in the survey were African American, the chosen regional comparison population was

also African American. No data were presented in this study regarding the relative importance of

inhalation versus dermal exposure. Residents living on or near the Koppers area reported a higher

prevalence of skin rashes (27.9%) during the first year of the surveillance than the comparison

neighborhood (4.9%), with a RR of 5.72 (P<0.05; 95% CI=3.01–10.87). During the second year of the

surveillance, the responses of the Koppers area residents were compared with the 1990 National Health

Interview Survey results, and similar results were obtained, with 34 Koppers residents reporting skin

rashes, compared to an expected incidence of 4. Rashes were associated with digging in the yard, having

contact with the soil, or wading in or having contact with a creek in the area. Most rashes were associated

with itching or burning. The recommendation of the Texas Department of Health was that residents in the

Koppers area should wear protective clothing when having contact with the soil, and should wash their
CREOSOTE 53

3. HEALTH EFFECTS

skin thoroughly when contact with the soil occurs. Other dermal effects of coal tar creosote, coal tar, or

coal tar pitch exposure are mentioned in Sections 3.2.3 and 3.4.1.3.

Ocular Effects. 

Coal Tar Products. Workers transferring coal tar pitch from a river barge to an ocean barge, or from a

railroad car to an ocean barge, were observed for 2 days to evaluate exposure conditions and health

complaints after exposure to coal tar pitch volatiles (NIOSH 1982). Eye irritation, including burning,

redness, swelling, and watering of the eyes lasting about 2 days was described, occasionally associated

with photophobia. Personal air samples from the workers indicated respirable coal tar pitch vapors in

concentrations up to 0.18 mg/m3

. However, all of the workers were wearing protective equipment,

including respirators and therefore, the measurements taken do not represent actual exposures. 

Conjunctivitis was observed in roofers exposed to coal tar pitch volatiles at levels $0.18 mg/m3

, but no

cases of conjunctivitis were observed in workers exposed to levels #0.11 mg/m3

 (Emmett 1986).

Pfitzer et al. (1965) exposed rats by inhalation to near-saturated vapors generated from coal tar creosote

for 1 day. The rats exhibited slight eye irritation. The actual exposure level was not determined.

Body Weight Effects. 

Coal Tar Products. Body weight changes were monitored in monkeys, rats, and rabbits after inhalation

exposure to 10 mg/m3

 coal tar aerosol (MacEwen et al. 1977). No other systemic effects were reported in

this article. No change in body weight was observed in male or female Macaca mulatta monkeys after

exposure for 6 hours/day, 5 days/week for 18 months, but when male and female Sprague-Dawley rats

were exposed to the same concentration of coal tar aerosol for the same period of time, a 14–15%

decrease in body weight was observed. Female New Zealand white rabbits exhibited a 31% decrease in

body weight after exposure to 10 mg/m3

 for 6 hours/day, 5 days/week for 9 months. 

Male Fischer 344 rats were exposed to high-boiling coal liquid (heavy distillate, HD) administered by

inhalation (700 mg/m3

) for 6 hours/day, 5 days/week for 6 consecutive weeks (Sasser et al. 1989). During

the study, the growth of the HD-exposed animals was suppressed significantly relative to the control

group. Subsequently, growth was resumed after the treatment was stopped, although HD-treated rats

weighed 17.5% less than control rats at necropsy. A significant decrease in body weight was reported for

female Sprague-Dawley rats exposed to 660 mg/m3

 of a coal tar aerosol for 6 hours/day on gestational
CREOSOTE 54

3. HEALTH EFFECTS

days 12–16, but not for female Sprague-Dawley rats exposed to 84 mg/m3 (Springer et al. 1982). In two

other studies, Fischer rats appeared to be more sensitive to the effects of inhaled coal tar aerosol than

CD-1 mice (Springer et al. 1986b, 1987). Body weights were significantly decreased in rats exposed to

$140 mg/m3

 (but not 30 mg/m3) of a coal tar aerosol for 6 hours/day, 5 days/week for 5 or 13 weeks, but

not in mice exposed to up to 690 mg/m3

 coal tar aerosol for 13 weeks (Springer et al. 1986b, 1987).

3.2.1.3 Immunological and Lymphoreticular Effects

No studies were located regarding immunological and lymphoreticular effects in humans or animals

following inhalation exposure to wood creosote or the creosote bush.

Coal Tar Products. No studies were located regarding immunological and lymphoreticular effects in

humans or animals following inhalation exposure to coal tar creosote, coal tar pitch, or coal tar pitch

volatiles. A significant increase in spleen weight and a significant decrease in thymus weight was

reported for female rats exposed to 660 mg/m3

 (but not 84 mg/m3) of a coal tar aerosol for 6 hours/day on

gestational days 12–16 (Springer et al. 1982). In two other already cited studies by Springer et al.

(1986b, 1987), Fischer rats appeared more sensitive to the effects of inhaled coal tar aerosol than CD-1

mice. Relative thymus weights were significantly decreased in female rats exposed to 690 mg/m3

 coal tar

aerosol 6 hours/day for 5 weeks and both males and females exposed to $140 mg/m3

 for 13 weeks

(Springer et al. 1986b). Males exposed to up to 690 mg/m3

 and females exposed to 30 mg/m3 for

5 weeks, and both sexes exposed to 30 mg/m3

 for 13 weeks, showed no change in thymus weight. The

thymus was atrophied in male rats exposed to 690 mg/m3

 (but not 140 mg/m3) coal tar aerosol for

6 hours/day for 5 weeks and in both male and female rats exposed for 13 weeks (Springer et al. 1986b). 

Examination of bone marrow smears showed that rats exposed to 690 mg/m3 coal tar aerosol for 13 weeks

had hypocellular marrows with a marked decrease in the number of megakaryocytes (Springer et al.

1986b). The number of megakaryocytes in the spleens of animals exposed to 690 mg/m3

 coal tar aerosol

for 5 or 13 weeks was also decreased relative to controls. Both absolute and relative thymus weights

were also significantly decreased in male mice exposed to 690 mg/m3

 (but not to 140 mg/m3) or in female

mice exposed to $140 mg/m3

 (but not to 29 mg/m3) of a coal tar aerosol for 6 hours/day, 5 days/week for

13 weeks, but no histological changes were observed (Springer et al. 1987). 
CREOSOTE 55

3. HEALTH EFFECTS

3.2.1.4 Neurological Effects

No studies were located regarding neurological effects in humans or animals following inhalation

exposure to wood creosote or the creosote bush.

Coal Tar Products. No studies were located regarding neurological effects in humans or animals

following inhalation exposure to coal tar creosote, coal tar pitch, or coal tar pitch volatiles. Inhalation of

up to 690 mg/m3

 coal tar aerosol by CD-1 mice for 13 weeks had no effect on brain weight or histology

(Springer et al. 1987). Inhalation of 690 mg/m3

 coal tar aerosol by male Fischer rats for 5 weeks and

inhalation of $140 mg/m3

 by male and female rats for 13 weeks produced a significant increase in relative

brain weights, but no change in absolute brain weight or histological abnormalities (Springer et al.

1986b). The rats had a significant reduction in body weight compared to controls, so it seems likely that

the change in relative brain weight reflects the body weight loss rather than an adverse neurological effect

that affected the absolute brain weight. There was no change in relative brain weight for male rats

exposed to up to 140 mg/m3

 or for female rats exposed to up to 690 mg/m3 for 5 weeks or for male and

female rats exposed to 30 mg/m3

 for 13 weeks.

3.2.1.5 Reproductive Effects

No studies were located regarding reproductive effects in animals following inhalation exposure to wood

creosote or the creosote bush. 

Coal Tar Products. No studies were located regarding reproductive effects in humans or animals

following inhalation exposure to coal tar pitch. No adverse effects on sperm characteristics, including

sperm count and morphology, were noted in workers exposed to coal tar pitch volatiles in an aluminum

reduction plant (Ward 1988). No adverse reproductive effects were reported for residents at a housing

development in Texarkana, Texas, that had been built on part of an abandoned Koppers Company, Inc.

creosote wood treatment plant and was studied as a site surveillance program by the Texas Department of

Health (Agency for Toxic Substances and Disease Registry 1994). There was no difference in the overall

reproductive outcome of female residents of the Koppers area compared to the comparison neighborhood

or the 1990 National Health Interview Survey. In particular, there was no effect on the number of

pregnancies, live births, premature births, spontaneous abortions, or still births. Koppers women who

reported having problems becoming pregnant during the first year of surveillance had an average of

1.3 pregnancies compared to an average of 3.4 pregnancies for women in the comparison neighborhood
CREOSOTE 56

3. HEALTH EFFECTS

who also reported difficulty in becoming pregnant, but no difference in pregnancy outcome was noted

during the second year of surveillance (Agency for Toxic Substances and Disease Registry 1994). It is

likely that reports of difficulty in becoming pregnant were confounded by perception of risk and possibly

also by the age of the mother as the difference was not significant when the results for the entire group

were adjusted for concerns about chemical exposure, or when women over the age of 39 were excluded

from the analysis.

A significant increase in the incidence of mid- and late-gestational resorptions was reported for female

rats exposed to 660 mg/m3

 (but not to 84 mg/m3) of a coal tar aerosol for 6 hours/day on gestational days

12–16 (Springer et al. 1982). Animals exposed to 660 mg/m3 coal tar showed some signs of maternal

toxicity. The thymus weight was significantly reduced and the weights of the lungs and spleen were

significantly increased, but maternal body weights (without the products of conception) were not

significantly reduced compared to controls and the weights of the liver, kidney, and adrenal glands were

similar to controls. No change in the relative weights of ovary or testis were recorded for Fischer rats

exposed to up to 690 mg/m3

 of a coal tar aerosol for 6 hours/day, 5 days/week for 5 weeks (Springer et al.

1986b). Relative ovary weights were significantly decreased in Fischer rats and CD-1 mice exposed to

690 mg/m3

 (but not to 140 mg/m3) of a coal tar aerosol for 6 hours/day, 5 days/week for 13 weeks

(Springer et al. 1986b, 1987). Testis weight in rats exposed to $140 mg/m3

 (but not to 30 mg/m3) coal tar

for 13 weeks was significantly increased relative to controls, while testis weight in male mice exposed to

690 mg/m3

 (but not to 140 mg/m3) coal tar was decreased relative to controls, but the difference was not

significant. Examination of ovarian sections showed a significant decrease in the amount of luteal tissue

in animals exposed to 690 mg/m3

 (but not to 140 mg/m3) coal tar for 5 or 13 weeks. 

3.2.1.6 Developmental Effects

No studies were located regarding developmental effects in humans or animals following inhalation

exposure to wood creosote or the creosote bush.

Coal Tar Products. No studies were located regarding developmental effects in humans or animals

following inhalation exposure to coal tar pitch or coal tar pitch volatiles. As cited above, a site

surveillance program conducted by the Texas Department of Health beginning in 1990 at a housing

development in Texarkana, Texas, that had been built on part of an abandoned Koppers Company, Inc.,

creosote wood treatment plant on soil contaminated with creosote revealed no adverse developmental
CREOSOTE 57

3. HEALTH EFFECTS

effects on the residents (Agency for Toxic Substances and Disease Registry 1994). Specifically, there

was no difference in the number of low birth weight births or in birth defects.

In a study by Springer et al. (1982) mated female rats were exposed to 0, 17, 84, or 660 mg/m3

 of a coal

tar aerosol for 6 hours/day on gestational days 12–16. There was a significant increase in the incidence of

mid- and late-gestational resorptions in the 660 mg/m3

 group compared with controls. Crown-rump

length, fetal weight, fetal lung weight, and placental weights were significantly reduced, and there was a

significantly increased incidence of reduced ossification in the 660 mg/m3

 group and a significant trend

for reduced ossification with increased coal tar concentration. Cleft palates were also observed in this

group, but the increased incidence was not significant. No significant changes in the number of

resorptions, size of fetuses, or incidence of abnormalities were observed for animals exposed to less than

660 mg/m3

. Animals exposed to 660 mg/m3 coal tar showed some signs of maternal toxicity. The thymus

weight was significantly reduced and the weights of the lungs and spleen were significantly increased, but

maternal body weights (without the products of conception) were not significantly reduced compared to

controls and the weights of the liver, kidney, and adrenal glands were similar to controls. 

3.2.1.7 Cancer

No studies were located regarding cancer in humans or animals following inhalation exposure to wood

creosote or the creosote bush.

Coal Tar Products. A number of studies have provided evidence of an association between occupational

exposure to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles and increased incidence of

cancer-related mortalities and cancer in humans (Armstrong et al. 1994; Bertrand et al. 1987; Bolt and

Golka 1993; Costantino et al. 1995; Gibbs and Horowitz 1979; Karlehagen et al. 1992; Kerr et al. 2000;

Lloyd 1971; Lloyd et al. 1970; Martin et al. 2000; Mazumdar et al. 1975; Park and Mirer 1996; Persson et

al. 1989; Redmond 1976; Redmond et al. 1972, 1976; Rockette and Arena 1983; Rönneberg and

Andersen 1995; Sakabe et al. 1975; Spinelli et al. 1991; Stern et al. 2000; TOMA 1982; Tremblay et al.

1995), although other industrial chemicals were present. Other studies have not shown a statistically

significant association between occupational exposure to coal tar products and increased incidence of

specific types of cancer (CEOH 1997; Kromhout et al. 1992; Kunze et al. 1992; Romundstad et al. 2000;

Schildt et al. 1999; Siemiatycki et al. 1994; Swaen and Slangen 1997). Interpretation of the data of many

of the studies mentioned above is limited by a variety of factors including small study populations,

concurrent cigarette smoking, and poor exposure data.
CREOSOTE 58

3. HEALTH EFFECTS

Industrial populations that have been studied include coke oven workers, aluminum smelter workers,

steelworkers, and people exposed to creosote through other activities (Armstrong et al. 1994; Bertrand et

al. 1987; Bolt and Golka 1993; CEOH 1997; Costantino et al. 1995; Gibbs and Horowitz 1979;

Kromhout et al. 1992; Kunze et al. 1992; Lloyd 1971; Lloyd et al. 1970; Mazumdar et al. 1975; Park and

Mirer 1996; Persson et al. 1989; Redmond 1976; Redmond et al. 1972, 1976; Rockette and Arena 1983;

Romundstad et al. 2000; Rönneberg and Andersen 1995; Sakabe et al. 1975; Siemiatycki et al. 1994;

Spinelli et al. 1991; Stern et al. 2000; Swaen and Slangen 1997; TOMA 1982; Tremblay et al. 1995). 

Following occupational inhalation exposure to coal tar creosote, coal tar, coal tar pitch, and coal tar pitch

volatiles, cancer was observed involving a number of tissues including the respiratory tract, lips and skin,

lung, pancreas, kidney, scrotum, prostate, rectum, bladder, and central nervous system; leukemia and

lymphoma were also diagnosed (Armstrong et al. 1994; Bertrand et al. 1987; Bolt and Golka 1993;

Costantino et al. 1995; Gibbs 1985; Gibbs and Horowitz 1979; Karlehagen et al. 1992; Liu et al. 1997;

Lloyd 1971; Mazumdar et al. 1975; Park and Mirer 1996; Persson et al. 1989; Redmond 1976; Redmond

et al. 1972, 1976; Rockette and Arena 1983; Rönneberg and Andersen 1995; Sakabe et al. 1975; Stern et

al. 2000; TOMA 1982; Tremblay et al. 1995). Exposure levels in these studies were not consistently

quantified. In addition, there were confounding factors. In all cases of occupational exposure, the

workers were not exposed to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles as single

agents, but in combination with other chemicals. For instance, some employees exposed themselves to

additional carcinogens via cigarette smoking (TOMA 1982). In other studies, exposure to coal tar

creosote, coal tar, coal tar pitch, or coal tar pitch volatiles was generally combined with other substances. 

Some studies had significant limitations. For example, TOMA (1982) is a retrospective study and no

attempt was made to estimate occupational exposure levels from any source. Additional limitations of the

study are the absence of data on smoking habits, short cut-off date of 10 days of employment, use of U.S.

male mortality rates for comparison as opposed to regional mortality rates, and mixed chemical exposure.

Spinelli et al. (1991) evaluated the mortality and cancer incidence over a 30-year period among a cohort

of workers exposed to coal tar pitch volatiles emitted during production of aluminum. Aluminum is

produced by one of two electrolytic processes wherein petroleum and coal tar pitch are baked in pots. 

These processes result in a continuous generation of coal tar pitch volatiles, which include PAHs. For

analysis of these data, the assignment of exposure level was based on data on coal tar pitch volatiles from

recent plant monitoring, as well as knowledge of historical operational and engineering changes. Based

on the time-weighted average (TWA) for coal tar pitch volatiles of 0.2 mg/m3

 benzene soluble material

(BSM), 4 coding systems were adopted:

(1) no exposure to coal tar pitch volatiles (0 mg/m3

 BSM),
CREOSOTE 59

3. HEALTH EFFECTS

(2) low exposure to coal tar pitch volatiles (<0.2 mg/m3 BSM),

(3) medium exposure to coal tar pitch volatiles (0.2–1.0 mg/m3

 BSM), and

(4) high exposure to coal tar pitch volatiles (>1.0 mg/m3

 BSM).

According to Spinelli et al. (1991), jobs with the highest exposure to coal tar pitch volatiles primarily

occurred before 1970 and included jobs located within the potrooms. The primary findings of this study

were a significantly elevated incidence of bladder cancer in the cohort and the significant trend toward

higher risk with greater lifetime exposure to coal tar pitch volatiles. Also observed was a nonstatistically

significant association between lung cancer and coal tar pitch volatiles. Adjusting for smoking did not

change the observed association. The authors state that the apparent discrepancy between the results of

this study (Spinelli et al. 1991) and those performed previously that found a strong association between

lung cancer and exposure to coal tar pitch volatiles (Anderson et al. 1982; Gibbs 1985; Gibbs and

Horowitz 1979) might relate to the latency period and the levels of coal tar pitch volatiles, both of which

were lower in the Spinelli et al. (1991) study relative to the previous studies.

Costantino et al. (1995) carried out an epidemiological study of 5,321 coke oven workers and 10,497 nonoven workers matched for place of work and socioeconomic status. The average daily exposure to coal

tar pitch volatiles was determined in previously published studies as 3.15 mg/m3

 for topside full time jobs,

1.99 mg/m3

 for topside part time jobs and 0.88 mg/m3 for side jobs. Mortality was assessed by race for

33 categories of cause of death. All RRs were adjusted for age, race, coke plant, and period of follow up

as appropriate. Statistically significant excess mortality occurred in coke workers for several categories

of death. The RR for all causes of death was 1.08 (P<0.01; 95% CI=1.02–1.14). The increase in overall

mortality was primarily due to increased deaths from the following cancers: all cancers (RR=1.34;

P<0.001; 95% CI=1.19–1.50), cancer of the lungs, bronchus, and trachea (RR=1.95; P<0.001; 95%

CI=1.59–2.33), and prostate cancer (RR=1.57; P<0.05; 95% CI=1.09–2.30). These findings were

consistent across racial categories, but excess risk was higher among nonwhite than white workers. There

were highly significant trends (P<0.001) for increased cancer risk with increasing duration of

employment and increasing exposure. The study did not control for smoking. However, the similar

socioeconomic status of the controls and exposed workers suggests that it is unlikely that there was a

substantial difference in smoking habits between the two groups.

Elevated risk of death from cancer and from lung cancer was reported in a retrospective cohort study of

6,635 male workers employed for more than 15 years during the period 1970–1985 in seven factories in

China (Liu et al. 1997). The main chemical exposure was to coal tar pitch volatiles. Significantly
CREOSOTE 60

3. HEALTH EFFECTS

elevated SMRs were observed in highly exposed workers for all causes of death (SMR 1.69, P<0.01), all

cancers (SMR 2.53, P<0.01), digestive cancer (SMR 1.97, P<0.01), esophageal cancer (SMR 3.97,

P<0.05), liver cancer (SMR 2.25, P<0.01), and lung cancer (SMR 4.3, P<0.01). The SMRs for highly

exposed nonsmokers were also elevated for all cancers (SMR 2.1, P<0.01) and lung cancer (SMR 3.0,

P<0.01), and there was a significant correlation between deaths from lung cancer and exposure to coal tar

pitch volatiles.

A cohort study (Karlehagen et al. 1992) that examined cancer incidence among 922 workers exposed to

coal tar creosote while impregnating wood (railroad cross ties and telegraph poles) at seven plants in

Sweden and six plants in Norway during the period of 1950–1975 reported a significant increase in

incidence of nonmelanoma skin cancer (observed=9, standardized incidence ratio (SIR)=2.37, 95%

CI=1.08–4.50, P=0.02) for the entire study population and a significant increase in cancer of the lip

(observed=5, expected=1.34, 95% CI=1.21–8.7, P=0.01) among individuals exposed over 20 years earlier

compared with the national male population. Workers were exposed to creosote vapors when removing

wood from the autoclave in which it was pressure-treated, but were also likely to receive dermal exposure

while handling the wood. The conclusions that can be drawn from this study are limited by the lack of

information about the smoking status or exposure to sunlight of the subjects and the absence of

measurements of exposure to creosote.

A study of proportionate mortality among the 11,144 members of the United Union of Roofers,

Waterproofers, and Allied Workers (Stern et al. 2000) found a significant excess in mortality due to

cancers of the lung, bladder, esophagus, larynx, and to pneumoconioses and other nonmalignant

respiratory diseases in these workers compared with U.S. age-, gender-, and race-specific proportional

mortality rates for the years of the study (1950–1996). These workers were occupationally exposed to

asphalt fumes and asbestos as well as coal tar pitch volatiles, and cigarette smoking must also be

considered as a likely confounding factor. Exposure to coal tar pitch volatiles is higher for waterproofers

than for roofers, and a comparison of proportional mortality of nine local unions with a large number of

waterproofers found that the risk of death due to cancer, lung cancer, esophageal cancer, and pharyngeal

cancer were higher in these workers (2,804 deaths) than in the workers (8,334 deaths) who did not do

much of waterproofing, but these differences were not analyzed for statistical significance.

A significant association between exposure to coal tar creosotes and lung cancer was reported in a

case-control study of a cohort of 1,535 male workers who were active in the French national electricity

and gas company (EDF-GDF) between 1978 and 1989 (Martin et al. 2000). Controls (four per case) were
CREOSOTE 61

3. HEALTH EFFECTS

matched to the 310 cases by year of birth. Occupational exposure was estimated using a job exposure

matrix, and in the absence of individual data on tobacco consumption, the socioeconomic status of the

subjects was used to control for this factor. Since a positive association between exposure to asbestos and

lung cancer had been previously established for this study population, an adjustment for asbestos

exposure was also included in the analysis. The unadjusted odds ratios (ORs) for workers exposed to coal

tar and coal tar creosotes were significantly increased. After adjusting for socioeconomic status and

asbestos exposure, the odds ratio for coal tar creosotes was still significant (OR=1.56, 95%

CI=1.08–2.27), but the odds ratio for coal tar was not significant. A similar pattern was seen when the

data were analyzed by level of exposure. Coal tar showed a significant association with increased lung

cancer risk at high exposures, but the odds ratio was no longer significant when the data were adjusted for

socioeconomic status and asbestos exposure. High exposure to coal tar creosotes was significantly

associated with increased odds ratios for lung cancer, both with and without adjustment for

socioeconomic status and asbestos exposure, and there was also a significant exposure-response

relationship between coal tar creosotes and lung cancer.

A case-control study conducted with 183 neuroblastoma cases, aged 0–14 years diagnosed among

residents of New York state (excluding New York City) between 1976 and 1987, found a significant

increase in risk of neuroblastoma associated with self-reported paternal exposure to creosote (21 cases,

20 controls, OR=2.1, 95% CI=1.1–4.3), coal soot (6 cases, 2 controls, OR=5.9, 95% CI=1.0–60.4), or

coal tar (10 cases, 7 controls, OR=2.8, 95% CI=1.0–8.4), or maternal exposure (both certain and potential

exposure combined) to coal soot (OR=10.4, 95% CI=1.2–495.3) or coal tar (OR=4.1, 95% CI=1.2–15.5)

(Kerr et al. 2000). Cases were histologically confirmed and were compared with 372 controls matched by

year of birth. Due to the small number of nonwhite cases, both cases and controls were limited to cases

born to white mothers. Individuals with amended or sealed (adopted) birth certificates were also excluded

from the study. Some specific exposure information was collected (via telephone interviews) for

creosote, but in general, exposure was based on job description. Possible sources of uncertainty in this

study include poor exposure information, the possibility of interviewer bias (interviewers were not

blinded to the disease status of the child), and the possibility of the reported increases in risk being chance

findings due to the large number of comparisons made. 

In a study of the effects of coal tar pitch exposure on the respiratory system, Wistar rats received

10 weekly intratracheal instillations of 0.648, 13.56, and 20.0 mg of coal tar pitch (equivalent to 5.18,

109.2, and 160.0 mg/kg) or 2 mg charcoal powder (control group) and were sacrificed and examined at 1,

3, 6, 12, and 18 months after treatment (Chang et al. 1992). The treatment produced inflammation,
CREOSOTE 62

3. HEALTH EFFECTS

hyperplastic, and metaplastic changes. All rats with lung cancer were found in the two highest treatment

groups. The pathogenesis of coal tar pitch-induced lung carcinomas seems to start from hyperplasia of

bronchiole-alveolar epithelium, progressing through squamous metaplasia and/or different stages of

dysplasia to carcinomas (Chang et al. 1992). According to Chang et al. (1992), the effects produced with

coal tar pitch were consistent with the effects reported after similar treatment with PAHs and tobacco

smoke condensate. Although the findings presented by Chang et al. (1992) suggest a correlation between

coal tar pitch and lung cancer, the relevance of this relationship to potential human exposures by

inhalation is questionable given the animal dosing technique.

In a study by Heinrich et al. (1994a, 1994b), groups of female Wistar rats were exposed to 0, 1.1, or

2.6 mg/m3

 coal tar pitch aerosol for 17 hours/day, 5 days/week for 10 months. This exposure was

followed by 20 months of clean air exposure. The lung tumor rates of animals exposed to 1.1 and

2.6 mg/m3

 coal tar pitch aerosol for 10 months were 4.2 and 38.9%, respectively. Most of the tumors

were benign and malignant keratinizing squamous cell tumors. Some broncho-alveolar adenomas and

adenocarcinomas were also found. No exposure-related tumors were found in other organs. No lung

tumors were found in the control animals. Similar results (i.e., increased incidence of benign lung

tumors) were also observed in Wistar rats exposed to 1.1 and 2.6 mg/m3

 (increased incidence of tumors

33.3 and 97.2%, respectively) coal tar pitch aerosol for 17 hours/day, 5 days/week for 20 months,

followed by clean air exposure for 10 months (Heinrich et al. 1994a, 1994b). 

In a study by MacEwen et al. (1977), groups of 40 male and 40 female Sprague-Dawley rats were

exposed to 10 mg/m3

 coal tar aerosol 6 hours/day, 5 days/week for 18 months. Control animals were held

in a vivarium. After exposures, the animals were returned to the vivarium and held for an additional

6 months of observation prior to necropsy. The tumors found in rats exposed to coal tar aerosol showed

31 of 38 females and all males (38 of 38) with squamous cell carcinoma (lung) and 3 of 38 females with

mammary fibroadenoma. Overall tumor incidences for controls were 0% for males and 13% for females. 

Overall tumor incidences for exposed animals were 100% for males and 82% for females.

MacEwen et al. (1977) indicated that tumor-susceptible ICR CF-1 female mice and tumor-resistant

CAF1-JAX female mice exposed to coal tar aerosol-BTX mixture continuously for 90 days at

concentrations of 0, 0.2, 2, and 10 mg/m3

 developed skin tumors at 2 and 10 mg/m3, respectively. In the

ICR CF-1 strain mice, tumors continued to develop for as long as 86 weeks postexposure. Skin tumor

incidences in ICR CF-1 mice exposed to 0, 0.2, 2, and 10 mg/m3

 coal tar aerosol-BTX mixture for

90 days were 3 of 225 (1%), 1 of 61 (2%), 14 of 75 (19%), and 44 of 55 (80%), respectively. Skin tumor
CREOSOTE 63

3. HEALTH EFFECTS

incidences in CAF1-JAX mice exposed to 0, 0.2, 2, and 10 mg/m3 coal tar aerosol-BTX mixture for

90 days were 0 of 225 (0%), 0 of 75 (0%), 3 of 65 (5%), and 18 of 43 (42%), respectively. Tumors were

confirmed by histological examination. Tumor-susceptible ICR CF-1 female mice and tumor-resistant

CAF1-JAX female mice were exposed to 0 or 10 mg/m3

 coal tar aerosol-BTX mixture intermittently for

18 months (MacEwen et al. 1977). For animals exposed intermittently, skin tumor incidences were 5 of

75 in ICR CF-1 mice and 3 of 75 in controls, and 2 of 50 in CAF1-JAX mice as compared to 1 of 50 in

controls. Calculation of total exposure indicated the amount of coal tar reaching the skin of the animals

was the same as in the 90-day continuous exposure study. However, the intermittent exposure allowed

daily normal cleaning of the fur. The incidence of tumors was less in the animals subjected to

intermittent exposure. Tumors found in control and exposed mice of both strains included alveolargenic

carcinoma, alveolargenic adenoma, bronchogenic carcinoma, squamous cell carcinoma, lymphosarcoma,

reticulum cell sarcoma, hemangiosarcoma, hemopoietic tumors, and subcutaneous sarcoma. The effects

of the carrier solvents (BTX) used in this study were not evaluated.

Levels of exposure associated with CELs of creosote are indicated in Table 3-1 and plotted in Figure 3-1.

3.2.2 Oral Exposure

This section describes the health effects observed in humans and laboratory animals associated with oral

exposure to coal tar and beechwood creosote at varying times and exposure levels. The LSEs by the oral

route presented in Tables 3-2 and 3-3 and Figures 3-2 and 3-3 include studies using beechwood creosote,

petroleum creosote, coal tar, and coal tar creosote. All reliable exposure levels have been reported. 

Although beechwood creosote, creosote bush resin, and coal tar creosote have some components in

common, such as phenols, it is not known whether these mixtures will induce the same effects. 

Furthermore, coal tar creosote contains a complex mixture of animal and human carcinogenic and

co-carcinogenic PAHs that probably accounts for the cancer risk associated with chronic exposure to coal

tar creosote while wood creosote does not.
CREOSOTE 64

3. HEALTH EFFECTS

3.2.2.1 Death

Wood Creosote. The acute toxicity of beechwood creosote in both rats and mice was studied following

single gavage administration of a 10% aqueous solution (Miyazato et al. 1981). The oral LD50 values of

beechwood creosote in Wistar rats were 885 mg/kg for males and 870 mg/kg for females. The highest

dose at which no death occurred was 600 mg/kg. There was no significant difference between male and

female rats with respect to mortality, and most animals died within 24 hours. However, no treatmentrelated deaths were observed when rats were given doses of beechwood creosote in the feed of up to 
Table 3-2 Levels of Significant Exposure to Creosote - Oral 

Exposure/ LOAEL 

Duration/ 

Key to Species Frequency 

ACUTE EXPOSURE 

Death 

Reference 

Chemical Form 

NOAEL Less Serious Serious a 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) 

1 Rat 5 d Gd 12-16 lxld 

(CD) (GI 

2 Rat once 

(Wistar) (G) 

Systemic 

3 Rat 5 d Gd 12-16 lxld 

(CD) (G) 

4 Rat once 

(Wistar) (G) 

Hepatic 

Renal 

Endocr 

Bd Wt 

Gastro 

Resp 

Hepatic 

Renal 

Endocr 

Bd Wt 

370 F 

370 F 

90 F (significant increase in adrenal 

weight) 

weight gain) 

140 F 180 F (significant decrease in body 

53 F 106 F (significant decrease in 

peristaltic movement of 

intestine) 

400 F 

400 F 

400 F 

400 F 

400 F (16.1% decreased maternal 

body weight) 

Hackett et al. 1984 

coal tar 

740 F (10 of 16 animals died) 

1700 M (LD50) 

Pfitzer et al. 1965 

coal tar 

Hackett et al. 1984 

coal tar 

Ogata et al. 1993 

wood creosote 

lyer et al. 1993 

petroleum creosote 

w 

0 

I 

rn 

0 

5 

F 

P 

0 

0 

R 

z 

s 

rn 
Table 3-2 Levels of Significant Exposure to Creosote - Oral (continued) 

Exposure/ LOAEL 

Duration1 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkg) (mg/kg) (mg1kC.l) Chemical Form 

Systemic 

Mouse once 

(CD-1) (GI 

lmmunollymphoret 

Rat 5 d Gd 12-16 lxld 

(CD) (G) 

Reproductive 

Rat 5 d Gd 12-16 Ixld 

(CD) (9 

9 Rat 3 d Gd 12-14 lxld 

(Sprague- (G) 

Dawley) 

10 Mouse 5 d Gd 5-9 lxld 

(ICR) (GI 

Developmental 

11 Rat 5 d Gd 12-16 Ixld 

(CD) (GI 

12 Rat 3 d Gd 12-14 lxld 

(Sprague- (G) 

Dawley) 

Gastro 0.08 M lsianificant reduction in 

propulsive motility of the colon) 

140 

740 

400 F 

90 

90 F 

180 

(significant increase in adrenal 

weight and decrease in thymus 

weight) 

(significant increase in the 

number of resorptions) 

Ogata et al. 1999 

wood creosote 

Hackett et al. 1984 

coal tar 

Hackett et al. 1984 

coal tar 

370 (significant decrease in number 

of live fetusesllitter and 

increase in the number of 

resorptions) 

Springer et al. 1986a 

coal tar 

lyer et al. 1993 

creosote 

Hackett et al. 1984 

coal tar 

140 (significant decrease in relative 370 (significant increase in the 

fetal lung weight and a 

significant increase in syndactyly/ectrodactyly and 

anomalous fetuses) 

incidence of cleft palate, 

missing toenails on hind feet) 

Springer et al. 1986a 740 (significant increase in early 

mortality, increased incidence coal tar 

of cleft palate and small lungs) 

w 

0 

I 

rn 

0 

5 

F 

9 

Z 

u 

0 

;D 

rn 

$ 

rn 

a 

a 
Table 3-2 Levels of Significant Exposure to Creosote - Oral (continued) 

Exposure/ LOAEL 

Duration/ 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) Chemical Form 

Developmental 

13 Mouse 5 d Gd 5-9 Ixld 

(ICR) (GI 

INTERMEDIATE EXPOSURE 

Systemic 

(Fischer- 344) (GO) 

14 Rat 3-5 wk Ix/d 

15 Mouse 28 d 

(B6C3F1) (F) 

16 Mouse 15 d ad lib 

(F) 

Gastro 

Bd Wt 

Bd Wt 

Other 

Bd Wt 

Other 

50 M 

50 M 

400 (12% decreased fetal weight, 

increased incidence of missing 

sternbrae) 

410 M 693 M (approx 16% decreased body 

693 M (significantly decreased food 

weight) 

intake) 

410 M 

659 M 1871 M (12.5% decreased body weight) 

659 M 1871 M (decreased food consumption) 

lyer et al. 1993 

creosote 

Chadwick et al. 1995 

coal tar 

Culp and Beland 1994 

coal tar 

Weyand et al. 1991 

coal tar 

w 

0 

I 

rn 

5 

F 

0 

9 

z 

0 

73 

I 

< 

0 

v, 

F 

0 

A 

m 

2 

s 

rn 

8 
Table 3-2 Levels of Significant Exposure to Creosote - Oral (continued) 

Exposure/ 

Duration/ 

LOAEL 

Key to a Species Frequency NOAEL Less Serious Serious Reference 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) Chemical Form 

Systemic 

(B6C3F1) (F) 

17 Mouse 185 d 

18 Mouse 94 d 

(B6C3F1) (F) 

Resp 462 

Cardio 462 

Gastro 462 

Hemato 462 

Hepatic 462 

Renal 462 

Endocr 462 

Bd Wt 462 

Resp 462 

Cardio 462 

Gastro 462 

Hemato 462 

Hepatic 462 

Renal 462 

Endocr 462 

Bd Wt 462 

Weyand et al. 1994 

coal tar 

Weyand et al. 1994 

coal tar 

0 

23 

rn 

$ 

3 

ni 

w 
Table 3-2 Levels of Significant Exposure to Creosote - Oral (continued) 

Exposure/ 

Duration/ 

LOAEL 

Reference 

Chemical Form 

NOAEL Less Serious Serious a 

Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) 

Systemic 

19 Mouse 260 d 

NJ (F) 

lmmunollymphoret 

20 Mouse 185 d 

(B6C3F1) (F) 

21 Mouse 94d 

(B6C3F1) (F) 

Reproductive 

22 Mouse 185 d 

(B6C3F1) (F) 

23 Mouse 94 d 

(B6C3F1) (F) 

Cancer 

24 Mouse 260 d 

NJ (F) 

CHRONIC EXPOSURE 

Death 

(B6C3Fl) (F) 

Systemic 

(66C3F1) (F) 

25 Mouse 2 yrs 

26 Mouse 2 yrs 

Bd Wt 236 F 

Bd Wt 

462 

462 

462 

462 

628 F 1364 F (decrease in body weight) 

Weyand et al. 1995 

coal tar 

Weyand et al. 1994 

coal tar 

Weyand et at. 1994 

coal tar 

Weyand et at. 1994 

coal tar 

Weyand et at. 1994 

coal tar 

Weyand et al. 1995 

incidence of lung tumors CEL: Coal tar 

70%10%) 

100 F (significant increase in 

Culp et al. 1998 

Coal tar 

333 F (significantly increased 

incidence of early mortality) 

Culp et at. 1996a 

coal tar 

0 

0 

I 

rn 

0 

E 

? 

D 

Z 

U 

-u 

I 

-< 

0 

v, 

F 
Table 3-2 Levels of Significant Exposure to Creosote - Oral (continued) 

Exposure/ 

Duration/ 

LOAEL 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mg/kg/da!4 Chemical Form 

Systemic 

(B6C3F1) (F) 

27 Mouse 2 yrs 

Cancer 

28 Mouse 2 yrs 

(B6C3F1) (F) 

29 Mouse 2 yrs 

(B6C3F1) (F) 

Resp 117 F 333 F (significantly decreased lung 

weight) 

Gastro 1300 F 

Hepatic 117 F 333 F (40% increase in liver weight) 

Renal 33 F 1 17 F (significantly decreased kidney 

Bd Wt 333 F (20% decrease in body weight 

Other 117 346 F (significantly reduced food 

weight) 

gain) 

consumption) 

117 F 

200 F 

333 F 

Culp et al. 1998 

coal tar 

Culp et al. 1996a 

(increased incidence of tumors 

of the forestomach CEL: 61%: Coal tar 

0% in controls) 

Culp et al. 1998 (significantly increased 

incidence of neoplasms of the Coal tar 

liver, lung and forestomach and 

of hemangiosarcomas and 

histiocytic sarcomas, CEL: 

27/47 alveolarlbronchiolar 

adenomas) 

aThe number corresponds to entries in Figure 3-2. 

Bd Wt = body weight; Cardio = cardiovascular; CEL = cancer effect level; d = day@); Endocr = endocrine; F = female; (F) = feed; (G) = Savage; Gastro = gastrointestinal; Gd = gestation day; Hemtao = hematological; hr = hour(s); LD50 = lethal dose, 50% kill; LOAEL = lowest-observable-adverse-effect level; M = male; mo = month(s); NOAEL = no-observable-adverse-effect level; Resp = respiratory; wk = week(s); x = times . 

0 xi 

rn 

E 

s 

rn 

D 

z 

U 
Figure 3-2 Levels of Significant Exposure to Creosote - Oral 

Acute (214 days) 

10000 

1000 

100 

10 

1 

0.1 

0.01 

H2r 

01r 

05m 

Q4r 

04r 

@6m 

Q7r 

c-Cat -Humans f-Ferret n-Mink + Cancer Effect Level-Animals 'I Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other 0 LOAEL, More Serious-Animals A LOAEL, More Serious-Humans : Minimal Risk Level 

r-Rat m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans : foreffects 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals A other than 

Cancer 

A NOAEL - Humans 

q-Cow a-Sheep g-Guinea Pig -____ _______ 

0 

0 

I 

m 

E 

F 

0 

P 

0 
Figure 3-2 Levels of Significant Exposure to Creosote - Oral (Continued) 

Intermediate (15-364 days) 

Systemic 

10000 

1 ooc 

1 O( 

11 

014r 

01 6m 

014r 

@16m 

c-Cat -Humans f-Ferret n-Mink *Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 I Minimal Risk Level 

d-Dog k-Monkey j-Pigeon o-Other 0 LOAEL, More Serious-Animals A LOAEL, More Serious-Humans 

I for effects r-Rat m-Mouse e-Gerbil @ LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans 

p-Pig h-Rabbit s-Hamster 0 NOAEL other than -Animals 

q-Cow a-Sheep 9-Guinea Pig Cancer 

A NOAEL - Humans 

-_ 

w 

0 

I 

rn 

5 

F 

0 

D 

z 

0 

0 

?J 

rn 

0 

$ 

-4 

10 
Figure 3-2 levels of Significant Exposure to Creosote - Oral (Continued) 

Intermediate (15-364 days) 

LD50/LC50 

: for effects A other than 

Cancer 

c-Cat -Humans f-Ferret n-Mink Cancer Effect Level-Animals Cancer Effect Level-Humans 

d-Dog k-Monkey j-Pigeon o-Other LOAEL, More Serious-Animals A LOAEL, More Serious-Humans : Minimal Risk Level 

r-Rat m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals NOAEL - Humans 

q-cow a-Sheep-g-GuineaPig--- __ - - ____ ___-___ ____ ___ __ 

rri 

-4 

w 

10000 

1000 

1 oc 

I( 

+24m 

*Doses represent the lowest dose tested per study that produced a tumorigenic 

response and do not imply the existence of a threshold for the cancer endpoint. 

0 
Figure 3-2 Levels of Significant Exposure to Creosote - Oral 

Chronic (2365 days) 

c-Cat -Humans f-Ferret n-Mink Cancer Effect Level-Animals Cancer Effect Level-Humans LD501LC50 

d-Dog k-Monkey ]-Pigeon o-Other 0 LOAEL, More Serious-Animals A LOAEL, More Serious-Humans 

r-Rat m-Mouse e-Gerbil 8 LOAEL, Less Serious-Animals .A LOAEL, Less Serious-Humans I foreffects 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals J-, other than 

I Minimal Risk Level 

a NOAEL - Humans 

Systemic 

-4 

P 

10000 

1000 

1 oa 

1( 

- q-Cow a-Sheep 9-GUinea !?$___. __ __~__ __~ __ - ___ - -~ ~ - 

027m 

027m 

827m 

a26m 

026m 

827m 827m +29m 

+28m 

*Doses represent the lowest dose tested per study that produced a tumorigenic 

response and do not imply the existence of a threshold for the cancer endpoint. 

0 

0 

I 

rn 

0 

s 

F 

P 

U 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral 

Exposure/ LOAEL 

Duration/ 

Key to Species Frequency 

ACUTE EXPOSURE 

Death 

Reference 

Chemical Form 

NOAEL Less Serious Serious a 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkg/day) 

1 Rat once 

(Wistar) (G) 

Neurological 

3 Rat once 

(wistar) (G) 

313 M 

885 M (LD50) 

870 F 

525 M (LD50) 

433 F 

600 (convulsions) 

376 M (convulsions) 

313 F 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

0 

0 

I 

rn 

s 

F 

0 

D 

Z 

0 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral (continued) 

Exposure/ LOAEL 

Duration/ Reference 

a NOAEL Less Serious Serious Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mg Wday) Chemical Form 

INTERMEDIATE 

Systemic 

(Wistar) (F) 

5 Rat 3 mo 

EXPOSURE 

Resp 

Cardio 

Hemato 

Hepatic 

Renal 

Endocr 

Bd Wt 

81 2 

812 

81 2 

163 F 168 M (increased relative liver weight) 

215 F 

210 M (increased relative kidney 

163 F 

168 M 

weight) 

812 

534 768 F (1 1% decreased body weight) 812 M (22% decreased body weight) 

Miyazato et al. 1981 

beechwood creosote 

0 

;I) 

rn 

0 

E 

-I 

rn 

u 

0 

I 

rn 

E 

F" 

0 

P 

O 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral (continued) 

Exposure/ LOAEL 

Duration1 

a NOAEL Less Serious -Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkdday) Chemical Form 

Systemic 

6 Mouse 3 mo 

(ddY) (F) 

lmmunollymphoret 

7 Rat 3 mo 

(Wistar) (F) 

8 Mouse 3 mo 

Neurological 

9 Rat 3 mo 

(Wistar) (F) 

(F) 

Resp 1427 

Cardio 1427 

Hemato 1427 

Hepatic 768 M 

1127 F 

Renal 1427 

Endocr 1427 

Bd Wt 450 M 

1127 F 

317 M 

768 F 

1810 

1065 M (significant increase in relative 

liver weight) 

314 F 

768 M (16% decreased body weight) 

1427 F (1 1% decreased body weight) 

805 M (increased relative spleen 

weight) 

768 F 257 M (increased relative brain weight) 

1810 

Miyazato et al. 1981 

beechwood creosote 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

w 

0 

I 

rn 

5 

F 

0 

P 

0 

T) 

I 

-< 

0 

v, 

F 

0 

R 

E 

3 

rri 

-4 

-4 
Table 3-3 Levels of Significant Exposure (continued) to Wood Creosote - Oral 

LOAEL Exposure1 

Duration/ Reference 

Key to Species Frequency figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) Chemical Form 

a NOAEL Less Serious Serious 

Reproductive 

I1 Rat 3 mo 

(Wistar) (F) 

12 Mouse 3 mo 

(ddY) (F) 

CHRONIC EXPOSURE 

Death 

(SpragueDawley) 

13 Rat 

14 Rat 

(Wistar) 

Systemic 

(SpragueDawley) 

15 Rat 

95 or 102 wk 

G 

96 wk 

(F) 

95 or 102 wk 

G 

Cardio 

Bd Wt 

317 M 805 M (increased relative testes 

weight) 

768 F 

1810 

Miyazato et al. 1981 

beechwood 

Miyazato et al. 1981 

beechwood 

Kuge et al. 2001 

Seirogan 

200 Significant increase in mortality 

in male and female rats. 

313 M (30/51 died) Miyazato et al. 1984b 

beechwood 

Kuge et al. 2001 

Seirogan 

200 M Significant reduction in heart 

weight. 

200 F Significant reduction in mean 

terminal body weight and body 

weight change. 

0 

R 

$ 

2 

rn 

0 

I 

m 

s: 

F’ 

0 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral (continued) 

Exposure/ 

Duration/ 

LOAEL 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

Chemical Form figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) 

Systemic 

16 Rat 96 wk 

(Wistar) (F) 

lmmunollymphoret 

(Sprague- G 

Dawle y) 

18 Rat 95 or 102 wk 

Cardio 

Hepatic 

Renal 

Endocr 

I BdWt 

Resp 

Hemato 

Hepatic 

Renal 

Bd Wt 

143 M 

394 F 

143 M 

394 F 

394 

532 

532 

532 

532 

532 

313 M (increased relative heart weight) 

143 M (increased relative liver weight 

and serum cholesterol) 

179 F (increased serum cholesterol) 

143 M (increased relative kidney 

weight, increased BUN, 

nephrosis) 

179 F 

313 M (increased relative weight of 

313 F 

adrenal glands) 

200 M Significant reduction in spleen 

weight. 

Miyazato et at. 1984b 

beechwood creosote 

Miyazato et al. 1984a 

beechwood creosote 

Kuge et al. 2001 

Seirogan 

u 

0 

I 

rn 

5 

0 

F 

P 

0 

W 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral (continued) 

Exposure/ LOAEL 

Duration/ 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mglkglday) (mglkglday) Chemical Form 

lmmunollymphoret 

(Sprague- G 

Dawley) 

19 Rat 95 or 102 wk 

20 Rat 96 wk 

(Wistar) (F) 

21 Mouse 52 wk 

(ddY) (F) 

Neurological 

22 Rat 96 wk 

(Wistar) (F) 

Reproductive 

(Sprague- G 

Dawley) 

24 Rat 95 or 102 wk 

25 Rat 96 wk 

(Wistar) (F) 

394 

532 

200 F Significant reduction in 

thyroid-parathyroid weight. 

179 F 143 M (increased relative brain weight) 

394 F 

394 

247 M (increased relative brain weight) 

297 F 

200 M Significant increase in testis 

weight 

Kuge et al. 2001 

Seirogan 

Miyazato et al. 1984b 

beechwood 

Miyazato et al. 1984a 

beechwood 

Miyazato et al. 1984b 

beechwood 

Miyazato et al. 1984a 

beechwood 

Kuge et al. 2001 

Seirogan 

Miyazato et al. 1984b 

beechwood 

0 

23 

rn 

0 

$ 

--I 

rn 

0 

I 

rn 

s 

0 

9 

r 

P 

0 

W 

0 
Table 3-3 Levels of Significant Exposure to Wood Creosote - Oral (continued) 

Exposure/ 

Duration/ 

LOAEL 

a NOAEL Less Serious Serious Reference Key to Species Frequency 

figure (Strain) (Specific Route) System (mglkglday) (mg/kg/day) (mglkglday) Chemical Form 

532 Miyazato et al. 1984a 

beechwood 

aThe number corresponds to entries in Figure 3-3. 

Differences in levels of health effects and cancer between males and females are not indicated in figure 3-3 

Bd Wt = body weight: BUN = blood urea nitrogen; Cardio = cardiovascular; CEL = cancer effect level; d = day(s): Endocr = endocrine; F = female; (F) = feed; (G) = gavage; Gastro 

= gastrointestinal: Gd = gestation day; Hemtao = hematological; hr = hour(s): LD50 = lethal dose, 50% kill; LOAEL = lowest-observable-adverse-effect level; M = male; mo = month@); NOAEL = no-observable-adverse-effect level; Resp = respiratory; wk = week(s); x = times 

0 

A 

rn 

$ 

s 

rn 

u 

0 

I 

rn 

s: 

? 

0 

D 

Z 

0 

73 

I 

< 

0 

v, 
Figure 3-3 Levels of Significant Exposure to Wood Creosote - Oral 

Acute (514 days) 

mglkglday o..'" 

1000 

101 

04m 04m 

co 

h) c-Cat -Humans f-Ferret n-Mink *Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other LOAEL, More Serious-Animals A LOAEL, More Serious-Humans : ; Minimal Risk Level foreffects 

r-Rat m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals LOAEL, Less Serious-Humans 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals A NOAEL - Humans A other than 

__-- Cancer q-cow a-sheep gSyineaPig--. - ~ __ _. - - __ ~ __~ 

u 

0 

I 

rn 

0 

5 

F 

P 

0 
Figure 3-3 Levels of Significant Exposure to Wood Creosote - Oral (Continued) 

Intermediate (1 5-364 days) 

Systemic 

10000 

1 ooc 

1 O( 

08m OlOm 012m 

06m 06m 06m 

06m 

06m 06m 

05r 06m 05r 05r Q7r 

05r 

06m 

07r 

09r 

Qgr 

05~ Q5r Q5r 05r 

QIIr 

&Cat -Humans f-Ferret n-Mink Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 

d-Dog k-Monkey j-Pigeon o-Other LOAEL, More Serious-Animals A LOAEL, More Serious-Humans : Minimal Risk Level 

r-Rat m-Mouse e-Gerbil 0 LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans : for effects 

p-Pig h-Rabbit s-Hamster 0 NOAEL -Animals NOAEL - Humans other than 

a-Cow a-Sheer, a-Guinea Pia Cancer 

0 

23 

m 

2 

3 

w 

0 

I 

m 

0 

5 

F 

D 

z 

0 

-0 

I 

-i 

0 

v, 

F 
Figure 3-3 Levels of Significant Exposure to Wood Creosote - Oral (Continued) 

Chronic (2365 days) 

1000 

101 

01711-1 

01 6r 

a16r 

015r 

016r 

01711-1 021m 026m 

016r 01 6r 020r a22r 02% 

a16r a16r 

a23m 

a23m 

015r a18r a19r a24r 

022r 

- 

n-Mink Cancer Effect Level-Animals Cancer Effect Level-Humans LD50/LC50 c-Cat -Humans f-Ferret &Dog k-Monkey j-Pigeon o-Other LOAEL, More Serious-Animals A LOAEL, More Serious-Humans 

r-Rat m-Mouse e-Gerbil LOAEL, Less Serious-Animals A LOAEL, Less Serious-Humans : for effects 

p-Pig h-Rabbit s-Hamster . 0 NOAEL -Animals A NOAEL - Humans other than 

: Minimal Risk Level 

q-Cow a-Sheep g-Gulnea Pig ____ ____ ___ Cancer 

w 

0 

I 

rn 

5 

F: 

0 
CREOSOTE 85

3. HEALTH EFFECTS

812 mg/kg/day (males) or 768 mg/kg/day (females) for 3 months (Miyazato et al. 1981). Male and

female Wistar rats fed diets that contained up to 313 or 394 mg/kg/day beechwood creosote for 96 weeks

exhibited deaths in all groups (Miyazato et al. 1984b). There was no treatment-related increase in

mortality in the females; the major cause of death in the females including controls was bronchpneumonia

and leukemia. The high-dose males had a slightly higher mortality rate than controls and low-dose males;

and this was due to chronic progressive nephropathy. Significant increases in mortality were observed in

male and female Sprague-Dawley rats administered wood creosote by gavage at 200 mg/kg/day for 40 or

80 weeks, respectively (Kuge et al. 2001). Mortality in groups of rats administered 20 or 50 mg/kg/day

did not exceed the mortality rate in the control group. Based on necropsy examinations, it was suggested

that mortality in the experimentally exposed animals may have been associated with aspiration of the test

material.

Mice appeared to be more susceptible to the lethal effects of beechwood creosote. The oral LD50 values

in gavaged ddY mice were 525 mg/kg for males and 433 mg/kg for females (Miyazato et al. 1981). The

highest dose at which no death occurred was 376 mg/kg (males) and 433 mg/kg (females). The mortality

in female mice was significantly higher than in male mice. Most animals died within 5 hours. However,

no treatment-related deaths were observed when mice were given doses of beechwood creosote in the

feed of up to 1,065 mg/kg/day (males) or 1,427 mg/kg/day (females) for 3 months (Miyazato et al. 1981). 

These results indicate that the acute oral toxicity of beechwood creosote is relatively low, and is

influenced by the method of administration. Some species and sex differences exist.

The LD50 values from each reliable study for each species and duration category are recorded in Table 3-3

and plotted in Figure 3-3.

Coal Tar Products. A 70-year-old man died following ingestion of an unspecified amount of "industrial"

creosote (presumably coal tar creosote) (Bowman et al. 1984). Death was attributed to multi-organ

failure and occurred 30 hours after admission to the hospital. It is not known if this man had a history of

prior coal tar creosote ingestion. Death has been reported to occur in adults and children 14–36 hours

after the ingestion of about 7 and 1–2 g coal tar creosote, respectively (Lewin 1929). Thus, ingestion of

creosote can be fatal to humans, but the dose level required to produce death cannot be accurately

estimated from these reports.

The acute oral LD50 for coal tar creosote is reported to be 1,700 mg/kg in male Wistar rats (Pfitzer et al.

1965). No deaths were reported in B6C3F1 mice after oral treatment with doses of manufactured gas
CREOSOTE 86

3. HEALTH EFFECTS

plant (MGP) residue, a form of coal tar, up to 462 mg/kg/day (males) or 344 mg/kg/day (females) for

94 or 185 days (Weyand et al. 1994). Cases of lethal poisoning resulting from ingestion of large amounts

of coal tar creosote have been reported in larger farm animals (Cribb 1968; Davis and Libke 1968; Giffee

1945; Graham et al. 1940; Harrison 1959; Luke 1954). Some of the reports are anecdotal and do not

include quantification of the amount of creosote ingested (Cribb 1968; Giffee 1945; Graham et al. 1940;

Luke 1954). Experimental feeding of powdered clay pigeon targets containing an unspecified amount of

coal tar pitch (15–30 g of powdered material daily for up to 15 days) caused death in 8 of 9 pigs (Davis

and Libke 1968). The acute fatal doses are 4 g/kg for sheep and over 4 g/kg for calves (Harrison 1959). 

Based on these data, coal tar creosote can be classified as mildly to moderately toxic in acute and

intermediate duration studies.

Mated female Sprague-Dawley CD rats (25–36 per group) were gavaged on gestational days 12–16 with

0, 90, 140, 180, 370, or 740 mg/kg/day coal tar (Hackett et al. 1984). Ten of the females receiving

740 mg/kg/day died within 4 days of the initial dose, but no deaths occurred at lower doses. In a feeding

study, 5-week-old female B6C3F1 mice were fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3,

0.6, and 1% coal tar samples from MGP waste sites for 2 years (Culp et al. 1998). Coal tar 1 was a

mixture of samples from seven waste sites and coal tar 2 was a mixture from two of the sites included in

coal tar 1 plus a third site with a very high benzo[a]pyrene content. This diet provided approximately 12,

33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%)

of coal tar 2. Dietary levels $0.3% (333 mg/kg/day coal tar 1 or 346 mg/kg/day coal tar 2) coal tar

produced a significant increase in early mortality compared with controls, while lower levels did not.

The LD50 and LOAEL values for death from each reliable study for each species and duration category

are recorded in Table 3-2 and plotted in Figure 3-2.

3.2.2.2 Systemic Effects

There is relatively little information available regarding the systemic effects of ingested wood creosote,

coal tar creosote, coal tar, or coal tar pitch. The database consists primarily of old anecdotal reports or

animal studies that would be considered inadequate by current standards. Some clinical reports describe

oral exposure of humans to wood creosote, but the amounts ingested are only estimates (Alderman et al.

1994; Clark and Reed 1992; Gordon et al. 1995). Three studies published by Miyazato et al. (1981,

1984a, 1984b) that evaluated the acute, intermediate, and chronic effects of beechwood creosote in rats

and mice and a chronic study in rats by Kuge et al. (2001) comprise the bulk of reliable information on
CREOSOTE 87

3. HEALTH EFFECTS

the systemic effects of ingested beechwood creosote. Based on the results of these studies, the liver,

kidney, and central nervous system appear to be target organs of creosote toxicity. Effects have also been

observed in the gastrointestinal, respiratory, and cardiovascular systems. No studies were located

regarding musculoskeletal, endocrine, ocular, or body weight effects in humans or musculoskeletal 

or dermal effects in animals after oral exposure to creosote. Studies regarding systemic effects that have

been observed in humans and animals after oral exposure to coal tar creosote or coal tar are discussed

below. Culp et al. (1996a, 1998), Goldstein et al. (1998), Hackett et al. (1984), Iyer et al. (1993), and

Weyand et al. (1994, 1995) comprise the bulk of the data for these compounds. The highest NOAEL

values and all LOAEL values from each reliable study for each systemic effect in each species and

duration category are recorded in Tables 3-2 and 3-3 and plotted in Figures 3-2 and 3-3.

Respiratory Effects. 

Creosote Bush. A report was found in the literature describing the medical condition of a 60-year-old

woman hospitalized after taking 1–2 capsules of chaparral (prepared by grinding leaves of an evergreen

desert shrub known as creosote bush or "greasewood;" active ingredient is nordihydroguaiaretic acid

[NDGA]) daily for 10 months (Gordon et al. 1995). The patient developed "flulike syndrome" and

increased her chaparral intake to six capsules/day 3 weeks before admission. She developed aspiration

pneumonia requiring antibiotic therapy and endotracheal intubation.

Wood Creosote. Beechwood creosote has been and continues to be used therapeutically on a limited

basis in Asia as an expectorant/cough suppressant based on its presumed ability to increase the flow of

respiratory fluids. The efficacy of creosote (type not specified, but presumably beechwood creosote) as

an expectorant was studied by measuring the output of respiratory tract fluids in cats given a single oral

dose of 0.1 or 5 mL/kg (concentration not specified) (Stevens et al. 1943). Creosote produced a slight

increase in the output of respiratory tract fluid under these conditions. This is not considered a toxic

effect. Given the limitations of this study (e.g., no dose information, no other respiratory effects

evaluated), it provides no useful information on the potential respiratory effects of beechwood creosote

after oral exposure.

No adverse effect on lung weight was noted for Wistar rats given up to 812 mg/kg/day (males) or

768 mg/kg/day (females) beechwood creosote or ddY mice given up to 1,065 mg/kg/day (males) or

1,427 mg/kg/day (females) beechwood creosote in the feed for 3 months (Miyazato et al. 1981). In a

chronic study, rales were observed in Sprague-Dawley rats administered wood creosote by gavage at
CREOSOTE 88

3. HEALTH EFFECTS

200 mg/kg/day (Kuge et al. 2001). These signs were not seen in rats administered wood creosote at 20 or

50 mg/kg/day. After 95 weeks, reddened lungs were evident in all groups of rats in this study, including

the control group, but were more prevalent in rats administered the high dose of wood creosote. The

cause of this lung reddening was not determined, but the authors suggested that it may have been

associated with aspiration of the test material. There were no increases in lung weight in any of the

experimental groups.

A slightly higher incidence of bronchitis or thickening of the tracheal mucous membrane was observed in

ddY mice that ingested feed containing 0.3% (equivalent to 247 mg/kg/day for males and 297 mg/kg/day

for females) and 0.6% (equivalent to 474 mg/kg/day for males and 532 mg/kg/day for females)

beechwood creosote for 52 weeks (Miyazato et al. 1984a). However, the authors attributed this to

irritation from long-term inhalation exposure to volatile components of beechwood creosote in the feed,

and not to a direct toxic effect on the respiratory tissue from oral exposure.

Coal Tar Products. No adverse effect on lung weight was observed in female ICR mice treated by

gavage with 400 mg/kg petroleum creosote in dimethyl sulfoxide (DMSO) on gestational days 5–9 (Iyer

et al. 1993). Five groups of B6C3F1 mice (24 males, 24 females) were fed a control gel diet or

adulterated diets containing 0.05, 0.25, or 0.50% MGP residue, a type of coal tar formed as a by-product

of coal gasification (Weyand et al. 1994). Consumption was equivalent to 0, 51, 251, or 462 mg/kg/day

for males and 0, 42, 196, or 344 mg/kg/day for females. Half of the animals in each group were sacrificed

after 94 days of treatment and all organs examined for gross lesions. The remaining animals from each

group were maintained on diets for an additional 91 days. After a total of 185 days of treatment, the

remaining animals were sacrificed and all organs examined for gross and microscopic lesions. There was

no adverse effect of treatment on the lung. In another feeding study 5-week-old female B6C3F1 mice

were fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar samples from

manufactured gas plant waste sites for 2 years (Culp et al. 1998). This diet provided approximately 12,

33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%)

of coal tar 2. The dietary level of 0.3% coal tar produced a significant decrease in lung weight compared

to controls, but lower dietary levels did not (Culp et al. 1998).

Two pigs that died after ingesting an unknown amount of coal tar pitch exhibited pneumonia (Luke

1954). Heavy respiration was observed in a Hereford bull that had accidentally ingested creosote from an

open drum; the actual amount ingested could not be estimated (Cribb 1968).
CREOSOTE 89

3. HEALTH EFFECTS

Cardiovascular Effects. The case of a 52-year-old woman who had been taking creosote (type and

dose not specified) for 9 years to treat chronic bronchitis was reported by Robinson (1938). The woman

was found to be weak, dizzy, light-headed, and hypertensive (blood pressure=206/140 mm Hg). A

modified diet and diuretic therapy relieved all of these symptoms. Upon reinstitution of creosote therapy,

her blood pressure rose to 235/130. The author concluded that creosote was responsible for the woman's

hypertension. This study provides anecdotal evidence of creosote-induced cardiovascular effects, but the

limited sample size, lack of detail on exposure, and possibility of confounding factors limit its usefulness.

Wood Creosote. No adverse effect on heart weight was noted for rats given up to 812 mg/kg/day (males)

or 768 mg/kg/day (females) beechwood creosote or mice given up to 1,065 mg/kg/day (males) or

1,427 mg/kg/day (females) beechwood creosote in the feed for 3 months (Miyazato et al. 1981), or female

rats given up to 394 mg/kg/day and male rats given 143 mg/kg/day beechwood creosote for 96 weeks

(Miyazato et al. 1984b) or male or female Sprague-Dawley rats administered 20 or 50 mg/kg/day of wood

creosote by gavage for 102 weeks (Kuge et al. 2001). However, male, but not female, rats administered

200 mg/kg/day for 95 weeks showed a significant reduction in heart weight. Male rats given

313 mg/kg/day beechwood creosote for 96 weeks exhibited an increase in heart weight (Miyazato et al.

1984b).

Coal Tar Products. In a feed study of MGP coal tar by Weyand et al. (1994) using B6C3F1 mice, there

was no adverse effect of treatment on the aorta after 94 or 185 days exposure to 0, 51, 251, or

462 mg/kg/day (males) and 0, 42, 196, or 344 mg/kg/day (females). One pig that died after ingesting an

unknown amount of coal tar pitch exhibited pericarditis (Luke 1954).

Gastrointestinal Effects. 

Wood Creosote. The antidiarrheal effect of beechwood creosote was studied in rats (Ogata et al. 1993,

1999). Female Wistar rats were dosed orally with creosote in concentrations of 0, 7, 13, 27, 53, 107, 213,

and 427 mg/kg mixed with 7.7 mg/kg of saline (Ogata et al. 1993). After 1 hour, 5.6 mg/kg castor oil was

administered through the stomach cannula to all groups of rats to induce diarrhea. Feces excreted were

then observed at 1 hour intervals during the next 7 hours. To assay antimotility effects, female Wistar

rats were given creosote at the same concentrations as above. After 1 hour, 0.2 mL of a charcoal meal

(12% wet weight [w/w] charcoal powder and 2% [w/w] gum arabic in water) was administered through

the stomach cannula and the rats sacrificed 20 minutes later; the small intestine was examined to

determine how far the charcoal meal had traveled from the stomach. Creosote administered 1 hour before
CREOSOTE 90

3. HEALTH EFFECTS

the castor oil treatment prevented diarrhea with an ED50 of 53 mg/kg. The gastrointestinal transit time of

the charcoal meal given to rats was significantly suppressed by 106 and 213 mg/kg (but not by 53 mg/kg)

creosote, which showed creosote inhibited peristaltic propulsive movement of the intestine. 

In a second study by Ogata et al. (1999), the effect of orally administered wood creosote on propulsive

motility of the intestine and the colon were tested in male CD-1 mice using a charcoal meal test and a

colonic bead expulsion test. The effect of treatment with wood creosote was compared with untreated

mice or mice treated with loperamide (a known antidiarrheal agent). Postdose plasma samples were

removed from mice 30 minutes after dosing and tested for the ability to suppress colonic propulsive

movement. Wood creosote showed only a slight inhibitory effect on the propulsive motility of the small

intestine at administered doses of 0.08 and 0.4 mg/kg, but not at an ordinary human therapeutic dose level

(2–10 mg/kg). In the colonic bead expulsion test orally administered wood creosote significantly

(p<0.05) increased bead expulsion time at doses of 0.08, 0.4, and 2 mg/kg; it was most marked at the dose

of 2 mg/kg. The reduction in colonic propulsive motility produced by wood creosote occurred within

15 minutes of dosing. Postdose plasma samples from creosote treated mice produced a significant

reduction in colonic propulsive motility when injected into untreated mice. This suggests that the effect is

mediated by wood creosote (or its metabolites) in the blood rather than wood creosote from the lumen of

the colon as the time period would not be sufficient for creosote to have reached the colon. 

Coal Tar Products. Ulceration of the oropharynx and petechial hemorrhages over the gastrointestinal

serosal surfaces were noted at autopsy of a 70-year-old man who died following ingestion of an

unspecified amount of industrial (presumably coal tar) creosote (Bowman et al. 1984). However, the

esophagus and stomach were intact. The authors attributed these effects to acute tissue damage resulting

from phenol-induced corrosive effects, since phenol is a component of coal tar creosote.

Wistar rats that died following the administration of single gavage doses of coal tar creosote in an acute

range-finding study (doses ranged from 613 to 5,000 mg/kg) exhibited hyperemia and distention of the

stomach upon necropsy (Pfitzer et al. 1965). No adverse gastrointestinal effects were noted in male

Fischer 344 rats treated with 50 mg/kg/day creosote by gavage for 1–5 weeks, including no change in the

weight of the small intestines, large intestines, or caecum (Chadwick et al. 1995). In a feed study of MGP

coal tar by Weyand et al. (1994) using B6C3F1 mice, there was no adverse effect of treatment on the

glandular stomach or forestomach after 94 or 185 days exposure to 0, 51, 251, or 462 mg/kg/day (males)

and 0, 42, 196, or 344 mg/kg/day (females). In another feeding study, 5-week-old female B6C3F1 mice

were fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar samples from
CREOSOTE 91

3. HEALTH EFFECTS

manufactured gas plant waste sites for 2 years (Culp et al. 1998). This diet provided approximately 12,

33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%)

of coal tar 2. No effect on the weight or histology of the stomach or small intestine was observed at any

dose (Culp et al. 1998). Pigs that died after ingesting an unknown amount of coal tar pitch exhibited

blood-stained fluid in the abdominal cavity (Luke 1954).

Hematological Effects. 

Creosote Bush. A report was found in the literature describing a 45-year-old woman who developed

painless jaundice, fatigue, anorexia, and pruritus after taking chaparral tablets, 160 mg/day for around

2 months (Alderman et al. 1994). Complete blood count, platelet count, and clotting times were normal. 

A 60-year-old woman was hospitalized with a 1-week history of upper quadrant abdominal pain,

anorexia, and jaundice (Gordon et al. 1995). The patient had been taking 1–2 capsules of chaparral daily

for the past 10 months. The patient developed "flulike syndrome" and increased her chaparral intake to

6 capsules a day 3 weeks before admission. The patient's prothrombin time increased from 15.9 to

28 seconds (normal values 10.9–13.7 seconds).

Wood Creosote. Various hematological parameters (red blood cell, white blood cell, lymphocyte, and

neutrophil counts, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin,

mean corpuscular hemoglobin concentration, and hematocrit) were measured by Miyazato et al. (1981,

1984a, 1984b) in Wistar rats and ddY mice fed beechwood creosote in the daily diet for 3 months,

52 weeks (mice), or 96 weeks (rats). No significant treatment-related changes were noted in mice of

either sex fed doses of up to 1,065 mg/kg/day (male) or 1,427 mg/kg/day (female) for 3 months

(Miyazato et al. 1981). These doses are considerably higher than the oral LD50 values reported for mice

by the same authors. One possible explanation for this discrepancy is that the LD50 values were

determined by bolus gavage and in the intermediate study, the beechwood creosote was administered in

the feed. A slight reduction in red blood cells (RBCs) was noted in male and female rats following

dietary exposure to doses of 210 (male) or 163 (female) mg/kg/day for 3 months, but this reduction was

not observed in mice exposed to higher doses (812 [male] or 768 [female] mg/kg/day), and was therefore

not considered to be toxicologically significant (Miyazato et al. 1981). Chronic (52 weeks) dietary

exposure of mice to up to 474 mg/kg/day (males) or 532 mg/kg/day (females) beechwood creosote

resulted in statistically significant dose-related differences in mean cell volume, mean corpuscular

hemoglobin, and absolute lymphocyte and neutrophil counts when compared to the corresponding control

values. These changes were not considered by the authors to be toxicologically significant; they claimed
CREOSOTE 92

3. HEALTH EFFECTS

that the values were within normal physiological ranges (Miyazato et al. 1984a). An unspecified set of

hematologic parameters were not affected in Sprague-Dawley rats administered wood creosote at 20, 50,

or 200 mg/kg/day for up to 102 weeks (Kuge et al. 2001).

Coal Tar Products. In a feed study of MGP coal tar by Weyand et al. (1994) using B6C3F1 mice, there

was no adverse effect of treatment on the bone marrow after 94 or 185 days exposure to 0, 51, 251, or

462 mg/kg/day (males) and 0, 42, 196, or 344 mg/kg/day (females). 

Hepatic Effects. 

Creosote Bush. Acute toxic hepatitis has been attributed to ingestion of chaparral, an herbal nutritional

supplement product derived from the leaves of the creosote bush (Clark and Reed 1992). A 42-year-old

man had icterus and jaundice after consuming three 500 mg capsules of chaparral a day for 6 weeks. 

Serum chemistry tests showed elevated bilirubin, gamma glutamyltranspeptidase (GGT), AST, and lactate

dehydrogenase. His illness was diagnosed as hepatic dysfunction secondary to chaparral ingestion. 

Three weeks after discontinuing the chaparral ingestion, his serum chemistry was normal, and he had no

other symptoms. The same article noted the case of a 41-year-old woman who had abdominal pain and

jaundice after consuming 150 tablets of chaparral over an 11-week period. Serum chemistry tests

revealed elevated bilirubin, AST, alanine aminotransferase (ALT), GGT, and lactate dehydrogenase. Six

weeks after discontinuation of chaparral ingestion, serum chemistry tests were normal, and there were no

other symptoms reported.

A 45-year-old woman developed painless jaundice, fatigue, anorexia, and pruritus after taking chaparral,

160 mg/day, for about 2 months (Alderman et al. 1994). Physical examination confirmed jaundice and a

14-cm liver with a smooth, nontender border. Serum enzyme levels were elevated; serum ALT was

1,611 IU (normal 0–65 IU); AST was 957 IU (normal 0–50 IU); alkaline phosphatase was 265 IU (normal

35–130 IU); GGT was 993 IU (normal 0–65 IU), and total bilirubin was 11.6 mg/dL (normal

<1.4 mg/dL). Tests for anti-hepatitis A IgG and IgM, hepatitis B surface antigen, antibody against

hepatitis B surface antigen and hepatitis B core antigen, and acute antibody against hepatitis virus were all

negative. Ultrasonography showed no abnormality. Endoscopic retrograde cholangiopancreatigraphy

(ERCP) showed sparse, smooth, but severely narrowed biliary ducts without sclerosing cholangitis, distal

obstruction, tumor, or stenosis. Specimens from percutaneous liver biopsy showed prominent acute

inflammation with neutrophil and lymphoplasmocytic infiltration, diffuse hepatocyte disarray and

necrosis, focal acute pericholangitis, some ductal dilatation, and proliferation of bile ductules in portal-
CREOSOTE 93

3. HEALTH EFFECTS

periportal regions. The patient was started on Prednisone at 60 mg/day, tapered to 10 mg/day and

discontinued in 7 weeks; the patient remained well with normal laboratory findings. The patient was

diagnosed with chaparral-induced toxic hepatitis after reports of two cases of chaparral hepatotoxicity

were published. In another report, a 60-year-old woman was hospitalized with a 1-week history of upper

quadrant abdominal pain, anorexia, and jaundice (Gordon et al. 1995). The patient had been taking

1–2 capsules of chaparral daily for the past 10 months. The patient developed "flulike syndrome" and

increased her chaparral intake to 6 capsules a day 3 weeks before admission. Jaundice occurred 2 weeks

later. On admission, she was confused and deeply jaundiced. Her total serum bilirubin increased from

212 mmol/L (12.4 mg/dL) to 607 mmol/L (35.5 mg/dL) (normal values 2–20 mmol/L [0.1–1.2 mg/dL]). 

The patient's liver failure was considered to be chaparral-induced toxic hepatitis. Viral hepatitis was ruled

out because antibodies to hepatitis A virus IgM, antibody to hepatitis B core antigen, and hepatitis C virus

were undetectable. An exploratory laparotomy performed 1 week after admission showed ascites and a

nodular liver. Liver biopsy showed severe acute hepatitis with areas of lobular collapse and nodular

regeneration, mixed portal inflammation and marked bile ductular proliferation. Her total serum bilirubin

increased to 607 mmol/L. The patient underwent orthotopic liver transplantation. The patient slowly

recovered and was discharged.

Serum liver enzymes, blood urea nitrogen, creatinine levels, glucose levels, electrolytes, bilirubin levels,

iron levels, ferritin levels, lipid levels, and complete blood count of four patients prescribed an extract of

creosote bush in 90% ethanol were within the normal range and were unchanged by exposure to the

extract of creosote bush (Heron and Yarnell 2001). The authors also reported that an additional eight

patients who had been prescribed an extract of creosote bush had no noticeable adverse effects, but no

information as to blood chemistry was available for these patients.

Wood Creosote. Liver-to-body-weight ratios tended to increase in male Wistar rats exposed to doses of

beechwood creosote >168 mg/kg/day in the diet for 3 months or in females exposed to $215 mg/kg/day

(but not 163 mg/kg/day) (Miyazato et al. 1981). A similar increase in relative liver weight was observed

for rats exposed to $143 (male) or 179 (female) mg/kg/day beechwood creosote for 96 weeks (Miyazato

et al. 1984b). Increased relative liver weights were observed in female ddY mice fed beechwood creosote

at doses $314 mg/kg/day (but not 164 mg/kg/day) and in male mice fed 1,065 mg/kg/day (but not

768 mg/kg/day) for 3 months and in female mice fed $297 mg/kg/day, but not in male mice fed up to

474 mg/kg/day for 52 weeks (Miyazato et al. 1981). Although this response is considered to be of

minimal pathologic significance, it may be an early indication of adverse changes since the liver is a

known target organ. No treatment-related histopathological alterations were observed. Liver weights
CREOSOTE 94

3. HEALTH EFFECTS

were unaffected in Sprague-Dawley rats administered wood creosote at 20 or 50 mg/kg/day for

102 weeks or 200 mg/kg/day for 95 weeks (Kuge et al. 2001).

A significant increase in serum glutamic-oxaloacetic transferase (GOT, currently known as AST) and

glutamic-pyruvic transferase (GPT, currently known as ALT) levels was also observed in the chronically

exposed female mice, but these levels were still within normal physiological range (Miyazato et al. 1981). 

A slight increase in serum cholesterol was noted in male and female rats following dietary exposure to

210 (male) or 578 (female) mg/kg/day beechwood creosote for 3 months (Miyazato et al. 1981). The

significance of the serum cholesterol changes is not known. Increases in serum cholesterol were also

noted in rats exposed to beechwood creosote in the diet for 96 weeks at doses of 143 (male) and

179 (female) mg/kg/day and above (Miyazato et al. 1984b). There was no effect of treatment on liver

weight or serum cholesterol in mice exposed to up to 1,065 mg/kg/day (males) or 1,427 mg/kg/day

(females) in the diet for 3 months or for mice exposed to up to 474 mg/kg/day (males) or 532 mg/kg/day

(females) beechwood creosote in the diet for 52 weeks (Miyazato et al. 1984a). Taken together, these

early changes indicate that if increased doses of beechwood creosote are used, more clear cut hepatotoxic

effects would be expected to occur.

Coal Tar Products. Degeneration and necrosis of hepatocytes were observed at autopsy in the case of a

70-year-old man who ingested industrial (coal tar) creosote (Bowman et al. 1984). The actual amount

ingested was not specified. Given the lack of comparison data for the condition of the liver in healthy

individuals of that age it is not possible to definitively attribute these effects to coal tar creosote ingestion.

No adverse effect on liver weight was observed in female ICR mice treated by gavage with 400 mg/kg

petroleum creosote in DMSO on gestational days 5–9 (Iyer et al. 1993). In a feed study of MGP coal tar

by Weyand et al. (1994), B6C3F1 mice were exposed to 0, 51, 251, or 462 mg/kg/day (males) and 0, 42,

196, or 344 mg/kg/day (females) in the feed for 94 or 185 days. Plasma clinical chemistry parameters

determined were as follows: glucose, creatine, blood urea nitrogen, total protein, ALT, ALT, and alkaline

phosphatase activity. Tissues obtained from the animals were examined for microscopic lesions. There

was no adverse effect of treatment on liver histopathology or serum enzymes. 

Anecdotal reports of mortality in pigs after ingestion of clay pigeons containing coal tar pitch from

pastures formerly used for target shooting were found in the literature (Giffee 1945; Graham et al. 1940). 

Lack of appetite, sluggishness, rough coat, and weakness, followed by death were reported. Autopsy

revealed degenerative hepatic changes. Experimental feeding of powdered clay pigeon targets containing
CREOSOTE 95

3. HEALTH EFFECTS

an unspecified amount of coal tar pitch (15–30 g powdered material daily for up to 15 days) caused death

in eight of nine pigs (Davis and Libke 1968). Twenty-four to 48 hours prior to death, a decrease in

hemoglobin, packed blood cell volume, and blood sugar concentration was noted. Autopsy revealed

centrilobular hepatic necrosis and hemorrhage of the liver. Four pigs that ingested an unknown amount of

coal tar pitch exhibited, at necropsy, marked enlargement of the liver (Luke 1954). The hepatic surface

was pitted, the lobules very prominent and the whole organ extremely friable. Fibrinous strands were

found on the liver, the cut surface of which presented a mottled mosaic-like pattern. Three pigs were fed

a small quantity of pitch ground up in their feed (Luke 1954). These three pigs received 2 pounds

(approximately 0.38 ounces/day) of pitch over a period of 28 days. At the end of the 28th day, the pigs

were sacrificed and examined. The addition of pitch did not interfere with their appetite and no marked

symptoms were observed. Enlargement of the liver was seen together with a varying degree of liver

damage. The liver lesions were extensive and there was a marked excess of peritoneal fluid. Histological

examination of the affected liver tissue showed marked central necrosis of the lobules, which, in some

cases, had completely destroyed the normal liver cells. These liver changes had a somewhat patchy

distribution with badly affected and normal lobules often occurring side by side. The factors in the pitch

responsible for the lesions were not identified.

No change in liver weight was observed in female rats gavaged on gestational days 12–16 with up to

370 mg/kg/day coal tar (Hackett et al. 1984). In a feeding study, 5-week-old female B6C3F1 mice were

fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar samples from

manufactured gas plant waste sites for 2 years (Culp et al. 1998). This diet provided approximately 12,

33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%)

of coal tar 2. The dietary level of 0.3% coal tar produced a significant increase in liver weight (40%)

compared with controls, exposure to lower doses had no effect on the liver (Culp et al. 1998).

Renal Effects. 

Creosote Bush. No adverse renal effects were noted in a 45-year-old woman who took 160 mg/kg/day

chaparral for approximately 2 months (Alderman et al. 1994). A 60-year-old woman was hospitalized

with a 1-week history of upper quadrant abdominal pain, anorexia, and jaundice (Gordon et al. 1995). 

The patient had been taking 1–2 capsules of chaparral daily for the past 10 months. The patient increased

her chaparral intake to six capsules/day 3 weeks before admission. Renal failure ensued, which required

hemodialysis. The patient underwent cadaveric renal transplantation. The patient slowly recovered and

was discharged.
CREOSOTE 96

3. HEALTH EFFECTS

Wood Creosote. Kidney-to-body-weight ratios were significantly increased in Wistar rats exposed to

$210 (male) or $163 (female) mg/kg/day or more beechwood creosote in the diet for 3 months or to

$143 (males) or $179 (females) mg/kg/day or more for 96 weeks (Miyazato et al. 1981, 1984b), although

the trend was not strictly dose-related. No effect on the relative weight of the kidney was observed in

mice exposed to up to 1,065 mg/kg/day (males) or 1,427 mg/kg/day (females) for 3 months, mice exposed

to 474 mg/kg/day (males) or 532 mg/kg/day (females) for 52 weeks, or male rats exposed to

168 mg/kg/day for 3 months (Miyazato et al. 1981). This response is of minimal pathologic significance

in the intermediately treated rats of both sexes and the chronically treated female rats since no treatmentrelated changes were noted at histopathological evaluation. Blood urea nitrogen and serum inorganic

phosphorus were elevated in the chronically treated male rats, which is indicative of uremia. Chronic

progressive nephropathy, which occurs spontaneously in old male rats, was also observed at a higher

incidence in the chronically treated male rats than in the control male rats, and probably accounts for the

biochemical changes observed. The authors concluded that long-term exposure to beechwood creosote at

the high dose (1.2% in feed or 534 mg/kg/day) accelerated the occurrence of chronic progressive

nephropathy in male rats (Miyazato et al. 1984b). These results suggest that beechwood creosote has the

potential to induce adverse effects in the kidney. Kidney weights were unaffected in Sprague-Dawley

rats administered wood creosote at 20 or 50 mg/kg/day for 102 weeks or 200 mg/kg/day for 95 weeks

(Kuge et al. 2001).

Coal Tar Products. A 70-year-old man who ingested a fatal dose of industrial (coal tar) creosote became

acidotic and anuric before he died, indicating probable kidney failure (Bowman et al. 1984). The actual

amount ingested was not specified. Acute renal tubular necrosis was revealed at necropsy. However, the

acute tubular necrosis may have been due to vascular insufficiency rather than a direct toxic effect on the

kidney. 

No adverse effect on kidney weight was observed in female ICR mice treated by gavage with 400 mg/kg

petroleum creosote in DMSO on gestational days 5–9 (Iyer et al. 1993). No change in kidney weight was

observed in female CD rats gavaged on gestational days 12–16 with up to 370 mg/kg/day coal tar

(Hackett et al. 1984). In a feed study of MGP coal tar by Weyand et al. (1994) using B6C3F1 mice, there

was no adverse effect of treatment on the kidney or bladder after 94 or 185 days exposure to 0, 51, 251, or

462 mg/kg/day (males) and 0, 42, 196, or 344 mg/kg/day (females). In another feeding study 5-week-old

female B6C3F1 mice were fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal

tar samples from manufactured gas plant waste sites for 2 years (Culp et al. 1998). This diet provided

approximately 12, 33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day
CREOSOTE 97

3. HEALTH EFFECTS

(0.03, 0.1, and 0.3%) of coal tar 2. The dietary level of 0.1% coal tar produced a significant decrease in

kidney weight compared with controls, but lower dietary levels did not (Culp et al. 1998).

Postmortem examination on 4 pigs that had ingested an unknown amount of pitch, showed cystic kidneys

(Luke 1954).

Endocrine Effects. 

Wood Creosote. No adverse effect on adrenal weight was noted for Wistar rats given up to 812 (males)

or 768 mg/kg/day (females) beechwood creosote or ddY mice given up to 1,065 (males) or

1,427 mg/kg/day (females) beechwood creosote in the feed for 3 months (Miyazato et al. 1981). Male

rats given 313 mg/kg/day beechwood creosote for 96 weeks exhibited an increase in relative adrenal

weight, but males receiving 143 mg/kg/day and females receiving up to 394 mg/kg/day did not (Miyazato

et al. 1984b). Significant reductions in thyroid-parathyroid weight were observed in female SpragueDawley rats administered wood creosote by gavage at 200 mg/kg/day for 95 weeks, but not in female rats

administered 20 or 50 mg/kg/day for 102 weeks (Kuge et al. 2001). There were no dose-related changes

in adrenal or pituitary weights in male or female rats in any dose group.

Coal Tar Products. Adrenal weights were significantly increased in pregnant rats gavaged with

$90 mg/kg/day coal tar on gestational days 12–16 (Hackett et al. 1984). No adverse effect on adrenal

weight was observed in female ICR mice treated by gavage with 400 mg/kg petroleum creosote in DMSO

on gestational days 5–9 (Iyer et al. 1993). Weyand et al. (1994) conducted a feed study of MGP coal tar

using B6C3F1 mice. There was no adverse effect of treatment on the salivary glands, pancreas, thymus,

parathyroid, or adrenal glands after 94 or 185 days exposure to 0, 51, 251, or 462 mg/kg/day for males

and 0, 42, 196, or 344 mg/kg/day for females.

Dermal Effects. 

Creosote Bush. A 45-year-old woman developed pruritus, probably secondary to chaparral-induced toxic

hepatitis, after taking 160 mg/kg/day chaparral for around 2 months (Alderman et al. 1994).
CREOSOTE 98

3. HEALTH EFFECTS

Body Weight Effects. 

Wood Creosote. Body weight gain was decreased 11–22% in Wistar rats given 768 (males) or

812 (females) mg/kg/day beechwood creosote, and 11–16% in ddY mice given 768 (males) or

1,427 (females) mg/kg/day beechwood creosote in the feed for 3 months (Miyazato et al. 1981). No

effect on body weight was observed in rats or mice exposed to lower doses (534 mg/kg/day, male rat;

578 mg/kg/day, female rat; 450 mg/kg/day, male mouse; 1,127 mg/kg/day, female mouse) of beechwood

creosote for 3 months. No effect on body weight was observed in rats or mice exposed to up to

313 (males) or 394 (females) mg/kg/day for 96 weeks, or to 474 (males) or 532 (females) mg/kg/day for

52 weeks (Miyazato et al. 1984a, 1984b). Significant body weight reductions were observed in male (7%

weight reduction) and female (15% weight reduction) Sprague-Dawley rats administered wood creosote

by gavage at 200 mg/kg/day for 95 weeks (Kuge et al. 2001). Terminal body weights were unaffected in

rats administered 20 or 50 mg wood creosote/kg/day for 102 weeks.

Coal Tar Products. No adverse effect on body weight was noted in male Fischer 344 rats treated with

50 mg/kg/day coal tar creosote by gavage for 3–5 weeks (Chadwick et al. 1995). However, body weight

was significantly decreased in female CD rats gavaged on gestational days 12–16 with 180 mg/kg/day

(but not 140 mg/kg/day) coal tar (Hackett et al. 1984). A 16% decrease in body weight gain was also

observed in female ICR mice after gavage treatment with 400 mg/kg petroleum creosote in DMSO on

gestational days 5–9; however, a similar reduction in weight gain was seen in the group treated with

DMSO only (Iyer et al. 1993). In another study, male B6C3F1 mice were given 0, 197, 410, 693, 1,067,

and 1,750 mg/kg/day coal tar in feed for 28 days (Culp and Beland 1994). Food consumption and change

in body weights were monitored for the coal-tar-fed animals. Dose-related decreases in body weight were

observed in all dose groups. Animals treated with 693 and 1,067 mg/kg/day coal tar showed average

body weights significantly decreased by approximately 16% from controls. Body weights for other

treated groups were not significantly different from those of controls. 

The relationship between ingestion of MGP residue and systemic availability of coal tar components in

male mice was evaluated by measuring whole animal body weight, DNA adduct formation binding in

several soft tissues, and urinary excretion of PAH metabolites (Weyand et al. 1991). Coal tar samples

collected from four different coal gasification sites were incorporated separately at varying concentrations

into the diet and fed to the mice for 15 days. Animal body weight was not affected in groups fed up to

0.2% (659 mg/kg/day) coal tar, but body weight was significantly reduced in animals fed diets containing

0.5% (1,871 mg/kg/day) coal tar because the animals refused to eat the higher concentration of coal tar.
CREOSOTE 99

3. HEALTH EFFECTS

Five groups of B6C3F1 mice (24 males, 24 females) were fed a control gel diet or adulterated diets

containing 0.05, 0.25, or 0.50% MGP (Weyand et al. 1994). Consumption was equivalent to 0, 51, 251,

or 462 mg/kg/day for males and 0, 42, 196, or 344 mg/kg/day for females. Half the animals in each group

were sacrificed after 94 days of treatment and all organs examined for gross lesions. The remaining

animals from each group were maintained on diets for an additional 91 days. After a total of 185 days of

treatment, the remaining animals were sacrificed and all organs examined for gross and microscopic

lesions. Differences in weight gain did not show any clear dose response. Control and treated males

ingesting 51 mg/kg/day feed had the highest weight gain. Body weight gains in the 251 and

462 mg/kg/day groups were considerably lower (statistical analysis not performed). Females exposed to

42 mg/kg/day diets had the highest body weight gains, while females on the 196 mg/kg/day diets had the

lowest. In a similar study Weyand et al. (1995) fed female A/J mice with a control diet or a diet

containing 0.1 or 0.25% coal tar samples from manufactured gas plant waste sites for 260 days. This diet

provided approximately 100 or 236 mg/kg/day coal tar. Consumption of coal tar did not significantly

alter body weight gain since mice fed the control and 0.25% coal tar diets had equally low body weight

gain compared to mice fed the 0.1% coal tar diet.

Culp et al. (1996a) fed diets containing 0, 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar to female B6C3F1 mice

for 2 years and noted a decrease in body weight (data not shown) at the two highest doses (1,364 and

2,000 mg/kg/day) compared with controls. No decrease was noted for animals exposed to #0.3%

(628 mg/kg/day) compared with controls. In another feeding study, 5-week-old female B6C3F1 mice

were fed a control gel diet or diets containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar samples from

manufactured gas plant waste sites for 2 years (Culp et al. 1998). This diet provided approximately 12,

33, 117, 333, 739, or 1,300 mg/kg/day of coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%)

of coal tar 2. The dietary level of 0.3% coal tar (333 mg/kg/day coal tar 1 or 346 mg/kg/day coal tar 2)

produced a significant decrease in body weight gain (20%) compared with controls, but lower dietary

levels did not (Culp et al. 1998).

Other Systemic Effects. 

Wood Creosote. Dose-related clinical signs consisting of salivation, decreased activity, signs of apparent

abdominal discomfort, and significant reductions in food consumption and food efficiency (food

consumption divided by body weight gain) were observed in Sprague-Dawley rats administered 200 mg

wood creosote/kg/day by gavage for 95 weeks, but not in rats administered 20 or 50 mg/kg/day for

102 weeks (Kuge et al. 2001).
CREOSOTE 100

3. HEALTH EFFECTS

Coal Tar Products. Consumption of food containing MGP residue was evaluated in male B6C3F1 mice

by measuring whole animal body weight and food consumption (Weyand et al. 1991). Coal tar samples

collected from four different coal gasification sites were incorporated separately at varying concentrations

into the diet and fed to the mice for 15 days. Food consumption was not affected in groups fed up to

0.2% (659 mg/kg/day) coal tar. However, animals fed diets containing 0.5% (1,871 mg/kg/day) or 1.0%

(3,125 mg/kg/day) coal tar refused to eat for 2 or 4 days, respectively, while animals fed 2% or more coal

tar continued to refuse to eat for the duration of the experiment. In another feeding experiment, male

B6C3F1 mice were given 0, 197, 410, 693, 1,067, and 1,750 mg/kg/day coal tar in feed for 28 days (Culp

and Beland 1994). Dose-related decreases in food consumption were observed in all treated groups. 

Animals treated with 693 and 1,067 mg/kg/day coal tar showed significantly decreased food consumption

compared to controls over a period of 28 days, animals receiving lower doses did not. Similar reductions

in food consumption were seen in another study of female B6C3F1 mice fed a control gel diet or diets

containing 0.01, 0.03, 0.1, 0.3, 0.6, and 1% coal tar samples from manufactured gas plant waste sites for

2 years (Culp et al. 1998). This diet provided approximately 12, 33, 117, 333, 739, or 1,300 mg/kg/day of

coal tar 1 and 40, 120, or 346 mg/kg/day (0.03, 0.1, and 0.3%) of coal tar 2. Mice fed coal tar 1 ate

significantly less food than controls. The reduction in food consumption was approximately 30% for

mice fed 1% coal tar 1 and 25% for mice fed 0.6% coal tar 1. Mice fed 0.3% coal tar 2 also ate

significantly less food than controls and had approximately a 20% reduction in food consumption. 
CREOSOTE 101

3. HEALTH EFFECTS

3.2.2.3 Immunological and Lymphoreticular Effects

No studies were located regarding immunologic/lymphoreticular effects in humans after oral exposure to

wood creosote, coal tar creosote, coal tar, or coal tar pitch.

Wood Creosote. In rats, the spleen may be affected by beechwood creosote exposure, although the data

are not conclusive (Miyazato et al. 1981). In particular, exposure to beechwood creosote at

805 mg/kg/day in the diet for 3 months resulted in increased relative spleen weight of male Wistar rats. 

Spleen weights of male rats exposed to lower levels of beechwood creosote in the diet and female rats at

doses up to 768 mg/kg/day indicated no consistent trend of either increase or decrease (Miyazato et al.

1981). In companion experiments using ddY mice, no effect on relative spleen weight was seen at doses

up to 1,810 (male) or 1,570 (female) mg/kg/day, in the feed (Miyazato et al. 1981). No effect on spleen

weight was observed in rats exposed to doses up to 394 mg/kg/day for 96 weeks, or mice exposed to

doses of 532 mg/kg/day for 52 weeks (Miyazato et al. 1984a, 1984b). Spleen weight was unaffected in

male and female Sprague-Dawley rats administered 20 or 50 mg wood creosote/kg/day by gavage for

102 weeks. Spleen weight in female rats administered 200 mg/kg/day for 95 weeks was similarly

unaffected, but male rats at the latter dose and duration showed a significant reduction in spleen weight

(Kuge et al. 2001).

All reliable NOAEL and LOAEL values for immunological and lymphoreticular effects for each species

and duration category are recorded in Table 3-3 and plotted in Figure 3-3.

Coal Tar Products. Coal tar may affect the spleen and thymus in rats, but not in mice. A significant

decrease in thymus weight and endocrine weight was observed in female CD rats gavaged on gestational

days 12–16 with 90 mg/kg/day coal tar (Hackett et al. 1984). B6C3F1 mice fed a control gel diet or diets

containing 0, 51, 251, or 462 mg/kg/day MGP coal tar (males) and 0, 42, 196, or 344 mg/kg/day

(females) MGP coal tar, exhibited no adverse gross or histopathological effects for the spleen, thymus, or

bone marrow after treatment for 94 or 185 days (Weyand et al. 1994). 

All reliable NOAEL and LOAEL values for immunological and lymphoreticular effects for each species

and duration category are recorded in Table 3-2 and plotted in Figure 3-2.
CREOSOTE 102

3. HEALTH EFFECTS

3.2.2.4 Neurological Effects

No studies were located regarding neurological effects in humans following oral exposure to coal tar

creosote, coal tar, or coal tar pitch. 

Creosote Bush. A 45-year-old woman developed fatigue and anorexia after taking 160 mg/kg/day

chaparral for around 2 months (Alderman et al. 1994). The patient was diagnosed with chaparral-induced

toxic hepatitis. In another report, a 60-year-old woman was hospitalized with a 1-week history of upper

quadrant abdominal pain, anorexia, and jaundice (Gordon et al. 1995). The patient had been taking

1–2 capsules of chaparral daily for the past 10 months. The patient developed "flulike syndrome" and

increased her chaparral intake to 6 capsules per day 3 weeks before admission. On admission, she was

confused; her encephalopathy worsened, and she developed seizure activity. The patient was diagnosed

with toxic hepatitis secondary to chaparral ingestion.

Wood Creosote. In rats and mice, the first sign of poisoning following the gavage administration of

single high doses (600 mg/kg in Wistar rats; 378 [male] or 313 [female] mg/kg in ddY mice) of

beechwood creosote was muscle twitching followed by convulsions within 1–2 minutes. This was

followed by asphyxiation, coma, and death (Miyazato et al. 1981). These effects were not observed in

male mice gavaged once with 313 mg/kg beechwood creosote (Miyazato et al. 1981). Dose-related

increased brain-to-body-weight ratios were observed in male rats exposed to doses of $257 mg/kg/day

beechwood creosote in the diet for 3 months, but not female rats exposed up to 768 mg/kg/day or male

and female mice exposed to up to 1,810 (male) or 1,570 (female) mg/kg/day (Miyazato et al. 1981). 

Increased relative brain weights were observed in male and female mice exposed to doses up to

247 (male) or 297 (female) mg/kg/day for 52 weeks in the diet, and in male rats exposed to

143 mg/kg/day and female rats exposed to 394 mg/kg/day (but not 179 mg/kg/day) for 96 weeks in the

diet (Miyazato et al. 1984b). This response is of questionable toxicological significance because of the

lack of a dose-response trend and/or the lack of treatment-related pathological findings at necropsy.

All reliable NOAEL and LOAEL values for neurological effects for each species and duration category

are recorded in Table 3-3 and plotted in Figure 3-3.

Coal Tar Products. Several cases of acute poisoning in cattle have been attributed to ingestion of coal tar

creosote. Six cattle believed to have licked creosote-treated electrical light poles as evidenced by burning

over the mucosa of the mouth, tongue, and lips showed the following signs: extremely rapid respiration,
CREOSOTE 103

3. HEALTH EFFECTS

contracted pupils, cold skin, apparent severe pain, and coma (Hanlon 1938). However, it is probable that

some of these effects may have been due to ingestion of pentachlorophenol. Pentachlorophenol, like

creosote, is an oil-borne wood preservative with extensive use in the public utility industry for treatment

of utility poles. Some of the effects observed by Hanlon (1938) are more compatible with the metabolic

effects (i.e., uncoupling of phosphorylative oxidation) associated with pentachlorophenol. For more

information on the effects of pentachlorophenol, please refer to the ATSDR Toxicological Profile for

Pentachlorophenol (Agency for Toxic Substances and Disease Registry 1999). Thus, it is not possible to

determine conclusively whether coal tar creosote is toxic to the central nervous system of animals based

on this report. In another report, one of two bulls that had ingested an unknown amount of creosote died

and the second one was observed to be walking stiffly (Cribb 1968). The surviving animal recovered

fully several days after being removed from the creosote.

All reliable NOAEL and LOAEL values for neurological effects for each species and duration category

are recorded in Table 3-2 and plotted in Figure 3-2.

3.2.2.5 Reproductive Effects

No studies were located regarding reproductive effects in humans following oral exposure to creosotes,

coal tar, or coal tar pitch. 

Wood Creosote. An increase in relative testis weight was observed in Wistar rats administered

805 mg/kg/day beechwood creosote in the diet for 3 months, but not in rats receiving 317 mg/kg/day or in

mice treated with up to 1,810 mg/kg/day beechwood creosote for 3 months (Miyazato et al. 1981). There

were no accompanying gross or histopathological lesions of the testes in these animals. No adverse

effects on ovary weight were noted in female rats (768 mg/kg/day) or mice (1,570 mg/kg/day) in the same

study. No effect on testis or ovary weight was observed in rats exposed to doses up to 394 mg/kg/day for

96 weeks, or mice exposed to doses of up to 532 mg/kg/day beechwood creosote for 52 weeks (Miyazato

et al. 1984a, 1984b). Ovary weights were unaffected in female Sprague-Dawley rats administered 20 or

50 mg wood creosote/kg/day for 102 weeks or 200 mg wood creosote/kg/day by gavage for 95 weeks

(Kuge et al. 2001). Testis weight was significantly increased in male rats administered 200 mg wood

creosote/kg/day for 95 weeks, but not in male rats administered 20 or 50 mg/kg/day for 102 weeks.

All reliable NOAEL and LOAEL values for reproductive effects for each species and duration category

are recorded in Table 3-3 and plotted in Figure 3-3.
CREOSOTE 104

3. HEALTH EFFECTS

Coal Tar Products. A significant decrease in both the number of live fetuses/litter and the number of

resorptions was observed in female Sprague-Dawley CD rats gavaged with 370 mg/kg/day coal tar on

gestational days 12–16 (Hackett et al. 1984). A significant increase in resorptions was also observed in

rats treated with 180 mg/kg/day (but not 140 mg/kg/day) coal tar, but there was no decrease in the number

of live fetuses/litter. Some maternal toxicity was observed in the body weight (minus the products of

gestation) of the dams was significantly reduced for the three highest dose groups and the weight of the

adrenal glands was significantly increased. However, the weights of the spleen, liver, kidneys, and

ovaries of all dosed groups were similar to controls. 

No significant difference in the number of live births was observed in female Sprague-Dawley rats

gavaged with 740 mg/kg/day coal tar on gestational days 12–14 (Springer et al. 1986a). Only moderate

maternal toxicity was observed. Body weight gain was significantly reduced in treated dams, but the

estimated weights of the products of conception were similar for control and treated animals, and no

significant reduction in litter size was observed. No adverse effects on reproductive indices, including the

number of live fetuses, dead fetuses, and resorptions were observed in female ICR mice dosed by gavage

with 400 mg/kg petroleum creosote in DMSO on gestational days 5–9 (Iyer et al. 1993). Moderate

maternal toxicity in the form of reduced body weight gain was observed for both creosote-treated and

vehicle control mice compared with untreated controls, but no differences in organ weights were observed

for any group. B6C3F1 mice fed a control gel diet or adulterated diets containing 0, 51, 251, or

462 mg/kg/day (males) and 0, 42, 196, or 344 mg/kg/day (females) MGP residue as a by-product of coal

gasification, exhibited no adverse effect on the epididymides, preputial gland, ovaries, uterus, or clitoral

gland after treatment for 94 or 185 days (Weyand et al. 1994).

Coal tar creosote was tested for estrogenic activity using an assay in ovariectomized (OVX) ICR and

DBA/2 mice (Fielden et al. 2000). Immature OVX mice were used to assess the ability of creosote to

induce an increase in uterine weight, and mature OVX mice were used to assess the ability of creosote to

induce both increased uterine weight and vaginal cell cornification. OVX mice were gavaged with 0, 10,

50, or 100 mg/kg creosote in sesame oil or 0.1 mg/kg 17α-ethynylestradiol (positive control) once a day

for 4 days beginning when mice were 30 (OVX ICR immature), 32 (OVX DBA/2 immature), 77 (OVX

ICR mature), or 85 (OVX DBA/2 mature) days old. Mice were sacrificed 24 hours after the last

treatment; body and uterine weights were recorded for all mice and vaginal smears were taken from the

mature mice. Treatment with 17α-ethynylestradiol produced a significant increase in uterine weight and

vaginal cell cornification compared with animals receiving only sesame oil, but no significant increase in

uterine weight or vaginal cell cornification was observed in animals treated with creosote. 
CREOSOTE 105

3. HEALTH EFFECTS

All reliable NOAEL and LOAEL values for reproductive effects for each species and duration category

are recorded in Table 3-2 and plotted in Figure 3-2.

3.2.2.6 Developmental Effects

No studies were located regarding the developmental effects in humans following oral exposure to wood

creosote, coal tar, or coal tar pitch. 

Coal Tar Products. A significant decrease in relative fetal lung weight and a significant increase in

anomalous fetuses was observed in female CD rats gavaged with 140 mg/kg/day (but not 90 mg/kg/day)

coal tar on gestational days 12–16 (Hackett et al. 1984). Further abnormalities, a significant increase in

the incidence of cleft palate, syndactyly/ectrodactyly and missing toenails on hind feet, were observed in

offspring of females treated with 370 mg/kg/day coal tar. In this study, maternal body weight gain was

significantly reduced at the three highest dose groups and the weight of the adrenal glands was

significantly increased. However, the weights of the spleen, liver, kidneys, and ovaries of all dose groups

were similar to controls. Maternal body weight gain, excluding uterine weight, was significantly reduced

at all doses. These findings suggest that maternal toxicity may have played a role in the development of

teratogenic effects in this study.

In another developmental study, female Sprague-Dawley rats were gavaged with 740 mg/kg/day coal tar

on gestational days 12–14 and allowed to deliver their pups (Springer et al. 1986a). Only moderate

maternal toxicity was observed. Body weight gain was significantly reduced in treated dams, but the

estimated weights of the products of conception were similar for control and treated animals, and no

significant reduction in litter size was observed. Pup development was followed for 21 days after birth. 

Early mortality was significantly increased in treated pups; within the first 3 days after birth, 54% of the

treated pups died compared with 9% of the untreated pups. Body and lung weights of treated pups that

died or were sacrificed at 1 or 3 days postdelivery were significantly reduced compared with controls. 

Body weight gain was significantly reduced (15%) for treated pups compared with controls at all time

points. Treated pups that died showed signs of severe dehydration and this became more pronounced as

the time to death increased. Thymus and lung weights in treated animals were significantly lower than in

the corresponding control animals. Lungs were defined as "small lungs" if their size was more than two

standard deviations below the mean of the control group. No controls had small lungs or cleft palates. In

treated pups that died, the incidence of small lungs was 27% (in 90% of litters), 10% (in 80% of litters)

had cleft palates, and 33% of pups (in 80% of litters) had both small lungs and cleft palates. Median
CREOSOTE 106

3. HEALTH EFFECTS

survival times for pups with cleft palate, both cleft palate and small lungs, and only small lungs were 2, 2,

and 10 hours, respectively. No malformations were detected in 30% of the treated pups that died and

microscopic examination of fetal lung tissue revealed no overt histological differences between treated

and control animals. The data from this study suggest that coal tar is a teratogen in Sprague-Dawley rats;

however, given the moderate, yet statistically significant, maternal toxicity, the possibility of fetal effects

secondary to maternal toxicity cannot be excluded.

A 12% decrease in mean fetal body weight was observed in the offspring of female ICR mice dosed by

gavage with 400 mg/kg petroleum creosote in DMSO on gestational days 5–9 compared to the solvent

control group (Iyer et al. 1993). An increase in the incidence of a skeletal anomaly (i.e., missing

sternebrae) was also observed in the creosote-treated litters, but the difference in the frequency of

occurrence was not significant compared to the control group. Moderate maternal toxicity in the form of

reduced body weight gain was observed for both creosote-treated and vehicle control mice compared with

untreated controls, but no differences in organ weights were observed for any group. The authors suggest

that creosote is embryotoxic but not teratogenic; however, interpretation of the results of this study is

complicated by the apparent toxicity of the carrier solvent (DMSO). 

Four sows were confined to wooden farrowing crates for 2–10 days before delivery. The platforms of the

crates were coated with 3 brush applications of a commercial wood preservative containing 98.5% coal

tar creosote (Schipper 1961). Following contact with creosote, 24 of the 41 pigs delivered were dead at

birth, and 11 pigs died by day 3 postfarrowing. The surviving pigs had rough skin and suffered from

dehydration and severe diarrhea. The pigs failed to gain weight until they were 5–6 weeks old. No toxic

effects on the sows were reported. However, 4 sows confined to untreated lumber crates at least 24 hours

before farrowing delivered 36 pigs; 1 died within 24 hours and 3 died postfarrowing. No toxic effects

were noted in mothers or baby pigs. These findings suggest that creosote was fetotoxic. The fetal effects

were observed in the absence of maternal toxicity.

Although some teratogenic effects were observed in the studies discussed in this section, it is not clear

that they were directly induced by creosote. In some studies, the observed fetal deformities appeared to

be related to maternal toxicity. If creosote is a teratogen, it would be a weak one. Some of the studies

suggest that creosote is fetotoxic. In particular, the study by Schipper (1961) showed an increase in fetal

mortality without apparent maternal toxicity.
CREOSOTE 107

3. HEALTH EFFECTS

The LOAEL and NOAEL values for developmental effects in mice and rats after oral exposure to

creosote are recorded in Table 3-2 and plotted in Figure 3-2.

3.2.2.7 Cancer

No studies were located that dealt directly with an association between cancer and ingested coal tar or

coal tar pitch in humans. 

Creosote Bush. A 56-year-old woman who had been consuming 3–4 cups daily of chaparral tea (an

infusion of the leaves of the creosote bush) for a period of 3 months approximately 1.5 years prior to

surgery was found to have cystic renal disease and cystic adenocarcinoma of the kidney (Smith et al.

1994). One of the components of chaparral tea is nordihydroguaiaretic acid. This chemical has been

shown to produce cystic nephropathy in rats fed a 2% concentration for 6 weeks (Evan and Gardner 1979;

Goodman et al. 1970). The concentration of nordihydroguaiaretic acid in chaparral tea is considerably

higher than that used to cause cystic nephropathy in animals and the authors conclude that the renal

disease seen in their patient was most likely to have been due to consumption of chaparral tea.

Wood Creosote. Wood creosote is a common Japanese folk remedy under the generic name "seirogan"

and its relationship to stomach cancer is reported in a study by Weiner (1986). This preparation was used

as a treatment for stomach aches, taken 3 times/day and the dose was equivalent to 260 mg creosote daily. 

The cancer distribution in Japan shows the highest incidence of stomach cancer reported in Toyoma

where seirogan was produced and in prefectures close to Toyoma. However, the author notes that there

may be other factors in addition to seirogan. At the time of the report, 35 different digestive remedies

contained creosote.

Dietary exposure of male and female ddY mice to beechwood creosote at concentrations up to

532 mg/kg/day (which induced signs of toxicity) for 52 weeks induced no treatment-related increase in

the incidence of tumors (Miyazato et al. 1984a). This study is limited, in that 52 weeks may not be a

sufficient treatment duration to observe an increase in the incidence of tumors in mice. However, these

same authors reported that dietary exposure of male and female rats to 394 mg/kg/day beechwood

creosote (which induced signs of toxicity) for 96 weeks also failed to result in any treatment-related

increase in the incidence of tumors (Miyazato et al. 1984b). Kuge et al. (2001) conducted a chronic study

of the carcinogenicity of wood creosote using 20, 50, or 200 mg wood creosote/kg/day administered by

gavage to Sprague-Dawley rats for up to 102 weeks. There was a significant increase in mortality in the
CREOSOTE 108

3. HEALTH EFFECTS

200 mg/kg/day group. Significant increases in the incidence of mammary gland adenocarcinoma,

adenoma, and fibroadenoma were observed in some groups of female rats, but the increases did not

appear to be dose-related. In male rats, there was an increase in pituitary gland adenoma in the animals

administered 20 mg wood creosote/kg/day, but not 50 mg wood creosote/kg/day. There was a high

incidence of neoplastic changes in the control group of rats that was were not administered wood

creosote. Based on the lack of dose-related increases in neoplasms in these studies, there is no clear

evidence that ingested beechwood creosote is carcinogenic to mice or rats.

Coal Tar Products. Excess cases of breast cancer have been observed in St. Louis Park, Minnesota, that

were tentatively associated with coal tar creosote contamination of the water supply (Dean et al. 1988). 

Coal tar creosote-derived PAHs were first detected in the water supply of St. Louis Park in November

1978, but may have been there for decades. A 100-acre plot of coal tar creosote-contaminated soil on

which stood a plant that used coal tar creosote and operated from 1917 to 1972 is believed to be the

source of contamination. The levels of coal tar creosote or creosote-derived PAHs in the contaminated

drinking water of St. Louis Park were not specified. There were 113 cases per 100,000 of breast cancer in

St. Louis Park compared to 78 cases per 100,000 in the metropolitan Minneapolis-St. Paul area during

1969–1971. An attempt was made to demonstrate that these excess cases could be explained by known

risk factors for breast cancer, such as age at first birth, parity, age at menarche and menopause, body mass

index, history of benign breast disease, and familial history, and thus had no association with

environmental exposure variables (Dean et al. 1988). The authors presented a method to adjust the breast

cancer morbidity in St. Louis Park using data from a larger population with documented risk factors for

breast cancer ("standard population"). These more stable rates based on breast cancer risk factors were

determined in a larger study conducted by Helmrich et al. (1983). Dean et al. (1988) determined that the

attributable risk due to the risk factors was higher for the breast cancer cases in St. Louis Park (0.598)

than in the metropolitan Minneapolis-St. Paul area (0.311). They then used these attributable risks to

calculate an adjusted morbidity ratio to estimate expected numbers of breast cancer cases in the

community. After this adjustment, there appeared to be a higher expected number of breast cancer cases

(n=134 per 100,000) than the observed number (113 per 100,000) in St. Louis Park, thereby negating any

association with creosote in the water supply. It is necessary when using any standardization method in

adjusting rates to ensure comparability among the groups in the study population that are being compared

and between the study population and the standard population. It would appear that differences do exist

between women in St. Louis Park, the metropolitan Minneapolis-St. Paul area, and the larger cohort

studied by Helmrich et al. (1983). These differences were not thoroughly examined by Dean et al. (1988)

and could include differences in demographic, economic, and/or environmental factors. However, Dean
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3. HEALTH EFFECTS

et al. (1988) did note a difference in religious backgrounds between the study population described by

Helmrich et al. (1983) and that of the St. Louis Park area. These dissimilarities indicate that the

populations were not directly comparable and, therefore, adjustment of rates was not appropriate. The

authors did not attempt to incorporate coal tar creosote contamination of water as an independent variable

in their analysis.

The Minnesota Department of Health (1985) also reviewed the St. Louis Park data and concluded that this

study did not provide adequate evidence to associate breast cancer with coal tar creosote-contaminated

ground water. They supported this conclusion with the following observations. It is not possible to

classify individuals or residences within St. Louis Park according to their relative degree of historical

exposure to PAH contaminants in drinking water because the pattern and history of municipal well

contamination are not known; contaminant levels were measured at the well head and not at the tap; water

treatment, storage, and distribution effects on contaminant concentration are not known; and much of the

water distribution system is lined with coatings made of coal tar or asphalt. Furthermore, given the

ubiquitous nature of PAHs, it is probable that exposures to PAHs from food would significantly exceed

exposures from contaminated St. Louis Park well water. In addition, it was found that the specific PAHs

(e.g., 3-methyl-cholanthrene) that have been shown to induce mammary tumors in rats (Dao 1964; Dao

and Sunderland 1959) were either not present in contaminated wells or were detected very rarely even in

the most highly contaminated wells. Furthermore, the many published case-control and cohort studies of

breast cancer have not demonstrated clear-cut evidence of an association between breast cancer and

smoking, which is a significant source of exposure to PAHs. These studies have also identified a number

of risk factors that account for some of the observed variations in rates among different groups of women,

and the women of St. Louis Park differ from those in the general Metro area with respect to several of the

factors that are known to influence breast cancer rates.

In another analysis of the St. Louis Park data, cancer incidence rates in St. Louis Park were compared

with those in Edina and Richfield and in the entire Minneapolis-St. Paul Standard Metropolitan Statistical

Area (SMSA), using data from the Third Cancer Survey for 3 years, 1969–1971 (Dusich et al. 1980). 

Richfield was selected because it was a SMSA suburb similar to St. Louis Park in social and economic

characteristics such as median school years completed, percentage high school graduates, occupation and

median family income. Edina was selected because the creosote contamination was believed at that time

to be moving toward Edina. The entire SMSA was used as a major comparison area. For males, no

cancer rates in St. Louis Park were statistically significant from those in the three comparison areas. 

Among females, age-adjusted rates for all cancers, cancers of the gastrointestinal tracts, and breast cancer
CREOSOTE 110

3. HEALTH EFFECTS

were higher in the St. Louis Park than in Edina, Richfield, and the SMSA. The excess in gastrointestinal

cancer rates for females was only slightly significant, but all cancer combined and breast cancer had

differences with a high degree of statistical significance. 

A feeding study in female A/J mice examined tumor induction after 260 days exposure to MGP residue

(Weyand et al. 1995). Treated mice ate diets to which had been added 0.25% MGP coal tar

(236 mg/kg/day) or 0.1% MGP coal tar (100 mg/kg/day), while controls received either unadulterated

food (negative control) or a diet containing benzo[a]pyrene (positive control). Mice that ingested coal tar

had a significant increase in the incidence of lung tumors (70%) compared with controls (0%), but

ingestion of coal tar did not produce any tumors of the forestomach. This is in contrast to ingestion of

benzo[a]pyrene, which produced a significant increase in incidence of tumors of the forestomach (but not

lung tumors) compared with controls. 

The most extensive studies of coal tar carcinogenicity to date are 2-year cancer bioassays carried out by

Culp et al. (1996a, 1998) using MGP residue. In the earlier of these two studies, female B6C3F1 mice

(5 weeks of age) were allocated to 14 dose groups consisting of 48 mice per group (Culp et al. 1996a). 

Coal tar was added to the animals’ feed at the following concentrations; 0, 0.01, 0.03, 0.1, 0.3, 0.6 (15 mg

coal tar/day), and 1% (22 mg coal tar/day). Three groups of mice received feed with the following

concentrations of benzo[a]pyrene; 5, 25, and 100 ppm. The coal tar was a mixture of samples from seven

waste sites and corresponds to coal tar 1 in the later study (Culp et al. 1998). Feeding was continued for

2 years. All mice, including those that died during the experiment were examined grossly at necropsy. 

Forestomach tumors were found in all groups of mice fed coal tar or benzo[a]pyrene and incidence

increased with dose. Tumors of the small intestine were only seen in mice fed 0.6 or 1.0% coal tar. 

In the later study, coal tar samples from manufactured gas plant waste sites were added to the feed of

5-week-old female B6C3F1 mice at the following concentrations; 0.01, 0.03, 0.1, 0.3, 0.6, and 1% (12, 33,

117, 333, 739, and 1,300 mg/kg/day) coal tar 1 and 0.03, 0.1, and 0.3% (40, 120, or 346 mg/kg/day) coal

tar 2 (Culp et al. 1998). Coal tar 1 was a mixture of samples from seven waste sites and coal tar 2 was a

mixture from two of the sites included in coal tar 1 plus a third site with a very high benzo[a]pyrene

content. Control mice received either unadulterated feed (negative control) or feed containing 5, 25, or

100 ppm benzo[a]pyrene. Mice fed coal tar 1 or 2 showed a significant concentration-related increase in

incidence of neoplasms of the liver, lung, and forestomach and of hemangiosarcomas, histiocytic

sarcomas, and sarcomas. Mice treated with coal tar 1 also showed a significant concentration-related

increase in incidence of neoplasms of the small intestine. In contrast mice treated with benzo[a]pyrene
CREOSOTE 111

3. HEALTH EFFECTS

showed a significant concentration-related increase in incidence of neoplasms of the forestomach,

esophagus, tongue, and larynx. The authors concluded that the forestomach neoplasms produced by coal

tar treatment may be due to the presence of benzo[a]pyrene, but that the other tumors produced by coal tar

are likely to be due to the presence of genotoxic compounds other than benzo[a]pyrene. The small

intestine-tumors produced by coal tar 1 may be due to chemically-induced cell proliferation that occurred

at high doses of coal tar.

A risk assessment based on the data from Culp et al. (1998) discussed the validity of using the

concentration of a single component of coal tar (benzo[a]pyrene) to estimate the relative cancer risk for

coal tar (Gaylor et al. 2000). In this experiment, benzo[a]pyrene dominated the cancer risk for coal tar

when it was present at concentrations >6,300 ppm in the coal tar mixture, and in this case, the

forestomach was the most sensitive tissue site. However, when benzo[a]pyrene was present in

concentrations <6,300 ppm, the lung was the most sensitive site and benzo[a]pyrene did not contribute to

the risk. The authors conclude that, in general, the concentration of benzo[a]pyrene in coal tar is unlikely

to be as high as 6,300 ppm and, therefore, it probably should not be used as a measure of the cancer risk

for coal tar.

Levels of exposure associated with CELs of creosote are indicated in Table 3-2 and Figure 3-2.

3.2.3 Dermal Exposure

This section describes the health effects observed in humans and laboratory animals associated with

dermal exposure to coal tar creosote. All reliable exposure levels have been reported. Several reports

were found that describe the occurrence of dermal and ocular irritation, burns, and "warts" (i.e., squamous

papillomas) following acute or prolonged skin contact with coal tar creosote. Coal tar creosote also

induces phototoxicity of the skin, and has been demonstrated to be a skin carcinogen in animals. 

Conclusions that can be drawn from the results of animal studies are limited by the possibility of

concurrent oral ingestion of creosote from the skin via normal preening behavior and by the fact that few

studies reported accurate doses. Details of these reports are given below.
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3. HEALTH EFFECTS

3.2.3.1 Death

No studies were located regarding death in humans following dermal or skin contact with creosotes, coal

tar, coal tar pitch, or coal tar pitch volatiles solely by this route. 

Coal Tar Products. Evaluations of human exposure during employment in coal tar plants indicated

significant increases in cancer-related deaths (TOMA 1982). No specific type of cancer was

predominant. Nevertheless, no clear relationship could be established because exposure routes in addition

to dermal were likely, such as inhalation and oral. Also, the ability to relate death to coal tar exposure

was further confounded by the possibility that the subjects were also exposed to other chemicals and

cigarette smoke (TOMA 1982). Additional limitations were identified in this study, including absence of

data on smoking habits, short cut-off date of 10 days of employment, unknown race classification for

20 of participants, use of U.S. male mortality rates for comparison as opposed to regional mortality rates,

and the relationship between the cohort and production history was not explored.

In test animals, a dermal LD50 in rabbits of >7,950 mg/kg was estimated following a 24-hour application

of coal tar creosote to both intact and abraded skin; two of four rabbits died at the high dose of

15,800 mg/kg (Pfitzer et al. 1965). This LOAEL value is recorded in Table 3-4. Additional reports of

deaths in test animals, after dermal application of coal tar or coal tar pitch volatiles, can be found in the

literature, although specific details of the studies are missing (Bonser and Manch 1932; Deelman 1962). 

Wallcave et al. (1971) treated groups of Swiss albino mice topically with 9% benzene solutions of two

coal tar pitches of known PAH content. An additional group of 15 male and female mice were painted

with benzene only and served as controls. Zones of approximately 1 square inch were shaved in the skin

of the back of each animal and the solutions of coal tar pitch were painted in this area 2 times/week with

25 mL of solution (approximately 1.7 mg coal tar pitch per treatment). Mean survival time for animals

painted with coal tar pitch and control animals was 31 and 82 weeks, respectively. The effect, if any, of

benzene on the dermal absorption of asphalt components was not evaluated in this study. Asphalt

(500 mg/mL) and coal tar pitch (30–84 mg/mL) were the materials used in assessing skin carcinogenesis

in nonpigmented Swiss CD-1 and pigmented C3H/HeJ male mice (Niemeier et al. 1988). The mean

survival time for treated C3H/HeJ ranged from 44.3 to 68.7 weeks compared to 65.6–73.9 for the

controls. The mean survival time for the treated CD-1 mice ranged from 52.6 to 67.8 weeks compared to

63.9–67.8 weeks for controls.
CREOSOTE 113

3. HEALTH EFFECTS

3.2.3.2 Systemic Effects

No studies were located regarding the musculoskeletal, endocrine, or body weight effects in humans or

respiratory, musculoskeletal, or endocrine effects in animals after dermal exposure to wood creosote, coal

tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles. Studies regarding the systemic effects that

have been observed in humans and animals after dermal exposure to creosotes are discussed below. The

highest NOAEL values and all LOAEL values from each reliable study for each systemic effect in each

species and duration category are recorded in Tables 3-4 and 3-5.

Respiratory Effects. 

Coal Tar Products. In an industrial health survey of employees in four wood preservative plants in

which coal tar creosote and coal tar were the main treatments used, decreased pulmonary function was

noted (TOMA 1979). Restrictive deficits in pulmonary function, as indicated by decreases in FVC, were

noted in 44 of 257 employees (10 of 47 nonsmokers). Obstructive deficits, as indicated by decreases in

percentage forced expiratory volume in one second (FEV1) were noted in 19 of 257 employees (3 of

54 nonsmokers). Nevertheless, no clear relationship could be established because exposure routes in 
Table 3-4 Levels of Significant Exposure to Creosote - Dermal 

Exposure1 

Reference 

Chemical Form 

Duration/ LOAEL 

Species Frequency 

(Strain) (Specific Route) System NOAEL Less Serious Serious 

ACUTE EXPOSURE 

Death 

Rabbit once 

Systemic 

Rat 4d Gd 11-15 Hepatic 

1 xld (Sprague- Dawley) 

Mouse 

(t.0.) 

Mouse 

(CD-1) 

Renal 500 (significant increase in 

mglkg'day relative kidney weight) 

Endocr 1500 F 

mglkglday 

Bd Wt 

1-3 wk 7 dlwk 1 

xld 

Dermal 

4 d Gd 11-15 Hepatic 

1 xld 

Rabbit once 

.. (New Zealand White) 

Renal 

Endocr 1500 F 

Bd Wt 1500 F 

mglkglday 

mglkglday 

5800 (2/4 died) mglkglday 

500 (significant increase in 

mglkglday relative liver weight) 

500 (1 5% decrease in body mglkglday "0° (30% decrease in body 

mglkglday weight) weight) 

(irritation) Percent (%) 

500 (significant increase in 

mglkglday relative liver weight) 

500 (significant increase in 

mglkglday relative kidney weight) 

(conjunctival redness) Ocular 0.1 M 

ml 

Pfitzer et al. 1965 

coal 

Zangar et al. 1989 

coal tar 

Wrench and Britten 1975 

coal tar 

Zangar et al. 1989 

coal tar 

Pfitzer et al. 1965 

coal tar 

w 

0 

I 

rn 

3 

F 

0 

P 

0 

73 

I 

< 

0 

v, 

F 

0 

R 

2 

2 

m 
Table (continued) 34 Levels of Significant Exposure to Creosote - Dermal 

Exposure/ 

Duration/ LOAEL Reference Species Frequency 

(Strain) (Specific Route) System NOAEL Less Serious Serious Chemical Form 

Systemic 

Rabbit once 

(New Zealand White) 

lmrnuno/lymphoret 

(Sprague- Dawley) 

Rat 4d Gd 11-15 

1 xld 

Mouse 4d Gd 11-15 

(CD-1) 1 xld 

Reproductive 

(Sprague- Dawley) 

Rat 4 d Gd 11-15 

1 xld 

Mouse 4dGd11-15 

(CD-1) 1 xld 

Developmental 

(Sprague- Dawley) 

Rat 4 d Gd 11-15 

1 x/d 

Mouse 

(CD-1) 

4dGd11-15 

1 xld 

15800 (intestinal hyperemia) 

Gastro 7950 M 

mglkglday rnglkglday 

’0° (significant decrease in 

mglkglday relative weight of thymus) 

500 (significant increase in 

mglkg‘day relative weight of spleen) 

500 (significant increase in 

mglkg‘day resorptions and decrease 

in uterine weight) 

500 (significant decrease in 500 (significant increase in 

mglkg’day uterine weight) mglkg’day resorptions) 

500 (significantly increased rnglkglday incidence of small lungs, 

cleft palate, edema, 

rnidcranial lesion and 

reduced cranial 

ossification) 

’0° (significantly increased 

dilated ureter and renal 

pelvic cavitation). 

mg’kglday incidence of cleft palate, 

Pfitzer et al. 1965 

coal tar 

Zangar et at. 1989 

coal tar 

Zangar et at. 1989 

coal tar 

Zangar et at. 1989 

coat tar 

Zangar et al. 1989 

coal tar 

Zangar et al. 1989 

coal tar 

Zangar et al. 1989 

coal tar 

w 

0 

I 

rn 

5 

? 

0 

P 

0 

0 

A 

m 

$ 

2 

m 
Table 34 Levels of Significant Exposure to Creosote - Dermal (continued) 

Exposure/ 

Duration1 LOAEL Reference Species Frequency 

(Strain) (Specific Route) System NOAEL Less Serious Serious Chemical Form 

Cancer 

Mouse once 

(CD-1) 

Mouse once 

(CD-1) 

INTERMEDIATE EXPOSURE 

Systemic 

Rabbit 3 wk 5 d/wk Dermal 

(Australian albino) 

Cancer 

(Sutter) 

Mouse 4-28 wk 2 x/wk 

Mouse 31wk2xlwk 

(Swiss- albino) 

Rabbit 15 wk 3 xlwk 

(Australian albino) 

5555 (initiation of skin tumors) mglkg 

203 (initiation of skin tumors) mglkg 

0.01 M 0.1 M (comedogenicity) Percent (%) Percent (%) 

0.025 (CEL: papillomas and 

ml carcinomas) 

1.7 (CEL: squamous cell 

mg carcinoma and 

papillomas in 53/58) 

lo (CEL: papillomas, 

Percent (%) squamous cell 

Mahlum 1983 

coal tar 

Springer et al. 1989 

coal tar 

w 

0 

I 

m 

s 

0 

D 

- 

Kligman and Kligman 1994 r 

coal tar 0 

73 

I 

< Boutwell and Bosch 1958 '" 

0 

F coal tar - 

P 

z 

coal tar pitch volatiles 3 

8 

A 

c 

Wallcave et at. 1971 

Kligman and Kligman 1994 

coal tar 

0 

A 

m 

$ 

9 

rn 

carcinoma,s 

keratoacanthomas & 

cutaneous horns) 
Table 34 Levels of Sianificant Exposure to Creosote - Dermal (continued) 

Exposure1 

Duration/ LOAEL Reference Species Frequency 

(Strain) (Specific Route) System NOAEL Less Serious Serious Chemical Form 

CHRONIC EXPOSURE 

Death 

Mouse 78 wk 2 x/wk 

(Swiss CD-1; C3Hl 

HeJ) 

Mouse 78 wk 2 xlwk 

(Swiss CD-1; C3Hl 

HeJ) 

Mouse 78 wk 2 xfwk 

(Swiss CD-1; C3Hl 

HeJ) 

Systemic 

Mouse 78wk2xlwk BdWt 30 M 

HeJ) mglml 

(Swiss CD-1; C3HI - 84 

Mouse 78 wk 2x/wk Bd Wt 500 M 

(Swiss CD-1; C3Hl mglml 

HeJ) 

Cancer 

Mouse 78 wk 2 x/wk 

(Swiss CD-1; C3HI 

. HeJ) 

Niemeier et al. 1988 

CTPV 

30 (mean survival time for 

84 C3HIHeJ; treated = mglml 44.3-68.7 wks, control = 

65.6-73.9 wks; for 

CD-1; treated = 52.6-67.8 wks, control = 

63.9-67.8 WkS) 

500 M 

mglml 

Niemeier et al. 1988 

CTPV 

(mean survival time for 

C3HlHeJ; treated = 44.3-68.7 wks, control = 65.6-73.9 wks; for 

CD-1; treated = 52.6-67.8 wks, control = 63.9-67.8 WkS) 

Niemeier et al. 1988 

CTPV 

’0° mglmL asphalt + 30-84 

mg’kg’day mglmL coal tar pitch 

(deaths) 

Niemeier et al. 1988 

CTPV 

Niemeier et al. 1988 

CTPV 

Niemeier et al. 1988 

CTPV 

30 (CEL: skin tumors) - 84 

mglml 

w 

0 

I 

rn 

5 

F 

0 

P 

U 

-0 

I 

< 

0 

0, 

F 

4 

0 

A 

rn 

0 

E 

--I 

rn 
Table 3-4 Levels of Significant Exposure to Creosote - Dermal (continued) 

Exposure/ 

Duration/ LOAEL 

Species Frequency Reference 

(Strain) (Specific Route) System NOAEL Less Serious Serious Chemical Form 

Cancer 

Mouse 78 wk 2 x/wk 

(Swiss CD-1; C3Hl 

HeJ) 

Mouse 78 wk 2 xlwk 

(Swiss CD-1; C3HI ' 

HeJ) 

Mouse lifetime 3 x/wk 

(C57L) 

500 M (CEL skin tumors) mglml 

Niemeier et al. 1988 

CTPV 

Niemeier et al. 1988 

'0° mgImL asphalt + 30-84 

(CEL tumors) mg'kg'day mgIrnL coal tar pitch CTPV 

Poel and Kammer 1957 

coal tar 

*O (CEL: papillomas 100% Percent (%I incidence) 

Bd Wt = body weight; CEL = cancer effect level; CTPV = coal tar pitch volatiles; d = day(s); Endocr = endocrine; F = female; Gastro = gastrointestinal; Gd = gestation day; hr = 

hour@); LOAEL = lowest-observable-adverse-effect level; M = male; mo = month(s); NOAEL = no-observable-adverse-effect level; wk =week@); x = times 

0 

;c1 

rn 

0 

v, 

0 

-I 

rn 

u 

0 

I 

rn 

0 

9 

5 

r9 

z 

0 
Table 3-5 Levels of Significant Exposure to Wood Creosote - Dermal 

Exposure/ 

Duration/ LOAEL Species Frequency Reference 

(Strain) (Specific Route) System NOAEL Less Serious Serious Chemical Form 

INTERMEDIATE EXPOSURE 

Systemic 

Rabbit 10 wk 5 dhvk Dermal 

(Australian albino) (small visible comedones Percent (%) in wks) 

Kligman and Kligman 1994 

birch tar 

d = days(s): LOAEL = lowest-observable-adverse-effect level: M = male: NOAEL = no-observable-adverse-effect level: wk = week(s) 

0 

R 

8 

0 

--I 

m 

0 

I 

m 

s 

0 

D 

r 

P 

0 
CREOSOTE 120

3. HEALTH EFFECTS

addition to dermal were likely, such as inhalation and oral. Also, the ability to relate respiratory effects to

coal tar exposure was further confounded by the possibility that the subjects were also exposed to other

chemicals and cigarette smoke (TOMA 1979). Additional limitations of the studies included seasonal and

geographical variation in plant locations, past employment history, voluntary participation in the study

that could have biased it in favor of healthy workers, lack of statistical analyses, lack of adequate

controls, and use of only current employees. 

A site surveillance program was conducted by the Texas Department of Health beginning in 1990 at a

housing development in Texarkana, Texas, that had been built on part of an abandoned Koppers

Company, Inc., creosote wood treatment plant (Agency for Toxic Substances and Disease Registry 1994). 

The plant had ceased creosoting activities in 1961, after operating for 51 years. A sand and gravel

company had operated on part of the abandoned site during the 1970s and 1980s. Because of soil and

groundwater contamination with PAHs and other chemicals, the EPA identified this site and placed it on

the NPL in 1984. Several residential lots were observed to have soil concentrations of benzo[a]pyrene in

excess of 325 mg/kg, or oily-stained areas, and were subject to emergency resodding by the EPA. 

Contaminated soils were scheduled to be treated for clean-up. A total of 214 residents (123 males,

91 females) of the contaminated residential area (Koppers) were interviewed twice during a period of

2 years, and were compared to 212 residents (122 males, 93 females) from a nearby town. Since all of the

residents from the Koppers area who were participating in the survey were African American, the chosen

regional comparison population was also African American. No data were presented in this study

regarding the relative importance of inhalation versus dermal exposure. During the second year of the

surveillance, the responses of the Koppers area residents were compared with the 1990 National Health

Interview Survey results. Residents of the Koppers area showed a significantly higher risk of chronic

bronchitis (RR=2.65, 95% CI=1.26–5.57) relative to the comparison population during the first year of

the study. During the second year of the study, 11 residents of the Koppers area reported chronic

bronchitis, whereas 7 were expected based on the 1990 National Health Interview Survey rates. These

study results are seriously limited by the study’s reliance on self reporting of health conditions for which

diagnosis verification was not always available.

Cardiovascular Effects. 

Coal Tar Products. In an industrial health survey of employees in a wood preservative plant in which

coal tar creosote, coal tar, and pentachlorophenol were the main treatments used, cardiovascular effects,

including increased diastolic blood pressure, were noted in 21% (24/113) of the employees examined
CREOSOTE 121

3. HEALTH EFFECTS

(TOMA 1979). Nevertheless, no clear relationship could be established because exposure routes in

addition to dermal were likely, such as inhalation and oral. Also, the ability to relate cardiovascular

effects to coal tar exposure was further confounded by the possibility that the subjects were also exposed

to other chemicals such as pentachlorophenol and cigarette smoke (TOMA 1979). Additional limitations

of the study are listed above under Respiratory Effects.

Gastrointestinal Effects. No studies were located regarding gastrointestinal effects in humans

following dermal exposure to creosotes, coal tar, or coal tar pitch. 

Coal Tar Products. In an acute animal study, New Zealand white rabbits that died following single

dermal applications of undiluted coal tar creosote (15,800 mg/kg) exhibited hyperemia of the intestines,

but animals treated with 7,950 mg/kg did not (Pfitzer et al. 1965).

Hematological Effects. 

Coal Tar Products. In an industrial health survey of employees in four wood preservative plants in

which coal tar creosote and coal tar were the main treatments used, hematological effects, including

increased number of white blood cells (basophils), were noted in 6% (15 of 257) of the employees

examined (TOMA 1979). Similarly, 8% of the employees in eight of nine coal tar plants surveyed had

increased white blood cells (eosinophils) (TOMA 1981). Industrial hygiene surveys of coal tar pitch

volatiles at the four wood preservative plants indicated that in 94% of the samples, airborne exposure to

benzene-soluble components of the coal tar pitch volatiles was within the OSHA permissible limit of

0.2 mg/m3

 (TOMA 1979). The other 6% of the samples ranged from 0.21 to 3.6 mg/m3 (TOMA 1979). 

No determination of exposure was made at the nine coal tar plants (TOMA 1981). Furthermore, no clear

relationship could be established because exposure routes in addition to dermal were likely, such as

inhalation and oral. Also, the ability to relate hematological effects to coal tar creosote and coal tar

exposure was further confounded by the possibility that the subjects were also exposed to other chemicals

and cigarette smoke (TOMA 1979, 1981). Additional limitations of the studies are noted above (see

"Respiratory Effects").

In a clinical study, 15 patients (Group A) with chronic plaque psoriasis were treated with increasing

concentrations (1–4%) of topical coal tar paste (Gilmour et al. 1993). These patients did not receive

ultraviolet (UV) therapy and served as controls. Seventeen subjects (Group B) received UV-B

phototherapy and four subjects (Group C) received psoralen photochemotherapy (PUVA). Another
CREOSOTE 122

3. HEALTH EFFECTS

control group (Group D) consisted of 4 nonpsoriatic subjects who were receiving UV-B as part of another

study. Samples of blood were collected before irradiation and 48 hours after irradiation, and full blood

counts were determined. Samples taken from Group A were taken before treatment and again 4 weeks

later. Samples taken from Group B and C were taken before treatment, 4 weeks after treatment (48 hours

after irradiation), and finally 4 weeks after irradiation. The blood counts were all normal. A similar lack

of adverse effect on the hematological system was observed by Tham et al. (1994) in psoriasis patients

who applied a total of 120 g of coal tar over a period of 2–6 weeks to the skin of one side of their body. 

Hepatic Effects. 

Coal Tar Products. Fifteen patients (Group A) with chronic plaque psoriasis were treated with increasing

concentrations (1–4%) of topical coal tar paste (Gilmour et al. 1993). An additional 17 subjects (Group

B) received UV-B phototherapy and 4 subjects (Group C) received psoralen photochemotherapy (PUVA). 

Another control group (Group D) consisted of 4 nonpsoriatic subjects who were receiving UV-B as part

of another study. Liver function was determined. Samples taken from Group A were taken before

treatment and again 4 weeks later. Samples taken from Group B and C were taken before treatment,

4 weeks after treatment (48 hours after irradiation), and finally 4 weeks after irradiation. Liver function

was within normal limits. A similar lack of adverse effect on liver function was observed by Tham et al.

(1994) in psoriasis patients applying 120 g of coal tar to their skin twice daily for 2–6 weeks. 

In a developmental study of Sprague-Dawley rats and CD-1 mice, exposure to 500 or 1,500 mg/kg coal

tar on gestational days 11–15 resulted in significant increases in maternal liver to body weight ratios for

treated animals from both species compared with controls (Zangar et al. 1989).

Renal Effects. 

Coal Tar Products. In an industrial health survey of employees in nine coal tar plants in which coal tar

creosote and coal tar were the main treatments used, renal effects, including protein and cells in the urine,

were noted in 1–8% (3–34 of 452) of the employees examined (TOMA 1981). Nevertheless, no clear

relationship could be established because exposure routes in addition to dermal were likely, such as

inhalation and oral. Also, the ability to relate renal effects to coal tar exposure was further confounded by

the possibility that the subjects were also exposed to other chemicals and cigarette smoke (TOMA 1981). 

A study performed by Wright et al. (1992b) evaluated the nephrotoxic effects of commercial coal tar

preparation for the scalp. The preparation was applied to healthy human subjects either for 15 minutes,
CREOSOTE 123

3. HEALTH EFFECTS

twice a week, for 8 weeks to uncovered skin, or for 30 minutes, every second day for 4 weeks under

occlusive bandage. The preparations tested contained 5 or 10% beechwood tar. The concentration of

coal tar in the preparation was not specified. Renal function and urinary phenol levels were assayed

before, during, and after treatment. No impairment of renal function was detected, nor was urinary

phenol content found to be related to the coal tar treatment (Wright et al. 1992b). No adverse effect on

urinalysis was observed for 15 patients with chronic plaque psoriasis were treated with increasing

concentrations (1–4%) of topical coal tar paste in urine samples taken before treatment and 4 weeks after

treatment (Gilmour et al. 1993). 

In a developmental study of Sprague-Dawley rats and CD-1 mice applied 500 or 1,500 mg/kg coal tar on

gestational days 11–15, there were significant increases in maternal kidney to body weight ratios for

treated animals compared with controls (Zangar et al. 1989).

Renal effects were also noted in a study conducted by Deelman (1962), in which mice were exposed

dermally to an unspecified amount of tar applied 6–18 times over 6–7 weeks. "Seriously affected"

kidneys were noted, although no details or data were presented. Ten groups of Swiss albino mice

received topical applications of 10% benzene solutions of eight petroleum asphalts of known polynuclear

aromatic hydrocarbon content (Wallcave et al. 1971). An additional group of 15 males and females were

painted with benzene only and served as controls. Zones of approximately 1 square inch were shaved in

the skin of the back of each animal and the solutions of asphalt were painted in this area 2 times/week

with 25 mL of solution (approximately 2.5 mg asphalt per treatment). Amyloidosis was frequently

observed in animals receiving asphalt, particularly in the kidney. The potential effect of benzene on the

dermal absorption of asphalt components was not evaluated in this study.

Endocrine Effects. 

Coal Tar Products. In a developmental study of Sprague-Dawley rats and CD-1 mice, exposure to 500 or

1,500 mg/kg coal tar on gestational days 11–15 produced no change in weight of the adrenal glands of

treated animals from both species compared with controls (Zangar et al. 1989).
CREOSOTE 124

3. HEALTH EFFECTS

Dermal Effects. 

Creosote Bush. Leonforte (1986) reported six confirmed cases of acute allergic dermatitis subsequent to

contact with the creosote bush. Two cases were the result of "casual occupations," two were the result of

household remedies, and two were the result of burning the bush. Based on his findings, the author

concluded that the allergens are probably contained in the plant's perfume, are volatile, and are not

destroyed by heat. In contrast, no adverse treatment-related effects were reported for 23 patients treated

topically with an extract of creosote bush (concentration not stated) in castor oil (Heron and Yarnell

2001).

Wood Creosote. Beechwood creosote has been found to irritate tissue other than skin. The effects of

beechwood creosote (dose not specified) on the periapical tissue (the connective tissue surrounding the

apex of the tooth) were studied in 10 teeth from 4 different dogs 7 days after its application following root

canal surgery (Attalla 1968). Beechwood creosote application resulted in localized inflammatory changes

and occasional abscess formation in the periapical region, presumably due to tissue damage caused by

coagulation of proteins. Bone resorption was observed in the alveolar process. The authors concluded

that beneficial disinfectant properties of beechwood creosote may be outweighed by irritant effects

following root canal surgery. Birch tar (10%) was applied to the ear of male Australian albino rabbits

5 days/week for 3 weeks (Kligman and Kligman 1994). Comedones were visible on the ear after 2 weeks

of treatment. 

Coal Tar Products. Burns and irritation of the skin are the most frequent manifestations of coal tar

creosote toxicity following dermal exposure. According to a review by EPA (1978b), burns from hot

pitch are relatively common in occupational settings. Burn scars and other sites of epidermal atrophy

may later be sites for skin cancer. Creosote chemical burns were observed in construction workers who

handled wood treated with creosote (presumably coal tar creosote) (Jonas 1943). Exposure levels were

not specified. It was found that 70% of the burn cases were mild and were characterized by erythema of

the face. These symptoms were more marked on the cheeks, nose, forehead, and posterior part of the

neck. The remainder of the burn cases (30%) were more severe and were characterized by intense

burning, itching, and considerable subsequent pigmentation followed by desquamation. There is no way

to determine, given the information provided, whether this response was due to primary irritation or an

allergenic response. 
CREOSOTE 125

3. HEALTH EFFECTS

Other reports of skin irritation after contact with coal tar (Cusano et al. 1992) were found. Patients

admitted over a 4-month period to the dermatology wards of Manchester Skin Hospital for the treatment

of psoriasis were patch tested with 3% coal tar (Burden et al. 1994). A positive reaction to coal tar was

followed by dilution series testing down to a 0.1% concentration of coal tar. Patients were asked about

previous psoriasis treatment and adverse reactions from topical preparations. Mean duration of psoriasis

was 20 years and many patients had been treated as inpatients previously on numerous occasions; 91% of

patients recalled previous treatment with coal tar. Thirteen patients showed clinical intolerance to coal tar

and two had positive patch test reaction to coal tar confirmed by serial dilutions. 

 In another study, 5% crude coal tar (CCT) was applied to the backs of eight subjects in six distinct sites

for 15, 30, 60, 90, 120, and 180 minutes (Diette et al. 1983). Tar was then vigorously removed with a

washcloth, Ivory® soap, and water. Immediately following tar removal, the minimal phototoxic dose

(MPD) of UV-A was determined at each site using 1-cm diameter apertures. In all subjects, the minimal

erythema dose (MED) and MPD were defined as the minimal dose of UV-A causing 1+ erythema with

distinct borders read at 24 hours after exposure. In addition, 5% CCT was applied to four separate sites

on the backs of 13 subjects for 1 hour. The following methods of tar removal were compared: (1) water,

(2) Ivory® soap and water, (3) mineral oil, and (4) Ivory® soap and water followed by mineral oil. 

Immediately after tar removal, all sites were exposed to UV-A and the MPD of UV-A was determined. 

UV-A exposure doses were identical to those used above. A 5% CCT ointment was applied to the backs

of 19 subjects and removed 1 hour later with a washcloth, Ivory® soap, and water. The subjects were

informed prior to testing about the photosensitizing effect of tar plus UV-A in producing a burning,

stinging, or smarting reaction at an unspecified time during UV-A exposure. These subjects would signal

the onset of symptoms and were encouraged not to wait until the burning sensation became unbearable. 

Subjects were tested immediately and at 0.5, 2, 4, 6, 24, and 30 hours following tar removal. At least

8 subjects were tested at each time; only at 24 and 30 hours were <10 subjects tested. Using the same

UV-A exposure times, the MED of UV-A was determined in those eight subjects tested at 24 and

30 hours. The minimal UV-A dose required to induce delayed erythema (the MPD) and the minimal

UV-A dose required to induce an immediate smarting reaction (minimal smarting dose or MSD) were

recorded. The effects of the following variables on MPD were noted: (1) interval of time tar is left on the

skin (TA); (2) methods of tar removal; and (3) time between removal of tar and UV-A irradiation. Tar

application for 30 minutes was photosensitizing in all eight subjects; six of the subjects showed photosensitization after only 15 minutes of tar application. The photosensitizing effect of tar increased rapidly

up to 60 minutes of application. MPD increased from 3.77±1.55 to 6.1±4.0 J/cm2

 after 30 minutes of

application. Longer time intervals between tar removal and UV-A exposure were accompanied by more
CREOSOTE 126

3. HEALTH EFFECTS

gradual, but consistent, increases in MPD. The MSD also significantly increased with increasing

intervals between tar removal and UV-A exposure. At times, the smarting reaction was associated with

an immediate erythema, which faded in several hours; this was not a consistent finding with 1 MSD of

UV-A. No urticarial response was noted at this dose level. 

Other studies confirm that coal tar creosote is capable of increasing skin sensitivity to sunlight. 

Phototoxicity is an exaggerated response to sun exposure characterized by excessive sunburn. The usual

sunburn is produced by UV-B light, whereas a phototoxic skin response occurs following absorption of

UV-A light by chemicals in or on the skin (NIOSH 1981a). Coal tar creosote exposure was evaluated in

six male dock builders of Scandinavian descent with fair skin. These builders had worked on this

particular construction site for 5 months, but had an average of 16.6 years of work as pile-drivers (NIOSH

1981a). The dermal burning and irritation experienced by these workers upon dermal contact with wood

treated with coal tar creosote was exacerbated on hot or sunny days. Skin examinations of these dermally

exposed workers revealed erythema and dry peeling skin on the face and neck with irritation and

folliculitis on the forearms. These symptoms were worse on hot or sunny days, at which time red,

swollen, and puffy eyes were observed. Thus, phototoxicity compounds the irritative response of the skin

to coal tar creosote. No skin tumors were observed in this study, but it is not clear if the exposure

duration in the group of workers was sufficient to allow development of skin tumors. Nevertheless, some

studies have reported latency periods for the development of dermatoses, such as squamous papillomas,

ranging from several months to 16 years or more (Cookson 1924; Henry 1946, 1947; O'Donovan 1920;

Shambaugh 1935). Effects similar to those seen in the NIOSH (1981a) study were noted in workers

transferring coal tar pitch from a river barge to an ocean barge (NIOSH 1982). Exposure levels of coal tar

pitch volatiles measured were considered to represent the minimum ambient air exposure in the barge area

because of unusual environmental sampling conditions. These levels ranged from below the detectable

limit to 0.06 mg/m3

 for breathing zone samples and from below the detectable limit to 0.02 mg/m3 for

area samples. Other studies have been published that describe similar effects of coal tar exposure,

although exposure levels are not specified (Emmett 1986). 

Coal tar creosote has been reported to produce types of noncancerous skin lesions other than burns and

irritation following dermal exposure (Haldin-Davis 1935; NIOSH 1982; Schwartz 1942; Shambaugh

1935). Haldin-Davis (1935) described the case of a man employed in the activity of dipping wood in

creosote tanks who received "heavy" dermal exposure to coal tar creosote (level not determined) on the

face, trunk, and thighs. He subsequently developed a number of lesions on the hands, forearms, and

thighs. One of these lesions was excised and examined, and classified as a benign squamous cell
CREOSOTE 127

3. HEALTH EFFECTS

papilloma. A study was made of the cases of cancer of the lip at various New England hospitals

(Shambaugh 1935). Men who were constantly exposed to tars were those who worked in "net lofts" 

where the fishing nets are repaired and tarred. It was common practice to hold the large wooden shuttlelike needle in the mouth while the tarred nets are being mended. The needle soon becomes smeared with

the tar, which is thus carried to the lip. It was found that the older workers who had been exposed to the

tar for many years showed typical tar warts on the hands and forearms. An irritative condition on the

forearms, which they call "pinginitis," evidently a pustular folliculitis (not cancerous), was observed. 

Three workers in factories erected for manufacturing armaments developed symptoms 1–2 weeks after

beginning work which were attributed to the creosote that evaporated off the wooden floors (Schwartz

1942). It was likely that the fresh creosote on the blocks came in contact with the ends of the trousers and

rubbed against the ankles. These employees noticed that their ankles began to itch above the shoe tops

and later an erythematous, papular, and vesicular eruption appeared. The lesion extended 4 or 5 inches

above the shoe tops, and when seen, presented the appearance of a scratched eczematoid dermatitis. Their

condition improved over the weekend. One patient, before the etiology of the condition was discovered,

had been treated with a coal tar ointment and the dermatitis became worse. Patch tests were not

performed with scrapings from the wooden blocks. It has been reported that chronic hyperpigmentation,

a darkening of the skin also known as pitch melanosis, may develop after $5 years of exposure to coal tar

pitch (EPA 1978b). Even unexposed areas may be affected.

In an industrial health survey of 251 employees in four wood preservative plants in which coal tar

creosote and coal tar were the main treatments used, 82 cases of dermal effects, including skin irritation,

eczema, folliculitis, and benign growths on the skin were reported. It is not stated in the report whether

multiple conditions were evident in any of the workers examined (TOMA 1979). Workers in nine coal

tar plants had a 20% incidence of dermal effects including keratosis, eczema, folliculitis, and chloracne

(TOMA 1981). The incidence of benign growths, eczema, and folliculitis was greater than that observed

in the general U.S. population, although the authors concluded that only the cases of folliculitis were

sufficiently severe to be significant. However, no clear relationship could be established because

exposure routes in addition to dermal were likely, such as inhalation and oral. Also, the ability to relate

dermal effects to coal tar creosote and coal tar exposure was further confounded by the possibility that the

subjects were also exposed to other chemicals and cigarette smoke (TOMA 1979, 1981). Additional

study limitations are noted above under “Respiratory Effects.”

The National Institute for Occupational Safety and Health (NIOSH) has investigated potential employeerelated health effects in mixers and laborers exposed to coal tar/coal tar creosote/clay products in a
CREOSOTE 128

3. HEALTH EFFECTS

refractory cement factory (NIOSH 1980a). Six of seven environmental samples collected exceeded the

Permissible Exposure Limit (PEL) for coal tar products (cyclohexane solubles, which include creosote) of

0.1 mg/m3

. Exposures were reported to be as high as 1.42 mg/m3. Because environmental levels

significantly exceeded the PEL, it is likely that considerable dermal exposure occurred. One worker

reported the need for medical treatment when coal tar creosote splashed in his eye, and another claimed

that he was hospitalized for 3 days after experiencing convulsions following an incident where he was

splashed with coal tar creosote. The medical records for these two men were not reviewed.

A site surveillance program conducted by the Texas Department of Health beginning in 1990 at a housing

development in Texarkana, Texas, that had been built on part of an abandoned Koppers Company, Inc.,

creosote wood treatment plant revealed dermal effects of creosote exposure in the residents (Agency for

Toxic Substances and Disease Registry 1994). Since all of the residents from the Koppers area who were

participating in the survey were African American, the chosen regional comparison population was also

African American. No data were presented in this study regarding the relative importance of inhalation

versus dermal exposure. Residents living in or near the Koppers area reported a higher prevalence of skin

rashes (27.9%) during the first year of the surveillance than the comparison neighborhood (4.9%), with a

RR of 5.72 (P<0.05; 95% CI=3.01–10.87). During the second year of the surveillance, the responses of

the Koppers area residents were compared with the 1990 National Health Interview Survey results, and

similar results were obtained, with 34 Koppers residents reporting skin rashes, compared to an expected

incidence of 4. Rashes were associated with digging in the yard, having contact with the soil, or wading

in or having contact with a creek in the area. Most rashes were associated with itching or burning. The

recommendation was that residents in the Koppers area should wear protective clothing when having

contact with the soil, and should wash their skin thoroughly when contact with the soil occurs.

Skin irritation is also observed in laboratory animals following dermal exposure to coal tar creosote. The

effects of dermally applied coal tar fractions, derived from creosote and anthracene oils by hightemperature boiling, were studied in mouse tail skin at concentrations of 5 and 10% (acids) in paraffin by

Wrench and Britten (1975). Several of the fractions caused irritation, and some caused peeling and

epidermal thickening. The authors concluded that the acids that boiled in the range from 280 to 340 EC

have a more specific action in inducing granular layers than the parent tars, oils, or whole acids at similar

concentrations. This study is of limited value because the chemical composition of the acid fractions was

not defined, and no dose levels could be quantified. It can only be concluded that certain fractions of coal

tar creosote irritate mouse skin. 
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Three samples of Scottish blast-furnace tar (I, II, and III), one sample of English tar, and an ether extract

of English tar were applied in a clipped area of skin in the region between the shoulder blades of 60 mice

(Bonser and Manch 1932). Tar was applied biweekly for the first 14 weeks, and thereafter once weekly. 

This change in the frequency of the tar applications was necessitated by the rather marked tendency to

ulceration of the skin exhibited by many of the mice. This experiment was continued for 56 weeks, by

which time all mice had died. At 30 weeks, 35 of 60 mice applied with ether extract of English tar died

and among the 25 survivors, 50% bore tumors. The first appearances of warts in mice applied with

Scottish tar (samples I, II, and III), English tar sample, and ether extract of English tar was in 16 (7 of

60 animals), 21 (8 of 60 animals), and 12 (24 of 60 animals) weeks, respectively. Warts were confirmed

histologically in 4, 3, and 16 mice (per sample), treated with Scottish tar (samples I, II, and III), English

tar, and ether extract of English tar, respectively. 

The skin of 10 groups of Swiss albino mice was treated with 9% benzene solutions of two coal tar pitches

of known PAH content (Wallcave et al. 1971). An additional group of 15 males and females were painted

with benzene only and served as controls. Zones of approximately 1 square inch were shaved in the skin

of the back of each animal and the solutions of coal tar pitch were painted in this area 2 times/week with

25 mL of solution (approximately 1.7 mg coal tar pitch per treatment). Animals exhibited hyperplasia of

the epidermis as a general phenomenon, frequently accompanied by inflammatory infiltration of the

dermis and on several occasions ulceration with formation of small abscesses. This effect was also seen

after application of a 10% solution of petroleum asphalts (Wallcave et al. 1971). The effect, if any, of

benzene on the dermal absorption of asphalt components was not evaluated in this study. 

Guinea pigs also exhibited phototoxicity after dermal treatment with coal tar pitch distillates and UV light

(Emmett 1986). In addition, the histological effects of coal and birch tar on guinea pig teat epidermis

treated over a period of 22 days have been investigated (Schweikert and Schnyder 1972a, 1972b). 

Preparations of both coal and birch tar induced a proliferate acanthosis. 

 

Rabbits given single dermal applications of undiluted coal tar creosote exhibited slight to moderate

erythema and moderate edema followed by severe hyperkeratosis (Pfitzer et al. 1965). 

Coal tar was applied to the ear of male Australian albino rabbits 5 days/week for 3 weeks (Kligman and

Kligman 1994). Comedones were visible on the ear after 3 weeks of treatment with 0.1 or 1.0% coal tar. 
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In summary, dermal application of either coal tar or beechwood creosote results in mild-to-severe

irritation of the skin, and other exposed tissues, as well as benign skin lesions in both humans and

animals. Coal tar creosote also induces phototoxicity, so that exposure to the sun exacerbates its irritant

effects. 

Ocular Effects. 

Coal Tar Products. Direct exposure of the eye to coal tar creosote is irritating to the superficial tissues. 

Factory and construction workers, roofers, and other workers who handle coal tar, or wood treated with

coal tar creosote have experienced conjunctiva burns and irritation resulting from accidental exposure

(Birdwood 1938; Emmett 1986; Jonas 1943; NIOSH 1980a, 1981a). Exposure to the sun exacerbated eye

irritation from exposure to creosote or coal tar fumes. It was reported in a review by EPA (1978b) that

acute episodes involving the eyes usually begin 2–4 hours after initial exposure to pitch fumes or pitch

dust. Symptoms may include reddening of the eyelids and conjunctiva. Discontinuation of exposure will

not always result in cessation of symptoms, but in mild cases, the symptoms disappear within 3 days. 

Chronic exposures may lead to damage to the cornea, chronic conjunctivitis, and restriction of the visual

field. The likelihood of adverse effects on the eye may be reduced by maintaining the levels of coal tar

pitch volatiles in air below 0.2 mg cyclohexane solubles per cubic meter. In one study, conjunctivitis was

not observed at coal tar pitch levels below 0.11 mg cyclohexane solubles per cubic meter (EPA 1978b).

Similar effects (tearing, phototoxicity, and keratoconjunctivitis) have been observed in animals, including

C3H/HeJ mice and New Zealand rabbits (Emmett 1986). Instillation of 0.1 mL undiluted coal tar

creosote in the eyes of New Zealand white rabbits produced a redness of the conjunctiva with congested

vessels that resolved within 7 days (Pfitzer et al. 1965).

Body Weight Effects. 

Coal Tar Products. In a developmental study of Sprague-Dawley rats and CD-1 mice exposed to 0, 500,

or 1,500 mg/kg coal tar on gestational days 11–15, rats had significant decreases in extragestational body

weight compared with controls, while mice had no significant change in extragestational body weight

compared with controls (Zangar et al. 1989). Body weight effects were noted in a study conducted by

Deelman (1962), in which mice were exposed dermally to an unspecified amount of tar applied

6–18 times over 6–7 weeks. "Diminished weight" was noted, although no details or data were presented. 

Asphalt (50 μL of a 500 mg/mL solution) and coal tar pitch (50 μL of a 30–84 mg/mL solution) applied
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to an unspecified area of the skin of Swiss CD-1 and pigmented C3H/HeJ male mice 2 times/week for

78 weeks had no adverse effect on body weight (Niemeier et al. 1988). 

3.2.3.3 Immunological and Lymphoreticular Effects

Creosote Bush. Several cases of acute allergic dermatitis have been reported following contact with the

creosote bush. Smith (1937) described the case of a patient who presented with erythematous and

vesicular dermatitis of the face, the upper part of the neck, and the backs of the hands after collecting

creosote bush. Patch tests confirmed the existence of an allergy to this plant. Leonforte (1986) reported

six cases of acute allergic dermatitis subsequent to contact with a creosote bush and confirmed by a patch

test. Two cases were a result of "casual occupations," two were a result of household remedies, and two

were a result of burning the bush. Based on his findings, the author concluded that the allergens are

probably contained in the plant's perfume, are volatile, and are not destroyed by heat. The relevance of

these findings to individuals who live in areas surrounding hazardous waste sites and who will most likely

be exposed to coal tar creosote is questionable. Creosote bush resin differs from creosote extracted from

coal and wood tar, but all contain phenolic derivatives. It is not known whether these derivatives are the

allergens in creosote bush resin.

Coal Tar Products. Contact dermatitis has also been reported after short-term contact with coal tar

(Cusano et al. 1992). No adverse immunological effects were observed in patients with chronic plaque

psoriasis who were treated with increasing concentrations (1–4%) of topical coal tar paste (Gilmour et al.

1993). Autoantibodies, serum immunoglobulin and complement levels were measured; two patients with

psoriasis had slightly elevated IgE levels and several had slightly raised concentrations of serum

immunoglobulin isotopes and complement components, but these were within normal ranges in most

psoriasis patients. Percentages of subsets of peripheral blood mononuclear cells (PBMC) were normal

and were not altered by treatment. Lymphocytic infiltration was noted in the pathological evaluation of a

tar carcinoma excised from the eyelid of a tar and pitch worker (Goulden and Stallard 1933). 

There is very little information describing immunological and lymphoreticular effects of coal tar products

in animals after dermal exposure. In a developmental study of Sprague-Dawley rats and CD-1 mice,

exposure of rats to 500 or 1,500 mg/kg coal tar on gestational days 11–15 resulted in significant decreases

in maternal thymus to body weight ratios for treated animals compared with controls, while spleen

weights were similar in control and treated animals (Zangar et al. 1989). Exposure of mice to coal tar

produced a significant increase in maternal spleen to body weight ratios for treated animals compared
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with controls, while thymus weights were similar in control and treated animals (Zangar et al. 1989). 

Amyloidosis of the spleen and inflammatory infiltration of the dermis were observed in Swiss mice after

topical application of 2.5 mg asphalt in 10% benzene solutions twice weekly for 81–82 weeks (Wallcave

et al. 1971). The effect, if any, of benzene on the dermal absorption of asphalt components was not

evaluated in this study.

3.2.3.4 Neurological Effects

No studies were located regarding neurological effects in animals following dermal exposure to wood

creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles.

Coal Tar Products. A worker who was splashed with coal tar creosote in a refinery claimed that he was

hospitalized for 3 days after experiencing convulsions (NIOSH 1980b). The medical records for this man

were not reviewed, so it cannot be concluded that creosote exposure was responsible for his convulsions. 

No additional information was provided. Observations were made of the effect of coal tar creosote on

workers constructing buildings with treated wood (Jonas 1943). Complications observed in 2.4% of the

workers included neurological symptoms including headache, weakness, confusion, vertigo, and nausea. 

3.2.3.5 Reproductive Effects

No studies on the reproductive effects produced by dermal exposure to wood creosote, coal tar pitch, or

coal tar pitch volatiles in human or animals were located. 

Coal Tar Products. One retrospective human study of dermal exposure to coal tar was located in which

64 women who had been treated with coal tar for psoriasis or dermatitis were issued questionnaires

(Franssen et al. 1999). Fifty-six of the women returned the questionnaires. The ratio of dermatitis to

psoriasis was 1:2 with a mean percentage treated body area of 78–90%, and the women were between

18 and 35 years of age for the period of the study (1981–1985). In total the women had been pregnant

103 times. In 59 out of 103 pregnancies, no coal tar had been used; in 21 pregnancies, it was unclear

whether coal tar had been used or not, and in the remainder, coal tar had been used at some point during

pregnancy. Untreated pregnancies resulted in 19% spontaneous abortion while treated pregnancies

resulted in 26% spontaneous abortion. The authors did not consider this to be a significant increase in

spontaneous abortion compared with the general population, but pointed out that their sample size was

small and this study probably did not have sufficient resolution to detect a modest increase in risk.
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A site surveillance program conducted by the Texas Department of Health beginning in 1990 at a housing

development in Texarkana, Texas, that had been built on part of an abandoned Koppers Company, Inc.,

creosote wood treatment plant revealed no adverse reproductive effects in the residents (Agency for Toxic

Substances and Disease Registry 1994). There was no difference in the reproductive outcome of female

residents of the Koppers area compared to the comparison neighborhood or the 1990 National Health

Interview Survey. In particular, there was no effect on number of pregnancies, live births, premature

births, spontaneous abortions, or still births. Koppers women who reported having problems becoming

pregnant during the first year of surveillance had an average of 1.3 pregnancies compared to an average

of 3.4 pregnancies from women in the comparison neighborhood who also reported difficulty in

becoming pregnant. No difference in pregnancy outcome was noted during the second year of

surveillance, and rates of stillbirth, low weight birth, or spontaneous abortions were similar to those of

unexposed populations (Agency for Toxic Substances and Disease Registry 1994). It is likely that reports

of difficulty in becoming pregnant were confounded by perception of risk and possibly also by the age of

the mother as the difference was not significant when the results for the entire group were adjusted for

concerns about chemical exposure, or when women over the age of 39 were excluded from the analysis. 

A retrospective study of dermal exposure to coal tar found no increased risk of spontaneous abortion

associated with exposure to coal tar during pregnancy, but this was a small study and was unlikely to have

sufficient resolution to detect a modest increase in risk (Franssen et al. 1999).

In a developmental study of Sprague-Dawley rats and CD-1 mice, exposure to 500 or 1,500 mg/kg coal

tar on gestational days 11–15 resulted in significant decreases in uterine weight (Zangar et al. 1989). No

difference in extragestational body weight gain of the mouse dams was observed, but some maternal

toxicity in the form of significantly increased weights of the liver, kidney, and spleen was seen. The

extragestational body weights of treated rats were significantly decreased compared to controls and the

relative weights of maternal liver and kidney were significantly increased while those of the thymus were

significantly decreased. The relative weights of the spleen and adrenal glands were unaffected by

treatment. Resorptions were significantly increased for all exposed rats and high dose mice compared to

controls. Early resorptions (occurred before dosing) were similar in all groups, but middle resorptions

(which corresponded to the dosing period) were significantly increased in exposed rats and high dose

mice. Late resorptions were also significantly increased in exposed rats. 
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3.2.3.6 Developmental Effects

No studies on the developmental effects produced by dermal exposure to wood creosote, coal tar, coal tar

pitch, or coal tar pitch volatiles in humans were located. 

Coal Tar Products. A site surveillance program was conducted by the Texas Department of Health

beginning in 1990 at a housing development in Texarkana, Texas, that had been built on part of an

abandoned Koppers Company, Inc. creosote wood treatment plant (Agency for Toxic Substances and

Disease Registry 1994). There was no difference in the number of low birth weight births or birth

defects. One retrospective human study of dermal exposure to coal tar was located in which 64 women

who had been treated with coal tar for psoriasis or dermatitis were issued questionnaires (Franssen et al.

1999). Fifty-six of the women returned the questionnaires. The ratio of dermatitis to psoriasis was

1:2 with a mean percentage treated body area of 78–90%, and the women were between 18 and 35 years

of age for the period of the study (1981–1985). In total, the women had been pregnant 103 times. In

59 out of 103 pregnancies no coal tar had been used, in 21 pregnancies it was unclear whether coal tar had

been used or not and in the remainder coal tar had been used at some point during pregnancy. Untreated

pregnancies resulted in 5% congenital disorders while treated pregnancies resulted in 4% congenital

disorders. The authors pointed out that their sample size was small and this study probably did not have

sufficient resolution to detect a small increase in risk.

In a developmental study of Sprague-Dawley rats and CD-1 mice, exposure of 0, 500, or 1,500 mg/kg

coal tar on gestational days 11–15 resulted in significant increases in developmental defects (Zangar et al.

1989). Both rats and mice exposed to coal tar showed a significant decrease in uterine weight compared

with controls. No difference in extragestational body weight gain of the mouse dams was observed, but

some maternal toxicity in the form of significantly increased weights of the liver, kidney, and spleen was

seen. The extragestational body weights of treated rats were significantly decreased compared to controls

and the relative weights of maternal liver and kidney were significantly increased while those of the

thymus were significantly decreased. The relative weights of the spleen and adrenal glands were

unaffected by treatment. Fetal and placental weights and crown-rump lengths decreased in a dose

dependant manner and fetal lung weights were decreased on absolute and relative weight basis for both

low and high dose rat groups. There was no significant difference between fetal weight, placental weight,

and fetal lung weights and crown-rump lengths in control and exposed mouse fetuses. A significantly

increased incidence of small lungs, cleft palate, edema, midcranial lesion, and reduced cranial ossification
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3. HEALTH EFFECTS

was observed in exposed rat fetuses and a significantly increased incidence of cleft palate, dilated ureter,

and renal pelvic cavitation was observed in exposed mouse fetuses.

Another animal study reported that dermal contact with coal tar creosote-treated wood produced fetotoxic

effects in pregnant sows (Schipper 1961). Four sows were confined to wooden farrowing crates for

2–10 days before delivery. The platforms of the crates were coated with three brush applications of a

commercial wood preservative containing 98.5% coal tar creosote. Following contact with creosote,

24 of the 41 pigs delivered were dead at birth, and 11 pigs died by day 3 postfarrowing. The surviving

pigs had rough skin and suffered from dehydration and severe diarrhea. The pigs failed to gain weight

until they were 5–6 weeks old. No toxic effects on the sows were reported. However, 4 sows confined to

untreated lumber crates at least 24 hours before farrowing delivered 36 pigs; 1 died within 24 hours and

3 died postfarrowing. No toxic effects were noted in mothers or baby pigs.

3.2.3.7 Cancer

Coal Tar Products. Various case reports and the results of cross-sectional occupational surveys associate

chronic occupational creosote (coal tar) exposure with the development of skin cancer (Cookson 1924;

Goulden and Stallard 1933; Henry 1947; Lenson 1956; Mackenzie 1898; O'Donovan 1920; Shambaugh

1935; Shimauchi et al. 2000). These papers reported similar neoplastic skin lesions for different groups

of workers exposed to creosote. Lesions included the development of dermatoses (e.g., squamous

papillomas), which progressed to carcinoma, usually squamous-cell carcinoma. Tumor locations included

regions of the face, head and neck, and upper limb. Cancer of the scrotum has also been associated with

prolonged exposure to coal tar creosote (Henry 1946). The latency period for the development of

dermatoses, such as squamous papillomas, was varied, ranging from several months to 16 years or more

(Cookson 1924; Henry 1946, 1947; O'Donovan 1920; Shambaugh 1935). Worker exposure in the past

was much greater than it is now because of less-sophisticated industrial practices, the lack of knowledge

concerning occupational hygiene, and the current recognition of the dangers of excessive exposure to the

health of workers. For example, chimney sweeps had a lower incidence of scrotal cancer after limiting

their exposure to coal tar creosote by regular washing of their skin. Other factors that should be

considered when extrapolating the findings of this older literature to present conditions are the role of

exposure to UV radiation in the form of sunshine in these workers (UV radiation is now known to be a

major cause of skin cancer), the composition of the creosote products, and other health factors that differ

in Great Britain prior to 1940 and the present. Although these studies lack information concerning

specific exposures and do not consider other risk factors for the development of skin cancer, when taken
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as a group, they suggest a relationship between chronic dermal coal tar creosote exposure, phototoxicity,

and the development of skin carcinoma in humans.

The effect of treatment with tar and/or artificial UV radiation on the risk of developing cutaneous

carcinoma was evaluated on skin cancer patients (59 cases) with severe psoriasis (Stern et al. 1980);

924 subjects without skin cancer were selected as unmatched controls. A matched group (58 cases and

126 matched controls) was also selected from the same group of controls. Patients were categorized

according to amount of tar use (<30, 30–90, or >90 months) and levels of radiation exposures (low,

moderate, or high). The relationship between tar exposure and UV radiation treatment and the

development of skin cancer both before and after 8-methoxypsoralen photochemotherapy (PUVA) were

evaluated. The estimated crude relative rate of cutaneous carcinoma for all patients with high exposure to

tar or UV radiation, or both, was 2.4, compared with patients without high exposure. The reported

relative rates were 1.8 for high-exposure groups of the prevalence cases and 3.0 for incidence cases. For

the matched set of cases and controls, the estimated relative rate for all cases was 4.7. Prevalence and

incidence cases in matched sets showed significantly increased risk. However, the conclusions that can

be drawn from this study regarding the association of coal tar exposure and skin cancer are limited by the

fact that the association of cancer risk and coal tar or UV radiation exposure was not examined separately

for each agent.

Bhate et al. (1993) reported that incidence of cancer (total, skin, breast, cervix, genitourinary tract,

bronchus, gastrointestinal tract, lynphoma, or other) was not significantly greater in 2,247 patients with

psoriasis than in 4,494 age-matched controls without psoriasis. However, they noted that there was a

statistically significant increase in skin cancer in the subgroup of 1,252 female psoriasis patients

(24/1,228 psoriasis, 25/2,479 controls, P=0.032) and postulated that this might be associated with the fact

that women were generally exposed to more treatments for psoriasis than men. The numbers of patients

exposed to particular treatments (1,641 psoriasis patients had received coal tar treatment, but many

patients had received more than one form of treatment) was too small to allow a statistical analysis of

therapeutic risk factors. The authors calculated that although their study population was large, cancer

incidence in psoriasis patients would have to be increased to 163% of control levels to be statistically

significant at the P=0.05 level.

Fisher (1953) examined a group of 241 tar workers who had not been previously exposed to other

carcinogens and found an increase in the number of “tar warts” (defined by the author as early squamouscelled epitheliomas) with duration of exposure. The percentage of workers with warts rose from 5% in
CREOSOTE 137

3. HEALTH EFFECTS

men with <5 years of exposure to 50% in men with 20–25 years exposure and 100% in men with more

than 40 years exposure. The author stated that age on starting exposure also influenced susceptibility to

tar warts, but did not present the data supporting this statement. No statistical analysis of the data was

performed. 

Other investigators who have examined the possibility of increased skin cancer incidence in psoriasis

patients (Jones et al.1985; Menter and Cram 1983; Torinuki and Tagami 1988) have concluded that coal

tar treatment did not produce an increase in cancer incidence, but all of these studies are limited in scope

and it is not likely that they would be sufficiently sensitive to detect a small increase in risk. Jones et al.

(1985) reported no increase in cancer incidence in 719 tar-treated psoriasis patients compared with the

general population. Torinuki and Tagami (1988) reported no effect of tar on cancer rates in patients

treated with coal tar and UV light, but only 5 of 43 patients had a follow-up duration of >6 years and this

is likely to be insufficient to detect a possible cancer effect. Menter and Cram (1983) reported their

opinion that there was no increase in incidence of skin cancer in patients treated with UV light and coal

tar, but this was a study of the efficacy of the treatment regime and thus, no untreated controls were

included for comparison and no statistical analysis was performed. 

Several other studies are available that suggest that there is no association between exposure to coal tar

creosote or other coal tar products and cancer in humans. Data from a population-based case-control

interview study of 1,867 white men (622 cases and 1,245 controls) in Iowa and Minnesota conducted

during 1980–83 were examined (Blair et al. 1993). Interviews were conducted with individuals or their

next of kin to obtain information on agricultural exposures, residential history, medical history, family

history of cancer, and a detailed occupational history. White men without hematopoietic or lymphatic

malignancy were selected as controls. Risks of non-Hodgkin's lymphoma (NHL) were evaluated by

intensity or probability of exposure to specific substances. No increased risk was noted with exposure to

creosote or asphalt. No increased incidence of nonmelanoma skin cancer was observed in 426 patients

25 years after they had undergone 4 years of coal tar medicinal therapy in combination with UV light for

the treatment of atopic dermatitis and neurodermatitis (Maugham et al. 1980). This study is limited in

that follow up occurred in only 72% of the patients, and there was no discussion of recall bias or of the

effects of mobility (i.e., relocation of the study participants) on the results. In a 25-year retrospective

study of 280 psoriatic patients treated with crude coal tar in combination with UV radiation at the Mayo

clinic, it was found that the incidence of skin cancer in these patients was not significantly increased

above the expected incidence for the general population (Pittelkow et al. 1981). Chemical and biological

analysis of coal tar-based therapeutic agents and industrial grade coal tar indicated that the therapeutic
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agents and the industrial materials were similar (Wright et al. 1985). The authors suggest that the lack of

carcinogenic effects after therapeutic exposure may be due to the presence of solvents and surfactants in

the preparations, which may alter deposition and absorption by the skin. Reducing the contact with the

therapeutic agents by regular washing may also be a factor (Wright et al. 1985). A case-control study was

carried out on 24 PUVA-treated patients with squamous cell cancer of the skin and 96 PUVA-treated

patients as matched controls (Lindelof and Sigurgeirsson 1993). Information on past therapies was

obtained by questionnaire designed to determine if previous therapy was a risk factor for skin cancer in

PUVA-treated patients. For subjects using previous tar therapy, there were 17 of 24 cases of skin cancer

(70% exposed) with an estimated RR of 1.3 (95% CI=0.5–3.5); control subjects reported 62 of 96 cases

(64% exposed). Prior treatment with tar was not considered to be a risk factor for skin cancer in

PUVA-treated patients. 

Another study was located that reported that there was no increase in the risk of skin, bladder, or lung

cancer in wood treatment plant workers, where coal tar creosote and coal tar pitch were the chemicals

used (TOMA 1980). Nevertheless, these findings are of limited value since the study population was

limited to those currently working at the plant, was small, and comprised of 46.5% blacks, who

experience a very low incidence of skin cancer compared to whites. In addition, the exposure and follow

up periods did not allow a long enough latency period for tumor development and there was no

verification provided that those studied were actually exposed to coal tar creosote or coal tar. No

association was found between bladder cancer and occupational exposures to coal tar and pitch or

creosote in a case-control study of 484 persons with confirmed bladder cancer (Siemiatycki et al. 1994).

A large body of evidence exists to show that coal tar is carcinogenic when applied to the skin of

laboratory animals. Many of the early studies are limited in that they lack appropriate negative control

data, the dose of creosote and the chemical composition of the fractions studied were not quantified, and

no other tissues were generally examined (Deelman 1962; Hueper and Payne 1960; Watson and Mellanby

1930). The results from later studies that include appropriate control groups are consistent with the

earlier studies that found that coal tar is carcinogenic following dermal application to rodent skin. The

more detailed dermal carcinogenicity studies are reviewed below, and the relevant CELs are presented in

Table 3-4.

The tumor-promoting potential of coal tar creosote was evaluated by applying various fractions (e.g.,

basic, phenolic, and neutral) to the skin of albino mice in conjunction with benzo[a]pyrene (Cabot et al.

1940). The various fractions of creosote oil were prepared by distillation and separation; 90% of the
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creosote oil distilled between 160 and 300 EC. The basic fraction was removed with aqueous

hydrochloric acid. The phenolic fraction was removed with aqueous sodium hydroxide. The remaining

neutral fraction was then steam distilled. The composition of the various fractions was not specified. 

The tumorigenic effect of benzo[a]pyrene was retarded by the creosote oil, neutral distillate, neutral

residue, and phenolic fractions. However, in three instances this effect was apparently related to skin

damage associated with the treatments rather to a specific inhibitory effect. Only the phenolic fraction

seemed to exhibit a primary antagonistic effect. Three other fractions (basic, neutral, and a low

concentration of neutral distillate) exhibited apparent tumor promoting effects.

Ten groups of Swiss albino mice were exposed topically with 9% benzene solutions of two coal tar

pitches of known PAH content (Wallcave et al. 1971). An additional group of 15 males and females was

painted with benzene only and served as controls. Zones of approximately 1 square inch were shaved in

the skin of the back of each animal and the solutions of coal tar pitch were painted in this area

2 times/week with 25 mL of solution (approximately 1.7 mg coal tar pitch per treatment). Animals were

weighed once a week (no data shown) and all tumors arising in the skin were charted. Animals were

sacrificed when moribund or when they developed highly advanced tumors on the skin. A complete

autopsy was performed on all animals, and sections of the skin as well as all grossly pathological organs

were studied histologically. Coal tar-painted animals developed squamous cell carcinomas and benign

tumors in the form of squamous cell papillomas and keratoacanthomata; 91.4% of animals bore some

kind of skin tumor. The potential effects of benzene on the dermal absorption of asphalt components

were not evaluated in this study.

Weanling C3H/HeJ mice were exposed to 50 mg solutions containing 25 mg of roofing materials

(traditional coal tar pitch, coal tar bitumen, standard asphalt from roofing operation, coal tar bitumen from

roofing operation, or roofing dust) 2 times/week for 80 weeks, or until a skin lesion was diagnosed as a

papilloma (Emmett et al. 1981). The material was dissolved or suspended in redistilled toluene in a 1:1

ratio (w/w) and applied to the intrascapular region of their backs, where hair had been previously

removed. A vehicle control group received 50 mg of toluene 2 times/week, and a positive control group

received 50 mg of 0.1% solution of benzo[a]pyrene in toluene 2 times/week. When the papilloma

progressed and was diagnosed grossly as a carcinoma, the mouse was sacrificed and autopsied. Selected

histopathologic examination of tumors was made to confirm the gross diagnosis. It was found that

traditional coal tar pitch and dust from removal of an old roof were significantly more carcinogenic than

coal-derived roofing bitumen, but all were strongly carcinogenic. The average times of the appearance of

papillomas (and percentage of mice developing tumors) were at 18 (98%), 21.5 (98%), 20.5 (93%),
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16.5 (86%), and 31.8 (79%) weeks for traditional coal tar pitch, coal tar bitumen, coal tar bitumen from

roofing operation, roofing dust, and positive control, respectively. No tumors were caused by standard

roofing asphalt or toluene. The percentage of benzo[a]pyrene in the materials was as follows: traditional

coal tar pitch, 0.064%; coal tar bitumen, 0.072%; standard asphalt, <0.004%; coal tar bitumen from

roofing operation, 0.064%; roofing dust 0.08%; toluene, 0%; and positive control, 0.1%. 

Asphalt and coal tar pitch were the materials used in assessing skin carcinogenesis in nonpigmented

Swiss CD-1 and pigmented C3H/HeJ male mice (Niemeier et al. 1988). Animals were divided into

48 experimental groups and treated as follows: (a) 32 groups treated for the primary factorial experiment

(i.e., 2 strains x 4 materials x 2 generation temperatures [232 and 316 EC] x 2 light exposure conditions

[presence or absence of simulated sunlight]); each animal dosed 2 times/week with 50 μm of the

appropriate test material; (b) 4 groups for the solvent control (i.e., 2 strains x 2 light exposure conditions;

each animal dosed 2 times/week with 50 μL of cyclohexane/acetone [1:1] vehicle); (c) 2 groups for cage

control (i.e., 2 strains x 2 light exposure conditions, dosed 2 times/week with 50 mL solvent and not sham

irradiated but always maintained in their individual cages); (d) 4 groups for the positive control (i.e.,

2 strains x 2 light exposure conditions, dosed 2 times/week with 50 μL of the solution of 0.01%

benzo[a]pyrene in cyclohexane:acetone [1:1]); (e) 4 groups for a combination treatment of asphalt and

coal tar pitch fume condensate (i.e., 2 strains x 2 light exposure conditions; each animal dosed

2 times/week with the high temperature condensate from Type III asphalt and Type I coal tar pitch, on

alternate weeks); and (f) 2 groups (i.e., 2 strains, for light exposure 2 times/week with no skin painting

treatment). Mice were observed daily for systemic toxicity and gross appearance of tumors. Mice found

dead were necropsied and those that were moribund were sacrificed and necropsied. Surviving mice at

the end of 78 weeks were also necropsied. Tissues were examined and skin lesions excised and prepared

for microscopic examination. The theoretical air concentrations of PAH from coal tar pitch at 232 and

316 EC were 5.0x106

 and 55.1x106 mg/m3, respectively. The theoretical air concentrations of

benzo[a]pyrene from coal tar pitch at 232 and 316 EC were 55.6x103

 and 366.7x103 mg/m3, respectively. 

The theoretical air concentrations of PAH from asphalt at 232 and 316 EC were 3,300 and 15,000 mg/m3

,

respectively. The theoretical air concentrations of benzo[a]pyrene from asphalt at 232 and 316 EC were

21 and 122 mg/m3

, respectively. 

Administration of condensed fumes from both types of coal tar pitches and both types of asphalt resulted

in benign tumors (papillomas, kerato-acanthomas, fibromas, and unclassified benign epitheliomas) and

malignant tumors such as squamous cell carcinoma and fibrosarcomas (seen more often in C3H/HeJ

mice) (Niemeier et al. 1988). CD-1 mice had a much lower incidence of malignant tumors than C3H/HeJ
CREOSOTE 141

3. HEALTH EFFECTS

mice (about 5 versus 60%). The average latent period ranged from 39.5 to 56.1 weeks among C3H/HeJ

groups and from 47.4 to 76.5 weeks among the CD-1 groups. The tumorigenic response of C3H/HeJ in

the coal tar pitch Type III group with concomitant exposure to light increased with high temperature. 

Both strains when exposed to condensed coal tar pitch fumes or benzo[a]pyrene in the presence of

simulated sunlight had inhibited tumorigenic responses; C3H/HeJ strain treated with 0.01%

benzo[a]pyrene and coal tar pitch showed increased tumorigenic response. In the CD-1 strain, only the

solar exposed pitch fume groups showed significantly increased tumorigenic response when compared to

the positive control. The tumorigenic response of C3H/HeJ to the condensed asphalt fumes increased

with high temperature, but no significant change in tumorigenic response was observed for CD-1 mice

exposed to fumes at the higher temperature. Simulated sunlight significantly inhibited tumorigenic

response in C3H/HeJ mice to both types of asphalt fumes collected at the lower temperature and no

overall significant effects were noted in the CD-1 strain. Both strains when exposed to benzo[a]pyrene in

the presence of simulated sunlight had inhibited tumorigenic responses; C3H/HeJ strain treated with

0.01% benzo[a]pyrene and those exposed to the high temperature asphalt fumes showed increased

tumorigenic response. In the CD-1 strain, only the nonsolar exposed asphalt fume exposed groups

showed significantly increased tumorigenic response when compared to the positive control. In

comparing the combination group to their respective controls, the C3H/HeJ strain showed no differences

in latency, but the combination group showed a significantly increased response by the onset rate analysis

method as compared to the asphalt group (Type III-316 EC) without light. The responses in CD-1 mice

were similar, in that the nonsolar exposed combination group had a significantly increased tumor

response, as assessed by the onset rate method, compared with the asphalt group. They also died earlier

(no data shown) and developed tumors at a significantly earlier time than the asphalt group. When the

combination groups were compared to the responses of the pitch groups, onset rate analysis showed that

the sham irradiated pitch group (Type I-316 EC) had a significantly greater tumor response than the

combination group. No other differences were noted. Both strains when exposed to benzo[a]pyrene or

combination of pitch and asphalt in the presence of simulated sunlight showed inhibited tumorigenic

responses; C3H/HeJ strain treated with 0.01% benzo[a]pyrene and the combination groups and those

exposed to the high temperature asphalt fumes showed increased tumorigenic response.

In conclusion, both coal tar pitch and asphalt produced benign and malignant skin tumors in mice

(Niemeier et al. 1988), but C3H/HeJ mice were more susceptible to the formation of malignant tumors

than CD-1 mice. Concomitant exposure to sunlight reduced tumor production by coal tar pitch, or

asphalt, or the combination of coal tar pitch and asphalt compared with nonsolar exposed animals. The
CREOSOTE 142

3. HEALTH EFFECTS

combination of exposure to both asphalt and coal tar pitch increased tumor formation compared with

asphalt alone, but was reduced compared with coal tar pitch alone.

The potential of basic fractions of coal tar creosote to accelerate tumor induction by known carcinogens

was evaluated by Sall and Shear (1940). A 1% solution of the basic fraction of creosote oil in benzene

was dermally applied to female strain A mice alone or in conjunction with 0.05 or 0.02% benzo[a]pyrene. 

The basic fraction alone did not induce skin tumors, but when applied in conjunction with either

concentration of benzo[a]pyrene, skin tumors appeared more rapidly than when benzo[a]pyrene alone was

applied. Maximum tumor induction was seen between 28 and 42 weeks; 19 of 20 mice developed

tumors. 

This is in contrast to the results of a tumor initiation study by Springer et al. (1989) in which Charles

River CD-1 female mice (30 per group) were treated with crude coal tar and a variety of coal tar fractions

in an initiation assay. The backs of the mice were shaved and the skin treated with 50 μL of an acetone

solution of the various test materials. Two weeks after initiation, the animals were promoted with

twice-weekly applications of 5 μg of 12-O-tetradecanoylphorbol-13-acetate (TPA) (also known as

phorbol myristate acetate or PMA) in 50 μL of acetone for 24 weeks. Tumors were identified visually

and were not characterized further by histopathology. The time of tumor appearance and the number of

tumors were recorded as measures of response. Test materials included: 5 mg (approximately 203 mg/kg

body weight) crude coal tar (boiling point: 300–850 EF); coal tar temperature fractions (boiling points:

300–700, 700–750, 750–800, 800–850, or >850 EF); chemical fractions of the 750–800 EF temperature

fraction (aliphatics and olefins, neutral PAH, nitrogen-containing polycyclic aromatic compounds,

hydroxy-PAH); 25 μg benzo[a]pyrene; 5 mg crude coal tar +25 μg benzo[a]pyrene; coal tar temperature

fractions +25 μg benzo[a]pyrene; chemical fractions +25 μg benzo[a]pyrene. The three lower

temperature coal tar fractions did not contain benzo[a]pyrene, while the other two contributed 8.5 μg

benzo[a]pyrene towards the total dose. Mice initiated with benzo[a]pyrene alone showed the greatest

tumor response. Administration of the lowest boiling point coal tar fraction did not produce significantly

more tumors than controls. Exposure to the crude coal tar or the 700–750 and 750–800 EF fractions

produced a small, but significant increase in tumors compared with controls. The two highest

temperature fractions showed substantial initiating activity. The aliphatic fraction did not have tumor

initiating activity, the other chemical fractions had some activity, with that of the PAH fraction being the

highest and similar to that of crude coal tar. Co-administration of benzo[a]pyrene and coal tar or coal tar

fractions resulted in a decrease in the initiation of tumors compared with benzo[a]pyrene alone. The

authors suggest that the reduction in benzo[a]pyrene tumor initiation by coal tar fractions may be caused
CREOSOTE 143

3. HEALTH EFFECTS

by altered rates or routes of metabolism of benzo[a]pyrene due to the presence of various components of

the coal tar. 

The ability of coal tar creosote to induce lung tumors after dermal application to mice was studied when it

was observed that mice housed in coal tar creosote-treated wooden cages had a high incidence of lung

tumors (Roe et al. 1958). Dermally applied coal tar creosote (0.25 mL undiluted twice weekly for

8 months) induced 5.8 lung adenomas/mouse in mice that were reared in stainless steel cages. Creosote

treatment following the same regimen in mice reared in creosote-treated cages induced 10.8 lung

adenomas per mouse. Untreated controls reared in untreated cages exhibited 0.5 lung adenomas per

mouse. A high incidence of skin tumors was also observed in the creosote-treated mice reared in either

type of cage. In a second experiment, topical application of "one drop" of coal tar creosote twice a week

for only 4 weeks induced lung adenomas, but not skin tumors in mice reared in stainless steel cages. This

study demonstrated that coal tar creosote induces tumors in the lungs and skin of mice when dermally

applied. Rearing animals in coal tar creosote-treated wooden cages exacerbated the tumorigenic effect of

dermally applied coal tar creosote. Based on this study, lung tumors may be a more sensitive end point of

creosote tumorigenic activity than skin tumors after skin contact and inhalation exposure. However, this

study did not take into account possible oral exposure due to normal preening behavior.

Seven groups of 30 female Sutter mice each were treated with 75 μL dimethylbenzanthracene (DMBA)

and 25 μL coal tar creosote (undiluted creosote oil), alone and in combinations of the two to evaluate the

carcinogenic, initiating, and promoting activity of coal tar creosote on mouse skin (Boutwell and Bosch

1958). Coal tar creosote alone, DMBA and coal tar creosote, and coal tar creosote with 25 μL croton oil

(0.5% in benzene) all induced the development of papillomas and carcinomas. Tumors first appeared at

10–20 weeks of application. DMBA pretreatment shortened the latent period and increased the tumor

yield of coal tar creosote treatment, but since a nearly maximal tumor induction response (i.e., percentage

of mice with papillomas just below 100) was seen with coal tar creosote alone, tumor-promoting activity

of coal tar creosote could not be definitely proven. The initiating activity of coal tar creosote was

demonstrated by its ability to induce tumors when applied prior to croton oil treatment (croton oil alone

was without effect). Coal tar creosote alone or in combination with DMBA or croton oil induced

papilloma formation more slowly, and carcinomas appeared by 14 weeks and accumulated more rapidly

than in the DMBA plus croton oil group. Thus, this study demonstrated the carcinogenic and tumorinitiating activity of coal tar creosote on Sutter mouse skin.
CREOSOTE 144

3. HEALTH EFFECTS

The complete carcinogenic and tumor-promoting activity of undiluted coal tar creosote, a 10% solution of

creosote oil, and 2% solution of the basic fraction of coal tar creosote was studied when dermally applied

to mice (Lijinsky et al. 1957). Undiluted creosote alone induced 23 skin tumors (16 malignant) in 13 of

26 treated mice with a latent period of 50 weeks. The authors concluded that creosote alone has a

carcinogenic activity comparable to a 0.01% solution of DMBA. When applied as a promoter following a

single application of DMBA, 32 skin tumors (26 malignant) were observed in 17 of 30 mice with a latent

period of 39 weeks. The basic fraction did not act as a tumor promoter when administered after a single

application of DMBA. Thus, coal tar creosote appeared to enhance the carcinogenic activity of DMBA,

but the promoting effect was not strong, when the results were compared to DMBA positive controls.

Three-month-old Charles River CD-1 male mice (30 per group) were treated with a variety of coal

derived complex mixtures in an initiation/promotion assay (Mahlum 1983). The backs of the mice were

shaved and the skin was treated with 50 μL of the various test materials. Groups of animals initiated with

DMBA or benzo[a]pyrene served as positive controls, negative controls received 50 μL acetone. Two

weeks after initiation, the animals were promoted with twice-weekly applications of 50 μL of phorbol

myristate acetate (PMA) (also known as 12-O-tetradecanoylphorbol-13-acetate or TPA) for 6 months. 

Tumors were identified visually and were not characterized further by histopathology. The time of tumor

appearance, the number of mice with tumors, and the number of tumors per mouse were recorded as

measures of response. The following coal distillates were used as initiators: heavy distillate (HD) boiling

point range 550–850 EF; 300–700 EF boiling point range fraction, and an 800–850 EF boiling point range

fraction. In addition the following chemical fractions were prepared from HD: basic (BF), basic tar

(BTF), neutral tar (NTF), and polynuclear aromatic (PNA) fractions. The promoting activity of middle

distillate (MD), boiling point range 380–550 EF, was tested by initiating with 50 μg DMBA, followed

2 weeks later, by twice weekly applications of a 50% solution (w/v) of MD in acetone. Animals that

received no DMBA, but were treated twice weekly with MD, were used as controls. DMBA was a more

potent initiator than benzo[a]pyrene. Initiation with HD resulted in about the same incidence of tumors as

benzo[a]pyrene. NTF was almost as active an initiator as HD, while BTF was only slightly less active. 

BF and PNA were considerably less active initiators. The 800–850 EF fraction showed a low degree of

initiating activity, while the response of the 300–700 EF group was the same as the acetone controls. MD

showed a low level of promotion in animals initiated with DMBA. No uninitiated mice showed tumors

after 12 months, 17% of initiated mice had tumors at 6 months, and incidence increased to 52% by

12 months.
CREOSOTE 145

3. HEALTH EFFECTS

The carcinogenic activity of two high-temperature-derived coal tar creosote oils ("light" and "blended")

was studied by Poel and Kammer (1957). The principal components of light oil are benzene, toluene,

xylene, and solvent naphtha. Blended oil is a mixture of creosote oil, anthracene oil and the oil drained

from the naphthalene recovery operation. Its principal components are methylated naphthalenes,

acenaphthene, fluorene, phenanthrene, anthracene, and carbazole. The blended or light oils were applied

by drops to the skin of mice at concentrations of 20 or 80% (blended oil) or 50% (light oil) 3 times/week

for life. Both oils induced skin tumors in every exposure group by 26 weeks of application. Seven of the

eight mice exposed to each concentration of blended oil had tumors that progressed to malignancy. One

tumor regressed before the death of a mouse in the 80% group and one mouse in the 20% group had a

papilloma that had not become malignant by the end of the experimental period. There was no evidence

of tumor regression in the tests with light oil. Several mice exhibited metastases to the lungs or regional

lymph nodes. The fractions tested did not contain benzo[a]pyrene (limit of detection=0.03%

benzo[a]pyrene), so the authors concluded that the carcinogenic activity of the coal tar creosote oil used

in the experiment was not due to benzo[a]pyrene.

Crude coal tar (10, 25, and 100%) in petrolatum was applied to the ear of male Australian albino rabbits

(3 per group) 3 times/week for 15 weeks (Kligman and Kligman 1994). Crude coal tar was both

comedogenic and carcinogenic at all doses tested (10, 25, or 100%). Tumors developed as early as

1–2 weeks after 3 weeks of treatment with 10% coal tar. The tumors were classified as papillomas,

squamous cell carcinomas, keratoacanthomas, and cutaneous horns, and became extremely numerous

with longer treatment. 

Standard Reference Material (SRM) 1597 obtained from the National Institute of Standards and

Technology, was tested in an assay of tumor initiation in female SENCAR mice (Marston et al. 2001). 

SRM 1597 is a mixture derived from a medium crude coke oven coal tar dissolved in toluene. Certified

values have been published for selected PAH components of this mixture including B[a]P. 

Dibenzo[a,l]pyrene (DB[a,l]P) is not a component of SRM 1597. SRM 1597 (1 mg per 125 μL, which

contains 10.4 μg B[a]P) was painted onto the shaved skin of 6–7-week-old mice over a period of 2 weeks

(the number of applications was not reported) and in some cases, treatment with SRM 1597 was followed

5 minutes later with B[a]P or DB[a,l]P). The treatment groups were as follows: 10 mice with 200 μL

toluene as a control; 30 mice with 1 mg SRM 1597; 35 mice with 200 nm (50.4 μg) B[a]P in 100 μL

toluene; 35 mice with 1 mg SRM 1597 plus 200 nm (50.4 μg) B[a]P in 100 μL toluene; 35 mice with

2 nmol (0.6 μg) DB[a,l]P; and 35 mice with 1 mg SRM 1597 plus 2 nmol DB[a,l]P. Two weeks after

initiation, twice-weekly promotion was begun with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) at
CREOSOTE 146

3. HEALTH EFFECTS

1 μg/200μL acetone per mouse for 25 weeks. Mice were examined weekly for papillomas and at

25 weeks, tumors were confirmed histologically at necropsy. In the test of SRM 1597 and B[a]P, no

papillomas were found in the control group, SRM 1597 initiated 5.3 tumors per tumor-bearing animal,

B[a]P initiated 8.9 tumors per tumor-bearing animal and B[a]P plus SRM 1597 produced 8.8 tumors per

tumor-bearing animal. Results of statistical analysis of mice treated with SRM 1597 compared with

controls were not reported. Compared with B[a]P, cotreatment with SRM 1597 did not significantly

change tumor incidence, either over time, or specifically at 25 weeks. In contrast, in the test of SRM

1597 and DB[a,l]P, 1 papilloma was found on one mouse in the control group, SRM 1597 initiated

4.1 tumors per tumor-bearing animal, DB[a,l]P initiated 8.1 tumors per tumor-bearing animal, and

DB[a,l]P plus SRM 1597 produced 5.2 tumors per tumor-bearing animal. There were significant

differences in the number of tumors per tumor-bearing animal for all three treated groups and, compared

with DB[a,l]P alone, cotreatment with SRM 1597 significantly reduced the number of tumors per tumorbearing animal. This reduction may be due to decreased metabolism of DB[a,l]P with consequent

reduction in DB[a,l]P metabolite-DNA adduct formation in the presence of SRM 1597 (see Section 3.3). 

In conclusion, the results of these studies indicate that coal tar creosote and several of its fractions can be

carcinogenic when applied to the skin of mice or rabbits. Dermally applied coal tar creosote can also act

as a tumor-initiating agent. Thus, it is likely that individuals whose skin comes into contact chronically

with coal tar creosote would be at higher risk for skin cancer, particularly when exposure to other

carcinogenic substances also occurs, as is a possible scenario in areas surrounding hazardous waste sites.

3.3 Genotoxicity

Creosote Bush. No studies were located regarding genotoxic effects of the creosote bush in humans or

animals.

Wood Creosote. Zeiger et al. (1992) tested beechwood creosote in the Ames assay using Salmonella

typhimurium strains TA 97, TA98, TA100, TA102, TA104, TA1535, TA1537, and TA 1538, with and

without metabolic activation, and found it to be nonmutagenic. 

Coal Tar Products. Studies of workers exposed to coal tar, bitumen fumes, coal tar pitch, or coal tar

pitch volatiles have shown an association between exposure to these mixtures and significant increases in

genotoxic effects; however, it must be noted that a recurrent limitation of these studies is the lack of

precise exposure data. Significant increases in the frequency of chromosomal abnormalities and sister
CREOSOTE 147

3. HEALTH EFFECTS

chromatid exchanges (SCE) were observed in the peripheral blood lymphocytes (PBL) of 49 workers

exposed to coal tar for 6–10 years compared with 50 age-matched, non-exposed individuals (Yadav and

Seth 1998). There were similar findings in a study of 30 steelworkers occupationally exposed to coal tar

pitch volatiles (Bender et al. 1988). Burgaz et al. (1998) reported an elevated incidence of SCE and

micronuclei (MN) in PBL of 28 workers exposed to bitumen fumes during paving operations. A study of

24 workers exposed to coal tar pitch for 7–32 years showed a significant increase in SCE and serum P21

(the protein product of the ras oncogene) compared to 10 non-exposed individuals (Wu et al. 1998). 

Urine samples taken from 19 individuals occupationally exposed to coke oven emissions in a steel mill

and 31 controls (De Meo et al. 1987) and urine samples from 30 coke oven workers and 26 controls

(Mielzynska and Snit 1992) showed an association between exposure and increased mutagenic activity in

the Ames Salmonella typhimurium test. However, an examination of the mutagenic activity of urine from

only three workers exposed to coal tar creosote vapors at a wood preserving factory (Bos and Jongeneelen

1988; Bos et al. 1984a, 1984c) reported no mutagenic activity in 10-day urine samples. The absence of

mutagens in these urine samples was ascribed by the study authors to a relatively low level of exposure,

improper timing for urine sample collection, and the insensitivity of the assay.

Some studies have also documented increases in the number of DNA adducts in the blood of patients

undergoing dermal coal tar therapy. For instance, Santella et al. (1995) reported increases in

benzo[a]pyrene (B[a]P) DNA adducts in blood of psoriasis patients treated with 20–100 g tar per day. 

However, Pavanello and Levis (1994) found that there were no differences between the number of PAHDNA adducts formed in vivo, determined by the 32P-postlabeling method, in the PBL of psoriatic patients

treated with 50% coal tar paste for up to 8 days and adduct levels in healthy individuals not treated with

coal tar. Moreover, the levels of PAH-DNA adducts detected in patients before, during, and 16 days after

coal tar therapy were statistically unchanged. In a previous study, Pavanello and Levis (1992) had

examined the effect of coal tar treatment on DNA adduct formation in vitro in human lymphocytes taken

from four male psoriatic patients 25–70 years old treated for 4–10 days with a paste containing 50% coal

tar and nine healthy individuals who did not take any medication. No significant difference was detected

in the total amount of B[a]P-DNA adducts in blood lymphocytes from patients or controls or between

patients before and after treatment. In contrast, patients treated with a 50% coal tar paste, a 2% coal tar

ointment, or a combination of pure coal tar and 2% ointment for 3–17 days had in vivo B[a]P-DNA

adduct levels, determined by ELISA technique, that were higher during therapy than 2–5 months after

therapy termination (Pavanello and Levis 1994). A study by Sarto et al. (1989) showed an association

between the frequency of chromosomal aberrations and SCE in blood lymphocytes and the level of
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3. HEALTH EFFECTS

exposure to coal tar of patients undergoing therapy for psoriasis with topical applications of pure coal tar

or 4% coal tar-containing ointment. 

Increases in the number of DNA adducts in skin biopsy samples have been observed in patients

undergoing coal tar therapy with ointments containing 3–5% coal tar for at least 7 days (Zhang et al.

1990) and in patients treated for an average of 21 days with an ointment containing as much as 10% coal

tar (Godschalk et al. 2001). Schoket et al. (1990) observed elevated levels of adducts in skin biopsy

samples taken from psoriasis patients receiving coal tar and juniper tar (cade oil) therapy. Sarto et al.

(1989) examined the mutagenicity of urine samples taken from patients treated for psoriasis with topical

applications of pure coal tar or 4% coal tar-containing ointment. The results suggest that urinary mutagen

levels were related to the levels of exposure to coal tar. Similar findings of mutagenicity of urine

collected from psoriatic patients treated with coal tar were reported in other studies (Clonfero et al. 1990;

Gabbani et al. 1999; Granella and Clonfero 1992).

There is some indication that genetic polymorphisms may play a role in the manifestation of genotoxic

effects in individuals exposed to coal tar products. A study of 15 patients treated with a 2% coal tar

ointment for at least 3 days showed that urinary mutagenicity, determined by S. typhimurium strains

TA98 and YG1024 in the presence of microsomal enzyme, was associated with glutathione S-transferase

M1 (GSTM1) genotype (Gabbani et al. 1999). The mean value of urinary mutagenicity of subjects with

genotype GSTM1-null was double that of GSTM1-positive subjects and the difference was significant. In

a study of 10 patients being treated for atopic eczema with an ointment containing up to 10% coal tar for

an average of 21 days, Godschalk et al. (2001) showed that aromatic DNA adduct levels in skin biopsies

of coal tar-treated patients were 2-fold higher in GSTM1(-/-) individuals compared to GSTM1(+)

individuals, but the difference was not statistically significant. Significantly (10-fold) higher levels of

p53 were found in the basal layer of GSTM1(-/-) individuals compared with GSTM1(+) patients. 

Analyses of skin biopsies of atopic dermatitis patients treated with 3–10% coal tar for 1 week revealed

that the presence of a mutant myeloperoxidase genotype was associated with a reduction in the formation

of B[a]P-adducts (Rojas et al. 2001). Adduct levels in patients without the mutant gene were 14.2 and

18.4 adducts per 108

 nucleotides, while in patients with the mutant gene adduct, levels were 2.2 and

5.0 adducts per 108

 nucleotides.

Several in vivo studies have shown increased DNA adduct formation in animals following oral

administration of coal tar or coal tar waste. Dose-related increases in DNA adduct levels were observed

in B6C3F1 mice fed up to 1,750 mg coal tar/kg/day for 28 days (Culp and Beland 1994; Culp et al.

1996a). DNA adducts were detected in liver, lung, and forestomach. Weyand et al. (1991) reported dose-
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3. HEALTH EFFECTS

related increases in DNA adduct formation in the lung of B6C3F1 mice fed up to 1% coal tar waste for

15 days but these increases were not correlated with the total PAH content of the coal tar. B6C3F1 mice

fed 0.05, 0.25, or 0.50% coal tar waste for 94 or 185 days showed dose-related increases in DNA adduct

formation in both lung and forestomach tissue (Weyand et al. 1994). Numerous other studies have also

documented the formation of DNA adducts in animals fed coal tar waste from manufactured gas plants

(Bordelon et al. 2000; Goldstein et al. 1998; Koganti et al. 2000). Some studies suggest that lungs are

more sensitive than forestomach tissue to DNA adduct formation in mice (Weyand and Wu 1995;

Weyand et al. 1994). The results of additional in vivo studies are summarized in Table 3-6.

The role of PAHs other than B[a]P in the mutagenicity of coal tar is still not clearly understood. Oral

administration of 636 mg/kg/day MGP residue to mice for 14 days produced a range of lung and

forestomach DNA adducts with three major components. Two of the adducts were identified as produced

by B[a]P (10% of the lung adducts and 47% of forestomach adducts) or benzo[b]fluoranthene (13% of the

lung adducts). The identity of the third adduct (41% of lung adducts, 32% of forestomach adducts) was

unknown (Weyand and Wu 1995). Culp et al. (2000) and Culp and Beland (1994) reported that DNA

adduct formation was higher in mice fed coal tar than in those fed B[a]P and Koganti et al. (2000)

proposed that 7H-benzo[c]fluorene, not B[a]P, was responsible for the formation of DNA adducts in

lungs of mice fed coal tar. Genotoxic effects have been observed in several tissues after dermal

application of coal tar products. For instance, DNA adducts were detected in mouse skin after dermal

application of coal tar fractions (Marston et al. 2001; Springer et al. 1989) and in skin, lungs, and

lymphocytes of rats after dermal application of bitumen fume condensates (Genevois et al. 1996). Dermal

application of 250 mg/kg creosote in olive oil to rats for 24 hours resulted in the excretion of mutagens in

urine (Bos et al. 1984c).

Various in vitro studies using the Ames S. typhimurium test (Bos et al. 1984a, 1984c) or the mouse

lymphoma assay (Mitchell and Tajiri 1978) have demonstrated the genotoxicity of several coal tar

products, including samples from creosote-treated wood. Using a modified Ames assay with

S. typhimurium, Machado et al. (1993) found that coal tar pitch was more strongly mutagenic than asphalt

fume condensates. The temperature at which the fumes were collected was positively correlated with

mutagenicity. Bos et al. (1987) showed that creosote contains mutagens that are volatile at 37 EC. 

Simmon and Shepherd (1978) demonstrated that the genetic mode of action of creosote is induction of a

frame-shift mutation. The results of additional in vitro studies are summarized in Table 3-7.
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Table 3-6. Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch, 

or Coal Tar Pitch Volatiles In Vivo

Species (test system) End point Results Reference

CREOSOTE

Mammalian systems:

Rat/liver DNA adducts + Chadwick et al. 1995

Mouse/lung, forestomach,

spleen

DNA adducts + Weyand et al. 1991

COAL TAR

Non-mammalian systems:

 Perch/liver

DNA adducts + Ericson et al. 1998,

1999

Mammalian systems:

Human/lymphocytes Chromosomal

aberrations/sister

chromatid exchange

+ Sarto et al. 1989

Human/lymphocytes Sister chromatid

exchange

+ Wu et al. 1998

Human/lymphocytes Chromosomal

aberrations/sister

chromatid exchange

+ Yadav and Seth 1998

Human/skin DNA adducts – Schoket et al. 1990

Human/skin DNA adducts + Zhang et al. 1990

Human/skin DNA adducts + Rojas et al. 2001

Human/skin, blood cells DNA adducts + Godschalk et al. 1998

Human/lymphocytes DNA adducts – Pavanello and Levis

1992

Human/lymphocytes DNA adducts + Pavanello and Levis

1994

Human/blood DNA adducts + Santella et al. 1995

Rat/liver, lung, forestomach DNA adducts + Culp and Beland 1994

Rat/lymphocytes, lung, skin DNA adducts + Genevois et al. 1996

Rat/lung, liver, forestomach DNA adducts + Goldstein et al. 1998

Rat/lung, liver DNA adducts + Bordelon et al. 2000

Mouse/forestomach, small

intestine

DNA adducts + Goldstein et al. 1998
CREOSOTE 151

3. HEALTH EFFECTS

Table 3-6. Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch, 

or Coal Tar Pitch Volatiles In Vivo (continued)

Species (test system) End point Results Reference

COAL TAR (cont’d)

Mammalian systems (cont’d):

Mouse/forestomach, small

intestine

DNA adducts + Culp et al. 1996a

Mouse/lung, forestomach DNA adducts + Weyand and Wu 1995

Mouse/lung, forestomach DNA adducts + Weyand et al. 1994

Mouse/skin, lung, liver, kidney

heart

DNA adducts + Randerath et al. 1996

Mouse/forestomach, lung, liver,

intestine

DNA adducts + Culp et al. 2000

Mouse/lung DNA adducts + Koganti et al. 2000

Mouse/lung DNA adducts + Koganti et al. 2001

Mouse/skin DNA adducts + Hughes et al. 1993

Mouse/skin DNA adducts + Phillips and Alldrick

1994

Mouse/skin DNA synthesis + Walter et al. 1978

Mouse/skin Gene mutation + Vogel et al. 2001

COAL TAR PITCH

AND BITUMEN 

VOLATILES

Mammalian systems:

Human blood cells Chromosomal aberrations + Bender et al. 1988

Human/white blood cells DNA adducts + Lewtas et al. 1997

Human/lymphocytes sister chromatid exchange

(SCE)/high frequency

SCE

(+/–) Burgaz et al. 1998

Human/lymphocytes Micronuclei + Burgaz et al. 1998

Rat/lung DNA adducts + Lewtas et al. 1997

+ = positive results; – = negative results; (+/–) = mixed results; DNA = deoxyribonucleic acid; SCE = sister

chromatid exchange
CREOSOTE 152

3. HEALTH EFFECTS

Table 3-7. Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch,

 or Coal Tar Pitch Volatiles In Vitro

Result

Species (test system) End point

With

activation

Without

activation Reference

Calf thymus DNA DNA adducts + No data Akkineni et al. 2001

Calf thymus DNA DNA adducts + No data Koganti et al. 2000

Calf thymus DNA DNA adducts + No data Reddy et al. 1997

Salmon testes DNA DNA adducts + – Genevois et al.

1998

Prokaryotic organisms:

Salmonella typhimurium

(histidine auxotrophs)

Gene mutation + – Simmon and

Shepherd 1978a

S. typhimurium Gene mutation + + Agurell and

Stensman 1992

S. typhimurium Gene mutation + No data Reeves et al. 2001

S. typhimurium Gene mutation + – Baranski et al. 1992

S. typhimurium Gene mutation + – Bos et al. 1983,

1984b, 1984c, 1985,

1987

S. typhimurium Gene mutation + – Donnelly et al. 1993,

1996

S. typhimurium Gene mutation + + Kesik and JanikSpiechowicz 1997

S. typhimurium Gene mutation + – Mayura et al. 1999

S. typhimurium Gene mutation Machado et al. 1993

S. typhimurium (taped-plate

assay; vapor exposure)

Gene mutation + – Bos et al. 1985,

1987

Escherichia coli WP2 (TK=/–),

(tryptophan auxotroph)

Gene mutation – – Simmon and

Shepherd 1978a

Mammalian cells:

Human mammary epithelial

cells

DNA adducts No data + Leadon et al. 1995

Mouse lymphoma cells Gene mutation + – Mitchell and Tajiri

1978

V79 Gene mutation – – U.S. Department of

Energy 1994

V79 Sister

chromatid

exchange

+ + U.S. Department of

Energy 1994
CREOSOTE 153

3. HEALTH EFFECTS

Table 3-7. Genotoxicity of Coal Tar Creosote, Coal Tar, Coal Tar Pitch, 

or Coal Tar Pitch Volatiles In Vitro (continued)

Result

Species (test system) End point

With

activation

Without

activation Reference

Mammalian cells (cont’d):

V79 Micronucleus + +

U.S. Department of

Energy 1994

Mammalian body fluids:

S. typhimurium (human urine

sample; occupational

exposure)

Gene mutation – No data Bos et al. 1984a

S. typhimurium (human urine

sample; coal tar treatment)

Gene mutation + No data Clonfero et al. 1990

S. typhimurium (human urine

sample; occupational

exposure)

Gene mutation + No data De Meo et al. 1987

S. typhimurium (human urine

sample; occupational

exposure)

Gene mutation + No data Gabbani et al. 1999

S. typhimurium (human urine

sample; coal tar treatment)

Gene mutation + No data Granella and

Clonfero 1992

S. typhimurium (human urine 

sample; occupational

exposure)

Gene mutation + No data Mielzynska and Snit

1992

S. typhimurium (human urine

sample; coal tar treatment)

Gene mutation + No data Sarto et al. 1989

S. typhimurium (rat urine

sample)

Gene mutation + No data Bos et al. 1984a

S. typhimurium (rat urine

sample)

Gene mutation + No data Chadwick et al.

1995

a

S. typhimurium strains TA1537, TA98, and TA100 showed increases in frameshift mutation; strain TA1535 and

E. coli straub WP2 showed no increase in base-pair substitutions.

+ = positive results; – = negative results; DNA=deoxyribonucleic acid
CREOSOTE 154

3. HEALTH EFFECTS

3.4 TOXICOKINETICS

Specific information regarding the toxicokinetics of creosotes, coal tar, coal tar pitch, and coal tar pitch

volatiles is limited. Several compounds have been detected in coal tar creosote, yet there are no definitive

data on which of these compounds people are exposed to in wood-treatment plants or at hazardous waste

sites. Analyses have revealed that PAHs are the major components of the coal tar creosote mixture

(TOMA 1981). Hence, pharmacokinetic studies on PAHs can be used as surrogates for coal tar creosote. 

However, this information is only speculative given the possible toxicokinetic interactions that occur

among the PAHs and other components in the coal tar creosote mixture, and will be used only when data

on coal tar creosote are not available. For more information on the toxicokinetics of PAHs, please refer to

the ATSDR Toxicological Profile for Polycyclic Aromatic Hydrocarbons (Agency for Toxic Substances

and Disease Registry 1995). Phenols and cresols are also components of coal tar products. For more

information on the toxicokinetics of these chemicals, please refer to the ATSDR Toxicological Profile for

Phenol (Agency for Toxic Substances and Disease Registry 1998) and the ATSDR Toxicological Profile

for Cresols (Agency for Toxic Substances and Disease Registry 1992). 

3.4.1 Absorption

3.4.1.1 Inhalation Exposure

No studies were located in humans or animals regarding the direct analysis of the extent or rate of

absorption of wood creosote following inhalation exposure.

Coal Tar Products. No studies were located in humans or animals regarding the direct analysis of the

extent or rate of coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatile absorption following

inhalation exposure. However, there is evidence to suggest that inhalation absorption of coal tar products

may occur. Employees of a coal tar creosote wood-impregnating plant, employees in a coal tar plant, and

coke oven workers excreted 1-hydroxypyrene, a metabolite of pyrene, a creosote component, in their

urine (Bos and Jongeneelen 1988; Jongeneelen et al. 1985, 1988). Similarly, workers asphalting roads

with coal tar excreted 1-hydroxypyrene in their urine (Bos and Jongeneelen 1988; Jongeneelen et al.

1988). Increased levels of 1-hydroxypyrene were observed over the course of the workday for all groups

of workers, indicating an accumulation of pyrene during the exposure period (Bos and Jongeneelen

1988). The presence of this metabolite in the urine suggested that coal tar creosote components were

absorbed and metabolized following inhalation exposure. However, it is possible that some dermal

exposure may have occurred as well.
CREOSOTE 155

3. HEALTH EFFECTS

Measurements were carried out in a creosote impregnation plant where six men volunteered to participate

in the study (Elovaara et al. 1995). Personal breathing zone air samples were taken on 5 consecutive days

followed by a work-free period of 64 hours. All workers wore leather protective gloves and cotton

overalls. Two employees worked overtime (until 6:30 a.m.) on Monday, which was an exception to the

regular 8-hour schedule. Particulate PAHs were collected during the whole shift and analyzed within

7 weeks. Workers were asked to collect all urine passed within the 24 hour period into divided samples

for the designated periods. Results showed that the geometric mean (range) air concentrations were

4.77 (1.2–13.7) mg/m3

 (n=30) for total particulate PAHs (including pyrene) and 1,254 (370–4,200) mg/m3

(n=30) for naphthalene. The PAH profile was similar in all samples. 1-Hydroxypyrene was found in the

urine samples.

Exposure of assemblers (all smokers) handling creosote-impregnated wood railroad ties and one worker

(smoker) chiselling coal tar pitch insulation to coal tar products was assessed by analyzing the breathing

zone air for airborne PAHs, and assaying urinary excretion of 1-hydroxypyrene (Heikkilä et al. 1995). 

The concentration of pyrene and 11 other PAHs in particulate matter had been measured both in the work

room and in the breathing zone of the assemblers a year earlier during 2 working days. In the present

setting the ties were impregnated with the same type of creosote as a year earlier, which contained

0.2 weight-percent (w%) of pyrene. Urine samples were collected during 3 working days (Monday,

Wednesday, and Friday) and over the following weekend. Urine samples from one chiseller were

collected in the morning before work, during lunch time, at the end of the shift, in the evening and on the

next morning. The total concentrations of PAH and of 4–6 aromatic ring-containing PAHs (when

chiselling) were 440 μg/m3

 (50-fold higher than assemblers) and 290 μg/m3 (200-fold higher than

assemblers), respectively. The estimated mean of inhaled pyrene for assemblers measured on Monday,

Wednesday, and Friday was found to be 0.009, 0.007, and 0.024 mmol/shift, respectively. The estimated

inhaled pyrene measured on the chiseller was 1.2 mmol/shift. Excretion of urinary 1-hydroxypyrene was

detected for all participants.

Four rotation crews of about 29 workers and one day crew of 22 workers worked in a 5-day shift,

8 hours/day in the potrooms (Ny et al. 1993). All workers wore disposable respirators that were renewed

4–5 times/day, thick cotton working clothes with long sleeves, safety shoes, safety glasses, gloves, and

helmets. Other groups that worked occasionally in the potrooms were also included in this study. Some

employees who worked in dusty environments also wore facial protective clothing. Personal breathing

zone air samples taken randomly from 38 workers were sampled once. Measurements were done on 3 out

of 5 working days for the rotation crews and on 4 days in 2 work weeks for the day crew. The filter

holders and the XAD-2 tubes used in sampling were analyzed. Urine samples were collected from 33 of
CREOSOTE 156

3. HEALTH EFFECTS

38 workers before and after the 5-day work week. Control urine samples were taken from 10 guards not

exposed to coal tar pitch volatiles. 1-Hydroxypyrene in urine was determined by liquid chromatography

(LC). Results showed that field blanks were not contaminated with coal tar pitch volatiles. No

benzo[a]pyrene was found on XAD-tubes. Vapor phase measurement showed 48% pyrene and 24% total

PAHs. The highest filter sample (particulate) concentration of pyrene was 170 mg/m3

, and the highest

sorbent tube (vapor) concentration of pyrene was 94 mg/m3

. The correlation between these two variables

was 0.70. Individuals who worked continuously in the potrooms were exposed to variable concentrations

of coal tar pitch volatiles, ranging from 10–2,710 mg/m3

. Multiple regression analysis of increased

urinary 1-hydroxypyrene was strongly related to the environmental PAH exposure. Increased urinary

1-hydroxypyrene was greater among those using facial protective clothing under their respirators; this

was probably caused by poor fitting or by facial coverings becoming contaminated by PAH. The

predicted limit value of change in urinary 1-hydroxypyrene, using the model for coal tar pitch volatiles

was 4.3 mmol/mol creatinine. The predicted limit value of change in urinary 1-hydroxypyrene, using the

model for benzo[a]pyrene, was 4.3 mmol/mol creatinine. 

Data from studies of inhabitants of log homes that were built with logs treated with pentachlorophenol

indicate inhalation exposure to pentachlorophenol fumes occurs (Hernandex and Stressman-Sundy 1980). 

Similar exposure may result from coal tar creosote-treated logs (Cammer 1982). 

Tumor-susceptible ICR CF-1 and tumor-resistant CAF1-JAX mice were exposed to 10 mg/m3

 coal tar

aerosol-BTX mixture continuously, or for 90 days, or intermittently for 18 months (MacEwen et al.

1977). Coal tar used to generate the aerosol was of various samples from multiple coke ovens blended

together with a 20% by volume amount of BTX fraction of the coke oven distillate. The coal tar-BTX

mixture was comparable to the material inhaled by topside coke oven workers. Mice were serially

sacrificed during the exposure period for the determination of coal tar lung burden and the time to tumor

induction. Control animals were held in a vivarium. All animals were examined daily during the

exposure and postexposure periods. Coal tar fluorescence retained in mouse lung and skin tissues (n=4)

were measured. The amount of coal tar found on mouse skin did not change to any great degree after the

first week of exposure. Lung tissue accumulated coal tar aerosol at a fairly steady rate during 18 months

of intermittent exposure as compared to a high increased rate (from graph) during the 90 days of

continuous exposure. The coal tar lung burden in mice was approximately equal for both exposure modes

for the 180-day exposure period. 

PAHs extracted from coal fly ash were intratracheally administered to pregnant Wistar rats at a dose of

20 mg/kg, once/day, on gestational days 18 and 19 (Srivastava et al. 1986). The presence of the PAHs in
CREOSOTE 157

3. HEALTH EFFECTS

both the maternal and fetal lungs and livers on gestational day 20 indicated that pulmonary absorption

occurred following intratracheal administration, but inhalation exposure was not examined.

Pulmonary absorption may be influenced by carrier particles, and by solubility of the matrix or vehicle in

which the compounds are found. Due to the variable composition of coal tar creosote, coal tar, and coal

tar pitch, the predictive value of inhalation absorption studies conducted with pure PAHs is limited.

3.4.1.2 Oral Exposure

No studies were located regarding the direct analysis of the extent or rate of coal tar creosote, coal tar,

coal tar pitch, or coal tar pitch volatile absorption following oral intake in humans or animals.

Wood Creosote. Eight healthy male volunteers were orally administered a single dose of 133 mg wood

creosote capsule and 200 mL water after a light breakfast (Ogata et al. 1995). Peripheral venous blood

and urine samples were collected at various time intervals. Phenols in serum and urine were analyzed by

HPLC. Wood creosote used in this study as determined by gas chromatography (GC) contained 11.3%

phenol, 24.3% guaiacol, 13.7% p-cresol, and 18.2% cresol (w/w). Concentrations found in peripheral

venous blood and urine were 15 mg/L phenol, 32 mg/L guaiacol, 18 mg/L p-cresol, and 24 mg/L cresol. 

HPLC analysis of 30-minute postdose serum detected low concentrations of guaiacol and p-cresol. 

Coal Tar Products. The presence of coal tar creosote metabolites in the urine of humans and rabbits

receiving calcium creosote (a calcium salt of creosote) tablets was evidence that this salt of creosote was

absorbed following ingestion (Fellows 1937, 1939b). Furthermore, evidence exists that certain PAHs

found in coal tar creosote such as anthracene (Rahman et al. 1986), benzo[a]pyrene (Hecht et al. 1979;

Rahman et al. 1986; Rees et al. 1971; Yamazaki et al. 1987), chrysene (Chang 1943; Modica et al. 1983),

and phenanthrene (Rahman et al. 1986) are absorbed following oral administration in animals.

Male B6C3F1 mice were given 0, 197, 410, 693, 1,067, and 1,750 mg/kg/day coal tar/day in feed for

28 days (Culp and Beland 1994). At the end of the feeding period, DNA adduct formation was quantified

in the liver, lungs, and forestomach by 32P-post-labeling. The adduct levels were then compared with

those obtained by feeding benzo[a]pyrene to mice for 3 weeks at concentrations corresponding to the

amount of benzo[a]pyrene in the coal tar doses. DNA adduct formation was found to increase as a

function of dose in each tissue with both coal tar and benzo[a]pyrene, indicating absorption after oral

exposure. Five groups of B6C3F1 mice (24 males, 24 females) were fed a control gel diet containing

0.05, 0.25, or 0.50% MGP (Weyand et al. 1994). The urinary excretion of 1-hydroxypyrene by male
CREOSOTE 158

3. HEALTH EFFECTS

mice (12 per group) treated with 0.25 and 0.50% MGP was evaluated throughout the 185 days of diet

administration. 1-Hydroxypyrene was detected in the urine, indicating absorption of MGP components.

Based on data on PAHs, absorption of PAH components of coal tar products after oral exposure may be

positively influenced by the presence of oils and fats in the stomach, and bile in the intestines (Agency for

Toxic Substances and Disease Registry 1995). Due to relative water insolubility of PAHs, absorption is

enhanced by solubilization in an intermediate phase than can be metabolized during the process of lipid

digestion and absorption. Excretion after oral exposure may be detected hours to days after exposure. 

Due to the variable composition of coal tar creosote, coal tar, and coal tar pitch, the predictive value of

oral absorption studies conducted with pure PAHs is limited.

3.4.1.3 Dermal Exposure

No studies were located in humans or animals regarding the direct analysis of the extent or rate of

absorption of wood creosote following dermal exposure.

Coal Tar Products. No studies were located in humans or animals regarding the direct analysis of the

extent or rate of coal tar creosote, coal tar, or coal tar pitch absorption following dermal exposure. 

However, reports of workers who developed cancer subsequent to dermal exposure suggested that coal tar

creosote was absorbed through the skin (Cookson 1924; Henry 1946, 1947; Lenson 1956). Human

exposure studies also demonstrate that coal tar creosote or its components are absorbed dermally in

humans, based on excretion of metabolites after dermal exposure (Bickers and Kappas 1978; Bos and

Jongeneelen 1988; Cernikova et al. 1983; Clonfero et al. 1989; Hansen et al. 1993; Jongeneelen et al.

1985; Santella et al. 1994; Sarto et al. 1989; Van Rooij et al. 1993a, 1993b; van Schooten et al. 1994;

Viau and Vyskocil 1995). Van Rooij et al. (1993a) examined differences in the absorption of PAH

between anatomical sites and individuals following dermal exposure of volunteers to 10% coal tar in a

vehicle of zinc oxide paste. The surface disappearance of PAH and the excretion of urinary

1-hydroxypyrene after coal tar application were used to assess dermal absorption following controlled

exposures. Surface disappearance measurements show low but significant differences in dermal PAH

absorption between anatomical sites: shoulder > forehead; forearm, groin > ankle, hand (palmar site). 

Differences between individuals in PAH absorption are small (7%) in comparison with differences

between anatomical sites (69%). Urinary excretion of 1-hydroxypyrene verified that the coal tar creosote

and its components were absorbed through the skin, but the site of application had no effect on the

excreted amount of 1-hydroxypyrene although the time to excrete half of the total metabolite varied

between 8.2 and 18.9 hours. 
CREOSOTE 159

3. HEALTH EFFECTS

Another study of dermal absorption was conducted by Van Rooij et al. (1993b) in a wood preserving

plant in the Netherlands in October 1991. Volunteers for this study worked near the impregnation

cylinders (three subjects) and the assembly hall (seven subjects). Exposure measurements were

performed in 2 consecutive weeks on a Monday after a weekend off. On one Monday, the workers wore

protective clothing over their clothes and on the other Monday, no protective clothing was used. PAH

contamination on the skin and PAH concentration was measured on the two Mondays tested for all

workers. Urine samples were collected from Sunday morning up to and including Tuesday morning for

the assessment of the internal exposure to PAH. For assessing PAH contamination on the skin, six

exposure pads were pasted on the skin of the workers (jaw, shoulder, upper arm, wrist, groin, and ankle)

during work hours. Immediately after exposure, the pads were removed, packed in aluminum foil and

stored until analysis. Results showed that extra protective clothing reduced the PAH contamination on

the pads of the shoulder, upper arm, and groin. At the other skin sites, no significant reduction was

found. On the average, the coveralls reduced the pyrene contamination on the worker's skin by 35%. The

excreted amount of 1-hydroxypyrene in urine decreased significantly from 6.6 to 3.2 mg

(30.2–14.7 nmol), indicating a change in the extent of absorption with the change in protective clothing. 

Another indication that coal tar components are absorbed transdermally was reported by Paleologa et al.

(1992). In particular, these investigators evaluated the occurrence of B[a]PDE-DNA adducts in white

blood cells of 23 psoriatic patients undergoing clinical coal tar therapy. Two to 5 months after therapy,

10 of the patients were reanalyzed. The actual dose levels varied among the treated individuals because

the application ranged from pure coal tar to 4% coal tar-based paste or ointment. No relationship

appeared to exist between exposure level and concentration of B[a]PDE-DNA adducts. The results show

that the mean adduct level during the treatment period was 0.26±0.16 fmole benzo[a]pyrene/g DNA

(7.7±4.9 adducts/108

 nucleotides), while 2–5 months later, the mean adduct level had decreased

significantly to 0.11±0.08 fmole benzo[a]pyrene/g DNA (3.3±2.4 adducts/108

 nucleotides).

A coal tar solution (crude coal tar diluted to 20% with ethanol and polysorbate 80) was applied to

clinically unaffected skin of three patients with severe atopic dermatitis and six patients with generalized

psoriasis (Bickers and Kappas 1978). Another skin area at least 10 cm away was not treated or was

treated with 100 mL of the vehicle alone. Twenty-four hours later, a 6-mm punch biopsy was obtained

from coal tar treated and control areas and the effect on AHH activity was determined. Application of

coal tar to the skin caused induction of cutaneous AHH activity that varied from 2.4- to 5.4-fold over the

enzyme activity in untreated skin areas, suggesting absorption after topical application. 
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3. HEALTH EFFECTS

Five female patients (two nonsmokers, three smokers) suffering from eczematous dermatitis on the arms

and legs were treated for several days with an ointment containing 10% pix lithanthracis dermata (coal

tar), representing 16.7 mg/g pyrene and 7.0 mg/g benzo[a]pyrene (Bos and Jongeneelen 1988). During

treatment, the ointment was removed daily and a fresh dose of approximately 40 g was rubbed in. Urine

samples were collected, one before application and two during the day for the first 3 days of treatment. 

1-Hydroxypyrene was detected in the urine of all patients, indicating absorption of a component of the

coal tar.

Twenty-eight patients that required coal tar treatment on an area larger than two-thirds of the body

surface were studied (Cernikova et al. 1983). Tar paste (10 and 20%) was used for treatment; in one

application, approximately 1–6 g of coal tar containing 0.6% acridine was spread on the patient's skin. 

Urine analysis was performed by TLC to obtain information on polyaromatic and heterocyclic substances

excreted in the urine. Further identification of the substance was performed by GC/mass spectrometry

(GC/MS). The presence of acridine in urine after the coal tar application was identified by MS. The

detection of acridine in urine provided proof of the absorption of a coal tar component through the skin. 

However, without additional information, no statements can be made regarding the dermal absorption of

other coal tar components or whether acridine was preferentially absorbed through the skin. 

Sixteen urine samples were collected from 4 male, nonsmoking psoriatic patients, undergoing treatment

with the Goeckerman regimen (cutaneous application of coal tar based ointment, followed by exposure to

UV irradiation) in the Dermatology Clinic of the University of Padua (Clonfero et al. 1989). Patient A

was treated with pure coal tar for 1 day; patients B, C, and D were treated with 4% coal tar based

ointment for 2, 8, and 13 days, respectively. Body surface involved by psoriasis was 30, 40, 35, and 60%

for patients A, B, C, and D, respectively. Total PAH (and pyrene) content of the two coal tar preparations

was 28,800 (3,100) and 470 (104) ppm, respectively. The samples were collected at different times after

the beginning of therapy (from 12 hours after the 1st application of coal tar to 72 hours after the last

application). 1-Hydroxypyrene and other PAHs were detected in the urine, indicating absorption of

components of the coal tar. 

Santella et al. (1994) also observed urinary excretion of PAH metabolites after dermal application of coal

tar, indicating absorption. Studies confirming that coal tar creosote is capable of inducing phototoxicity

of the skin indicate dermal absorption after exposure (Diette et al. 1983). 

It can also be concluded that dermal absorption occurred as evidenced by the development of skin tumors

(Boutwell and Bosch 1958; Lijinsky et al. 1957; Poel and Kammer 1957; Roe et al. 1958) and lung
CREOSOTE 161

3. HEALTH EFFECTS

tumors (Roe et al. 1958) in mice following the dermal application of coal tar creosote (see

Section 3.2.3.7). Other studies in animals support absorption of coal tar products after dermal

application. Coal tar solution (0.05 mL of a 20% solution) was applied to the skin of six neonatal rats

(4–6 days of age) and 24 hours later AHH activity was measured in the skin and liver (Bickers and

Kappas 1978). There was greater than a 10-fold induction of skin AHH activity (298±13 versus

26.3±19 pmol hydroxy-benzo[a]pyrene/mg protein/hour in controls) and marked increased hepatic AHH

activity (16,300±899 versus 750±35 pmol hydroxy-benzo[a]pyrene/mg protein/hour in controls) after

topical application of the coal tar solution. 

Based on data on PAHs, absorption of PAH components of coal tar products after dermal exposure may

be limited by binding and/or metabolism in the skin, thus leaving less for systemic absorption (Agency

for Toxic Substances and Disease Registry 1995). Excretion of PAHs following dermal application may

be detected in hours or days, and is improved by solubilization of the compounds in a fat or oil mixture

prior to application. Due to the variable composition of coal tar creosote, coal tar, and coal tar pitch, the

predictive value of dermal absorption studies conducted with pure PAHs is limited. A further problem

with the use of individual PAHs to estimate absorption of coal tar is that individual PAHs differ in their

rates of absorption. The concentrations of nine different PAHs were measured after topical application of

coal tar to a blood-perfused pig-ear (VanøRooij et al. 1995). There was a variation of accumulations of

the various PAHs in the perfused blood, ranging between 830 pmol cm-2 for phenanthrene to <4 pmol

cm-2 for benzo[b]fluoranthene, benzo[a]pyrene, and indeno[123-cd]pyrene. These data show that

different components of coal tar are absorbed at different rates, and that using a single PAH to represent

absorption of the mixture is likely to over- or under-estimate the absorption of other components.

3.4.2 Distribution
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3. HEALTH EFFECTS

3.4.2.1 Inhalation Exposure

No studies were located in humans regarding the distribution of wood creosote following inhalation

exposure. 

Coal Tar Products. No studies were located in humans regarding the distribution of coal tar creosote,

coal tar, coal tar pitch, or coal tar pitch volatiles following inhalation exposure. Because coal tar products

are composed of hydrocarbons, they are likely to distribute to lipid-rich tissues (Agency for Toxic

Substances and Disease Registry 1995). PAHs and their metabolites are known to cross the placenta

(Agency for Toxic Substances and Disease Registry 1995). PAHs have also been detected in human

breast milk (Madhavan and Naiduka 1995). Individuals concerned with the potential exposure of breastfeeding infants to PAHs should consult their doctor. Coal tar creosote is also likely to distribute to the

liver as evidenced by the presence of metabolites in the urine, indicating microsomal enzyme induction.

Tumor-susceptible ICR CF-1 and tumor-resistant CAF1-JAX mice were exposed to 10 mg/m3

 coal tar

aerosol-BTX mixture continuously, or for 90 days, or intermittently for 18 months (MacEwen et al.

1977). The coal tar-BTX mixture was comparable to the material inhaled by topside coke oven workers. 

Mice were serially sacrificed during the exposure period for the determination of coal tar lung burden and

the time to tumor induction. Control animals were held in a vivarium. All animals were examined daily

during the exposure and postexposure periods. Coal tar fluorescence retained in mouse lung and skin

tissues were measured. The amount of coal tar found on mouse skin did not change to any great degree

after the first week of exposure. Lung tissue accumulated coal tar aerosol at a fairly steady rate during

18 months of intermittent exposure as compared to a high increased rate (from graph) during the 90 days

of continuous exposure. The coal tar lung burden in mice was approximately equal for both exposure

modes around the 180-day exposure period. 

When [3

H]-benzo[a]pyrene was administered intratracheally to rats at a dose of 0.001 mg/kg, radioactivity

was distributed to all tissues (Weyand and Bevan 1987). During the 6 hours following administration,

>20% of the dose was detected in the carcass. The activity steadily increased in the intestine and the

intestinal contents over the 6 hours. Levels of activity in the liver and lung were moderate and declined

over time. Trace amounts of activity were detected in other tissues (Weyand and Bevan 1987).

Intratracheal administration of [3

H]-benzo[a]pyrene, along with the benzene extract of coal fly ash, to

pregnant rats (20 mg/kg/day) on days 18 and 19 of gestation resulted in their distribution to the maternal

lung and liver (Srivastava et al. 1986). The amount of radioactivity found in the maternal liver was
CREOSOTE 163

3. HEALTH EFFECTS

approximately 68% of the amount of radioactivity found in the maternal lung. The amounts of

radioactivity found in the placenta, fetal lung, and fetal liver were approximately 4, 1.9, and 1.4%,

respectively, of the amount of radioactivity found in the maternal lung. Much of the radioactivity was

attributable to metabolites. These results in rats suggest that components of coal tar creosote and their

metabolites can pass through the placenta and distribute to fetal tissue.

3.4.2.2 Oral Exposure

No studies were located in humans or animals regarding the distribution of, coal tar creosote, or coal tar

pitch volatiles following ingestion. Based on chemical structure, it is likely that PAHs would have a

strong affinity for adipose tissue. For example, benz[a]anthracene, chrysene, and triphenylene distributed

to all tissues following oral administration (22.8 mg/kg) to female rats, but its greatest distribution was to

adipose tissue. In this study, benz[a]anthracene concentrations were 10 times higher in adipose than in

other tissues (Bartosek et al. 1984). 

The distribution of nonmetabolized PAHs is dependent on their water-solubility. The more water-soluble

PAHs, such as triphenylene, are generally more available to tissues other than fat (Bartosek et al. 1984). 

In humans, distribution of coal tar creosote following ingestion is likely to be qualitatively similar to that

seen in the animal studies. The lipophilicity of PAHs allows the chemicals to be readily absorbed and

preferentially accumulated in fatty tissues. Furthermore, PAHs are likely to be present in adipose and

highly perfused organs such as the lungs and liver.

Wood Creosote. Eight healthy male volunteers were orally administered a single dose of 133 mg wood

creosote by capsule with 200 mL water after a light breakfast (Ogata et al. 1995). Peripheral venous

blood and urine samples were collected at various time intervals. Phenols in serum and urine were

analyzed by HPLC. Wood creosote used in this study as determined by GC contained 11.3% phenol,

24.3% guaiacol, 13.7% p-cresol, and 18.2% cresol (w/w). Concentrations found in peripheral venous

blood and urine were 15 mg phenol, 32 mg guaiacol, 18 mg p-cresol, and 24 mg cresol. HPLC analysis

of 30-minute postdose serum detected low concentrations of guaiacol and p-cresol.

Coal Tar Products. Culp and Beland (1994) fed male B6C3F1 mice 0, 197, 410, 693, 1,067, and

1,750 mg/kg/day coal tar/day in feed for 28 days. A second group of mice was fed benzo[a]pyrene for

21 days at levels corresponding to those found in the coal tar-containing feed mixtures. At the end of the

feeding period, DNA adduct formation was quantified in the liver, lungs, and forestomach by 32P-postlabeling. The adduct levels were then compared with those obtained from the mice fed benzo[a]pyrene. 
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3. HEALTH EFFECTS

DNA adduct formation was found to increase as a function of dose in each tissue with both coal tar and

benzo[a]pyrene. DNA adduct levels were in the order forestomach > liver > lung at lower dose groups,

while the order changed to liver > forestomach > lung at the highest dose group. Total DNA binding was

greater in the coal tar fed mice than in the benzo[a]pyrene fed animals (.10- to 30-fold greater in the liver

and forestomach, and over 90-fold greater in the lungs at the lower doses). 

3.4.2.3 Dermal Exposure

No studies were located in humans or animals regarding the distribution of wood creosote, coal tar

creosote, coal tar, or coal tar pitch following dermal exposure. Distribution of creosotes or coal tar

products in humans following dermal exposure is expected to be qualitatively similar to that seen in

animals or in humans following any route of exposure.

3.4.3 Metabolism

Generally, the PAH components of wood creosote, coal tar creosote, coal tar, and coal tar pitch are

metabolized by oxidative enzymes in the liver and lungs to generate active metabolites that can bind to

macromolecules. The metabolic profiles vary among species and compounds, but the components follow

the same major reaction pathways. Hence, the metabolites are structurally very similar. The proposed

metabolic scheme for a representative PAH, benzo[a]pyrene, is presented in Figure 3-4. The principal 
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3. HEALTH EFFECTS

12 1

2

3

4

7 6 5

8

11

10

9

GLUTATHIONE

CONJUGATES

ARENE OXIDES PHENOLS QUINONES

GLUTATHIONE

CONJUGATES

 GLUCURONIDES

 AND

SULFATE ESTERS

DIHYDRODIOLS PHENOL-DIOLS GLUCURONIDES

 AND

SULFATE ESTERS

GLUTATHIONE

CONJUGATES

DIOL EPOXIDES TETRAOLS

 4,5-

 7,8-

9,10-

 1- 7-

3- 9-

6-

 1,6-

 3,6-

6,12-

 4,5-

 7,8-

9,10-

9-OH-4,5-diol

6-OH-7,8-diol

1-(3)-OH-9,10-diol

7,8-diol-9,10-Epoxide

9,10-diol-7,8-Epoxide

Figure 3-4. Proposed Metabolic Scheme for Benzo[a]pyrene
CREOSOTE 166

3. HEALTH EFFECTS

products include phenols, dihydrodiols, quinones, anhydrides, and conjugates of these products (Autrup

and Seremet 1986; Dahl et al. 1985; Fellows 1939b; Geddie et al. 1987; Hopkins et al. 1962; Jongeneelen

et al. 1985, 1986, 1988; Ogata et al. 1995; Petridou-Fischer et al. 1988; Povey et al. 1987; Rice et al.

1986; Santella et al. 1994; Weyand and Bevan 1987). 

Metabolic studies of wood or coal tar creosote have generally been confined to measurements of

metabolites in the blood or urine (Bieniek 1997; Bowman et al. 1997; Chadwick et al. 1995; Fellows

1939b; Grimmer et al. 1997; Heikkila et al. 1997; Jongeneelen et al. 1985, 1986, 1988; Malkin et al.

1996; Ogata et al. 1995; Santella et al. 1994; Weston et al. 1994). However, a number of studies have

examined the role of individual enzymes in the metabolism of coal tar products. Experiments by Bickers

and Kappas (1978), Li et al. (1995), Luukanen et al. (1997), Genevois et al. (1998), and Fielden et al.

(2000) assessed metabolic induction and activity of AHH, glucuronosyltransferase, and cytochrome P450

in response to coal tar. 

Application of coal tar for 24 hours to the healthy skin of psoriasis and dermatitis patients caused a

2–5-fold induction of AHH activity compared to untreated skin from the same individuals (Bickers and

Kappas 1978). Incubation of human skin with coal tar solution in vitro also caused induction of AHH,

which reached a maximum after 24 hours. Application of coal tar to the skin of rats produced significant

induction of AHH both in skin (10-fold) and in liver (>20-fold).

Dermal treatment of healthy volunteers with 10% coal tar for 4 days produced an 18-fold induction of

CYP1A1 mRNA levels in coal-tar-treated skin (Li et al. 1995). In vitro incubation of DNA with coal tar

fume concentrates in the presence of mouse and yeast microsomes expressing various cytochrome P450

isoforms or the aryl hydrocarbon hydroxylase receptor (AHR) demonstrated that coal tar fume

condensates require metabolic activation to produce DNA adducts (Genevois et al. 1998). Both the AHR

and CYP1A were involved in the metabolism of coal tar fume condensate. It was also shown that the

reactive metabolites formed by CYP1A are substrates for microsomal epoxide hydrolase. 

Microsome preparations from the livers of rats gavaged with coal tar creosote were used to assay the

activities of two glucuronosyltransferases, 1-hydroxypyrene UGT and p-nitrophenol UGT, and to

estimate the kinetic parameters of the two enzymes (Luukanen et al. 1997). Pretreatment with creosote

increased the ratio of Vmax/Km by 18-fold for 1-hydroxypyrene UGT and by 2–3-fold for p-nitrophenol,

suggesting that a highly efficient form of glucuronosyltransferase was selectively induced by creosote.
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3. HEALTH EFFECTS

3.4.3.1 Inhalation Exposure

Coal Tar Products. Workers in a coal tar creosote wood-impregnating plant were exposed to coal tar

creosote by inhalation during the course of their jobs (Jongeneelen et al. 1985, 1988). The creosote that

these employees inhaled contained 19.8 mg pyrene/g creosote (approximately 2%). A metabolite of

pyrene, 1-hydroxypyrene, was detected in their urine at levels that were above the mean values of

controls (Jongeneelen et al. 1985, 1988). Similarly, workers asphalting roads with coal tar excreted

1-hydroxypyrene in their urine (Jongeneelen et al. 1988). 

A study of workers occupationally exposed to coal tar creosote compared the concentration of 1-naphthol

(a urinary metabolite of napthalene) in six workers from a creosote impregnation plant and five male

smokers not occupationally exposed to creosote (Heikkila et al. 1997). Exposed workers wore gloves and

cotton overalls to reduce dermal exposure to creosote, but did not wear respirators. The average

concentrations of naphthalene in the workers air varied from 0.4 to 4.2 mg/m3

. There was a poor

correlation between the amount of naphthalene in the air and the concentration of PAHs. However, the

concentration of 1-naphthol was consistently greater in exposed workers than in unexposed controls and

was highest for exposed workers at the end of the work shift. There was a correlation of r=0.745 between

the concentration of naphthalene in breathing zone air and urinary 1-naphthol concentrations at the end of

the shift.

A similar study was carried out in a coke plant in Zabrze, Poland (Bieniek 1997). The concentrations of

1-naphthol and 2-naphthol in the urine of 102 workers from the coke plant were compared with those of

36 controls not occupationally exposed to coal tar volatiles. Significant differences were found between

the concentrations of 1- and 2-naphthols in the urine of exposed and unexposed workers (P<0.05). The

correlation between the concentrations of naphthols in urine and napthalene in air were statistically

significant (P<0.001).

Another study of metabolites of coal tar volatiles was carried out by Grimmer et al. (1997). Urine

samples were collected from workers at a coke plant over a period of four days. Two workers were

exposed to high levels of PAH and two were exposed to lower levels. The concentration of metabolites

of phenanthrene, fluoranthene, pyrene, chrysene, and benzo[a]pyrene (in total, about 25 compounds) in

urine were measured by GC/MS. The urinary metabolite profile for each individual remained similar

over the four days analyzed. However, there was a significant difference between individuals for the

absolute amounts of metabolites excreted and also for the ratio of metabolites produced (e.g., only one

worker formed the 3,4-dihydrodiol of phenanthrene, the other two did not). 
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3. HEALTH EFFECTS

Similar results were obtained for measurements of the concentrations of metabolites of phenanthrene,

fluoranthene, pyrene, chrysene and benzo[a]pyrene in urine of female Wistar rats exposed to coal tar pitch

aerosols (dose and duration not stated) (Grimmer et al. 1997). The urinary metabolite profile for each

individual rat did not show significant variation during the course of the experiment, but there was a

significant difference between individuals for both the absolute amounts of metabolites excreted and also

for the ratio of metabolites produced. 

3.4.3.2 Oral Exposure

Wood Creosote. Eight healthy male volunteers were orally administered a single dose of 133 mg wood

creosote by capsule with 200 mL water after a light breakfast (Ogata et al. 1995). Peripheral venous

blood and urine samples were collected at various time intervals. The metabolites in the serum started to

rise 15 minutes after the oral dose, reaching the maximum 30 minutes after dosing. The maximum serum

concentrations (Cmax) of glucuronides were 0.18±0.07, 0.91±0.38, 0.33±0.18, and 0.47±0.23 mg/L, and

of sulfates were 0.16±0.06, 0.22±0.09, 0.17±0.07, and <0.04 mg/L for phenol, guaiacol, p-cresol, and

cresol, respectively. The Cmax for unconjugated phenols were 0.06±0.01, 0.05±0.01, 0.12±0.05, and

<0.04 mg/L for phenol, guaiacol, p-cresol and cresol, respectively. Rats receiving a single dose of either

0.0002, 0.002, 0.02, 0.2, or 2.0 mg pyrene/kg by gavage in olive oil excreted 1-hydroxypyrene in the

urine in a dose-dependent manner (Jongeneelen et al. 1986). This metabolite could be detected up to

96 hours after administration. No unchanged pyrene was excreted. 

Coal Tar Products. Calcium creosotate was orally administered to humans at daily doses of 7–30 mg/kg

for 3 days (Fellows 1939b). Calcium creosotate phenols were excreted in the urine. In addition, large

unspecified doses of calcium creosotate were orally administered to rabbits. Analysis of the rabbit urine

revealed that free and conjugated phenols were excreted (Fellows 1939b).

Induction of glucuronosyltransferase activity in liver microsomes from male Wister rats treated with coal

tar creosote (200 mg/4 mL olive oil/kg) by gavage 72 and 24 hours before death was compared with

activity in microsomes from untreated control animals (Luukanen et al. 1997). Microsome preparations

from the livers of these rats were used to assay the activities of 1-hydroxypyrene UGT and p-nitrophenol

UGT and estimate the kinetic parameters of the two enzymes. Pretreatment with creosote lowered the

apparent Km value for 1-hydroxypyrene UGT and significantly increased the estimated maximum velocity

Vmax over 4-fold. The apparent Km values of p-nitrophenol UGT were higher and the Vmax values lower

than the ones for 1-hydroxypyrene UGT, but again, treatment with creosote lowered the apparent Km

value and increased the estimated maximum velocity Vmax. Pretreatment with creosote increased the ratio
CREOSOTE 169

3. HEALTH EFFECTS

of Vmax/Km for 1-hydroxypyrene UGT by 18-fold and for p-nitrophenol 2–3-fold. These results suggest

that a highly efficient form of glucuronosyltransferase was selectively induced by creosote.

Male Fischer 344 rats received 50 mg/kg coal tar creosote in peanut oil daily by gavage for 1 or

3–5 weeks (Chadwick et al. 1995). Controls were dosed with the vehicle. After treatment with creosote,

six control and six treated rats were administered 75 mg/kg 2,6-DNT in DMSO by gavage and 24-hour

urine was collected. Urine was also collected from two control and two treated rats dosed with DMSO. 

Urinary excretion of mutagenic metabolites from rats pretreated with creosote and dosed with DNT at 1,

3, and 5 weeks peaked after 3 weeks and then declined by 33% after 5 weeks of treatment. Low levels of

mutagenic metabolites were also found in the urine of animals treated with creosote alone.

Induction of CYP1A1 and CYP2B10 in liver microsomes from ovariectomized mature and immature

DBA/2 mice and ICR mice gavaged with 10, 50, or 100 mg/kg creosote in sesame oil once a day for

4 days was compared with that in microsomes derived from control animals that received only sesame oil

(Fielden et al. 2000). CYP1A1 and CYP2B10 activities were assessed based on EROD (ethoxyresorufinO-deethylase) and PROD (pentoxyresorufin-O-depentylase) activities, respectively. Creosote treatment

significantly increased the activity of CYP1A1 and CYP2B10 in both immature and mature mice, but the

CYP1A1 increase was age-dependant, with immature mice showing a 5.9-fold increase in EROD activity

after treatment with 100 mg/kg/day creosote while mature mice treated similarly had an 11.4-fold increase

in liver EROD activity. No age-dependent difference was seen in induction of CYP2B10 since PROD

activity was increased by creosote treatment 1.6–2.2-fold in both mature and immature mice. 

It is evident in both human and animal studies that hydroxylation is a principal oxidative pathway of PAH

metabolism, and consequently, coal tar creosote metabolism. In these studies, there were no discussions

to suggest that the researchers attempted to identify other metabolites.

3.4.3.3 Dermal Exposure
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3. HEALTH EFFECTS

Coal Tar Products. A number of studies have shown that PAH components of coal tar appear to be

metabolized following dermal exposure in humans. Two patients suffering from eczema on the arms and

legs were treated for several days with an ointment containing 10% pix lithanthracis dermata (coal tar)

(Jongeneelen et al. 1985). The daily dermal dose was approximately 1 mg/kg. Analysis of the urine

samples collected from these patients prior to treatment and in the morning and evening of the first 3 days

of treatment showed that 1-hydroxypyrene was excreted at levels 200 times that which was detected

before the treatment started (Jongeneelen et al. 1985).

Urine samples collected from 43 patients being treated in the hospital for psoriasis with a coal tar

ointment and from 37 controls who had never been treated with coal tar were analyzed for the presence of

1-hydroxypyrene-glucuronide and r-7,t-8,t-9,c-10-tetrahydroxy-7,8,9,10-tetrahydro-benzo[a]pyrene

(Bowman et al. 1997). The metabolite, r-7,t-8,t-9,c-10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene,

was detected in urine of 20 (47%) of the patients, but only 4 (10%) of the controls. The other metabolite

studied, 1-hydroxypyrene-glucuronide, was detected in all samples, but the mean level for patients was

40.96±72.62 pmol μmol-1 creatinine and that for controls was 0.38±0.32 pmol μmol-1; this difference was

significant (P<0.0001). The ratio of urinary levels of the two metabolites was examined in the coal

tar-treated patients and found to vary by approximately 6,000-fold, suggesting wide variation between

individuals in the ability to metabolize benzo[a]pyrene and pyrene.

Similar results were obtained in another study of psoriasis patients (43 patients and 39 untreated controls)

being treated with a coal tar ointment (Weston et al. 1994). The benzo[a]pyrene metabolite,

r7,t8,t9,c10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene, was detected in urine of 18 psoriasis

patients (42%) and 4 untreated subjects (10%). There was a significant difference in the levels of

r7,t8,t9,c10-tetrahydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene in patients and untreated individuals with

levels varying from undetectable to 330 fmol/mL for patients and from undetectable to 40 fmol/mL for

untreated individuals. A second metabolite 1-hydroxypyrene-glucuronidide was found in all urine

samples, but levels were significantly higher in psoriasis patients than in untreated controls, ranging from

180 to 50,000 fmol/mL in patients and 36–650 fmol/mL in untreated individuals.

Patients with psoriasis (57) and healthy volunteers (53) with no reported exposures to coal tar shampoos

or ointments, self-applied either an ointment or a gel-based coal tar product, or both, to the entire body

surface at least once a day, followed by UV-B treatment (Santella et al. 1994). The estimated exposure

was 20–100 g of tar/day. Twenty-four hour urine samples were collected from all subjects. Urinary

1-hydroxypyrene was analyzed by HPLC. Urinary PAH metabolites measured by PAH-ELISA were
CREOSOTE 171

3. HEALTH EFFECTS

elevated in patients (mean 730±1,370 mmol) as compared to untreated volunteers (110±90 mmol

equivalents of B[a]P/mol creatinine). Urinary levels of 1-hydroxypyrene were also elevated in patients

(mean 547±928 mmol/mol creatinine) as compared with untreated volunteers (mean 0.14±0.17 mmol). 

Metabolism of pyrene was reported for 18 workers from a coke oven included in a NIOSH environmental

survey (Malkin et al. 1996). Personal breathing zone air was checked for the presence of PAHs and coal

tar pitch volatiles (identity not specified). The levels of naphthalene, benzene and pyrene were

specifically recorded. Sludge samples were also analyzed for the presence of PAHs. Preshift and

postshift urine samples were collected from the workers and analyzed for the presence of

1-hydroxypyrene, a metabolite of pyrene. Pyrene was found in analysis of the sludge samples at levels

between 6.3 and 36 mg/g, but was detected in only one breathing zone air sample. Preshift

1-hydroxypyrene levels were significantly increased at the end of the work shift. Preshift levels varied

from 0.16 to 3.0 μmol/mol creatinine (mean 1.0) and postshift levels ranged from 0.24 to 4.85 μmol/mol

creatinine (mean 1.7). Smoking was not found to be significantly related to 1-hydroxypyrene levels in

exposed workers, although preshift levels were slightly increased in smokers relative to nonsmokers. 

Experiments by Bickers and Kappas (1978), Li et al. (1995) and Genevois et al. (1998) have examined

the role of AHH and cytochrome P450 in the metabolism of coal tar products. A coal tar solution (crude

coal tar diluted to 20% with ethanol and polysorbate 80) was applied to clinically unaffected skin of three

patients with severe atopic dermatitis and six patients with generalized psoriasis (Bickers and Kappas

1978). Another skin area at least 10 cm away was not treated or was treated with 100 mL of the vehicle

alone. Twenty-four hours later, a 6-mm punch biopsy was obtained from coal tar treated and control

areas and the effect on AHH activity was determined. Application of coal tar to the skin caused induction

of cutaneous AHH activity that varied from 2.4–5.4-fold over the enzyme activity in untreated skin areas. 

There were no sex differences in inducibility between patients with psoriasis and patients with atopic

dermatitis. Relative inducibility of human skin AHH by coal tar did not appear to be a function of the

basal level of the enzyme. 

Coal tar solution (0.05 mL of a 20% solution) was applied to the skin of six neonatal rats (4–6 days of

age), and 24 hours later, AHH activity was measured in the skin and liver (Bickers and Kappas 1978). 

There was greater than a 10-fold induction of skin AHH activity (298±13 versus 26.3±19 pmol hydroxy

benzopyrene/mg protein/hour in controls) and marked increased hepatic AHH activity

(16,300±899 versus 750±35 pmol hydroxy benzopyrene/mg protein/hour in controls) after topical

application of the coal tar solution. 
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3. HEALTH EFFECTS

Cytochrome P4501A1 (CYP1A1) expression was increased in healthy volunteers treated dermally with

10% coal tar for 4 days producing an 18-fold induction of CYP1A1 mRNA levels in coal-tar-treated skin

(Li et al. 1995). In vitro incubation of DNA with coal tar fume concentrates in the presence of mouse and

yeast microsomes expressing various cytochrome P450 isoforms or the AHR demonstrated that coal tar

fume condensates require metabolic activation to produce DNA adducts (Genevois et al. 1998). Both the

AHR and CYP1A were involved in the metabolism of coal tar fume condensate, but neither was

absolutely required. The role of microsomal epoxide hydrolase was also tested, and it was shown that the

reactive metabolites formed by CYP1A are substrates for epoxide hydrolase. Addition of epoxide

hydrolase to the microsome preparations caused an 80% reduction in the relative level of DNA adducts

produced from coal tar fume condensates by CYP1A1.

3.4.4 Elimination and Excretion

Coal Tar Products. Excretion of the PAH compounds of coal tar creosote is controlled by their rate of

metabolism. Excretion of these metabolites or any remaining parent compound is primarily in the urine,

bile, and feces. Weyand and Bevan (1987) demonstrated this by cannulating the bile ducts of rats that

received [3

H]-benzo[a]pyrene intratracheally. Those rats with the biliary cannulas had significantly lower

levels of activity in their intestines, intestinal contents, and stomach than rats without biliary cannulas. 

Sanders et al. (1986) showed that PAHs were primarily removed in the feces after dermal administration

of [14C]-benzo[a]pyrene and [14C]-7,12-dimethylbenz[a]-anthracene, suggesting hepatobiliary excretion. 

Urinary excretion of PAH metabolites also occurs, but to a lesser extent than by the other routes. 

Excretion of the major portion of experimental doses of PAHs suggests half-lives in hours to days, with

inhalation exposure yielding the fastest elimination, followed by oral exposure and dermal exposure

(Agency for Toxic Substances and Disease Registry 1995). It is known that PAHs and their metabolites

cross the placenta (Agency for Toxic Substances and Disease Registry 1995) and have been detected in

human breast milk (Madhavan and Naiduka 1995). Individuals concerned with the potential exposure of

breast-feeding infants to PAHs should consult their doctor.

Studies of excretion of coal tar products have used urinary levels of PAHs and their metabolites as an

estimate of excretion of the parent mixture. These studies give information as to the rates of elimination

of individual PAHs, but not their extent, since a significant proportion of these chemicals is eliminated in

the bile and feces. The conclusions that can be drawn from these studies are also limited by evidence that

the rates at which individual PAHs are absorbed can vary by several orders of magnitude (VanøRooij et

al. 1995) so that no individual PAH can be taken as representative of the entire coal tar mixture.
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3. HEALTH EFFECTS

3.4.4.1 Inhalation Exposure

No studies were located regarding the excretion of wood creosote following inhalation exposure in

humans or animals. Some studies were located that estimate excretion of individual PAHs or their

metabolites in urine. Excretion of PAHs and their metabolites after inhalation exposure may be detected

hours to days after exposure (Agency for Toxic Substances and Disease Registry 1995).

Coal Tar Products. Measurements were carried out in a creosote impregnation plant where 6 men

volunteered to participate in the study (Elovaara et al. 1995). Personal breathing zone air samples were

taken on 5 consecutive days followed by a work free period of 64 hours. All workers wore leather

protective gloves and cotton overalls. Two employees worked overtime (until 6:30 a.m.) on Monday,

which was an exception to the regular 8-hour schedule. Particulate PAHs were collected during the

whole shift and analyzed within 7 weeks. Workers were asked to collect all urine passed within the

24-hour period into divided samples for the designated periods. Results showed that the geometric mean

(range) air concentration of total particulate PAHs (including pyrene) was 4.77 (1.2–13.7) mg/m3

 and that

of naphthalene was 1,254 (370–4,200) mg/m3

. The PAH profile was similar in all samples. The lowest

concentrations of 1-hydroxypyrene in creosote workers were found in the Monday morning urine samples

after 64 hours off work. The highest concentrations were consistently found in the evening samples

(6–9 hours after work) but lower at the end of the shift. The urinary 1-hydroxypyrene levels on Monday

morning before work ranged from 4 to 22 mmol/mol creatinine; levels on Tuesday morning to Saturday

morning ranged from 16 to 120 mmol/mol creatinine; and levels at end of shift ranged from 19 to

85 mmol/mol creatinine. The evening after work (taken on Monday, Wednesday, and Friday) urinary

levels of 1-hydroxypyrene ranged from 27 to 122 mmol/mol creatinine. 

Exposure of assemblers (all smokers) handling creosote-impregnated wood and one worker (smoker)

chiselling coal tar pitch insulation to coal tar products was assessed by analyzing the breathing zone air

for airborne PAHs, and assaying urinary excretion of 1-hydroxypyrene (Heikkilä et al. 1995). The

concentration of pyrene and 11 other PAHs in particulate matter had been measured both in the work

room and in the breathing zone of the assemblers a year earlier during 2 working days. In the present

setting the ties were impregnated with the same type of creosote as a year earlier, which contained

0.2 w% of pyrene. Urine samples were collected during 3 working days (Monday, Wednesday, and

Friday) and over the following weekend. Urine samples from one chiseller were collected in the morning

before work, during lunch time, at the end of the shift, in the evening, and the next morning. The total

concentrations of PAHs and of 4–6 aromatic ring-containing PAH (when chiselling) were 440 (50-fold

higher than assemblers) and 290 (200-fold higher than assemblers) mg/m3

, respectively. The estimated
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3. HEALTH EFFECTS

means of inhaled pyrene for assemblers measured on Monday, Wednesday, and Friday were found to be

0.009, 0.007, and 0.024 mmol/shift, respectively. The estimated inhaled pyrene measured on the chiseller

was 1.2 mmol/shift. Excretion of urinary 1-hydroxypyrene for assemblers measured on Monday,

Wednesday, and Friday for assemblers showed mean pyrene doses (pyrene doses=breathing volume

[25 L/minute] x work period x pyrene concentration x 50% retention) of 0.010, 0.13, and

0.19 mmol/24 hours, respectively. Excretion of urinary 1-hydroxypyrene measured on the chiseller

showed a pyrene dose of 0.492 mmol/24 hours. 

Four rotation crews of about 29 workers and one day crew of 22 workers worked a 5-day shift of

8 hours/day in the potrooms (Ny et al. 1993). All workers wore disposable respirators that were renewed

4–5 times/day, thick cotton working clothes with long sleeves, safety shoes, safety glasses, gloves, and

helmets. Other groups that worked occasionally in the potrooms were also included in this study. Some

employees who worked in dusty environments also wore facial protective clothing. Personal breathing

zone air samples were taken randomly one time from 38 workers. Measurements were done on 3 of

5 working days for the rotation crews and on 4 days in 2 work weeks for the day crew. The filter holders

and the XAD-2 tubes used in sampling were analyzed. Urine samples were collected from 33 of

38 workers before and after the 5-day work week. Control urine samples were taken from 10 guards not

exposed to coal tar pitch volatiles. 1-Hydroxypyrene in urine was determined by liquid chromatography. 

Results showed that field blanks were not contaminated with coal tar pitch volatiles. No benzo[a]pyrene

was found on XAD-tubes. Vapor phase measurement showed 48% pyrene and 24% total PAHs. The

highest filter sample (particulate) concentration of pyrene was 170 mg/m3

 and the highest sorbent tube

(vapor) concentration of pyrene was 94 mg/m3

. The correlation between these 2 variables was 0.70. 

Individuals who worked continuously in the potrooms were exposed to variable concentrations of coal tar

pitch volatiles, ranging from 10–2,710 mg/m3

. Multiple regression analysis of increased urinary

1-hydroxypyrene was strongly related to the environmental PAH exposure. Increased urinary

1-hydroxypyrene was greater among those using facial protective clothing under their respirators; this

was probably caused by poor fitting or by facial coverings becoming contaminated by PAH. The

predicted limit value of change in urinary 1-hydroxypyrene, using the model for coal tar pitch volatiles

was 4.3 mmol/mol creatinine. The predicted limit value of change in urinary 1-hydroxypyrene, using the

model for benzo[a]pyrene was 4.3 mmol/mol creatinine. 

Urine samples collected from two reference groups of nonoccupationally exposed individuals and four

groups of workers were measured for urinary excretion of 1-hydroxypyrene (Viau et al. 1995). The study

groups are described as follows: reference group 1 (12 males, 9 females) was workers with no

occupational exposure to PAH (single spot urine sample collected during the day); reference group 2
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(7 males) was administrative workers in a silicon carbide plant (urine samples obtained Monday morning

upon arrival at work); the silicon carbide group (83 males) worked in a silicon carbide plant involved in

various occupations (urine samples collected at the beginning and end of work shift on a Monday and

Friday); the creosote group (19 males) was workers exposed to creosote in a wood treatment plant (one

urine sample collected towards the end of the work week and another sample obtained after at least

64 hours of exposure); the decontamination group (29 males) was workers in various occupations related

to the removal of soil contaminated with PAH from the pyrolysis of used tires after a major fire at a dump

(single urine sample collected at beginning of shift); and the brushwood cutting group (10 males) was

workers responsible for the clearing of brushwood under electricity power lines (single urine sample

collected at end of shift). Urine samples from reference group 1, creosote, decontamination, and

brushwood cutting groups were analyzed by high performance chromatography; samples from reference

group 2 and silicon carbide group were analyzed by GC/MS. Results showed that the creosote group was

largely exposed to pyrene. Even after >64 hours without exposure, the mean (geometric) excretion of

1-hydroxypyrene was higher for the creosote group (0.53 mmol/mol creatinine) than for the reference

groups 1 (0.08 mmol/mol creatinine) and 2 (0.10 mmol/mol creatinine). The mean (geometric) excretion

in creosote workers during their working week was 1.63 (0.18–10.47) mmol/mol creatinine. The

brushwood cutting workers excreted more 1-hydroxypyrene than the referents. These results were pooled

with those of the nonoccupationally exposed reference groups yielding a total of 140 individuals having a

mean (geometric) excretion of 0.08 mmol/mol creatinine and the 5th, 50th, and 95th percentiles of 0.02,

0.09, and 0.32 mmol/mol creatinine, respectively. The mean (geometric) excretion in the 95 nonsmokers

and 45 smokers of this pool were 0.07 and 0.12 mmol/mol creatinine, respectively.

3.4.4.2 Oral Exposure
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Wood Creosote. Eight healthy male volunteers were orally administered a single dose of 133 mg wood

creosote by capsule with 200 mL water after a light breakfast (Ogata et al. 1995). Urine samples were

collected at various time intervals. Phenols in urine were analyzed by HPLC. Wood creosote used in this

study as determined by GC contained 11.3% phenol, 24.3% guaiacol, 13.7% p-cresol, and 18.2% cresol

(w/w). The urinary recoveries of the sum of the conjugated and unconjugated forms of each phenolic

compound were 75±35, 45±36, 103±51, and 74±36% for phenol, guaiacol, p-cresol, and cresol,

respectively. 

Coal Tar Products. No studies were located regarding the excretion of coal tar creosote, coal tar, coal tar

pitch, or coal tar pitch volatiles following oral exposure in humans. 

Weyand et al. (1991) fed male mice 0.25% MGP residue, a form of coal tar, in feed for 15 days. The coal

tar mixtures were of five different compositions. Analysis of urine collected on the first and last day of

exposure indicated that 1-hydroxypyrene was the major metabolite excreted by all groups. Urinary levels

of 1-hydroxypyrene were greater on day 15 of ingestion compared to day 1 of ingestion. 1-Naphthol,

1-hydroxyphenanthrene, and 2-hydroxyphenanthrene were also detected in the urine. Animals fed coal

tar with a high content of pyrene excreted more 1-hydroxypyrene than animals fed coal tar with low

pyrene content. In another study by Weyand et al. (1994), five groups of B6C3F1 mice (24 males,

24 females) were fed a control gel diet containing 0.05, 0.25, or 0.50% MGP residue, a type of coal tar

formed as a by-product of coal gasification. The urinary excretion of 1-hydroxypyrene by male mice

(12 per group) treated with 0.25 and 0.50% MGP was evaluated throughout the 185 days of diet

administration. Urine was collected overnight on days 1, 34, 64, 88, 116, and 182 of diet administration

and analyzed by HPLC. Urine collected overnight on days 1, 34, 64, 88, 116, and 182 resulted in

increased urinary excretion of 1-hydroxypyrene 19 (day 1) to 203 (day 182) mg/mL per mouse. This

increase in concentration paralleled a notable decrease in the total volume of urine excreted by animals. 

Thus, the total amount of 1-hydroxypyrene excreted reached a maximum of 5–6 mg within 34 days of

diet administration. 

Male Fischer 344 rats received 50 mg/kg creosote in peanut oil daily by gavage for 1 week, or 3–5 weeks

(Chadwick et al. 1995). Controls were dosed with the vehicle. After treatment with creosote, six control

and six treated rats were administered 75 mg/kg 2,6-DNT in DMSO by gavage and 24-hour urine

collected. Urine was also collected from two control and two treated rats dosed with DMSO. Urinary

excretion of mutagenic metabolites from rats pretreated with creosote and dosed with DNT at 1, 3, and
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5 weeks peaked after 3 weeks and then declined by 33% after 5 weeks of treatment. Low levels of

mutagenic metabolites were also found in the urine of animals treated with creosote alone.

3.4.4.3 Dermal Exposure

No studies were located regarding the excretion of wood creosote following dermal exposure in humans

or animals. 

Coal Tar Products. Human exposure studies demonstrate that coal tar creosote or its components are

absorbed dermally in humans, based on excretion of metabolites after dermal exposure (Bickers and

Kappas 1978; Bos and Jongeneelen 1988; Cernikova et al. 1983; Clonfero et al. 1989; Diette et al. 1983;

Hansen et al. 1993; Jongeneelen et al. 1985; Santella et al. 1994; Sarto et al. 1989; Van Rooij et al. 1993a,

1993b; van Schooten et al. 1994; Viau and Vyskocil 1995). Van Rooij et al. (1993a) examined

differences in absorption of PAH between anatomical sites and individuals following dermal exposure of

volunteers to 10% coal tar in a vehicle of zinc oxide paste. Differences between individuals in PAH

absorption are small (7%) in comparison with differences between anatomical sites (69%). Urinary

excretion of 1-hydroxypyrene verified that the coal tar creosote and its components were absorbed

through the skin, but the site of application had no effect on the excreted amount of 1-hydroxypyrene

although the time to excrete half of the total metabolite varied between 8.2 and 18.9 hours. Another study

of excretion after dermal absorption was conducted by Van Rooij et al. (1993b) in a wood preserving

plant in the Netherlands in October 1991. Volunteers for this study were workers who worked near the

impregnation cylinders (three subjects) and the assembly hall (seven subjects). Exposure measurements

were performed in 2 consecutive weeks on a Monday after a weekend off. On one Monday, the workers

wore protective clothing over their clothes and on the other Monday, no protective clothing was used. 

PAH contamination on the skin and PAH concentration was measured on the two Mondays on all

workers. Urine samples were collected from Sunday morning through Tuesday morning for the

assessment of the internal exposure to PAH. The excreted amount of 1-hydroxypyrene in urine decreased

significantly from 6.6 to 3.2 mg (30.2–14.7 nmol). 

Sarto et al. (1989) examined the excretion of coal tar metabolites in male psoriatic patients treated

dermally with an ointment containing 2 or 4%, or pure coal tar on 35–60% of the surface skin for

1–13 days. Coal tar content was reported to be 0.49 mg/g for the 4% coal tar ointment, and about

29 mg/g for the pure coal tar. PAHs appeared in the urine within a day after treatment, with peak

concentrations 7–10 days after treatment.
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Five female patients (two nonsmokers, three smokers) suffering from eczematous dermatitis on the arms

and legs were treated for several days with an ointment containing 10% pix lithanthracis dermata (coal

tar), representing 16.7 mg/g pyrene and 7.0 mg/g benzo[a]pyrene (Bos and Jongeneelen 1988). During

treatment, the ointment was removed daily and a fresh dose of approximately 40 g was rubbed in. Urine

samples were collected, one before application and two during the day for the first 3 days of treatment. 

High concentrations of toxic compounds in the urine samples were found and mutagenicity tests were not

successful. One out of two nonsmoking patients excreted a large amount of thioether products during the

beginning of the treatment: 19.6 mmol thioether (SH)/mol creatinine was measured in the evening urine

sample of the first day of treatment and 24.5 mmol SH/mol creatinine in the morning urine sample of the

second day of treatment. The concentrations were within the normal range in urine samples measured on

the evening of the second day (5.4 mmol SH/mol creatinine) and on the morning of the third day

(3.3 mmol SH/mol creatinine). No similar increase in thioether excretion during coal tar treatment was

found for other patients, whose values were within or slightly above the normal range. The concentration

of 1-hydroxypyrene rose rapidly to 100 times the control value after the beginning of the treatment of

these patients reaching 50–500 μmol/mol creatinine. Pretreatment urine samples of the smoker patients

contained somewhat higher levels of 1-hydroxypyrene than those for a separate group of control smokers.

Twenty-eight patients who required coal tar treatment on an area larger than two-thirds of the body

surface were selected for this study (Cernikova et al. 1983). Tar paste (10 and 20%) was used for

treatment; in one application approximately 1–6 g of coal tar containing 0.6% acridine was spread on the

patient's skin. Urine analysis was performed by TLC to obtain information on polyaromatic and

heterocyclic substances excreted in the urine. Further identification of the substance was performed by

GC/MS. The presence of acridine in urine after the coal tar application was identified by MS. Acridine

was not quantified. 

Sixteen urine samples were collected from four male, nonsmoking psoriatic patients undergoing treatment

with the Goeckerman regimen (cutaneous application of coal tar based ointment, followed by exposure to

UV irradiation) in the Dermatology Clinic of the University of Padua (Clonfero et al. 1989). Patient A

was treated with pure coal tar for 1 day; patients B, C, and D were treated with 4% coal tar based

ointment for 2, 8, and 13 days, respectively. Body surface involved by psoriasis was 30, 40, 35, and 60%

for patients A, B, C, and D, respectively. Total PAH (and pyrene) content of the two coal tar preparations

was 28,800 (3,100) and 470 (104) ppm, respectively. The samples were collected at different times after

the beginning of therapy (from 12 hours after the first application of coal tar to 72 hours after the last

application). Levels of 1-hydroxypyrene ranged from 25.4 mg/g creatinine to 1,565 mg/g creatinine. 

Total PAH content in urine ranged from 6.4 mg/g creatinine to 64.2 mg/g creatinine. Baseline levels of
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3. HEALTH EFFECTS

total PAH and mutagenic activity were determined in evening urinary samples of 5 healthy, nonsmoking

subjects, not exposed to PAHs. The control group for the determination of 1-hydroxypyrene levels

consisted of 52 nonsmokers who exhibited values of 1.3 mg/g creatinine. Results showed levels of

1-hydroxypyrene are 20 and 1,000 times higher in the exposed group than in controls; total PAHs were

3.5–20 times higher in the exposed group than in controls. In 5 of 15 cases, the urinary mutagenicity of

the exposed group was not significantly higher than that of the controls, while in one case it was not

evaluated due to toxic effects. The mutagenic activity of the urinary extracts of the exposed subjects was

at most 8 times greater than the average mutagenicity of the controls. 

Patients with psoriasis (57) and healthy volunteers (53) with no reported exposures to coal tar shampoos

or ointments, self-applied either an ointment or a gel-based coal tar product, or both, to the entire body

surface at least once a day, followed by UV-B treatment (Santella et al. 1994). The estimated exposure

was 20–100 g/tar/day. Twenty-four-hour urine samples were collected from all subjects. Urinary

1-hydroxypyrene was analyzed by HPLC. Urinary PAH metabolites measured by the PAH-ELISA were

elevated in patients (mean 730±1,370 mmol) as compared to untreated volunteers (110±90 mmol

equivalents of B[a]P/mol creatinine). Urinary levels of 1-hydroxypyrene were also elevated in patients

(mean 547±928 mmol/mol creatinine) compared with untreated volunteers (mean 0.14±0.17 mmol). 

No studies were located regarding the excretion of coal tar creosote, coal tar, coal tar pitch, or coal tar

pitch volatiles following dermal exposure in animals. 

3.4.5 Physiologically Based Pharmacokinetic (PBPK)/Pharmacodynamic (PD) Models

Physiologically based pharmacokinetic (PBPK) models use mathematical descriptions of the uptake and

disposition of chemical substances to quantitatively describe the relationships among critical biological

processes (Krishnan et al. 1994). PBPK models are also called biologically based tissue dosimetry

models. PBPK models are increasingly used in risk assessments, primarily to predict the concentration of

potentially toxic moieties of a chemical that will be delivered to any given target tissue following various

combinations of route, dose level, and test species (Clewell and Andersen 1985). Physiologically based

pharmacodynamic (PBPD) models use mathematical descriptions of the dose-response function to

quantitatively describe the relationship between target tissue dose and toxic end points. 

PBPK/PD models refine our understanding of complex quantitative dose behaviors by helping to

delineate and characterize the relationships between: (1) the external/exposure concentration and target

tissue dose of the toxic moiety, and (2) the target tissue dose and observed responses (Andersen et al.
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3. HEALTH EFFECTS

1987; Andersen and Krishnan 1994). These models are biologically and mechanistically based and can

be used to extrapolate the pharmacokinetic behavior of chemical substances from high to low dose, from

route to route, between species, and between subpopulations within a species. The biological basis of

PBPK models results in more meaningful extrapolations than those generated with the more conventional

use of uncertainty factors. 

The PBPK model for a chemical substance is developed in four interconnected steps: (1) model

representation, (2) model parametrization, (3) model simulation, and (4) model validation (Krishnan and

Andersen 1994). In the early 1990s, validated PBPK models were developed for a number of

toxicologically important chemical substances, both volatile and nonvolatile (Krishnan and Andersen

1994; Leung 1993). PBPK models for a particular substance require estimates of the chemical substancespecific physicochemical parameters, and species-specific physiological and biological parameters. The

numerical estimates of these model parameters are incorporated within a set of differential and algebraic

equations that describe the pharmacokinetic processes. Solving these differential and algebraic equations

provides the predictions of tissue dose. Computers then provide process simulations based on these

solutions. 

The structure and mathematical expressions used in PBPK models significantly simplify the true

complexities of biological systems. If the uptake and disposition of the chemical substance(s) is

adequately described, however, this simplification is desirable because data are often unavailable for

many biological processes. A simplified scheme reduces the magnitude of cumulative uncertainty. The

adequacy of the model is, therefore, of great importance, and model validation is essential to the use of

PBPK models in risk assessment.

PBPK models improve the pharmacokinetic extrapolations used in risk assessments that identify the

maximal (i.e., the safe) levels for human exposure to chemical substances (Andersen and Krishnan 1994). 

PBPK models provide a scientifically sound means to predict the target tissue dose of chemicals in

humans who are exposed to environmental levels (for example, levels that might occur at hazardous waste

sites) based on the results of studies where doses were higher or were administered in different species. 

Figure 3-5 shows a conceptualized representation of a PBPK model.

The pharmacokinetics of wood creosote, coal tar creosote, coal tar, coal tar pitch, and coal tar pitch

volatiles have not been defined because of their chemical complexity. Creosotes vary tremendously in

composition and hence, mechanisms of action most likely differ among individual samples of creosotes. 
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Information on individual components is not adequate to define the properties of the whole mixture and

for this reason no PBPK models have been proposed for creosote. 

3.5 MECHANISMS OF ACTION

3.5.1 Pharmacokinetic Mechanisms

Absorption. No studies were located in humans or animals regarding the direct analysis of absorption

of wood creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles via the inhalation,

oral, or dermal routes. Studies of humans exposed to coal tar creosote have measured increased levels of

urinary metabolites of various components of coal tar creosote suggesting that at least some components

of coal tar creosote are absorbed by all routes. However, these studies do not provide any information as

to the mechanism of absorption. PAHs are lipophilic compounds that are probably absorbed by passive

diffusion, but no information was located for mechanism of absorption of other components of creosote. 

From data on individual PAHs (Agency for Toxic Substances and Disease Registry 1995), gastrointestinal absorption of the PAH components of coal tar creosote may be increased by the presence of oils

and fats in the stomach and bile in the intestines, while dermal absorption is affected by the anatomical

site to which it is applied. Dermal absorption of PAHs may also be increased when they are solubilized in

a fat or oil mixture prior to application or conversely may be reduced by binding and/or metabolism in the

skin. However, due to the variable composition of coal tar creosote, coal tar pitch, and coal tar, the

predictive value of studies carried out on single PAHs is limited. For further information on PAHs please

refer to the ATSDR Toxicological Profile for Polycyclic Aromatic Hydrocarbons (Agency for Toxic

Substances and Disease Registry 1995).
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Figure 3-5. Conceptual Representation of a Physiologically 

Based Pharmacokinetic (PBPK) Model for a 

Hypothetical Chemical Substance

Source: adapted from Krishnan et al. 1994

Note: This is a conceptual representation of a physiologically based pharmacokinetic (PBPK) model for a hypothetical

chemical substance. The chemical substance is shown to be absorbed via the skin, by inhalation, or by ingestion,

metabolized in the liver, and excreted in the urine or by exhalation.
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Distribution. No studies were located in humans or animals regarding the distribution of wood

creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles following inhalation, oral, or

dermal exposure. Coal tar is composed of hydrocarbons, which are lipophilic substances and distribute to

lipid-rich tissues including breast milk and the placenta. The frequent presence of metabolites of coal tar

in the urine also suggests that it is likely to distribute to the liver. The distribution of nonmetabolized

PAHs is dependent on their water-solubility. The most lipophilic PAHs may be preferentially distributed

to fatty tissues where they may accumulate while more water-soluble PAHs may be more easily excreted. 

PAHs are distributed to tissues by transport through the blood, therefore, highly perfused tissues such as

the lung and liver are likely to contain PAHs. This may also be the case with phenol and cresol as

analysis of blood from volunteers who ingested wood creosote (Ogata et al. 1995) demonstrated the

presence of phenol, guiacol, and cresols in the blood. A study of the distribution of intratracheally

administered radioactive benzo[a]pyrene mixed with a benzene extract of coal fly ash in pregnant rats

found that most radioactivity was distributed to the maternal lung, while 68% of the amount in lung was

found in the maternal liver (Srivastava et al. 1986). A small amount of radioactivity was also distributed

to the fetal lung and liver and to the placenta, respectively 1.9, 1.4, and 4% of the amount in maternal

lung. The route of administration of creosote may affect distribution in that entry via the lungs may

initially bypass metabolism in the liver so that parent compounds reach peripheral tissues in higher

concentrations than would be seen after oral administration.

Metabolism. No studies were located in humans or animals that specifically addressed the metabolism

of wood creosote, coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles following inhalation,

oral, or dermal exposure. The PAH components of creosote are metabolized by oxidative enzymes in the

liver and lungs to generate active metabolites that can bind to macromolecules. The metabolic profiles of

these substances vary among species and compounds, but the components follow the same reaction

pathways and so the metabolites are structurally similar. The major products include phenols,

dihydrodiols, quinones, anhydrides, and conjugates of these products. Enzymes involved in the

metabolism of PAHs vary depending on tissue and the particular PAH, but can include various isoforms

of cytochrome P450 (predominantly CYP1A1, but also CYP1A2, CYP1B1, or CYP2C) (Genevois et al.

1998), epoxide hydrolase, glutathione-S-transferases, glucuronidases, and AHH (Agency for Toxic

Substances and Disease Registry 1995). For more information on the metabolism of PAHs the reader is

referred to the ATSDR Toxicological Profile on Polycyclic Aromatic Hydrocarbons (Agency for Toxic

Substances and Disease Registry 1995). Phenol is metabolized via three pathways in mammals; P450

catalyzed hydroxylation, sulphate conjugation, or glucuronide conjugation. The two conjugation

pathways can be considered competitive pathways in most species of mammal. Thus, the relative

amounts of each product formed depend on dose level as well as the relative abundance and kinetic
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parameters of the two enzyme systems. For further information on the metabolism of phenol the reader is

referred to the ATSDR Toxicological Profile on Phenol (Agency for Toxic Substances and Disease

Registry 1998).

Excretion. No studies were located in humans or animals regarding the excretion of wood creosote,

coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles following inhalation, oral, or dermal

exposure. Phenol is a normal constituent of human urine and phenol administered via all routes of

absorption is rapidly eliminated in the urine and the bile (Agency for Toxic Substances and Disease

Registry 1998). PAHs are lipophilic compounds that could remain indefinitely within fatty tissues, but

metabolism of PAHs renders them more water soluble and more excretable. Excretion of the metabolites

of PAHs is primarily in the urine, bile, and feces. Experimental data suggests half-lives of hours to days

with elimination being fastest after inhalation exposure followed by oral and dermal exposure (Agency

for Toxic Substances and Disease Registry 1995). PAHs have been detected in human breast milk

(Madhavan and Naiduka 1995).

3.5.2 Mechanisms of Toxicity

Defining a general mechanism of toxicity for creosotes, coal tar, coal tar pitch, and coal tar pitch volatiles

is essentially impossible because of their diversity and variability in biological effect and composition. 

The creosotes vary tremendously in respect to their sources (wood or coal), components, and preparation

conditions. Similarly, coal tar, coal tar pitch, and coal tar pitch volatiles will differ in composition

depending on the source of the coal. Hence, mechanisms of action most likely differ among individual

creosotes, coal tars, coal tar pitch, and coal tar pitch volatiles. 

In addition, although a great deal is known about the mechanisms of action for many of the individual

components of creosote, the use of individual components to define the properties of the whole mixture

may or may not supply adequate information upon which risk from exposure to the whole can be

appropriately assessed. An excellent example of this is presented by Warshawsky et al. (1993), who

reported that the carcinogenicity for mice of specific coal tar creosote components mixed in different

formulations differed in incidence and latency of appearance from their individual carcinogenicities. For

instance, coal tar in toluene, which was determined to contain 0.0006% B[a]P, produced tumors in 51% of

mice with a latent period of 73 weeks. In contrast, the same concentration of B[a]P administered in

toluene without coal tar did not produce tumors. The addition of another solvent, n-dodecane, resulted in

increased tumor incidence and reduced latency period. Solutions of methylbenz[a]anthracenes in toluene

did not produce tumors, but did result in tumors when administered in n-dodecane. The findings of this
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study indicated that (1) low doses of noncarcinogenic PAHs could have an impact on the carcinogenic

potential of B[a]P in mixtures, (2) the carcinogenic activity of coal tar cannot be accounted for by the

level of B[a]P present, and (3) certain noncarcinogenic components of coal tar can have their carcinogenic

potential altered by the presence of other aliphatic compounds. 

Individual components of creosote are also metabolized by several different enzyme systems including

cytochrome P450, epoxide hydrolase, glutathione-S-transferases, glucuronidases, AHH, phenol

sulfotransferase, and glucuronyltransferase. Human polymorphisms are known to exist for many of these

enzymes and are likely to affect the relative toxicity of creosote for these individuals. The relative

activity of metabolic enzymes may also vary with the age of the individual, which will again affect the

relative toxicity of particular components of creosote for old or young individuals (for further discussion

of age-related effects, the reader is referred to Section 3.7). Therefore, for creosotes, coal tar, coal tar

pitch, and coal tar pitch volatiles, it is not presently possible to define mechanisms of transport,

distribution, or the precise chemical or physiological events that lead to toxic damage or carcinogenicity

in the biological system. 

3.5.3 Animal-to-Human Extrapolations

Animal-to-human extrapolations of the toxicity of creosote are complicated by the inherent chemical

variety of these substances. Creosotes are complex mixtures of variable composition and the individual

components are likely to show interspecies variation in toxicity. Only one study was located that treated

more than one species of animal with the same sample of creosote (Miyazato et al. 1981), and although

this study suggested that mice were more susceptible to the acute effects of beechwood creosote than rats,

the differential susceptibility observed with this particular sample cannot be applied to creosotes of

different composition. In general, the adverse effects observed in animals are similar to those reported for

humans with cancer being the most serious, but it is not possible at present to assess whether the doses

required to produce adverse effects in animal systems are similar to those required to produce similar

effects in humans.

3.6 TOXICITIES MEDIATED THROUGH THE NEUROENDOCRINE AXIS
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Recently, attention has focused on the potential hazardous effects of certain chemicals on the endocrine

system because of the ability of these chemicals to mimic or block endogenous hormones. Chemicals

with this type of activity are most commonly referred to as endocrine disruptors. However, appropriate

terminology to describe such effects remains controversial. The terminology endocrine disruptors,

initially used by Colborn and Clement (1992), was also used in 1996 when Congress mandated the

Environmental Protection Agency (EPA) to develop a screening program for “...certain substances

[which] may have an effect produced by a naturally occurring estrogen, or other such endocrine

effect[s]...”. To meet this mandate, EPA convened a panel called the Endocrine Disruptors Screening and

Testing Advisory Committee (EDSTAC), which in 1998 completed its deliberations and made

recommendations to EPA concerning endocrine disruptors. In 1999, the National Academy of Sciences

released a report that referred to these same types of chemicals as hormonally active agents. The

terminology endocrine modulators has also been used to convey the fact that effects caused by such

chemicals may not necessarily be adverse. Many scientists agree that chemicals with the ability to disrupt

or modulate the endocrine system are a potential threat to the health of humans, aquatic animals, and

wildlife. However, others think that endocrine-active chemicals do not pose a significant health risk,

particularly in view of the fact that hormone mimics exist in the natural environment. Examples of

natural hormone mimics are the isoflavinoid phytoestrogens (Adlercreutz 1995; Livingston 1978; Mayr et

al. 1992). These chemicals are derived from plants and are similar in structure and action to endogenous

estrogen. Although the public health significance and descriptive terminology of substances capable of

affecting the endocrine system remains controversial, scientists agree that these chemicals may affect the

synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body responsible

for maintaining homeostasis, reproduction, development, and/or behavior (EPA 1997). Stated differently,

such compounds may cause toxicities that are mediated through the neuroendocrine axis. As a result,

these chemicals may play a role in altering, for example, metabolic, sexual, immune, and neurobehavioral

function. Such chemicals are also thought to be involved in inducing breast, testicular, and prostate

cancers, as well as endometriosis (Berger 1994; Giwercman et al. 1993; Hoel et al. 1992).

No studies were located regarding endocrine disruption in humans after exposure to wood creosote, coal

tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles. 

Wood Creosote. Effects of wood creosote on the endocrine organs are confined to changes in testis and

adrenal gland weights without any accompanying histological alterations. Miyazato et al. (1981) reported

that oral exposure of rats to beechwood creosote in the diet for 3 months increased relative weight of the

testis. However, there were no accompanying histological changes in the testis and no changes in ovary
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weights. No change in testis or ovary weight was observed for mice exposed to beechwood creosote for

up to 96 weeks (Miyazato et al. 1981, 1984a, 1984b). Oral exposure of male rats to 313 mg/kg/day

beechwood creosote for 96 weeks produced a significant increase in the relative weight of the adrenal

glands of male rats (Miyazato et al. 1984b). However, another study of beechwood creosote found no

effect on the adrenal glands (Miyazato et al. 1981).

Coal Tar Products. An excess of breast cancer cases in St. Louis Park, Minnesota, was tentatively

associated with coal tar contamination of the water supply (Dean et al. 1988). However, in a subsequent

analysis of these data, the Minnesota Department of Health (1985) concluded that this study did not

provide adequate evidence to associate breast-cancer with coal tar creosote-contaminated water (for a

detailed discussion of these data, see Section 3.2.2.7 Cancer). No adverse effects on sperm characteristics

were reported in male workers exposed to coal tar pitch volatiles in an industrial setting (Ward 1988). In

addition, no adverse reproductive outcomes were detected in a survey of inhabitants of a housing

development built on an abandoned creosote factory site, which was known to be contaminated with

creosote (Agency for Toxic Substances and Disease Registry 1994). A retrospective study of dermal

exposure to coal tar found no increased risk of spontaneous abortion associated with exposure to coal tar

during pregnancy, but this was a small study and was unlikely to have sufficient resolution to detect a

modest increase in risk (Franssen et al. 1999). 

Coal tar creosote was tested for estrogenic activity using both in vivo and in vitro assays with

inconclusive results (Fielden et al. 2000). Results from the in vitro tests showed that creosote binds both

the estrogen receptor (ER) and the human sex hormone-binding globulin (SHBG), and can induce ERmediated gene expression. However, in vivo assays using ovariectomized DBA/2 mice and ICR mice

gavaged with 0, 10, 50, or 100 mg/kg creosote in sesame oil or 0.1 mg/kg 17α-ethynylestradiol (positive

control) once a day for 4 days were negative. Treatment with 17α-ethynylestradiol produced a significant

increase in uterine weight and vaginal cell cornification compared with animals receiving only sesame oil,

but no significant increase in uterine weight or vaginal cell cornification was observed in animals treated

with creosote. The study authors also tested the ability of creosote to induce gene expression via the AhR

in Hepa 1c1c7 cells, to induce CYP1A1 and CYP2B10 in liver microsomes, and to interact with the

estrogen-inducible/dioxin-suppressible pS2-Luc reporter gene. Creosote induced gene expression via the

AhR and increased the activity of CYP1A1 and CYP2B10, but although treatment of cells expressing the

pS2-Luc reporter gene with increasing concentrations of creosote produced a dose-dependent increase in

activity, no consistent inhibition of E2-induced activity in these cells was noted. The AhR in DBA/2

mice is known to be much less responsive to PAHs than that of ICR mice; however, estrogenic effects of

creosote were not observed in either strain and the authors concluded that although creosote has the
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potential to interact with the endocrine system, it does not appear to be sufficiently potent to produce an

effect in this assay. 

There is evidence from some animal studies that exposure to coal tar has adverse effects on reproductive

success, but these effects are likely to be due to fetotoxicity or maternal toxicity rather than maternal

endocrine disruption, and other studies have found no adverse effects. A significant decrease in number

of live fetuses/litter and the number of resorptions was observed in female rats gavaged with

370 mg/kg/day coal tar on gestational days 12–16, but no significant difference in the number of live

births was observed in female rats gavaged with 740 mg/kg/day coal tar on gestational days

12–14 (Hackett et al. 1984; Springer et al. 1986a). Dermal exposure of rats and mice to 500 or

1,500 mg/kg coal tar on gestational days 11–15 resulted in significant increases in prenatal mortality in all

exposed rat fetuses and high dose mice fetuses compared to controls (Zangar et al. 1989). Early

resorptions (occurred before dosing) were similar in all groups, but middle resorptions (which

corresponded to the dosing period) were significantly increased in exposed rats and high dose mice. Late

resorptions were also significantly increased in exposed rats. No adverse effects on reproductive indices

were reported by Iyer et al. (1993) after oral exposure of mice to coal tar creosote in DMSO on gestation

days 5–9. A similar lack of effect on reproductive organs was observed by Weyand et al. (1994) after

oral exposure of mice to MGP residue, a form of coal tar, for 185 days. 

There have been some reports of adverse effects of creosote on the reproductive organs of animals, but

these are largely confined to changes in organ weight and several other studies have found no effect. 

Relative ovary weights were significantly decreased in rats and mice exposed to 690 mg/m3

 of a coal tar

aerosol for 6 hours/day, 5 days/week for 13 weeks (Springer et al. 1986b, 1987). Testis weight in rats

exposed to 140 and 690 mg/m3

 coal tar was significantly increased relative to controls, while testis weight

in male mice exposed to 690 mg/m3

 coal tar was decreased relative to controls, but the difference was not

significant. Examination of ovarian sections showed a decrease in the amount of luteal tissue in animals

exposed to 690 mg/m3

 coal tar. Dermal exposure of rats and mice to 500 or 1,500 mg/kg coal tar on

gestational days 11–15 resulted in significant decreases in uterine weight (Zangar et al. 1989).

Adverse effects in other endocrine organs are limited to a few reports of weight changes in the adrenal

glands. An increase in adrenal weight was observed in rats gavaged on gestational days 12–16 with

90 mg/kg/day coal tar (Hackett et al. 1984). However, other studies of coal tar creosote have shown no

effect on the adrenal glands (Iyer et al. 1993; Springer et al. 1986b, 1987; Zangar et al. 1989).
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There is some evidence that certain PAHs, (e.g., benzo[a]pyrene) may act as endocrine disruptors

(Agency for Toxic Substances and Disease Registry 1995); however, without data regarding possible

synergistic or antagonistic effects, it is not known whether these individual compounds have similar

effects when incorporated into a complex mixture such as coal tar creosote. For more information on the

health effects of these compounds, the reader can refer to the ATSDR Toxicological Profile for Polycyclic

Aromatic Hydrocarbons (Agency for Toxic Substances and Disease Registry 1995). 

3.7 CHILDREN’S SUSCEPTIBILITY

This section discusses potential health effects from exposures during the period from conception to

maturity at 18 years of age in humans, when all biological systems will have fully developed. Potential

effects on offspring resulting from exposures of parental germ cells are considered, as well as any indirect

effects on the fetus and neonate resulting from maternal exposure during gestation and lactation. 

Relevant animal and in vitro models are also discussed.

Children are not small adults. They differ from adults in their exposures and may differ in their

susceptibility to hazardous chemicals. Children’s unique physiology and behavior can influence the

extent of their exposure. Exposures of children are discussed in Section 6.6 Exposures of Children.

Children sometimes differ from adults in their susceptibility to hazardous chemicals, but whether there is

a difference depends on the chemical (Guzelian et al. 1992; NRC 1993). Children may be more or less

susceptible than adults to health effects, and the relationship may change with developmental age

(Guzelian et al. 1992; NRC 1993). Vulnerability often depends on developmental stage. There are

critical periods of structural and functional development during both prenatal and postnatal life and a

particular structure or function will be most sensitive to disruption during its critical period(s). Damage

may not be evident until a later stage of development. There are often differences in pharmacokinetics

and metabolism between children and adults. For example, absorption may be different in neonates

because of the immaturity of their gastrointestinal tract and their larger skin surface area in proportion to

body weight (Morselli et al. 1980; NRC 1993); the gastrointestinal absorption of lead is greatest in infants

and young children (Ziegler et al. 1978). Distribution of xenobiotics may be different; for example,

infants have a larger proportion of their bodies as extracellular water and their brains and livers are

proportionately larger (Altman and Dittmer 1974; Fomon 1966; Fomon et al. 1982; Owen and Brozek

1966; Widdowson and Dickerson 1964). The infant also has an immature blood-brain barrier (Adinolfi

1985; Johanson 1980) and probably an immature blood-testis barrier (Setchell and Waites 1975). Many

xenobiotic metabolizing enzymes have distinctive developmental patterns. At various stages of growth
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and development, levels of particular enzymes may be higher or lower than those of adults, and

sometimes unique enzymes may exist at particular developmental stages (Komori et al. 1990; Leeder and

Kearns 1997; NRC 1993; Vieira et al. 1996). Whether differences in xenobiotic metabolism make the

child more or less susceptible also depends on whether the relevant enzymes are involved in activation of

the parent compound to its toxic form or in detoxification. There may also be differences in excretion,

particularly in newborns who all have a low glomerular filtration rate and have not developed efficient

tubular secretion and resorption capacities (Altman and Dittmer 1974; NRC 1993; West et al. 1948). 

Children and adults may differ in their capacity to repair damage from chemical insults. Children also

have a longer remaining lifetime in which to express damage from chemicals; this potential is particularly

relevant to cancer.

Certain characteristics of the developing human may increase exposure or susceptibility, whereas others

may decrease susceptibility to the same chemical. For example, although infants breathe more air per

kilogram of body weight than adults breathe, this difference might be somewhat counterbalanced by their

alveoli being less developed, which results in a disproportionately smaller surface area for alveolar

absorption (NRC 1993).

The effects of creosote have not been thoroughly studied in children, but they would likely experience the

same health effects seen in adults exposed to creosote. The pharmacokinetics of wood creosote, coal tar

creosote, coal tar, coal tar pitch, and coal tar pitch volatiles have not been defined because of their

chemical complexity. Creosotes vary tremendously in composition and hence, mechanisms of action

most likely differ among individual samples of creosotes. Information on individual components is not

adequate to define the properties of the whole mixture and for this reason no PBPK models have been

developed for creosote. Individual components of creosote are metabolized by several different enzyme

systems including phase I (cytochrome P450 isozymes, AHH, epoxide hydrolase) and phase II

(glutathione-S-transferases, glucuronidases, phenol sulfotransferase, and glucuronyltransferase). Human

polymorphisms are known to exist for many of these enzymes and are likely to affect the relative toxicity

of creosote for these individuals. The relative activity of metabolic enzymes may also vary with the age

of the individual, which will again affect the relative toxicity of particular components of creosote for old

or young individuals. For instance, several cytochrome P450 isozymes are known to be absent or

expressed at very low levels in the developing human fetus while glucuronyl transferases and

sulphotransferases do not reach adult levels until 1–3 years of age (Leeder and Kearns 1997). 

Creosote Bush. No information was located pertaining to adverse health effects in children or young

animals from the creosote bush. There are very few data on human exposure to the creosote bush. Case
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reports of people who drank chaparral tea indicate kidney damage as a likely outcome (Gordon et al.

1995), while dermal exposure to the creosote bush may cause skin irritation (Leonforte 1986; Smith

1937).

Wood Creosote. No information was located pertaining to adverse health effects in children or young

animals from wood creosote. There are very few data on human exposure to wood creosote. Ingestion of

beechwood creosote exacerbates chronic nephrosis in rats (Miyazato et al. 1984b), and dermal exposure

to beechwood creosote may cause skin irritation (Attalla 1968). These studies suggest that dermal contact

with creosote from toxic waste sites could cause skin irritation.

No reports of adverse developmental effects on humans or animals after exposure to wood creosote were

found in the literature. 

Coal Tar Products. Only one study was located that examined effects of exposure to coal tar creosote in

children (Agency for Toxic Substances and Disease Registry 1994). This was a survey of inhabitants of a

housing development that had been built on part of an abandoned creosote wood treatment plant. In this

study, increased incidence of skin rashes compared to unexposed controls was the only health effect

reported in children (less than 11 years of age) exposed to coal tar creosote. The incidence of rashes in

different age groups varied, but did not show any definite trend. 

Data from studies of adult humans occupationally exposed to coal tar creosote indicate that cancer is

likely to be the most severe adverse effect of coal tar exposure, although there is also evidence of skin and

eye irritation (see Chapter 2 and Section 3.2 for more details). Studies of animals after inhalation, oral, or

dermal exposure to coal tar creosote confirm cancer as a likely outcome of coal tar exposure and suggest

that there may also be adverse effects to the lungs, liver, spleen, thymus, skin, and eyes (see Chapter 2

and Section 3.2 for more details). However, the concentrations of coal tar used in animal studies are

higher than could be expected from proximity to a hazardous waste site and so it is not clear how relevant

some of these systemic effects are to children. Children exposed to creosote will probably have a longer

potential latency period and may therefore be at greater risk of developing cancer from these substances

than individuals exposed as adults.

No reports of adverse developmental effects on humans after exposure to coal tar were found in the

literature. No adverse developmental outcomes were detected in a survey of inhabitants of a housing

development built on an abandoned creosote factory site, which was known to be contaminated with

creosote (Agency for Toxic Substances and Disease Registry 1994). A retrospective study of dermal
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exposure to coal tar found no increased risk of birth defects associated with exposure to coal tar during

pregnancy, but this was a small study and was unlikely to have sufficient resolution to detect a modest

increase in risk (Franssen et al. 1999). 

A series of studies (Hackett et al. 1984; Springer et al.1982, 1986a; Zangar et al. 1989) have demonstrated

serious developmental toxicity for rats and mice exposed to coal tar. However, some evidence of

maternal toxicity in the form of reduced body weight gain and changes in organ weights was also

observed for animals treated with doses of coal tar producing developmental toxicity (Hackett et al. 1984;

Iyer et al. 1993; Springer et al. 1986a). Treatment of pregnant rats with coal tar by all routes of exposure

produces reduced growth (reduced crown-rump length and delayed ossification) of the offspring, and an

increase in the incidence of cleft palates and small lungs (Hackett et al. 1984; Springer et al. 1982, 1986a;

Zangar et al. 1989). Dermal exposure of pregnant mice to coal tar produces an increase in the incidence

of cleft palates dilated ureters and renal pelvic cavitation (Zangar et al. 1989). Zangar et al. (1989)

carried out a comparison of the doses producing significant developmental effects in rats (Hackett et al.

1984; Springer et al. 1982; Zangar et al. 1989) and concluded that inhalation may be the most effective

route for induction of developmental toxicity, followed by the oral and dermal routes, in that order. 

However, the authors noted that inhalation dosimetry is more difficult to calculate accurately due to

unknown contributions from the oral and dermal routes.

Adverse perinatal effects of coal tar creosote were reported for a study in pigs (Schipper 1961). 

Farrowing sows housed in cages treated with coal tar creosote had an increase in the number of stillborn

piglets compared to control animals farrowing in untreated cages. The surviving piglets were dehydrated,

with rough skins and severe diarrhea. Weight gain of the surviving piglets was reduced until the animals

were 5–6 weeks old. One-week-old pigs were reported to have a greater tolerance to creosote than

newborn animals, suggesting that more mature animals may be less sensitive to some of the effects of

coal tar. However, the results of this study are severely limited by lack of exposure data, unequal

duration of exposure between treated and untreated groups, and the lack of statistical analysis of the

results.

Adverse developmental effects due to coal tar were also seen in a chick embryotoxicity screening test

(CHEST) (Mayura et al. 1999). Injection of coal tar (dissolved in corn oil and 0.5% DMSO) into the

yolks of 4-day-old chicken eggs produced a dose-dependant increase in embryo mortality. Doses greater

than 0.5 mg/kg coal tar produced 100% mortality, 0.25 mg/kg produced 55% mortality, 0.125 mg/kg

produced 20% mortality, and 0.0625 mg/kg produced 5% mortality. The main exposure-related

abnormalities noted were liver lesions, discoloration of the liver, and edema.
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Coal tar exposure produces developmental toxicity in rats and mice, and may also do so in pigs. 

However, the developmental risk to humans of exposure to coal tar is less clear. The doses that produced

developmental toxicity in animals were relatively high and are unlikely to be attained through

environmental exposure in the vicinity of toxic waste sites. However, some evidence for species

sensitivity exists and the possibility of developmental toxicity in humans from coal tar exposure cannot be

discounted.

Data suggest that the PAHs found in coal tar creosote produce developmental toxicity and that children

may be more susceptible to the adverse effects of these compounds, but it is not clear whether PAHs that

form part of the complex mixture of coal tar creosote will have the same effects as PAHs studied alone. 

For more information on the health effects of these compounds, the reader can refer to the ATSDR

Toxicological Profile for Polycyclic Aromatic Hydrocarbons (Agency for Toxic Substances and Disease

Registry 1995). 

Coal tar is composed of hydrocarbons, which are lipophilic substances and are therefore likely to

distribute to lipid-rich tissues (Agency for Toxic Substances and Disease Registry 1995). For instance,

PAHs and their metabolites are known to cross the placenta (Agency for Toxic Substances and Disease

Registry 1995) and have been detected in human breast milk (Madhavan and Naiduka 1995). A study of

the distribution of intratracheally administered radioactive benzo[a]pyrene mixed with a benzene extract

of coal fly ash in pregnant rats found that a small proportion of the radioactivity was distributed to the

fetal lung and liver and to the placenta (respectively 1.9, 1.4, and 4% of the amount in maternal lung). 

3.8 BIOMARKERS OF EXPOSURE AND EFFECT
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Biomarkers are broadly defined as indicators signaling events in biologic systems or samples. They have

been classified as markers of exposure, markers of effect, and markers of susceptibility (NAS/NRC 1989).

Due to a nascent understanding of the use and interpretation of biomarkers, implementation of biomarkers

as tools of exposure in the general population is very limited. A biomarker of exposure is a xenobiotic

substance or its metabolite(s) or the product of an interaction between a xenobiotic agent and some target

molecule(s) or cell(s) that is measured within a compartment of an organism (NAS/NRC 1989). The

preferred biomarkers of exposure are generally the substance itself or substance-specific metabolites in

readily obtainable body fluid(s), or excreta. However, several factors can confound the use and

interpretation of biomarkers of exposure. The body burden of a substance may be the result of exposures

from more than one source. The substance being measured may be a metabolite of another xenobiotic

substance (e.g., high urinary levels of phenol can result from exposure to several different aromatic

compounds). Depending on the properties of the substance (e.g., biologic half-life) and environmental

conditions (e.g., duration and route of exposure), the substance and all of its metabolites may have left the

body by the time samples can be taken. It may be difficult to identify individuals exposed to hazardous

substances that are commonly found in body tissues and fluids (e.g., essential mineral nutrients such as

copper, zinc, and selenium). Biomarkers of exposure to creosote are discussed in Section 3.8.1.

Biomarkers of effect are defined as any measurable biochemical, physiologic, or other alteration within an

organism that, depending on magnitude, can be recognized as an established or potential health

impairment or disease (NAS/NRC 1989). This definition encompasses biochemical or cellular signals of

tissue dysfunction (e.g., increased liver enzyme activity or pathologic changes in female genital epithelial

cells), as well as physiologic signs of dysfunction such as increased blood pressure or decreased lung

capacity. Note that these markers are not often substance specific. They also may not be directly

adverse, but can indicate potential health impairment (e.g., DNA adducts). Biomarkers of effects caused

by creosote are discussed in Section 3.8.2.

A biomarker of susceptibility is an indicator of an inherent or acquired limitation of an organism's ability

to respond to the challenge of exposure to a specific xenobiotic substance. It can be an intrinsic genetic

or other characteristic or a preexisting disease that results in an increase in absorbed dose, a decrease in

the biologically effective dose, or a target tissue response. If biomarkers of susceptibility exist, they are

discussed in Section 3.10 “Populations That Are Unusually Susceptible”.
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3.8.1 Biomarkers Used to Identify or Quantify Exposure to Creosote

Wood Creosote. No method is currently available to measure the parent wood creosote mixtures. 

However, phenols can be measured in the urine after exposure to wood creosote (Ogata et al. 1995). 

Male volunteers were given 133 mg of wood creosote in a capsule, followed by 200 mL water. Urine

samples were collected at various time intervals. Phenol, guaiacol, p-cresol, and cresol were detected in

the urine. 

Coal Tar Products. No method is currently available to measure the parent creosote mixture and other

coal tar products in human tissues or fluids. However, individual components of the mixture can be

measured. Urinary naphthols have been shown to be accurate biomarkers of naphthalene exposure during

tar distillation or impregnation of wood with coal tar creosote (Bieniek 1997; Heikkilä et al. 1997). PAH

components of the creosote mixture and their metabolites can also be measured in the urine of exposed

individuals (Bickers and Kappas 1978; Bos and Jongeneelen 1988; Bowman et al. 1997; Cernikova et al.

1983; Clonfero et al. 1989; Diette et al. 1983; Elovaara et al. 1995; Grimmer et al. 1997; Hansen et al.

1993; Heikkilä et al. 1995; Jongeneelen et al. 1985, 1988; Malkin et al. 1996; Ny et al. 1993; Santella et

al. 1994; Sarto et al. 1989; Van Rooij et al. 1993a, 1993b; van Schooten et al. 1994; Viau and Vyskocil

1995; Viau et al. 1995; Weston et al. 1994). For example, Jongeneelen et al. (1985) found a metabolite of

pyrene (which is a constituent of coal tar creosote), 1-hydroxypyrene, in concentrations of 1–40 μg/g

creatinine in urine samples taken from workers who handled approximately 2,400 g creosote/day. The

amount of 1-hydroxypyrene detected in urine samples taken during the weekend was less than that

detected during the weekdays, when the exposure was presumably higher than on the weekends. No

correlation was found between occupational exposure levels and urine levels, so it is not known whether

urine metabolites could be detected following exposure to low levels of creosote. However, in another

study, workers exposed to coal tar while asphalting roads with coal tar excreted 1-hydroxypyrene in their

urine (Jongeneelen et al. 1988). In these workers, occupational exposure appeared to be related to the

amount of 1-hydroxypyrene in the urine. The identification of 1-hydroxypyrene in the urine could serve

as a method of biological monitoring of exposed workers, and possibly individuals living in the vicinity

of hazardous waste sites where creosote has been detected following both short-and long-term exposure. 

However, because PAHs are ubiquitous in the environment, detection of PAH metabolites in the body

tissues or fluids is not specific for exposure to creosote. PAH exposure can occur from a variety of

sources, and there is no way to determine if creosote was the source.

PAHs form DNA adducts that can be measured in body tissues or blood following exposure to creosote

that contains PAHs (Culp and Beland 1994; Pavanello and Levis 1994; Schoket et al. 1990; Zhang et al.
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1990). These PAH-DNA adducts are not specific for coal tar creosote, and the adducts measured could

have been from exposure to other sources of PAHs.

3.8.2 Biomarkers Used to Characterize Effects Caused by Creosote

Coal Tar Products. The available genotoxicity data derived by in vitro techniques indicate that coal tar

products such as coal tar creosote and coal tar pitch are indirect mutagens (i.e., requiring the presence of

an exogenous mammalian metabolic system) and induce gene mutation in bacteria and mouse lymphoma

cells. The mutagenicity of creosote and coal tar pitch observed in the conventional S. typhimurium assay

is at least partially contributed to by the PAHs such as B[a]P and benzanthracene. However, because

these results are exclusively from in vitro tests and the limited genotoxicity tests conducted on urine

obtained from humans exposed to creosote have been negative, or have been positive in instances where

exposure to other mutagens may have occurred, these changes cannot be considered specific biomarkers

of effects caused by creosote, nor is it possible to determine whether the genotoxic effects result from

either acute or chronic exposure to either low or high levels of coal tar creosote because all of the data

were from in vitro studies. The same can be said for determination of chromosomal aberrations in

peripheral lymphocytes from exposed humans (Bender et al. 1988; Sarto et al. 1989). Furthermore,

because the mutagenicity of coal tar creosote is at least partially due to its PAH components, exposure to

PAHs from other sources could produce the same results. Coal tar creosote exerts its acute toxic effects

primarily via dermal exposure, causing architectural damage to the tissues with which it comes in contact. 

Therefore, burns and irritation of the skin and eyes are the most frequent manifestations of coal tar

creosote toxicity following acute dermal exposure to high levels. However, damage to the skin is not

specific to creosote, and can be seen with other corrosive or photosensitizing agents. No other biomarkers

(specific or otherwise) have been identified following exposure to coal tar creosote. 

For more information on biomarkers for renal and hepatic effects of chemicals, see Agency for Toxic

Substances and Disease Registry/Centers for Disease Control and Prevention (1990) and for information

on biomarkers for neurological effects, see OTA (1990).

3.9 INTERACTIONS WITH OTHER CHEMICALS

Coal Tar Products. The primary interactions known to occur between coal tar creosote and other

substances involve the induction of cancer. Coal tar creosote is a complex mixture of organic substances

consisting predominantly of liquid and solid aromatic hydrocarbons. Several of these components of coal

tar creosote are known animal carcinogens as well as cocarcinogens, initiators, promoters, potentiators, or
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inhibitors of carcinogenesis. Pretreatment of male Fischer 344 rats with orally administered coal tar

creosote resulted in urinary excretion of mutagenic metabolites of creosote, and increased the

bioactivation of orally administered 2,6-DNT to mutagenic metabolites, as measured in the Ames assay. 

Urinary excretion of mutagenic metabolites from rats pretreated with creosote and dosed with DNT at 1,

3, and 5 weeks peaked after 3 weeks and then declined by 33% after 5 weeks of treatment. The increase

in urinary excretion of mutagenic metabolites was significantly greater than in rats that received only

DNT at weeks 1 and 3, but not at week 5 (Chadwick et al. 1995).

As discussed in Section 3.2.3.7, coal tar creosote and several of its fractions are carcinogenic when

applied to the skin of mice. Dermally applied creosote can also act as a tumor-initiating agent when

applied prior to croton oil treatment, and can enhance and accelerate tumor induction by B[a]P. Thus, the

risk of cancer following dermal exposure to creosote is likely to be enhanced when concurrent exposure

to other potential co-carcinogens, tumor promoters, initiators, and potentiators occurs. Due to the

ubiquitous nature of PAHs and other carcinogenic substances in the environment, particularly at

hazardous waste sites, the likelihood that these types of synergistic interactions with creosote will occur

could be important in assessing potential hazards.

Another effect of coal tar creosote exposure that could be affected by interaction with other chemicals is

photosensitivity. Certain pharmaceutical agents (e.g., tetracycline) that, in and of themselves, cause

photosensitivity whose action may be synergistic with that of coal tar creosote or coal tar.

Pentachlorophenol and arsenical compounds are also used in wood preserving. For this reason, it is likely

that they will be found with creosote at hazardous waste sites. However, there is no information available

on the potential interactions of creosote with pentachlorophenol or arsenical compounds.

3.10 POPULATIONS THAT ARE UNUSUALLY SUSCEPTIBLE

A susceptible population will exhibit a different or enhanced response to creosote than will most persons

exposed to the same level of creosote in the environment. Reasons may include genetic makeup, age,

health and nutritional status, and exposure to other toxic substances (e.g., cigarette smoke). These

parameters result in reduced detoxification or excretion of creosote, or compromised function of organs

affected by creosote. Populations who are at greater risk due to their unusually high exposure to creosote

are discussed in Section 6.7, Populations With Potentially High Exposures.
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Coal Tar Products. Data indicate that some populations may be at increased risk of developing skin

cancer following prolonged dermal exposure to industrial grade coal tar creosote, coal tar, coal tar pitch,

and coal tar pitch volatiles. The results of earlier occupational studies (Henry 1946, 1947), case reports

(Cookson 1924; Lenson 1956; O'Donovan 1920), and experimental animal studies (Boutwell and Bosch

1958; Poel and Kammer 1957; Roe et al. 1958) indicate that prolonged dermal exposure to coal tar

creosote may increase the risk of developing skin cancer. This risk may be increased for people with skin

damaged from excessive sun exposure, disease, or exposure to other substances that potentiate the

carcinogenic effect of coal tar creosote (Lenson 1956; Lijinsky et al. 1957; Sall and Shear 1940; TOMA

1979, 1981).

There is limited evidence, based on animal studies and the known health effects of the PAH constituents

of coal tar creosote, that additional subsections of the population may be susceptible to the toxic effects of

creosote. These include people with pre-existing respiratory, kidney, or liver disease. People with

deficient immune systems may also be at high risk of developing adverse health effects due to exposure to

carcinogens, such as PAHs (Stjernsward 1966, 1969; Szakal and Hanna 1972). Another potentially

susceptible group are those individuals with the genetic trait of inducible AHH, one of the mixed function

oxidases. When this enzyme is induced, the rate at which aryl compounds, such as PAHs, are

biotransformed into toxic intermediates is increased, rendering these individuals at higher risk. It has

been proposed that genetically expressed AHH inducibility is related to the development of bronchogenic

carcinoma in persons exposed to PAHs contained in tobacco smoke. Approximately 45% of the general

population are considered to be at high risk, and 9% of the 45% are considered to be at very high risk of

developing bronchogenic carcinoma following exposure to PAHs (Calabrese 1978). These percentages

were estimated from the population frequency of genetically controlled AHH induction (Calabrese 1978). 

Individual components of creosote are metabolized by several different enzyme systems including phase I

(cytochrome P450 isozymes, AHH, epoxide hydrolase) and phase II (glutathione-S-transferases,

glucuronidases, phenol sulfotransferase, and glucuronyltransferase) enzymes. Human polymorphisms are

known to exist for many of these enzymes and are likely to affect the relative toxicity of creosote for

these individuals. These enzymes are also known to have age-dependant expression and susceptibility

may therefore vary with the age of the individual. However, no studies were located that addressed

differential susceptibility of children to the effects of creosote. A detailed discussion of children’s

susceptibility can be found in Section 3.7. 

Coal tar exposure produces developmental toxicity in rats and mice, and may also do so in pigs. 

However, the developmental risk to humans of exposure to coal tar is less clear. The doses that produced

developmental toxicity in animals were relatively high and are unlikely to be attained through
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environmental exposure in the vicinity of toxic waste sites. However, some evidence for species

sensitivity exists and the possibility of developmental toxicity in humans due to coal tar exposure cannot

be discounted and the human fetus may be another susceptible population. 

3.11 METHODS FOR REDUCING TOXIC EFFECTS

This section will describe clinical practice and research concerning methods for reducing toxic effects of

exposure to creosote. However, because some of the treatments discussed may be experimental and

unproven, this section should not be used as a guide for treatment of exposures to creosote. When

specific exposures have occurred, poison control centers and medical toxicologists should be consulted

for medical advice. The following texts provide specific information about treatment following exposures

to creosote:

Ellenhorn MJ, ed. 1997. Medical toxicology: Diagnosis and treatment of human poisoning. 2nd ed. New

York, NY: Elsevier Publishing.

Haddad LM, Shannon MW, Winchester JF, eds. 1998. Clinical management of poisoning and drug

overdose. 3rd ed. Philadelphia, PA: WB Saunders.

Viccellio P, Bania T, Brent J, et al., eds. 1998. Emergency toxicology. 2nd ed. Philadelphia, PA: 

Lippincott-Raven Publishers.

3.11.1 Reducing Peak Absorption Following Exposure

Human exposure to creosotes and coal tar mixtures generally means an exposure to a combination of

large molecular toxins (including PAHs) and more immediately chemically reactive phenolic chemicals. 

The phenolic components act as direct caustic agents to skin, mucosa, and cornea, causing burns and

scarring. The tars are photosensitizers and potential DNA-combining agents with different and latent

clinical consequences, including cancer. Exposure to these compounds may occur via ingestion and

direct liquid application. Although relatively nonvolatile, tar absorption following inhalation exposure to

mists can occur through mucocilliary trapping and transport followed by gastrointestinal absorption.

The suggested emergency management of direct cutaneous exposure to creosote is prompt and

comprehensive decontamination (Haddad et al. 1998). Treatment commonly includes removal of all

contaminated clothing and washing of the skin, hair, and nails with large volumes of soapy water. It is

recommended that those administering the treatment wear rubber gloves for their own protection. In

order to reduce dermal irritation from creosote-contaminated soil and water, limited exposure, through the
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wearing of protective clothing, and immediate washing of exposed skin were the recommendations of the

Texas Department of Health to residents of a housing development built on an abandoned creosote

factory site (Agency for Toxic Substances and Disease Registry 1994). 

The treatment to manage exposure from ingestion also focuses on the acute effects of the phenolic and

PAH components. Phenolic compounds cause corrosive esophageal burns and there may also be a risk of

causing pneumonitis in the patient by aspiration of PAHs in coal tar derivatives, so emesis is

contraindicated as a means of elimination (Agency for Toxic Substances and Disease Registry 1995;

Haddad et al. 1998). Activated charcoal has been used as a treatment to reduce absorption of

hydrocarbons such as PAHs, however, its efficacy is not documented by clinical studies and it could

potentially interfere with endoscopic examination of the gastrointestinal tract (Viccellio et al. 1998). 

Gastric lavage with olive oil avoids the dangers of additional esophageal damage while eliminating the

phenols from continued mucosal contact and may be the preferred method of removing creosote,

particularly if a substantial amount has been ingested (Haddad et al. 1998; Viccellio et al. 1998). 

The treatment for contaminated eyes commonly includes irrigation with copious amounts of room

temperature water, or saline if available, for at least 15 minutes. If irritation, lacrimation, or especially

pain, swelling, and photophobia persist after 15 minutes of irrigation, it is recommended that an

ophthalmologic examination be performed. Phenol burns are more corrosive than organic acids in

damaging corneal tissue and delaying recovery.

Should an inhalation exposure occur, treatment commonly includes moving the exposed individual to

fresh air and monitoring for respiratory distress. Injuries to the lungs are more likely when there is severe

upper respiratory irritation and persistent cough. Emergency airway support and 100% humidified

supplemental oxygen with assisted ventilation may be needed.

3.11.2 Reducing Body Burden

Most of the damage relating to the phenolic components in creosote and coal tar is immediate and

requires no specific chronic management. It is recommended that mucosal surfaces be evaluated for

possible scarring (especially the esophagus or cornea) if exposure was directly injurious. As with other

ingested or inhaled PAHs (e.g., from combustion products like cigarette smoke), there are no documented

means to enhance elimination of coal tars.
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With regard to the possible absorption of the PAH component of coal tar creosote or other coal tar

products, there are no known ways of reducing the body burden of PAHs. Data from acute-duration

studies in animals indicate that PAHs are rapidly metabolized and eliminated in the urine and feces within

days. No data are available to describe possible bioaccumulation after chronic exposure. Since PAHs are

lipid soluble, however, it is possible that some accumulation could occur in the tissue fat.

3.11.3 Interfering with the Mechanism of Action for Toxic Effects

Coal tars produce photosensitivity and photoreactive dermatitis when applied to the skin (Hathaway et al.

1991) even in areas not usually exposed to direct sunlight (e.g., beneath the chin). It is recommended that

patients be cautioned about sun exposure and the need for appropriate clothing several days after

exposure, to prevent accelerated sunburning. These agents are physically heavy oils and are known to be

both irritating and comedogenic (Amdur et al. 1991), so physical sun barriers are preferred to chemical

sun screens or oils.

Phenols can produce a "lightening" effect on cutaneous coloration (TOMES 1994) with depigmentation

and vitiligo. This is seen most commonly with repeated cutaneous application, but can also follow

cutaneous burns. Sun exposure magnifies the evidence of this process and should be avoided. Most

patients with chemical vitiligo recover with normal skin color returning after several months. 

3.12 ADEQUACY OF THE DATABASE

Section 104(I)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the

Administrator of EPA and agencies and programs of the Public Health Service) to assess whether

adequate information on the health effects of creosote is available. Where adequate information is not

available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the

initiation of a program of research designed to determine the health effects (and techniques for developing

methods to determine such health effects) of creosote.

The following categories of possible data needs have been identified by a joint team of scientists from

ATSDR, NTP, and EPA. They are defined as substance-specific informational needs that if met would

reduce the uncertainties of human health assessment. This definition should not be interpreted to mean

that all data needs discussed in this section must be filled. In the future, the identified data needs will be

evaluated and prioritized, and a substance-specific research agenda will be proposed.
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3.12.1 Existing Information on Health Effects of Creosote

The existing data on health effects of inhalation, oral, and dermal exposure of humans and animals to

creosote are summarized in Figure 3-6. The purpose of this figure is to illustrate the existing information

concerning the health effects of creosote. Each dot in the figure indicates that one or more studies

provide information associated with that particular effect. The dot does not necessarily imply anything

about the quality of the study or studies, nor should missing information in this figure be interpreted as a

“data need”. A data need, as defined in ATSDR’s Decision Guide for Identifying Substance-Specific

Data Needs Related to Toxicological Profiles (Agency for Toxic Substances and Disease Registry

1989c), is substance-specific information necessary to conduct comprehensive public health assessments. 

Generally, ATSDR defines a data gap more broadly as any substance-specific information missing from

the scientific literature.
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Figure 3-6. Existing Information on Health Effects of Creosote
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The database for the health effects of both wood creosote and coal tar products in experimental animals is

inadequate, and consists primarily of acute lethality studies or early animal studies that would be

considered inadequate by current standards. The systemic effects of ingested creosote have only been

well described for beechwood creosote, although some studies exist for coal tar products. Little

information is available on the effects of coal tar creosote following inhalation exposure. However,

dermal exposure of mice to coal tar creosote and other coal tar products has been shown in numerous

studies to induce skin tumors and, in two cases, lung tumors, while oral exposure has induced tumors in

the lung, liver, and forestomach. Since coal tar creosote is a complex mixture consisting primarily of

PAHs, the toxic effects of coal tar creosote may be inferred from available information on these

constituents. However, given the fact that many of these constituents are known cocarcinogens, initiators,

promoters, and potentiators of carcinogenesis, the possibility for the occurrence of synergistic interactions

in creosote cannot be ruled out. Thus, information on the toxicity of the various components of coal tar

creosote cannot take the place of sound data on the toxic effects of the creosote mixture itself. This can

also be assumed to be true for the other coal tar products. An additional factor to be considered when

reviewing the database for creosote is the effect of weathering. When creosote is released into the

environment, weathering produces rapid changes in chemical composition (see Section 6.3). Thus,

although data on toxic effects of unweathered creosote would be useful for individuals who are

occupationally exposed to creosote, it is not clear how useful such data will be for individuals undergoing

environmental exposure to weathered creosote. 

3.12.2 Identification of Data Needs

Acute-Duration Exposure. Information is available on the effects of oral and dermal acute-duration

exposures to wood creosotes (Miyazato et al. 1981; Ogata et al. 1993, 1999) and coal tar products

(Hackett et al. 1984; Iyer et al. 1993; Mahlum 1983; Pfitzer et al. 1965; Springer et al. 1986a, 1989;

Wrench and Britten 1975; Zangar et al. 1989) in humans and animals. However, there are few wellconducted animal or human studies describing health effects following inhalation exposure (Emmett

1986; Springer et al. 1982). The type of information available includes primarily LD50 values and data on

acute toxicity in animals (coal tar products and beechwood creosote), and acute toxicity following

accidental or intentional ingestion or dermal exposure in humans (coal tar creosote and other coal tar

products). Coal tar creosote exerts its acute toxic effects primarily via dermal exposure, causing

architectural damage to the tissues with which it comes in contact, such as the skin and eyes. Acute

ingestion of coal tar creosote appears to affect primarily the kidney and liver. Thus, the toxic effects of

coal tar creosote on the skin following single-dose dermal exposure in humans are well characterized, but

little else is known regarding the systemic effects of this form of creosote in either humans or animals. 
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The available information is insufficient to derive either an acute oral or inhalation MRL for coal tar

creosote or other coal tar products because human reports that identified target organs lacked exposure

information, and no short-term animal studies exist that describe effects other than death or

developmental defects. Identification of target organs from short-term animal studies following oral and

dermal exposure would be useful in assessing the risk associated with the acute ingestion or skin contact

with coal tar creosote-contaminated water or soils by humans. The pharmacokinetic data on coal tar

creosote are insufficient to determine whether similar effects may be expected to occur across different

routes of exposure. However, since creosote appears to cause route-of-entry adverse effects (e.g., damage

to the skin following dermal contact), it is impossible to predict effects following exposure by one route

based on effects observed following exposure by another route.

Intermediate-Duration Exposure. Information is available on the effects of intermediate-duration

dermal exposures to coal tar in humans (Franssen et al. 1999; Jones et al.1985; Menter and Cram 1983;

Torinuki and Tagami 1988) and the effects of intermediate-duration exposures to beechwood creosote

(oral) (Miyazato et al. 1981) and coal tar creosote (oral and dermal) in animals (Boutwell and Bosch

1958; Chadwick et al. 1995; Culp and Beland 1994; Kligman and Kligman 1994; Wallcave et al. 1971;

Weyand et al. 1991, 1994, 1995). However, there are few well-conducted animal studies describing the

health effects of inhalation exposure to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch volatiles

(Heinrich et al. 1994a, 1994b; MacEwen et al. 1977; Sasser et al. 1989; Springer et al. 1986b, 1987). The

exact duration and level of exposure in the human studies generally cannot be quantified because the

information is derived from anecdotal case reports rather than controlled epidemiological studies. The

animal studies with beechwood creosote describe predominantly hepatic and renal end points, and those

conducted with coal tar creosote describe dermal, hepatic, renal, hematological, and respiratory end

points. Little or no in depth information on respiratory, cardiovascular, gastrointestinal, hematological, or

musculoskeletal effects in animals is available. The available information is insufficient to derive either

an intermediate oral or inhalation MRL for coal tar creosote or other coal tar products because no

intermediate-duration human or animal studies exist that describe adverse effects other than on the skin. 

Given the widespread use of coal tar creosote as a wood preservative, and the fact that beechwood

creosote is rarely used today, more information on the systemic effects of intermediate-duration exposures

to coal tar creosote and other coal tar products by the oral and dermal routes (by conducting 90-day

intermediate toxicity studies) would be useful to identify target organs in animals in order to assess the

risk associated with the intermediate-duration ingestion of, or skin contact with, coal tar creosotecontaminated water or soils by humans. Since coal tar products give off volatile components, studies of

inhalation exposure to these compounds would also be useful. The pharmacokinetic data on coal tar

creosote are insufficient to determine whether similar effects may be expected to occur across different
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routes of exposure. However, since creosote appears to cause route-of-entry adverse effects (e.g., damage

to the skin following dermal contact), it may not be possible to predict effects following exposure by one

route based on effects observed following exposure by another route.

Chronic-Duration Exposure and Cancer. Some information is available on the effects of chronicduration dermal exposures to coal tar creosote and other coal tar products in humans (Cookson 1924;

Goulden and Stallard 1933; Henry 1946, 1947; Lenson 1956; Mackenzie 1898; O'Donovan 1920;

Shambaugh 1935; Shimauchi et al. 2000) and the effects of chronic-duration exposures to beechwood

creosote (oral) (Miyazato et al. 1984b) and coal tar creosote (dermal) in animals (Niemeier et al. 1988;

Poel and Kammer 1957). However, there are few well-conducted animal studies describing the health

effects of chronic oral or inhalation exposure to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch

volatiles (Culp et al. 1996a, 1996b, 1998; Heinrich et al. 1994a, 1994b; MacEwen et al. 1977). The exact

duration and level of exposure in the human studies generally cannot be quantified because the

information is derived from anecdotal case reports rather than controlled epidemiological studies. The

animal studies with beechwood creosote describe predominantly hepatic and renal end points, and those

conducted with coal tar creosote describe dermal, but very rarely other systemic effects. Little or no

reliable information on respiratory, cardiovascular, gastrointestinal, hematological, or musculoskeletal

effects in animals is available. The available information is insufficient to derive either a chronic oral or

inhalation MRL for coal tar creosote because no chronic-duration human or animal studies exist that

describe effects other than on the skin. Given the widespread use of coal tar creosote as a wood

preservative, and the fact that beechwood creosote is rarely used today, more information on the systemic

effects of chronic-duration exposures to coal tar creosote by the oral and dermal routes would be useful to

identify target organs in animals in order to assess the risk associated with the chronic-duration ingestion

of, or skin contact with, coal tar creosote-contaminated water or soils by humans. The pharmacokinetic

data on coal tar creosote are insufficient to determine whether similar effects may be expected to occur

across different routes of exposure. However, since creosote appears to cause route-of-entry adverse

effects (e.g., damage to the skin following dermal contact), it may not be possible to predict effects

following exposure by one route based on effects observed following exposure by another route.

Various case reports and the results of cross-sectional occupational surveys associate chronic

occupational creosote exposure with the development of skin cancer (Cookson 1924; Goulden and

Stallard 1933; Henry 1947; Lenson 1956; Mackenzie 1898; O'Donovan 1920; Shambaugh 1935;

Shimauchi et al. 2000). More recent cancer epidemiological studies and surveys of the literature help to

fill in data gaps, but are retrospective, and often fail to provide exact information concerning exposure

(Franssen et al. 1999; Liu et al. 1997; Pittelkow et al. 1981; TOMA 1982). Several skin painting studies
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have been conducted in animals using coal tar creosote and its various fractions (Cabot et al. 1940;

Deelman 1962; Emmett et al. 1981; Hueper and Payne 1960; Lijinsky et al. 1957; Mahlum 1983;

Niemeier et al. 1988; Wallcave et al. 1971; Watson and Mellanby 1930). Although some of these studies

would be considered inadequate by current standards, the results nevertheless indicate that coal tar

creosote and its constituents can induce skin tumors as well as act as tumor initiators and promoters. 

Carcinogenicity studies conducted with beechwood creosote by the oral route, found no evidence of

cancer in mice (Miyazato et al. 1984a, 1984b). However, oral cancer bioassays with coal tar in mice

found a significant incidence of liver, lung, and forestomach tumors (Culp et al. 1996a, 1998; Weyand et

al. 1995). More information on the carcinogenic potential of chronically ingested coal tar creosote (e.g.,

an oral bioassay in rats) would be useful. The pharmacokinetic data on coal tar creosote are insufficient

to determine whether similar effects may be expected to occur across different routes of exposure. 

However, since creosote appears to cause route-of-entry adverse effects (e.g., skin tumors following

dermal contact), it may not be possible to predict effects following exposure by one route based on effects

observed following exposure by another route. 

Genotoxicity. The genotoxic potential of coal tar creosote has been investigated almost exclusively

using in vitro assays (Agurell and Stensman 1992; Baranski et al. 1992; Bos et al. 1983, 1984b, 1984c,

1985, 1987; Donelly et al. 1993, 1996; Kesik and Janik-Spiechowicz 1997; Machado et al. 1993; Mayura

et al. 1999; Reeves et al. 2001; Simmon and Shepherd 1978) and animal tissues (Chadwick et al. 1995;

Ericson et al. 1998, 1999; Weyand et al. 1991) although some evaluations of chromosomal aberrations in

peripheral lymphocytes and DNA adducts in skin and other tissues have been conducted in humans

(Pavanello and Levis 1992, 1994; Yadav and Seth 1998; Zhang et al. 1990). The limited genotoxicity

tests that have been conducted on urine obtained from humans exposed to creosote had varied results. 

The available data indicate that creosote is an indirect mutagen and induces gene mutation in bacteria and

mouse lymphoma cells. However, a substantial database exists on the genotoxic effects of the PAHs

found in the creosote mixture. More in vivo assays using human tissues with coal tar creosote, coal tar,

coal tar pitch, and coal tar pitch volatiles, or specific components of these mixtures, would be useful to

more completely characterize the genotoxic potential of these mixtures.

Reproductive Toxicity. Little information on the reproductive effects of coal tar creosote in humans

or animals is available. One epidemiological study in humans indicates no reproductive hazard from

exposure through environmental contamination (Agency for Toxic Substances and Disease Registry

1994) and another indicated no increased risk of spontaneous abortion from the use of coal tar as a dermal

treatment for psoriasis during pregnancy (Franssen et al. 1999). However, animal studies have shown that

exposure to coal tar causes increased resorptions, decreased ovary weights (with a loss of luteal tissue),
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and increased testis weights in mice and rats (Hackett et al. 1984; Springer et al. 1982, 1986b, 1987). An

increase in relative testis weight was also observed in rats administered beechwood creosote in the diet for

3 months (Miyazato et al. 1981). There were no accompanying gross or histopathological lesions of the

testes in these animals, so the toxicological significance of this change is not known. Given the

widespread potential for exposure to coal tar creosote, and industrial exposure to other coal tar products,

and the indication from animal studies that creosote may be a reproductive toxicant, multi-generation

reproductive toxicity studies should be conducted by the oral and dermal routes of exposure. The

pharmacokinetic data on coal tar creosote are insufficient to determine whether similar effects may be

expected to occur across different routes of exposure. However, since coal tar has been shown to produce

reproductive toxicity in animals by the oral, dermal, and inhalation routes, it appears that reproductive

toxicity may not be route-dependent.

Developmental Toxicity. Information on the developmental effects of creosote in humans was not

found. Studies have demonstrated serious developmental toxicity for rats and mice exposed to coal tar by

all routes, including reductions in fetal ossification, crown-rump length, fetal weight, fetal lung weight,

and placental weights (Springer et al. 1982), a significant increase in the incidence of cleft palate (Hackett

et al. 1984), increased early mortality in pups of treated dams (Springer et al. 1986a), and significant

increases in prenatal mortality in exposed rat and mouse fetuses (Zangar et al. 1989).

In many of these studies, it is not possible to exclude the potential role of maternal toxicity in the

development of adverse fetal effects. It would be useful to carry out studies to explicitly evaluate the role

of maternal toxicity in the development of creosote-induced adverse developmental effects. The

pharmacokinetic data on coal tar creosote are insufficient to determine whether similar effects may be

expected to occur across different routes of exposure. However, since coal tar has been shown to produce

developmental toxicity in animals by the oral, dermal, and inhalation routes, it appears that developmental

toxicity may not be route-dependent.

Immunotoxicity. The only available information on the immunological effects of creosote in humans

describes the occurrence of acute allergic dermatitis following exposure to creosote bush resin (Leonforte

1986; Smith 1937) and coal tar (Cusano et al. 1992). Animal studies have provided evidence of weight

and morphological changes in lymphoreticular tissues following exposure to coal tar (Hackett et al. 1984;

Zangar et al. 1989), but no information regarding associated changes in the immune system have been

reported. The relevance of these findings to human exposure to creosotes is not known. However, these

data are suggestive of possible immunotoxic effects. Immunotoxicity studies of coal tar creosote, coal tar,

and coal tar pitch by inhalation and dermal routes and studies of wood creosote by inhalation, oral, and

dermal routes would fill the data needs for these mixtures.
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Neurotoxicity. The available information about the possible neurotoxic effects of creosote is very

limited, but some signs of neurological involvement in humans and animals following exposure to

beechwood creosote and creosote bush (Gordon et al. 1995; Miyazato et al. 1981) and coal tar (Hanlon

1938; NIOSH 1980b) have been described. These effects were generally excitatory in nature (e.g.,

convulsions). No reliable data are available on the short-term neurotoxic effects of coal tar creosote, coal

tar, coal tar pitch, or coal tar pitch volatile exposure by the inhalation, oral, or dermal routes, or long-term

neurotoxic effects of low-level exposure to coal tar creosote, coal tar, coal tar pitch, or coal tar pitch

volatiles by the inhalation, oral, or dermal routes in humans or animals. Reports of individuals exposed to

creosote suggest that neurotoxicity (e.g., dizziness, altered vision, etc.) may be an early sign of toxic

exposure to creosote. Short-term and long-term neurotoxicity studies in animals, using sensitive

functional and neuropathological tests, and exposure by the inhalation, oral and dermal routes would be

useful in determining if coal tar creosote is a neurotoxic agent. 

Epidemiological and Human Dosimetry Studies. Few controlled epidemiological studies have

been conducted in humans on the effects of exposure to coal tar creosote. In particular, epidemiological

studies of workers in creosote treatment plants accompanied by accurate occupational exposure data

would be useful to more fully assess the risk of inhalation and dermal exposure to coal tar creosote. Most

of the available information on the effects of coal tar creosote in humans comes from occupational studies

in the wood-preserving and construction industries (Armstrong et al. 1994; Bertrand et al. 1987; Bolt and

Golka 1993; Costantino et al. 1995; Gibbs and Horowitz 1979; Karlehagen et al. 1992; Kerr et al. 2000;

Lloyd 1971; Lloyd et al. 1970; Martin et al. 2000; Mazumdar et al. 1975; Park and Mirer 1996; Persson et

al. 1989; Redmond 1976; Redmond et al. 1972, 1976; Rockette and Arena 1983; Rönneberg and

Andersen 1995; Sakabe et al. 1975; Spinelli et al. 1991; Stern et al. 2000; TOMA 1982; Tremblay et al.

1995). Limitations inherent in these studies include unknown exposure concentrations and durations, as

well as concomitant exposure to other potentially toxic substances. The few available industrial surveys

and epidemiological studies are limited in their usefulness because of small sample size, short follow up

periods, and brief exposure periods. Despite their inadequacies, studies in humans suggest that coal tar

creosote is a dermal irritant and a carcinogen following dermal exposure. Only one epidemiological study

of people living in close proximity to a coal tar creosote-contaminated area was found in the literature

(Agency for Toxic Substances and Disease Registry 1994). Additional well-controlled epidemiological

studies of people with documented exposure to creosote, living in close proximity to areas where coal tar

creosote has been detected in surface and ground water, or near hazardous waste sites, and of people

occupationally exposed to creosote could add to and clarify the existing database on creosote-induced

human health effects. Particular health effects that should be examined in future studies include cancer,
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developmental, reproductive, immunotoxic, and neurotoxic effects as well as adverse noncancer dermal

effects.

Biomarkers of Exposure and Effect. 

Exposure. No method is currently available to measure the parent creosote mixture in human tissues or

fluids. However, 1-hydroxypyrene, the metabolite of pyrene, a component of the creosote mixture, can

be measured in the urine of exposed individuals following relatively high-level exposures of acute and

chronic duration (Bos and Jongeneelen 1988; Jongeneelen et al. 1985, 1988). The identification of PAH

metabolites in urine could potentially serve as a method of biological monitoring of exposed workers and

possibly individuals living in the vicinity of hazardous waste sites where creosote has been detected. 

However, because of the ubiquitous nature of PAHs in the environment, detection of PAH metabolites in

the body tissues or fluids cannot always be attributed to creosote exposure. PAHs form DNA adducts that

can be measured in body tissues or blood following exposure to creosote containing PAHs. Again, these

PAH-DNA adducts are not specific for coal tar creosote, and the adducts measured could have been from

exposure to other sources of PAHs. Therefore, a biomarker of exposure specific to creosote would be

useful to monitor exposure to this mixture.

Effect. The formation of benzo[a]pyrene-DNA adducts has been demonstrated (Pavanello and Levis

1992; Zhang et al. 1990) and may also serve as a biomarker of PAH-induced carcinogenicity. However,

these adducts are not specific for coal tar creosote exposure, as exposure to benzo[a]pyrene from sources

other than coal tar creosote can occur. Studies to identify and measure effects more diagnostic of coal tar

creosote-specific injury would be useful. Also, increasing the sensitivity of these tests would be valuable

in evaluating the health status of individuals who have been exposed to low levels of creosote.

Absorption, Distribution, Metabolism, and Excretion. Studies monitoring the pharmacokinetics

of the coal tar creosote mixture are limited. Much of the information regarding the disposition of creosote

is based on indirect evidence or the pharmacokinetic information available on a single class of creosote

components, the PAHs. For more information on the toxicokinetics of PAHs, please refer to the ATSDR

Toxicological Profile for Polycyclic Aromatic Hydrocarbons (Agency for Toxic Substances and Disease

Registry 1995).

Absorption of creosote occurs following all routes of exposure. The presence of creosote components in

tissues and the presence of metabolites in urine are evidence of its absorption. However, no studies are

available that quantify the extent and rate of creosote absorption. Studies in humans regarding the
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distribution of creosote are not available and little information is available for animals. Its distribution is

based on assumptions derived from studies that monitored the distribution of PAHs, components of

creosote.

The metabolism of creosote has not been extensively studied, but preliminary results indicate that

hydroxylation of the major PAH components is a principal degradation pathway in both humans and

animals following all routes of exposure. 1-Hydroxypyrene is one metabolite that has been identified, but

there were no studies available regarding the identification of other metabolites. Elucidation of additional

biotransformation pathways and products is also important in examining potential toxic effects of

creosote. Also, no studies were located regarding the rate or extent of creosote metabolism. 

Studies regarding the excretion of creosote by humans or animals were not available. It is known that

PAHs and their metabolites are primarily excreted in the bile and the feces. However, direct excretion

studies with creosote would be more useful. Information is available regarding the disposition of

creosote's individual components, but no information is available regarding how these components

interact to affect the overall disposition.

In summary, no data are available regarding the toxicokinetics of the creosote mixture and all information

must currently be inferred from what is known about the PAH components of creosote. Interactions

between the components of the creosote mixture could occur that could alter the rate and extent of

absorption, distribution, metabolism, and excretion of creosote from what might be predicted based on

what is known about the individual PAH components. Therefore, more information on the toxicokinetics

of the creosote mixture itself would be useful to predict possible target organs of toxicity as well as allow

for extrapolation of toxic effects across routes of exposure.

Comparative Toxicokinetics. The available information indicates that the absorption, distribution,

metabolism, and excretion of creosote is qualitatively similar in humans and rodents. This general

conclusion was primarily based on evidence derived from studies on the individual PAH components of

creosote. Recent papers have described specific kinetic aspects of individual components of the coal tar

products. Little work has been done to address this topic for wood creosote. Detailed pharmacokinetic

studies in humans and animals specific to the creosote mixture would provide a better indication of

species differences and indicate whether the ability to extrapolate across species may be possible in the

future.
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Methods for Reducing Toxic Effects. Current methods for reducing toxic effects focus on

reducing peak absorption after exposure. Recommendations are primarily based on methods devised for

phenolic compounds, and it is not certain how appropriate these are for all forms of creosote, particularly

those derived from coal tar. There is currently no method for reducing body burden of creosote once it

has been absorbed or of interfering with its toxic effects. Treatment is generally supportive of respiratory

and cardiovascular functions. Clinical information as to the efficacy of currently recommended practices

such as gastric lavage would be a useful addition to the database for these chemicals.

Children’s Susceptibility. Studies addressing the effects of creosote in children are limited to a

single survey of health effects among residents of a housing development that had been built on a

creosote waste site (Agency for Toxic Substances and Disease Registry 1994). Other human studies are

predominantly of occupationally exposed adults. Studies of effects in young animals are also limited, but

include several developmental studies that demonstrate fetotoxicity and developmental defects in mice

and rats due to coal tar exposure (Hackett et al. 1984; Springer et al. 1982, 1986a; Zangar et al. 1989). 

Data needs relating to both prenatal and childhood exposures, and developmental effects expressed either

prenatally or during childhood, are discussed in detail in the Developmental Toxicity subsection above. 

No data are available to determine whether children vary from adults either in the health effects they are

likely to experience from creosote exposure, or in their relative susceptibility to these effects. 

Epidemiological studies of environmentally exposed populations (if such a population could be located),

which include children might help to clarify the types of health effects observed in children after creosote

exposure. A small retrospective study of women exposed to coal tar (as a treatment for psoriasis) during

pregnancy found no increased incidence of abortion or birth defects (Franssen et al. 1999). Expanding

this study to include a larger number of individuals and data as to the stage of pregnancy during which the

women were exposed, could provide information as to whether the developmental defects observed in

animals are also of concern for humans. Animal studies that compare the effects of creosote exposure on

animals of different ages would provide information on the comparative susceptibility of young and adult

individuals. 

The pharmacokinetics of creosote have not been defined because of the chemical complexity of these

mixtures. Information on individual components is not sufficient to define the properties of the mixture

and for this reason no PBPK models have been proposed for creosote. Individual components of creosote

are metabolized by several different enzyme systems including phase I and phase II enzymes. Human

polymorphisms are known to exist for many of these enzymes and are likely to affect the relative toxicity

of creosote for these individuals. The relative activity of metabolic enzymes may also vary with the age
CREOSOTE 213

3. HEALTH EFFECTS

of the individual, which will again affect the relative toxicity of particular components of creosote for old

or young individuals. However, the interactions taking place when creosote components are metabolized

are likely to be extremely complex so that information on age-related activity of any particular enzyme

will probably not be very informative as to differential toxicity of the mixture.

Child health data needs relating to exposure are discussed in 6.8.1 Identification of Data Needs:

Exposures of Children.

3.12.3 Ongoing Studies

Creosote is currently subject to an EPA Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)

registration standard and data call-in, and the Creosote Council II is currently conducting a research

program that includes testing in intermediate inhalation, intermediate dermal, developmental, and

reproductive toxicity. The Federal Research in Progress database (FEDRIP 2000) listed ongoing studies

of CYP1A1 as a biomarker of exposure and susceptibility to creosote, the effect of wood creosote on

diarrhea in rats, and modifiers of PAH carcinogenesis.
CREOSOTE 214

3. HEALTH EFFECTS
CREOSOTE 215
CREOSOTE 216

4. CHEMICAL AND PHYSICAL INFORMATION

4. CHEMICAL AND PHYSICAL INFORMATION

4.1 CHEMICAL IDENTITY

The chemical synonyms and identification numbers for wood creosote, coal tar creosote, and coal tar are

listed in Tables 4-1 through 4-3. Coal tar pitch is similar in composition to coal tar creosote and is not

presented separately. Coal tar pitch volatiles are compounds given off from coal tar pitch when it is

heated. The volatile component is not shown separately because it varies with the composition of the

pitch. Creosotes and coal tars are complex mixtures of variable composition containing primarily

condensed aromatic ring compounds (coal-derived substances) or phenols (wood creosote). Therefore, it

is not possible to represent these materials with a single chemical formula and structure. The sources,

chemical properties, and composition of coal tar creosote, coal tar pitch, and coal tar justify treating these

materials as a whole. Wood creosote is discussed separately because it is different in nature, use, and

risk.

Information regarding the chemical identity of wood creosote, coal tar creosote, and coal tar is located in

Tables 4-1 through 4-3.

4.2 PHYSICAL AND CHEMICAL PROPERTIES

Wood creosote, coal tar creosote, coal tar, and coal tar pitch differ from each other with respect to their

composition. Descriptions of each mixture are presented below. 

4.2.1 Wood Creosote

Wood creosotes are derived from beechwood (referred to herein as beechwood creosote) and the resin

from leaves of the creosote bush (Larrea, referred to herein as creosote bush resin). Beechwood creosote

consists mainly of phenol, cresols, guaiacols, and xylenols. It is a colorless or pale yellowish liquid, and

it has a characteristic smoky odor and burnt taste (Miyazato et al. 1981). It had therapeutic applications

in the past as a disinfectant, laxative, and a stimulating expectorant, but it is not a major pharmaceutical

ingredient today in the United States. Beechwood creosote is obtained from fractional distillation

(200–220 EC at atmospheric pressure) of beechwood or related plants. The mixture has only recently

been characterized to any significant extent (Ogata and Baba 1989). Phenol, p-cresol, and guaiacols
CREOSOTE 217

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-1. Chemical Identity of Wood Creosote

Characteristic Information Reference

Chemical name Wood creosote Merck 1989

Synonym(s) Beechwood creosote, creosote, creasote Merck 1989

Registered trade name(s) Not applicable

Chemical formula Not applicable

Chemical structurea Not applicable

Identification numbers: Windholz 1983

CAS registry 8021-39-4 Merck 1989

NIOSH RTECS G05870000 HSDB 2000

EPA hazardous waste U051 HSDB 2000

OHM/TADS No data

DOT/UN/NA/IMCO UN 2810; IMO 6.1 HSDB 2000

HSDB 1979 HSDB 2000

a

Wood creosote is a mixture composed primarily of phenolic compounds.

CAS = Chemical Abstracts Services; DOT/UN/NA/IMCO = Department of Transportation/United Nations/North

America/International Maritime Dangerous Goods Code; EPA = Environmental Protection Agency;

HSDB = Hazardous Substance Data Bank; NIOSH = National Institute for Occupational Safety and Health;

OHM/TADS = Oil and Hazardous Materials/Technical Assistance Data System; RTECS = Registry of Toxic Effects

of Chemical Substances
CREOSOTE 218

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-2. Chemical Identity of Coal Tar Creosote

Characteristic Information Reference

Chemical name Coal tar creosote American Wood Preserver’s

Association 1988

Synonym(s) Creosote, creosote oil, dead oil, brick

oil, coal tar oil, creosote P1, heavy oil,

liquid pitch oil, wash oil, creosotum,

cresylic creosote, naphthalene oil, tar

oil, AWPA #1, Preserv-o-sote

HSDB 2000

Registered trade name(s) Sakresote 100 HSDB 2000

Chemical formula Not applicable

Chemical structurea Not applicable

Identification numbers:

CAS registry 8001-58-9 Merck 1989; Weiss 1986

NIOSH RTECS GF9615000 HSDB 2000

EPA hazardous waste U051 HSDB 2000

OHM/TADS No data

DOT/UN/NA/IMCO shipping UN 1136/1137; IMO 3.2/3.3 HSDB 2000

HSDB 6299 HSDB 2000

NCI No data

a

Coal tar creosote is a mixed compound composed primarily of polycyclic aromatic hydrocarbons including

phenanthrene, acenaphthene, fluorene, anthracene, and pyridine.

CAS = Chemical Abstracts Services; DOT/UN/NA/IMCO = Department of Transportation/United Nations/North

America/International Maritime Dangerous Goods Code; EPA = Environmental Protection Agency;

HSDB = Hazardous Substance Data Bank; NCI = National Cancer Institute; NIOSH = National Institute for

Occupational Safety and Health; OHM/TADS = Oil and Hazardous Materials/Technical Assistance Data System;

RTECS = Registry of Toxic Effects of Chemical Substances
CREOSOTE 219

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-3. Chemical Identity of Coal Tar

Characteristic Information Reference

Chemical name Coal tar Merck 1989

Synonym(s) Crude coal tar, pixalbol, tar HSDB 2000

Registered trade name(s) Psorigel, Clinitar Merck 1989

Chemical formula Not applicable

Chemical structurea Not applicable

Identification numbers:

CAS registry 8007-45-2 HSDB 2000

NIOSH RTECS No data

EPA hazardous waste No data

OHM/TADS No data

DOT/UN/NA/IMCO UN 1999; IMO 3.2/3.3 HSDB 2000

HSDB 5050 HSDB 2000

NCI No data

a

Coal tar is a mixed compound composed primarily of polycyclic aromatic hydrocarbons including phenanthrene,

acenaphthene, fluorene, anthracene, and pyridine.

CAS = Chemical Abstracts Services; DOT/UN/NA/IMCO = Department of Transportation/United Nations/North

America/International Maritime Dangerous Goods Code; EPA = Environmental Protection Agency;

HSDB = Hazardous Substance Data Bank; NCI = National Cancer Institute; NIOSH = National Institute for

Occupational Safety and Health; OHM/TADS = Oil and Hazardous Materials/Technical Assistance Data System;

RTECS = Registry of Toxic Effects of Chemical Substances
CREOSOTE 220

4. CHEMICAL AND PHYSICAL INFORMATION

(guaiacol and 4-methylguaiacol) comprise the bulk of beechwood creosote. Xylenols, other methylated

guaiacols, and trimethylphenols account for virtually all of the remaining phenolics in the material. Since

beechwood creosote is obtained from different sources using nonstandardized procedures, its composition

may vary to some degree. For the sample analyzed by Ogata and Baba (1989), more than two-thirds of

the more than 20 compounds identified (Table 4-4) were represented by just four components (phenol,

p-cresol, guaiacol, and 4-methylguaiacol). Selected chemical and physical properties of wood creosote

are shown in Table 4-5. 

Creosote bush resin consists of phenolics (e.g., flavonoids and nordihydroguaiaretic acid), neutrals (e.g.,

waxes), basics (e.g., alkaloids), and acidics (e.g., phenolic acids). The phenolic portion comprises

83–91% of the total resin. Nordihydroguaiaretic acid accounts for 5–10% of the dry weight of the leaves

(Leonforte 1986). No other relevant chemical/physical data are available for creosote bush resin; the

substance is therefore not addressed further in this profile. 

4.2.2 Coal Tar Creosote, Coal Tar, and Coal Tar Pitch

These three substances are very similar mixtures obtained from the distillation of coal tars. The physical

and chemical properties of each are similar, although limited data are available for coal tar, and coal tar

pitch. Chemical Abstracts Service Numbers (CAS #) are associated with coal tar creosote (8001-58-9),

coal tar pitch (67996-93-2), and coal tar (8007-45-2). Literature searches for coal tar pitch produce data

identical to that obtained for coal tar creosote. A distinction between these materials is provided in the

following discussion.

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. Physically,

they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. 

The coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic

oxygen, sulfur, and nitrogen compounds. By comparison, coal tar creosotes are distillation products of

coal tar. They have an oily liquid consistency and range in color from yellowish-dark green to brown. 

The coal tar creosotes consist of aromatic hydrocarbons, anthracene, naphthalene, and phenanthrene

derivatives. At least 75% of the coal tar creosote mixture is polycyclic aromatic hydrocarbons (PAHs). 

Unlike the coal tars and coal tar creosotes, coal tar pitch is a residue produced during the distillation of

coal tar. The pitch is a shiny, dark brown to black residue which contains polycyclic aromatic

hydrocarbons and their methyl and polymethyl derivatives, as well as heteronuclear compounds 
CREOSOTE 221

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-4. Identity of Major Components of Wood Creosotea

Compound

Relative peak area,

(percent total peak area)

phenol 14.45

methylhydroxycyclopentenone 0.23

o-cresol 3.22

dimethylhydroxycyclopentenone 0.50

p-cresol 13.60

guaiacol 23.76

2,6-xylenol 1.04

3,4-xylenol 0.70

6-methylguaiacol 0.31

3,5-xylenol 2.94

2,4-xylenol 2.80

2,5-xylenol 0.68

unknown 1.31

2,3-xylenol 0.70

3-methylguaiacol 1.85

5-methylguaiacol 1.29

4-methylguaiacol 19.01

2,4,6-trimethylphenol 0.40

2,3,6-trimethylphenol 0.48

4-ethylguaiacol 6.36

4-ethyl-5-methylguaiacol 0.21

4-propylguaiacol 0.45

a

As identified by gas chromatography/mass spectrometry (Ogata and Baba 1989);

composition of wood creosotes may vary from source to source.
CREOSOTE 222

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-5. Physical and Chemical Properties of Wood Creosote

Property Information Reference

Molecular weight Not applicable

Color Yellowish to colorless Merck 1989

Physical state Liquid Weiss 1986

Melting point No data

Boiling point .203 EC Merck 1989

Specific gravity at 25 EC 1.08 Merck 1989

Odor Characteristic smokey odor Merck 1989

Taste Caustic, burning taste Merck 1989

Odor threshold:

Water

Air

No data

No data

Solubility:

Water

Organic solvent(s)

150–200 parts

Miscible with alcohol, ether, fixed, or

volatile oils

Merck 1989

Merck 1989

Partition coefficients: No data

Vapor pressure No data

Henry's law constant No data

Autoignition temperature No data

Flashpoint 74 EC (closed cup) Clayton and Clayton 1981

Flammability limits in air No data

Explosive limits No data

Other The major components of wood

creosote (phenols) are susceptible

to oxidative degradation when

exposed to air (oxygen), particularly

if the material is basic (high pH).

Not applicable
CREOSOTE 223

4. CHEMICAL AND PHYSICAL INFORMATION

(American Wood Preserver's Association 1988). Coal tar creosote is defined by the latter organization as:

A distillate derived from coal tar. As used in the wood preserving industry, creosote denotes

a distillate of coal tar produced by the high temperature carbonization of bituminous coal. 

Coal tar creosote consists principally of liquid and solid aromatic hydrocarbons and contains

some tar acids and tar bases; it is heavier than water and has a continuous boiling range

beginning at about 200 EC.

Coal tar creosote is now commonly defined by function, and refers to "the fractions or blends of fractions

specifically used for timber preservation" (IARC 1987). Coal tar creosote is referred to as “creosote” by

the U.S. EPA. The substance is a complex mixture typically composed of approximately 85% PAHs and

2–17% phenolics (Bedient et al. 1984). The composition of the mixture may also vary across lots and

across manufacturers. Properties of coal tar creosote are shown in Table 4-6.

Coal tar pitch is the tar distillation residue produced during coking operations (NIOSH 1977). The grade

of pitch thus produced is dependent on distillation conditions, including time and temperature. The

fraction consists primarily of condensed ring aromatics, including 2–6 ring systems, with minor amounts

of phenolic compounds and aromatic nitrogen bases. The number of constituents in coal tar pitch is

estimated to be in the thousands (HSDB 2000). A list of the components comprising the PAH fraction of

coal tar pitch is shown in Table 4-7. Properties for this substance are similar or identical to those shown

in Table 4-6 for coal tar creosote.

Coal tar itself is produced by the carbonization, or coking of coal. Coal tar is defined by Hawley (1977)

as:

A black, viscous liquid (or semi-solid), naphthalene-like odor, sharp burning taste; obtained by the

destructive distillation of bituminous coal, as in coke ovens; 1 ton of coal yields 8.8 gallons of coal

tar. Combustible. Specific gravity 1.18–1.23 (66/60 EF). Soluble in ether, benzene, carbon

disulfide, chloroform; partially soluble in alcohol, acetone, methanol, and benzene; only slightly

soluble in water.

The composition of the creosote mixture is dependent on the sources and preparation parameters of the

coal tar, and as a result the creosote components are rarely consistent in their type and concentration. An

example of the composition variability among creosote samples was recently presented by Weyand et al.

(1991). In that study, the concentrations of several PAHs were analyzed in four coal tars. All of the

PAHs identified exhibited 2-fold to nearly 20-fold differences in concentration among the four samples. 
CREOSOTE 224

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-6. Physical and Chemical Properties of Coal Tar Creosote

Property Information Reference

Molecular weight Not applicable

Color Translucent brown to

black; oily liquid;

yellowish to dark greenbrown

Merck 1989

Physical state Liquid Weiss 1986

Melting point No data

Boiling point 194–400 EC Clayton and Clayton 1981

Specific gravity 1.07–1.08 Clayton and Clayton 1981

Odor Aromatic smokey smell

Characteristic sharp odor

DOT 1985

Merck 1989

Odor threshold:

Water

Air

No data

No data

Taste Burning, caustic taste Clayton and Clayton 1981

Solubility:

Water

Organic solvent(s)

Slightly soluble

Miscible with alcohol,

ether, fixed or volatile oils

Clayton and Clayton 1981

Clayton and Clayton 1981

Partition coefficients: 1.0 (log Kow) HSDB 2000

Vapor pressure No data

Autoignition temperature 335 EC Merck 1996

Flashpoint 74 EC Merck 1989

Flammability limits in air No data

Explosive limits No data
CREOSOTE 225

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-7. Identity of PAH Components of Coal Tar Pitcha

Peak No. Compoundb Peak No. Compoundb

1 naphthalene 31 acridine

2 benzo(b)thiophene 32 phenanthridine

3 quinoline 33 carbazole

4 2-methylnaphthalene 34 methylphenanthrene, -anthracene

5 1-methylnaphthalene 35 methylphenanthrene, -anthracene

6 biphenyl 36 methylphenanthrene, -anthracene

7 2-ethylnaphthalene 37 4H-cyclopenta(def)phenanthrene

8 dimethylnaphthalene 38 methylphenanthrene, -anthracene

9 dimethylnaphthalene 39 methylphenanthrene, -anthracene

10 dimethylnaphthalene 40 methylcarbazole

11 methylbiphenyl 41 methylcarbazole

12 acenaphthene 42 2-phenylnaphthalene

13 naphthonitrile or azaacenaphthylene 43 dihydropyrene or isomer

14 dibenzofuran 44 fluoranthene

15 fluorene 45 azafluoranthene, -pyrene

16 methylacenaphthene 46 phenanthro(4,5-bcd)thiophene

17 methylacenaphthene 47 azafluoranthene, -pyrene

18 methylacenaphthene 48 pyrene

19 methyldibenzofuran 49 benzonaphthofuran

20 methyldibenzofuran 50 benzacenaphthene or isomer

21 9,10-dihydroanthracene 51 benzacenaphthene or isomer

22 9,10-dihydrophenanthrene 52 benzonaphthofuran

23 methylfluorene 53 benzonaphthofuran

24 methylfluorene 54 benzo(lmn)phenanthridine

25 methylfluorene 55 benzo(kl)xanthene

26 methylfluorene 56 methylfluoranthene, -pyrene

27 1,2,3,4-tetrahydroanthracene 57 4H-benzo(def)carbazole

28 dibenzo(bd)thiophene 58 azafluoranthene, -pyrene

29 phenanthrene 59 benzo(a)fluorene

30 anthracene 60 methylfluoranthene, -pyrene
CREOSOTE 226

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-7. Identity of PAH Components of Coal Tar Pitcha (continued)

Peak No. Compoundb Peak No. Compoundb

61 benzo(a)fluorene 91 7H-benzo(c)carbazole

62 benzo(c)fluorene or isomer 92 methylbenz(a)anthracene or isomer

63 methylbenzacenaphthene or isomer 93 tetramethylfluoranthene or isomer

64 methylbenzonaphthofuran or isomer 94 5H-benzo(b)carbazole

65 methylpyrene or isomer 95 methylbenzophenanthridine or isomer

66 methylpyrene or isomer 96 dimethylbenzo(cdf)carbazole

67 methylbenzonaphthofuran or isomer 97 methylchrysene or isomer

68 methylbenzonaphthofuran or isomer 98 methylchrysene or isomer

69 methylazapyrene or isomer 99 methylbenz(a)anthracene or isomer

70 methylbenzonaphthofuran or isomer 100 dimethylbenz(a)anthracene or isomer

71 methylbenzofluorene 101 methylbenz(a)anthracene or isomer

72 dihydrochrysene or isomer 102 dimethylbenz(a)anthracene or isomer

73 dimethylfluoranthene, -pyrene 103 11H-benz(bc)aceanthrylene or isomer

74 trimethylfluoranthene, -pyrene 104 methylbenz(a)anthracene or isomer

75 dimethylfluoranthene, -pyrene 105 4H-cyclopenta(def)chrysene or isomer

76 benzo(b)naphtho(2,1-d)thiophene 106 methylbenz(a)anthracene or isomer

77 benzo(c)phenanthrene 107 binaphthalene or isomer

78 benzo(ghi)fluoranthene 108 4H-cyclopenta(def)triphenylene or isomer

79 dimethylbenzonaphthofuran 109 dimethylbenz(a)anthracene or isomer

80 benzo(b)naphtho(1,2-d)thiophene 110 methylbenz(a)anthracene or isomer

81 dibenzoquinoline or isomer 111 binaphthalene or isomer

82 tetrahydrochrysene or isomer 112 dimethylbenz(a)anthracene or isomer

83 benzo(a)naphtho(2,3-d)thiophene 113 methylbenz(a)anthracene or isomer

84 benz(a)anthracene 114 binaphthalene or isomer

85 chrysene 115 phenylphenanthrene or isomer

86 11H-benzo(a)carbazole 116 dihydrobenzofluoranthene or isomer

87 naphthacene 117 dimethylchrysene or isomer

88 methylbenzonaphthothiophene 118 dibenzophenanthridine or isomer

89 methylbenz(a)anthracene or isomer 119 biquinoline

90 tetramethylfluoranthene or isomer 120 biquinoline
CREOSOTE 227

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-7. Identity of PAH Components of Coal Tar Pitcha (continued)

Peak No. Compoundb Peak No. Compoundb

121 benzo(j)fluoranthene 151 methylbenzopyrene or isomer

122 dihydrobenzofluoranthene or isomer 152 methylbenzopyrene or isomer

123 benzo(b)fluoranthene 153 11H-cyclopenta(ghi)perylene or isomer

124 dihydrobenzofluoranthene or isomer 154 methylbenzopyrene or isomer

125 benzo(k)fluoranthene 155 dimethylbenzopyrene or isomer

126 dibenzonaphthofuran or isomer 156 methylbenzopyrene or isomer

127 dihydrobenzofluoranthene or isomer 157 methylbenzopyrene or isomer

128 dimethylchrysene or isomer 158 dimethylbenzopyrene or isomer

129 azabenzopyrene or isomer 159 11H-indeno(2,1,7-cde)pyrene or isomer

130 dibenzonaphthofuran or isomer 160 dimethylbenzopyrene or isomer

131 benzophenanthrothiophene 161 dinaphthothiophene

132 azabenzopyrene or isomer 162 dimethylbenzopyrene or isomer

133 benzo(e)pyrene 163 dibenzophenanthridine or isomer

134 dibenzonaphthofuran or isomer 164 dibenzonaphthothiophene

135 benzo(a)pyrene 165 dimethylbenzopyrene or isomer

136 dibenzonaphthofuran or isomer 166 dibenzocarbazole

137 perylene 167 dimethylbenzopyrene or isomer

138 dibenzonaphthofuran or isomer 168 dibenzo(bg)phenanthrene or isomer

139 methylbenzofluoranthene or isomer 169 benzo(g)chrysene or isomer

140 methylbenzofluoranthene or isomer 170 dinaphthothiophene

141 azabenzopyrene or isomer 171 dimethylbenzofluoranthene or isomer

142 4H-naphtho(1,2,3,4-def)carbazole or

isomer

172 dibenzoacridine or isomer

143 methylbenzofluoranthene or isomer 173 dinaphthothiophene

144 dibenzofluorene or isomer 174 dinaphthothiophene

145 dihydroindenopyrene or isomer 175 benzo(c)chrysene or isomer

146 dibenzofluorene or isomer 176 dibenzocarbazole

147 dibenzofluorene or isomer 177 dimethylbenzofluoranthene or isomer

148 methylbenzopyrene or isomer 178 dibenz(aj)anthracene

149 dibenzo(cg)phenanthrene or isomer 179 indenopyrene or isomer

150 dimethyldibenzonaphthofuran or isomer 180 dimethyldibenzonaphthofuran
CREOSOTE 228

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-7. Identity of PAH Components of Coal Tar Pitcha (continued)

Peak No. Compoundb Peak No. Compoundb

181 methyldibenzophenanthrene,

-anthracene

191 dimethyldibenzonaphthofuran

182 indenopyrene or isomer 192 picene

183 methylbenzophenanthrothiophene 193 dimethylbenzopyrene or isomer

184 dibenz(ac)anthracene 194 dimethyldibenzonaphthofuran

185 methyldibenzophenanthrene,

-anthracene

195 benzo(ghi)perylene

186 dimethylbenzofluoranthene or isomer 196 benzo(a)naphthacene or pentacene

187 dibenz(ah)anthracene 197 dimethyldibenzonaphthofuran

188 trimethylbenzofluoranthene or isomer 198 anthanthrene

189 dimethyldibenzophenanthrene,

-anthracene

199 methyl indenopyrene or isomer

190 benzo(b)chrysene

a

As reported by Guillén et al. 1992; compounds presented in elution order b

Tentative identification by gas chromatography/mass spectrometry
CREOSOTE 229

4. CHEMICAL AND PHYSICAL INFORMATION

Benzo[a]pyrene, a component whose individual toxicity has been examined extensively, ranged from

nondetectable levels (detection limit 0.3 g/kg) to 1.7, 6.4, and 3.9 g/kg of coal tar.

Limited chemical/physical data exist for coal tar. Table 4-8 summarizes the current information. Because

of the variability in feedstock and manufacturing processes, presentation of exact values for various

properties presented in Tables 4-6 and 4-8 is not possible.
CREOSOTE 230

4. CHEMICAL AND PHYSICAL INFORMATION

Table 4-8. Physical and Chemical Properties of Coal Tar

Property Information Reference

Molecular weight Not applicable

Color Almost black, thick liquid, or

semisolid

Merck 1989

Physical state Semisolid Weiss 1986

Melting point No data

Boiling point No data

Specific gravity 1.18–1.23 Hawley 1981

Odor Naphthalene-like Osol 1980

Odor threshold:

Water

Air

No data

No data

Taste Sharp, burning taste Osol 1980

Solubility:

Water

Organic solvent(s)

Slightly soluble

Mostly dissolves in benzene;

partially dissolves in alcohol,

ether, chloroform, acetone, and

petroleum ether

Merck 1989

Merck 1989

Partition coefficients No data

Vapor pressure No data

Autoignition temperature No data

Flashpoint No data

Flammability limits No data

Explosive limits No data

CREOSOTE 232

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

5.1 PRODUCTION

Wood creosote, coal tar creosote, coal tar, and coal tar pitch differ from each other in composition. Wood

creosotes (CAS Registry number 8021-39-4) are derived from beechwood (referred to herein as

beechwood creosote) and the resin from leaves of the creosote bush (Larrea, referred to herein as creosote

bush resin). Beechwood creosote is not commercially produced in the United States (HSDB 2000).

Coal tars are by-products of the carbonization of coal to produce coke and/or natural gas. By comparison,

coal tar creosotes are distillation products of coal tar. Unlike the coal tars and coal tar creosotes, coal tar

pitch is a residue produced during the distillation of coal tar. Coal tar pitch volatiles are compounds given

off by coal tar pitch when it is heated, and thus vary with the composition of the coal tar pitch (see

Table 4-7). The volatile component of coal tar has not been addressed separately from coal tar pitch in

this section.

Because coal tar is a by-product of steel manufacturing, domestic production of coal tar products may

vary depending on demand for steel (USITC 1987). Coal tar production in the United States was

168.6 million gallons in 1986 (USITC 1987) and 188.5 million gallons in 1987 (USITC 1988). In 1992,

7.03x108

 kg (1.55x109 pounds) of crude coal tar was produced (USITC 1994). Creosote has been

produced commercially in the United States since 1917 (IARC 1985). Creosote production falls into two

categories: distillate (100% creosote), and creosote in coal tar solution. Distillate production in 1986 was

46.8 million gallons; creosote in coal tar solution was 31.6 million gallons (USITC 1987). Distillate

production in 1987 was 47.3 million gallons. Production of creosote in coal tar solution in 1987 was not

disclosed, but solution sales in 1987 were 34.3 million gallons (USITC 1988). Distillate production in

1992 was 2.41x108

 kg (5.32x108 pounds); creosote in coal tar solution was 1.10x108 kg (2.43x109 pounds)

(USITC 1994). The U.S. International Trade Commission classifies pitch of tar as hard (melting point

$161 EF), medium (melting point 110–160 EF), or soft (melting point 80–109 EF) (USITC 1994). 

Production of hard pitch in 1987 was 4.93x105

 tons. Soft pitch production data for 1987 were not

disclosed, but 6.52x105

 tons were sold (USITC 1988). Production of hard pitch was 6.08x108 kg

(1.34x109

 pounds) in 1992. Production and sales figures for medium and soft pitch were not disclosed for

1992 (USITC 1994).
CREOSOTE 233

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

Table 5-1 lists the number of facilities in each state that manufacture or process coal tar creosote, the

intended use, and the range of maximum amounts of creosote that are stored on site. The data listed in

Table 5-1 are derived from the Toxics Release Inventory (TRI) (TRI99 2001). Only certain types of

facilities are legally required to report; therefore, this is not an exhaustive list.

5.2 IMPORT/EXPORT

Available figures on imports and exports (NTDB 1994) are based on millions of gallons of all forms of

creosote. Figures from the period 1984–1987 show fluctuations in the range of 1–10 million gallons of

creosote products in both import and export levels. Recent data pertaining to the import or export of

creosote (NTDB 1995) are presented in Table 5-2. The categories used by the National Trade Data Bank

do not directly correspond to the four categories described in Section 5.1.

5.3 USE

Coal tar creosote has been used as a wood preservative pesticide in the United States for over 100 years. 

Wood preservation accounts for over 97% of current coal tar creosote production (Santodonato et al.

1985). Coal tar creosote is applied to wood by commercial pressure treatment or by home and farm

dipping or brushing, although this latter use is not significant since creosote now has restricted use as a

wood preservative pesticide (EPA 1986b). Coal tar creosote is a wood preservative and water-proofing

agent for log homes, railroad ties, telephone poles, marine pilings, and fence posts. In addition, coal tar

creosote prevents animal and vegetable growth on concrete marine pilings, and is a component of roofing

pitch, fuel oil, and lamp black, and a lubricant for die molds (Cammer 1982; HSDB 2000). Other uses

include animal and bird repellent, insecticide, animal dip, fungicide, and a pharmaceutical agent for the

treatment of psoriasis (IARC 1985). Coal tar is registered as a pesticide active ingredient with the U.S.

EPA and in 1998 was being evaluated for re-registration (HSDB 2000). The leaves of the creosote bush

are ground to produce an herbal nutritional supplement for use as an antioxidant or free radical scavenger

to retard aging and to treat a variety of skin conditions including acne. The supplement is claimed, in

nonscientific publications, to have antiamoebic, antifungal, and antiviral properties. Suggested uses

include oral applications for colds, influenza, diarrhea, urinary tract infections, and topical applications

for dandruff (Katz and Saibil 1990).
CREOSOTE 234

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

Table 5-1. Facilities that Produce, Process, or Use Coal Tar Creosote

Statea Number of facilities

Minimum amount on

site in poundsb

Maximum amount

on site in poundsb

Activities and

usesc

AL 7 10,000 9,999,999 1, 4, 9

AR 3 10,000 9,999,999 1, 3, 8, 9, 13

AZ 1 10,000 99,999 9

CA 4 100 999,999 8, 9, 13

CO 2 1,000 9,999,999 2, 4, 9

CT 1 100,000 999,999 9

FL 1 100,000 999,999 9

GA 2 100,000 999,999 2, 4, 8, 9, 12

ID 1 10,000 99,999 13

IL 4 100,000 49,999,999 1, 4, 9

IN 3 100,000 9,999,999 1, 3, 9

KY 4 100,000 9,999,999 8, 9, 13

LA 4 100,000 9,999,999 9

MI 1 1,000,000 9,999,999 8

MO 1 1,000,000 9,999,999 9

MS 7 10,000 49,999,999 2, 3, 9

NC 1 1,000 9,999 13

NE 1 10,000 99,999 13

NJ 2 1,000 999,999 9, 13

NY 1 100,000 999,999 2, 3, 4, 9

OH 3 1,000 49,999,999 1, 4, 13

OK 2 1,000 999,999 9, 13

OR 5 1,000 9,999,999 1, 6, 8, 9, 13

PA 5 100,000 49,999,999 1, 2, 4, 8, 9

SC 2 100,000 9,999,999 9, 13

SD 1 10,000 99,999 9

TN 1 10,000 99,999 9, 10

TX 5 10,000 9,999,999 9, 12, 13
CREOSOTE 235

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

Table 5-1. Facilities that Produce, Process, or Use Coal Tar Creosote

(continued)

Statea Number of facilities

Minimum amount on

site in poundsb

Maximum amount

on site in poundsb

Activities and

usesc

UT 3 1,000 9,999,999 1, 4, 13

VA 3 100,000 9,999,999 8, 9

WA 1 100,000 999,999 12

WI 3 1,000 999,999 9

WV 5 100 49,999,999 1, 3, 4, 8, 9, 12

Source: TRI99 2001

a

Post office state abbreviations used

b

Amounts on site reported by facilities in each state c

Activities/Uses:

1. Produce

2. Import

3. Onsite use/processing

4. Sale/Distribution

5. Byproduct

6. Impurity

7. Reactant

8. Formulation Component

9. Article Component

10. Repackaging

11. Chemical Processing Aid

12. Manufacturing Aid 

13. Ancillary/Other Uses
CREOSOTE 236

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

Table 5-2. Import/Export Volumes for Creosote

Tariff

Category Imports/Exports 1991 1992 1993 1994 1995

Creosote oils Exports (1,000 kg)

3,978 8,027 9,158 14,900 6,838

Imports (1,000 L)

NR 17,584 22,674 17,994 9,466

Other oils and products

of coal tar distillation

Exports (1,000 kg)

10,842 0 0 0 0

Imports (1,000 L)

NR 10,690 40,475 219,424 12,643

Pitch from coal and

other mineral tars

Exports (1,000 kg)

39,592 76,586 91,659 103,034 43,740

Imports (1,000 L)

NR 6,226 115,688 77,791 50,315

Source: National Trade Data Bank (NTDB 1995)

NR = not reported
CREOSOTE 237

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

Beechwood creosote and its compounds calcium creosotate, creosote carbonate, and creosote valerate

were used in the past as antiseptics and expectorants (Merck 1989). Treatments for leprosy (Samson and

Limkako 1923), pneumonia (McKinlay 1933), and tuberculosis (Fellows 1939a) also involved ingestion

of beechwood creosote. Beechwood creosote is rarely used in the United States for medicinal purposes

today.

The major use of coal tar pitch is as the binder for aluminum smelting electrodes. Pitch is also used in

roofing, surface coatings, and for pitch coke production. Pipe-coating enamels made from pitch are used

to protect buried oil, gas, and water pipes from corrosion (IARC 1985).

5.4 DISPOSAL

According to the TRI, 616,938 pounds of coal tar creosote were transferred off-site from facilities that use

or process coal tar creosote, presumably for treatment and disposal (TRI99 2001). Treatment of creosote

sludge generated from coal tar creosote production includes fixing, solidifying, and covering with clay. 

In the past, settling lagoons were used in treatment. However, they are no longer being used, and those

which were used are now being remediated. "Disposal in place" requires groundwater monitoring for a

30-year period (Ball et al. 1985). Four Resource Conservation and Recovery Act (RCRA) hazardous

wastes are listed due, in part, to their creosote content (40 CFR 261.31 and 261.32 [EPA 1981a, 1981b]). 

These are:

C Waste waters, process residuals, preservative dripage, and spent formulations from wood

preserving processes generated at plants that use creosote formulations

C Bottom sediment sludge from the treatment of waste waters from wood preserving processes

C Waste water treatment sludges generated in the production of creosote

C Off-specification creosote (does not meet desired chemical composition).

Due to RCRA Land Disposal Restrictions, creosote can no longer be disposed in hazardous waste

landfills unless it meets EPA specified treatment standards (EPA 1990c). No technology- or

concentration-based standards for the three RCRA hazardous wastes containing creosote specify creosote

as a constituent for monitoring treatment performance (40 CFR 268.43 [EPA 1988b]). Industrially used

creosote-treated wood can be burned in an industrial incinerator or boiler (EPA 1986b). Treated wood

used in the home or farm should be buried or disposed with household garbage; it should not be
CREOSOTE 238

5. PRODUCTION, IMPORT/EXPORT, USE, AND DISPOSAL

incinerated (American Wood Preserver's Association 1988). The potential for many types of hazardous

pollutants to be included with creosote wastes seriously diminishes the potential for recycling or re-use.

CREOSOTE 240

6. POTENTIAL FOR HUMAN EXPOSURE

6.1 OVERVIEW

Creosote has been identified in at least 46 of the 1,613 hazardous waste sites that have been proposed for

inclusion on the EPA National Priorities List (NPL) (HazDat 2002). However, the number of sites

evaluated for creosote is not known. The frequency of these sites can be seen in Figure 6-1. Of these

sites, all 46 are located within the United States and none are located in the Commonwealth of Puerto

Rico (not shown).

Coal tar creosote is a complex commercial mixture of some 300 organic constituents. The most common

forms are derived from coal tar distillation, yielding coal tar creosote in temperature ranges between

210 and 280 EC. Coal tar and coal tar pitch share many of the polycyclic aromatic hydrocarbons (PAHs)

components of coal tar creosote. For the coal tar derivatives, the composition of the mixture varies from

batch to batch depending on the coking process used. Creosote consists primarily of PAHs and, therefore,

the fate of many of the components of the mixture is similar to that of PAHs. 

Coal tar creosote has been widely used as a wood-treatment pesticide since the turn of the century. As a

result of this widespread and long-term use, workers in the wood-preserving industry have been exposed

to coal tar creosote for many years. Human exposure to coal tar creosote can occur by inhalation or direct

dermal contact. Studies have indicated that dermal exposure to creosote used in wood treatment or in

coking oven processes contributed more significantly to the total body burden than respiratory exposures

(Klingner and McCorkle 1994; Malkin et al. 1996; Van Rooij et al. 1993b). In other industries, such as

rubber processing, occupational exposure to coal tar pitch volatiles may lead to excessive respiratory

exposure to PAHs, including benzo[a]pyrene (Rogaczewska and Ligocka 1994). Individuals working in

wood-preserving facilities are one of the largest exposed groups. Exposure may also occur during

handling and installation of treated wood products in structures such as bridges, piers, retaining walls,

cross ties, and fencing; as a result of burning treated scrap wood; and through contact with contaminated

media at hazardous waste sites. The general public is unlikely to experience any significant exposure to

liquid creosote through the direct use of wood preservative products because EPA canceled all nonwood

uses of the material and restricted use of coal tar creosote products to certified applicators in January 1986

(EPA 1986b; R.U.P. 1994).
1

23456

Frequency of

NPL Sites

Derived from HazDat 2002

Figure 6-1. Frequency of NPL Sites with Creosote Contamination
CREOSOTE 242

6. POTENTIAL FOR HUMAN EXPOSURE

Children are exposed to creosote via the same routes that adults are, and small children are more likely

than adults to be in close contact with yard dirt or playground dirt, lawns, and indoor (carpet) dust, all of

which may be contaminated with creosote residues. Because of a tendency to put their unwashed hands

and foreign objects into their mouths, and to chew on objects, children may be exposed to creosote

through oral ingestion of the chemical. Dermal exposure may occur through contact with treated wood

used for utility poles, bridges, fences, and railroad crossties. Children may be exposed by playing near

pools of discarded creosote or by playing at abandoned hazardous waste sites. 

Pharmaceutical creosote preparations are derived from the processing of such woody plants as beechwood

(von Burg and Stout 1992). Wood creosote (beechwood creosote) is a yellow, transparent liquid with a

characteristic smoky odor, obtained by fractional distillation of wood tar. It is composed primarily of

phenol, phenols, cresols, guaiacols, xylenols, and small amounts of alkyl-2-hydroxy2-cyclopenten-1-ones. It has been used as an expectorant, a “gastric sedative,” a gastrointestinal

antiseptic, and particularly as an antidiarrheal agent (Ogata et al. 1993). Wood creosote and coal tar

creosote are chemically distinct, and should not be confused with one another (see Chapter 4). 

Coal tar creosote has been identified in at least 46 of the 1,613 current or former EPA National Priorities

List (NPL) hazardous waste sites (HazDat 2002). However, the number of sites evaluated for creosote is

not known. The frequency of these sites within the United States can be seen in Figure 6-1. Biotransformation by microbes is the primary process by which creosote constituents are degraded in soils,

surface waters, and groundwater. The mixture is relatively stable and persistent in the environment;

half-life data are not available. Wood creosote was not identified at any of the current or former NPL

hazardous waste sites.

6.2 RELEASES TO THE ENVIRONMENT

There are no known natural sources of the creosote mixture (IARC 1973). However, several of the PAH

constituents of the mixture are known to have natural sources; the reader is referred to the ATSDR

Toxicological Profile for Polycyclic Aromatic Hydrocarbons (Agency for Toxic Substances and Disease

Registry 1995) and the ATSDR Toxicological Profile for Cresols (Agency for Toxic Substances and

Disease Registry 1992) for additional information on natural sources, releases, and levels of PAHs and

cresols associated with creosote production, use, and disposal.
CREOSOTE 243

6. POTENTIAL FOR HUMAN EXPOSURE

Creosote has been identified in a variety of environmental media (surface water, ground water, soil, and

sediment) collected at 46 of the 1,613 EPA NPL hazardous waste sites (HazDat 2002).

According to the U.S. Department of Agriculture (USDA), the major source of creosote released to the

environment is waste water effluents from wood treatment facilities (USDA 1980). Companies that

preserve wood with coal tar creosote may treat their aqueous wastes in on-site biological treatment plants

or release the waste water into a municipal water treatment system (EPA 1975, 1978a). According to the

Toxics Release Inventory (TRI), coal tar creosote manufacturing and processing facilities listed for 1999

(TRI99 2001) report that the major portion of creosote released to the environment is released to air and

soil. Table 6-1 lists releases to the environment in 1999 from facilities that manufacture or process coal

tar creosote. Only certain types of facilities are legally required to report; this is not an exhaustive list.

Coal tar creosote components may also be slowly released from the surface of treated wood products by

oil exudation, leaching by rain water, or volatilization. Losses of creosote from impregnated wood are

dependent on the kind of coal used to produce the coal tar, the kind of coke oven used to make the coal

tar, and the conditions under which the wood is used (Leach and Weinert 1976). 

Treatment of waste waters from wood-preserving processes that use creosote and/or pentachlorophenol

produces bottom sediment sludge. EPA defines these as K001 sludges (EPA 1980); in the early 1990s,

approximately 1,000 metric tons per year of K001 sludges were produced from active wood-preserving

facilities (Davis et al. 1993). At that time, 55 wood-preserving facilities had been identified as NPL sites

primarily because of contamination with K001 sludge (Davis et al. 1993). 

Creosote-containing materials are also encountered at abandoned dump sites or abandoned facilities

where creosote was produced or used in significant amounts. In addition to wood-preserving facilities,

coal tar creosote was a by-product of the production of so-called town gas, an illuminating gas made from

coal (Arvin and Flyvbjerg 1992; EPA 1987b; Flyvbjerg et al. 1993). Around the turn of the century,

virtually every large community in the United States had such a manufactured gas facility (EPA 1987b). 

From 1816 to 1947, more than 11 billion gallons of coal tar were generated at manufactured gas plants in

the United States (Lee et al. 1992). The total number of town-gas sites may have approached 11,000. 

Several hundred of the larger sites have been evaluated for the NPL. Coke-producing facilities also

generate coal tar wastes, including cresol emissions to the atmosphere (Grosjean 1991).
Table 6-1. Releases to the Environment from Facilities that Produce, Process, or Use Coa

Reported amounts released in pounds per yeara

Stateb

Number offacilities Airc Water

Undergroundinjection Land

Total on-sitereleased

Total offreleasee 

AL 7 234,952 1,914 No data 0 236,866 20,3AR 3 31,068 1,209 No data 900 33,177 3,5AZ 1 7,505 No data No data No data 7,505 No daCA 4 4,215 10,564 No data 29,672 44,451 2CO 2 8,593 280 No data 2,087 10,960 288,0CT 1 500 No data No data No data 500 No daFL 1 255 No data No data No data 255 No daGA 2 2,300 8 No data No data 2,308 No daID 1 5 No data No data 30,000 30,005 No daIL 4 26,968 2,901 No data 0 29,869 17,6IN 3 7,055 400 No data 16,845 24,300 No daKY 4 13,394 66 No data 0 13,460 4,7LA 4 94,977 103 No data 0 95,080 No daMI 1 10,529 No data No data No data 10,529 No daMO 1 3,600 300 No data No data 3,900 No daMS 7 31,231 1,770 No data 0 33,001 79,9NC 1 13 No data No data No data 13 No daNE 1 5 No data No data 0 5 No daNJ 2 3,037 0 No data 0 3,037 NY 1 78 No data No data No data 78 No daOH 3 61,945 1 No data No data 61,946 1,5OK 2 14 No data No data 129,980 129,994 14,1OR 5 17,370 5 No data 270,673 288,048 7PA 5 27,416 66 No data 0 27,482 79,1SC 2 14,450 53 No data 716,348 730,851 
Table 6-1. Releases to the Environment from Facilities that Produce, Process, or Use Coa

(continued)

Reported amounts released in pounds per yeara

Stateb

Number offacilities Airc Water

Undergroundinjection Land

Total on-sitereleased

Total offreleasee 

SD 1 3,020 110 No data No data 3,130 10,0TN 1 500 No data No data No data 500 No daTX 5 51,483 2,186 0 0 53,669 51,1UT 3 9,195 No data No data 12,478 21,673 2VA 3 13,244 359 No data 0 13,603 12,7WA 1 1,805 10 No data No data 1,815 6,4WI 3 15,336 No data No data 0 15,336 WV 5 47,019 14 No data 0 47,033 26,0Total 90 743,077 22,319 0 1,208,983 1,974,379 616,9Source: TRI99 2001aData in TRI are maximum amounts released by each facility.bPost office state abbreviations are used.cThe sum of fugitive and stack releases are included in releases to air by a given facility. dThe sum of all releases of the chemical to air, land, water, and underground injection wells. eTotal amount of chemical transferred off-site, including to publicly owned treatment works (POTW).
CREOSOTE 246

6. POTENTIAL FOR HUMAN EXPOSURE

At older production facilities or places where wastes have been disposed off-site, the creosote materials

are often mixed with other chemicals. For instance, pentachlorophenol (PCP) is commonly encountered

at NPL sites involved with wood-preserving operations along with such metals as copper, chromium, and

arsenic (Davis et al. 1993; Kuehl et al. 1990; Mueller et al. 1989, 1991). At many of these sites, PAHs 

from combustion sources other than coal tar may have been introduced. The wastes from old town-gas

sites may contain benzene, toluene, ethylenebenzene, or xylenes, and sometimes cyanides (Arvin and

Flyvbjerg 1992; EPA 1987b; Flyvbjerg et al. 1993).

No major sources of wood creosote releases to the environment have been reported.

6.2.1 Air

Atmospheric releases of creosote from wood-preserving plants are not well defined. Coal tar creosote

constituents such as naphthalene, acenaphthalene, acenaphthene, phenanthrene, and fluorene have been

detected in emissions at a pressure treatment facility that treated logs for use as utility poles and marine

pilings (EPA 1986d). Releases may occur at several points in the treatment process, such as when

cylinder doors are opened after a treatment cycle, or when creosote is transferred from the heater to the

cylinder at the beginning of the impregnation process. Atmospheric releases vary from plant to plant,

depending on the process design, and are considered to be significantly smaller than releases to surface

water in aqueous effluents (Henningsson 1983). It should be noted, however, that the more volatile PAHs

may be less toxic (and especially less carcinogenic) than the less volatile PAHs.

On a hot, sunny day evaporation of creosote from the surface of treated wood may release coal tar

creosote constituents to the atmosphere. Only the volatile creosote components such as acenaphthene and

naphthalene will volatilize; the heavier fractions will remain on the wood (USDA 1980). Volatilization

may also be greater during warmer months when ambient temperatures are higher. Gevao and Jones

(1998) observed greater volatilization of acenaphthene, fluorene, phenanthrene, anthracene, and

fluoranthene from creosote-treated wood at 30 EC than at 4 EC.

In a terrestrial microcosm study, release of 14C-labeled creosote components to the atmosphere from

treated wood accounted for 1.0% of total acenaphthene and 1.4% of phenanthrene, whereas 93.5 and 95%

of these components, respectively, were retained in the wood (Gile et al. 1982). 
CREOSOTE 247

6. POTENTIAL FOR HUMAN EXPOSURE

Other potential sources of atmospheric releases include incineration of scrap wood treated with the

mixture and re-entrainment of dust and soils contaminated with components of the mixture in the vicinity

of hazardous waste sites. Creosote was not detected in any air samples of the 46 current or former NPL

sites where creosote was identified in some environmental medium (HazDat 2002). 

According to TRI99 (TRI99 2001), an estimated total of 743,077 pounds of coal tar creosote, amounting

to 37.6% of the total environmental release, was discharged to air from manufacturing and processing

facilities in the United States in 1999. The TRI data should be used with caution because only certain

types of facilities are required to report. This is not an exhaustive list.

No sources of wood creosote releases to the atmosphere have been reported.

6.2.2 Water

The major source of creosote released into surface waters and ground water is waste water effluents from

wood-preserving facilities (USDA 1980). In previous years, waste water generated from wood treatment

facilities was often discharged to unlined evaporation/settling lagoons where a sludge was formed. 

Water-soluble creosote components then percolated through the soil to reach the groundwater table. 

Waste waters may include process water generated from steam conditioning of the wood; preservative

formulation recovery and regeneration water; water used to wash excess preservative from the surface of

the wood; condensate from drying kilns used to dry preserved or surface-protected wood; water that

accumulates in door and retort sumps; and rain falling on or in the immediate vicinity of the treating

cylinder and work tank area. Groundwater contamination from creosote waste waters and sludge stored

in unlined surface water impoundments at a wood treatment facility has been reported in Pensacola,

Florida (USGS 1988a; Elder and Dresler 1988; Goerlitz et al. 1985). Similar contamination problems

have been reported in Conroe, Texas (Borden 1986), and St. Louis Park, Minnesota (Hickock et al. 1982).

Given the very viscous nature of coal tar creosote or creosote-containing wastes, significant migration

into groundwater supplies is seldom encountered unless the soils are extremely porous. For instance, a

very sandy substrate at the American Creosote Works NPL site at Pensacola, Florida, allowed a

significant plume of wood-preserving wastes to enter the ground water (Goerlitz et al. 1985). In most

instances, the main concern over creosote materials entering well water is that minute quantities (ng/L) of

coal tar components produce extremely objectionable tastes and odors (Arvin and Flyvbjerg 1992).
CREOSOTE 248

6. POTENTIAL FOR HUMAN EXPOSURE

In addition to discharges or migration into ground water from disposal sites, coal tar creosote has often

been introduced to receiving waters as the result of spills while transporting coal tar materials on barges

or during loading and unloading accidents around docks or navigation facilities. Well documented

examples include a spill near Slidell, Louisiana, on the Bayou Bonfouca (DeLeon et al. 1988). During the

years 1986–1991, 1,400 incidents of chemical and petroleum spills into the Newark Bay were

documented; among these were spills of 53,000 gallons of liquid asphalt and 75 gallons of creosote

(Gunster et al. 1993).

Water-soluble creosote constituents (e.g., phenols) may be released to surface water or ground water by

leaching from the surface of creosote-contaminated soils at hazardous waste sites or from treated wood

products, such as marine pilings, coming into contact with water. For example, some studies have shown

that creosote is lost to a greater extent from marine timber than from timber placed in fresh water as a

result of wood cell contraction caused by the high concentration of salts in sea water (Henningsson 1983). 

Creosote has been detected in groundwater samples collected at 27 of the 46 NPL sites and in surface

water samples collected at 8 of the 46 sites where creosote has been identified in some medium (HazDat

2002). 

According to TRI99 (2001), an estimated total of 22,319 pounds of coal tar creosote, amounting to 1.1%

of the total environmental release, was discharged to water from manufacturing and processing facilities

in the United States in 1999. The TRI data should be used with caution because only certain types of

facilities are required to report. This is not an exhaustive list.

No sources of wood creosote releases to water have been reported.

6.2.3 Soil

Coal tar creosote may be released to soils at wood treatment facilities as a result of bleeding of the

product from treated timber in stockyard and storage areas. Rain water may also wash the soluble

components directly from the surface of treated timber and into the soil (Henningsson 1983). Localized,

but severe, contamination of soils is often encountered on the grounds of older (often abandoned) woodpreserving or town-gas facilities (Davis et al. 1993; EPA 1987b).
CREOSOTE 249

6. POTENTIAL FOR HUMAN EXPOSURE

There is also a potential for release of creosote to soil from hazardous waste sites. Creosote has been

detected in soil samples collected at 30 of the 46 NPL sites and in sediment samples collected at 6 of the

46 NPL sites where creosote has been identified in some medium (HazDat 2002). 

According to TRI99 (2001), an estimated total of 1,208,983 pounds of creosote, amounting to 61.2% of

the total environmental release, was discharged to land from manufacturing and processing facilities in

the United States in 1999. The TRI data (Table 6-1) should be used with caution because only certain

types of facilities are required to report. This is not an exhaustive list.

No sources of wood creosote releases to soil have been reported.

6.3 ENVIRONMENTAL FATE

As with other chemical mixtures, the fate and transport processes affecting creosote can be extremely

complex. Creosote components may partition to the air, water, soil, or biota depending on their physical

and chemical properties. Compounds initially released to the atmosphere may undergo atmospheric

deposition and reach surface water directly or through runoff carrying soil-bound compounds (Stangroom

et al. 1998). For coal tar creosote materials encountered in old production facilities or waste disposal

sites, materials contained in the top several feet of soil will have become "weathered," with virtually all

the phenolic and heterocyclic fractions having volatilized, oxidized, or biodegraded (von Burg and Stout

1992). The lighter fractions of the PAH materials will also have degraded. The remaining weathered

creosote will show limited ability to move off-site. Johnston et al. (1993) studied the PAH composition

of coal-tar-containing samples collected at a number of coal gasworks sites in Australia. Most of these

sites were abandoned nearly a century ago. The samples were taken from areas where the coal tar

components would have undergone environmental modification to varying degrees since deposition. 

They concluded that aqueous partitioning and volatilization are probably the main processes that control

environmental modification of coal tar at gasworks sites.

Newly produced creosote, or materials from a spill or a more recent disposal site, may pose more serious

toxicity concerns. A complicating factor in interpreting the available literature is that creosote alone may

not by the only source of toxicity. Especially at NPL or other waste disposal sites, such chemicals as

pentachlorophenol (PCP) or heavy metals may be involved. Without an extensive battery of chemical

analyses, perhaps combined with bioassay tests, making even semi-quantitative judgements on toxicity

issues can be problematic. Much of the remedial work conducted under the Superfund program has
CREOSOTE 250

6. POTENTIAL FOR HUMAN EXPOSURE

simply aimed to reduce the volume of wastes at NPL sites with creosote contamination. A large

percentage reduction by total weight does not always translate into a corresponding reduction in toxicity

(Brooks et al. 1998; Hyötyäinen and Oikari 1999b; Mueller et al. 1991).

6.3.1 Transport and Partitioning

Coal tar creosote constituents released to surface waters will differentially partition to the water column

or to sediments depending on their water solubility and sorptive properties. For example, PAHs, the

major constituents of creosote, generally tend to sorb strongly to soil and sediment particulates, and often

have low aqueous solubilities and mobility (Hickock et al. 1982). Many components in the PAH fraction,

particularly the higher molecular weight (HMW) PAHs, will remain in a virtually stationary tar-like mass

at the place where they were deposited. Nitrogenous bases present in creosote waste water (e.g., aniline,

toluidines, and xylidines) are relatively soluble, mobile, and persistent in ground water (Pereira et al.

1983). However, behavior at a given site is also dependent on site-specific characteristics. For example,

PAHs, phenol, and heterocyclic components of creosote wood treatment process wastes were found to

migrate en masse in ground water through a contaminated sand and gravel aquifer in Pensacola, Florida;

sorption of these different classes of organic constituents in the low organic carbon (<0.1%) aquifer

materials was not important (USGS 1986). In an investigation of coal-tar contaminated surface

sediments, PAHs were observed to have moved 400 meters in ground water from buried subsurface coal

tar; persistence of the PAHs, naphthalene in particular, was partially attributed to anoxic conditions

(Madsen et al. 1993, 1996). Additionally, sediment-bound creosote components may be released over

time. In a laboratory study of creosote-contaminated sediment and natural lake water, Hyötyäinen and

Oikari (1999b) found that creosote-derived 4- to 6-ring PAHs released from the sediment during

incubation were toxic to water fleas (Daphnia magna) and to the photoluminescent bacteria Vibrio

fischeri.

In an investigation of the partitioning of PAHs from coal tar wastes at manufactured gas plant sites into

ground water, partitioning of the various fractions of the complex mixture was observed to be inversely

related to solubility, with the more soluble compounds partitioning to water more readily (Lee et al.

1992). Although coal tar is a complex mixture of compounds with varying physical and chemical

properties, data analyzed with regard to a partitioning model indicated that ideal behavior was observed

for the individual compounds and that the model was useful in estimating concentrations in ground water. 
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6. POTENTIAL FOR HUMAN EXPOSURE

In an investigation of the extent of creosote contamination at four wood-preservative plants with process

water surface impoundments, unspecified creosote components were found to have moved 20–60 feet

vertically from the impoundments to the water table and up to 500 feet horizontally from the sources (Ball

1987).

In a 50-day microcosm study of the aquifer materials of the Libby, Montana, Superfund site, 59% of

radiolabeled phenanthrene was bound to the soil, while only 2.2% was volatilized (Mohammed et al.

1998). 

In a terrestrial microcosm study, 2.7% of radiolabeled phenanthrene and 4.3% of radiolabeled

acenaphthene were found in soil samples taken in a 10-cm zone around creosote-treated posts, whereas

concentrations of the compounds that remained in the posts were 95 and 93.5% of the amounts applied,

respectively, after 2.5 months (Gile et al. 1982).

In an investigation of the release of creosote from treated wood into fresh water and sea water,

naphthalene, phenanthrene, acenaphthene, dibenzofuran, fluorene, and 2-methylnaphthalene were found

to be the major components that migrated into water (Ingram et al. 1982). The rate of migration was

found to increase significantly with increasing temperature within the range of 20–40 EC; slower

migration occurred from aged than from freshly treated pilings. In a microcosm study of the leaching of

PAHs from creosote-impregnated pilings into aquatic environments, the aqueous concentration of PAHs

increased with the number of pilings used (Bestari et al. 1998). These authors calculated a rate loss of

creosote from the wood pilings into the water of approximately 50 μg/cm2

/day (273 mg/piling/day). 

Creosote was observed to be removed from the water rapidly after 7 days, and was close to background

concentrations (0.8–6.7 μg/L) by 84 days; losses were attributed to photolysis and microbial degradation,

while sorption to sediment was not significant.

In an investigation of the volatilization of PAHs from creosote-treated wood, desorption of acenaphthene,

fluorene, phenanthrene, anthracene, and fluoranthene was directly related to concentration and was

greater at 30 EC than at 4 EC (Gevao and Jones 1998). The authors reported desorption half-lives of

0.7–31 years at 4 EC and 0.3–1 year at 30 EC for fluoranthene and acenaphthene, respectively. It is also

possible to have volatilization from surface soil to the atmosphere. Coal tar constituents have Henry’s

law constant ranging from 0.11 to 8.65x10-8 atm m3

/mole and vapor pressures of 1.2x10-8 to 95 mmHg

(Swann et al. 1983), indicating that some newly leached compounds may rapidly volatilize from both

moist and dry soil before binding to soil can occur.
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6. POTENTIAL FOR HUMAN EXPOSURE

Limited uptake of some creosote constituents has been detected in plants exposed to creosote-treated

wood in nearby soil. Only 0.04% of applied acenaphthene and 0.1% of phenanthrene partitioned to plant

tissue in one study (Gile et al. 1982). While systemic uptake may be minimal, such coal tar creosote

components as PAHs can adsorb to plant roots or surfaces. This seems a common way that vegetables or

other produce for human consumption can pick up trace amounts of creosote materials (Agency for Toxic

Substances and Disease Registry 1995).

Animals such as voles, crickets, snails, pill bugs, and worms have exhibited the capacity to assimilate

radiolabeled creosote components in terrestrial microcosm studies. Creosote components were found to

accumulate to the greatest extent in the vole, with bioconcentration factors (BCFs) of 12–31. The 14C

mass balance content of the animals was 1.2% of applied acenaphthene and 0.8% of applied phenanthrene

versus 4.3 and 2.7%, respectively, in soils (Gile et al. 1982). In addition, mussels taken from

creosote-treated pilings have been found to contain significantly more benzo[a]pyrene, a creosote

constituent, than those growing elsewhere (Dunn and Stich 1976). Accumulation of creosote-derived

PAHs has been reported in benthic organisms in Pensacola Bay (Elder and Dresler 1988; Rostad and

Pereira 1987). Fluoranthene, pyrene, benzo[a]pyrene, anthracene, chrysene, and phenanthrene were

detected in higher concentrations in tissues of snails (Thais haemastoma) and oysters (Crassostrea

virginica) taken from offshore sites near an onshore wood-treatment plant compared with those from

control sites. Experimental and estimated log Kow values for many of the main constituents of coal tar are

1.22–5.22 (HSDB 2000; Meylan and Howard 1995). Based on these values, BCFs of 5–5,500 have been

estimated and are consistent with reported experimental BCFs of 2–9,200 for fish and aquatic organisms,

indicating that bioaccumulation may be important in the fate of some components of coal tar (Kobayashi

et al. 1979; Linder et al. 1985).

6.3.2 Transformation and Degradation

6.3.2.1 Air

Little information was found in the available literature concerning the transformation of wood or coal tar

creosote components in the atmosphere. Some volatile coal tar constituents may undergo oxidation by

vapor phase reaction with photochemically produced hydroxyl radicals, with calculated half-lives of

2 hours to 10 days based on experimental and estimated rate constants of 1.12–103x1012 cm/moleculessecond at 25 EC and using an average atmospheric hydroxyl radical concentration of 5x105

 molecules/cm3

(Atkinson 1989; Meylan and Howard 1993). Rates may be slowed since some components will exist as
CREOSOTE 253

6. POTENTIAL FOR HUMAN EXPOSURE

particulate matter in the atmosphere (Eisenreich et al. 1981). Additionally, some components of coal tar

may undergo nighttime reactions with nitrate radicals (Atkinson et al. 1987). Based on an experimental

rate constant of 3.8x10-12 cm/molecules-second for phenol, and an atmospheric nitrate radical

concentration of 2x108

 molecules/cm3, a half-life of 15 minutes can be calculated for the compound

(Atkinson 1989).

Among the more volatile constituents of creosote are the cresols in its phenolic fraction. These materials

comprise only about 1% of the creosote by weight, but it is the cresol components that give creosote its

distinctive odor and its resin-like properties. The more generally recognized source categories related to

coal tar production or products containing creosote include coal tar distillation facilities or coke ovens,

but another source may come from chemical transformation in the air around urban centers (Grosjean

1991). 

The air of many urban areas shows appreciable levels of volatile organic compounds (VOCs) such as

toluene. A major source is often nonstationary sources such as automobiles since toluene is an octane

booster in nonleaded gasolines. Toluene can react with hydroxyl radicals to form the same types of

cresols found in the phenols portion of creosote. Although other reaction pathways can lead to the rapid

degradation of these cresols, appreciable transient build-ups of cresol vapors are possible. Degradation

products include a variety of nitrocresols, aliphatic carbonyls, and ketoacids. These degradation products

can become part of other atmospheric reactions in the air of typical urban areas. These transient cresol

concentrations could amount to 10–13% of the toluene levels. This cresol source is worth further study in

urban areas showing exceptionally high levels of VOCs in the ambient air (Grosjean 1991).

6.3.2.2 Water

Coal tar constituents present in surface waters may be degraded by direct and indirect photolysis. 

Estimated aqueous photolysis half-lives of 8.4, 71, and 21 hours have been reported for phenanthrene,

naphthalene and fluoranthene, respectively (Zepp and Schlotzhauer 1979). Other coal tar constituents

which may undergo aqueous photolysis are acenaphthalene, anthracene, benzene, quinoline, phenol,

cresol, and carbazide. In a microcosm study, PAHs leached from creosote-impregnated wood pilings

were degraded in aquatic environments by photolysis and microbial degradation, while sorption to

sediment was not significant (Bestari et al. 1998). Photolysis in water is not expected to be a major route

of the environmental fate of creosote constituents, particularly for the less soluble compounds. 
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6. POTENTIAL FOR HUMAN EXPOSURE

Coal tar creosote components are degraded in aquatic environments mainly by microfaunal metabolism

(Borthwick and Patrick 1982; Ingram et al. 1982). Microorganisms may act on the creosote-treated wood

itself or on creosote components that have leached from the treated wood. Quinoline, the major tar base

in creosote, has been reported to be degraded in surface water and ground water by bacteria of the genus

Pseudomonas (Bennett et al. 1985). Biotransformation of the phenolic components of creosote

apparently also occurs under anaerobic conditions in contaminated ground water (Ehrlich et al. 1983;

Goerlitz et al. 1985). Adaptation of soil microorganisms to PAH contaminants in ground water

originating from creosote treatment plant wastes has also been reported (Wilson et al. 1985).

Work on NPL sites has helped identify numerous bacteria and fungi that can biodegrade creosote

materials. In addition to Pseudomonas, bacteria in the genus Alcaligenes can degrade phenolic

compounds under aerobic conditions (Mueller et al. 1989). So long as the ground water is not completely

anoxic, numerous soil microorganisms can degrade creosote materials. Work at NPL sites suggests that

up to 90% of the creosote degradation is associated with biologically mediated processes. Although this

can lead to an appreciable reduction in the quantity of the creosote materials, it is the phenolic and lower

molecular weight (LMW) PAHs that are degraded while the HMW PAHs that have been shown to resist

biological attack may persist. In a study of biodegradation of creosote-contaminated ground water from

the American Creosote Superfund Site, Mueller et al. (1991) observed a toxic and teratogenic response of

inland silverside (Merida beryllina) embryos to the biotreated water at both 10 and 100% concentrations. 

They attributed the response to the cumulative effects of carcinogenic HMW PAHs that remained after

14 days of incubation. The higher levels of biodegradation observed for the LMW PAHs was attributed

to their greater aqueous solubility and consequent greater bioavailability.

Much less is known about biodegradation processes under more anoxic conditions, which would be

typical of ground water and vadose zone waters. Work on town-gas sites in Europe has demonstrated that

where nitrate levels are high, or where nitrate is supplied to ground water, various facultative bacteria can

degrade coal tar components using the nitrate or nitrite as an electron acceptor (Flyvbjerg et al. 1993). In

general, however, biodegradation under anoxic conditions appears to proceed very slowly. Even when

supplied with ample quantities of such electron acceptors as nitrates, half-lives in excess of 20 days were

observed in laboratory microcosms for the anoxic biodegradation of dimethylphenol components in

creosote, and cresol components showed little indication of significant disappearance unless the

experiments were continued in excess of 90 days (Arvin and Flyvbjerg 1992).
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6. POTENTIAL FOR HUMAN EXPOSURE

Creosote components have been detected in surface water samples taken near a wood-treatment facility

that ceased operation 30 years earlier (Black 1982). The creosote, which appeared to have permeated the

sandy surface soils down to an impervious clay layer, was entering the river via seepages and springs. 

Weathering processes produced only minor constitutive changes in the creosote with relative losses of the

lower molecular weight components. These changes probably reflected the greater volatility and

solubilities of the 2–3 carbon ring PAHs.

6.3.2.3 Sediment and Soil

Coal tar creosote components are slowly released from treated wood products by oil exudation, rainwater

leaching, and by volatilization of the lighter fractions (Henningsson 1983). USDA (1980) reported that

the major components of creosote were not detected in soil samples taken to a depth of 6 inches within

2–24 inches from treated poles, presumably as a result of biotransformation of mobilized components by

soil microorganisms. Creosote components released to soils in waste water effluents have been found to

be biotransformed by soil microbes under aerobic conditions (Middleton 1984). Bacteria of the genus

Pseudomonas isolated from a creosote-contaminated waste site have been reported to degrade

creosote-derived quinoline (Bennett et al. 1985). Acclimation to creosote phenolic constituents by soil

microorganisms has also been demonstrated (Smith et al. 1985).

Where the coal tar creosote is in well-oxygenated conditions, lignin degrading fungi like the white rot

fungus Phanerochaete sordida can remove much of the PAH fraction (Davis et al. 1993). This fungus

can also biodegrade PCP, which has often become mixed with the wastes found at creosote production or

disposal sites.

Many of the same bacteria and fungi capable of biodegrading creosote components in aqueous systems

can be found in soils. Especially where the creosote is close to the surface and under aerobic conditions,

the vast majority of the phenolics can be consumed in less than a year (von Burg and Stout 1992). The

majority of the lighter fractions of the PAH components (from 53 to 75% by weight) can be biodegraded

within 2 months (there was no significant depletion of heavier fractions with 5-ring or higher PAHs)

(Davis et al. 1993).

While biodegradation of PAHs in soil may be enhanced using bioremediation procedures, not all

techniques are equally effective at reducing toxicity. In a study of PAH-contaminated soil from the Reilly

Tar Superfund Site in St. Louis Park, Minnesota, although total EPA priority pollutant PAH
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6. POTENTIAL FOR HUMAN EXPOSURE

concentrations were decreased 48–74% following treatment with one of four bioremediation technologies,

following two of the four techniques, toxic (mutagenic) compounds were still present (Brooks et al.

1998). None of the four techniques tested was successful at removing the 5- and 6-ring HMW PAHs. 

However, persistence of the PAHs, naphthalene in particular, has been observed in seep sediments where

groundwater contaminated from buried subsurface coal tar emerged at the base of a hill; persistence of the

LMW PAH naphthalene was attributed mainly to anoxic conditions (Madsen et al. 1993, 1996). 

For sediments, much of the literature involves biologically oriented tests to identify hotspots with

pronounced degrees of toxicity to aquatic and marine species. For instance, bioassays using benthic

amphipods and highly creosote-contaminated sediments from Eagle Harbor in Washington's Puget Sound

showed several toxic hotspots with acute toxicity to the infaunal marine amphipod Rhepoxynius abronius

(Swartz et al. 1989). The authors suggest similar causal factors may underlie the common pattern of

hepatic lesions and neoplasms observed in English sole from Eagle Harbor. As with bioremediation,

natural attenuation of creosote-contaminated sediment may continue to present risks to aquatic organisms

as sediment-bound creosote constituents may be released over time. In a laboratory study using

contaminated sediment and natural lake water, Hyötyäinen and Oikari (1999b) found that creosotederived 4- to 6-ring PAHs released from the sediment during incubation were toxic to water fleas (D.

magna) and to the photoluminescent bacteria V. fischeri.

Work at coal tar creosote-contaminated sites on the Elizabeth River in Virginia, indicates a strong positive

correlation between exposure to the creosote-contaminated sediments and the incidence of hepatic

neoplasms on a resident forage fish, the mummichog (Fundulus heteroclitus) (Vogelbein et al. 1990). 

Similar cancer epizootics in fishes are found at other major harbor sites (e.g., the lower Hudson River,

Boston Harbor, and Los Angeles harbor) showing creosote or PAH-laden sediments. Such findings have

been proposed (Vogelbein et al. 1990) as indicators of serious toxic concerns in coastal and estuarine

environments that may have human health implications if bioaccumulation can be documented.

6.3.2.4 Other Media

Very little information was found in the available literature on the transformation or degradation of coal

tar creosote or wood creosote in animals or plants. Eisler (1987) found that many aquatic organisms are

able to rapidly metabolize and eliminate PAHs, the major constituents of the commercial mixture. 
CREOSOTE 257

6. POTENTIAL FOR HUMAN EXPOSURE

Transport and transformation of creosote in the environment may affect the coal tar creosote constituents

in treated wood. The USDA reported that the relative levels of 18 major creosote residues in treated

marine pilings did not change following 9.5 years of service; of the originally applied creosote, 93% was

retained on the wood (HSDB 2000). Both creosote and total PAHs decreased during the in-service

period. 

6.4 LEVELS MONITORED OR ESTIMATED IN THE ENVIRONMENT

Reliable evaluation of the potential for human exposure to creosote depends in part on the reliability of

supporting analytical data from environmental samples and biological specimens. In reviewing data on

creosote levels monitored in the environment, it should also be noted that the amount of chemical

identified analytically is not necessarily equivalent to the amount that is bioavailable.

6.4.1 Air

No information was found in the available literature regarding ambient atmospheric concentrations of

wood or coal tar creosote-derived components (i.e., PAHs) in the United States (HSDB 2000). 

Workplace air concentration data are discussed in Section 6.5. Data on ambient atmospheric

concentrations of PAHs derived from other sources can be found in the ATSDR Toxicological Profile for

Polycyclic Aromatic Hydrocarbons (Agency for Toxic Substances and Disease Registry 1995).

6.4.2 Water

No information was found in the available literature regarding ambient water concentrations of wood or

coal tar creosote-derived components (i.e., PAHs) in the United States (HSDB 2000). However, in a

microcosm study, Bestari et al. (1998) reported that measured background concentrations of 16 monitored

creosote-derived PAHs in the microcosm water ranged from nondetectable to 1.5 μg/L which was

comparable to background estimates for a variety of natural water sources.

Results from 2 years of groundwater sampling at an abandoned wood treatment facility in Conroe, Texas,

where coal tar creosote had been used for about 20 years, showed that monitoring wells were

contaminated with levels of up to 3,490 μg/L naphthalene, 1,263 μg/L methylnaphthalene, 425 μg/L

dibenzofuran, and 302 μg/L fluorene. The contaminants had apparently migrated through the clay and
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6. POTENTIAL FOR HUMAN EXPOSURE

sand soils on the site from three waste pits. A plume of groundwater contamination by organics at trace

levels was found to extend up to 300 feet from the waste pit locations (Bedient et al. 1984). 

At the Koppers Company, Inc. NPL site in Texarkana, Texas, where a creosote wood treatment facility

existed for 51 years prior to being converted to a residential area and an industrial site (sand and gravel

company), creosote-derived naphthalene, acenaphthene, fluorene, pyrene, and phenanthrene were

measured in ground water at levels ranging from nondetectable to 105

 ppb (Agency for Toxic Substances

and Disease Registry 1994). Surface water at the site had no detectable levels of the acid or base/neutral

compounds that were monitored.

6.4.3 Sediment and Soil

PAH contamination of soil has been found at the site of a wood-preservation facility that operated in

Slidell, Louisiana, from 1892 to 1970, when a fire destroyed the plant facilities. It is believed that

environmental releases of creosote occurred throughout the plant's operating history and as the result of

the 1970 fire, when creosote was released from storage tanks and flowed over the ground and into

adjacent water bodies. Waste creosote and debris have accumulated in eight areas at the site. The

deposits are up to 2 feet thick and have contaminated underlying soils (based on visual inspection) to as

much as 1 foot below the surface. PAH concentrations show a rapid decrease with increasing depth,

ranging from 15,680 mg/kg (ppm) at the surface to 1 mg/kg (ppm) within 9 feet. PAH concentrations as

high as 2,488 mg/kg also have been measured in the soils matrix of the shallow aquifer (Acharya and Ives

1994).

Several PAH constituents of creosote were detected in soil samples taken at an abandoned wood treatment

facility in Conroe, Texas, at depths of up to 25 feet. Maximum concentrations of the compounds were

detected in samples collected at the 0.7–1.8-foot depth. Maximum concentration levels were 3.7 mg/kg

for naphthalene, 3.4 mg/kg for methylnaphthalene, 3.8 mg/kg for dibenzofuran, 4.2 mg/kg for fluorene,

and 2.2 mg/kg for anthracene. An investigation of vertical variations in contaminant concentrations in the

soil zone above the water table revealed that, in general, >90% of the organics were removed within the

first 5 feet at the location studied. Organics can be degraded by microbes, adsorbed onto soil, or altered

by interactions with soil humus (Bedient et al. 1984).

At the Koppers Company, Inc. NPL site in Texarkana, Texas, where a creosote wood treatment facility

existed for 51 years prior to being converted to a residential area and an industrial site (sand and gravel
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6. POTENTIAL FOR HUMAN EXPOSURE

company), creosote-derived pyrene, fluoranthene, phenanthrene, and anthracene (base/neutral

compounds) were measured in surface and subsurface soils at levels ranging from nondetectable to

1,000 ppm (Agency for Toxic Substances and Disease Registry 1994). 

In sediment samples from a creek adjacent to the Koppers Company, Inc. NPL site, creosote-derived

base/neutral compounds were detected at concentrations up to 100 ppm; one creosote-derived base/neutral

compound was detected in downstream sediment at a maximum of 1 ppm (Agency for Toxic Substances

and Disease Registry 1994). Creosote-derived base/neutral compounds were also detected in the

sediment of the drainage ditch at the site, at levels ranging from 1–100 ppm. 

Coal tar creosote-derived phenanthrene, 1,2-benzanthracene, and benzo[a]pyrene have been detected in

river sediments at concentrations of up to 231, 62, and 16 mg/kg (wet basis), respectively, directly

downstream from the site of a former wood treatment facility. At 4,000 meters from the source, these

levels decreased to 0.35, 1.02, and 0.40 mg/kg (wet basis), respectively (Black 1982). Creosote-derived

PAHs were also detected in the sediments of Pensacola Bay and a drainage stream in the vicinity of a

former wood treatment facility near Pensacola, Florida. PAH concentrations ranged from 200 μg/g for

naphthalene to 140 mg/kg for anthracene in stream sediments; concentrations in Pensacola Bay ranged

from 75 μg/kg for benzanthracene to 190 μg/kg for fluoranthene (Elder and Dresler 1988).

PAH concentrations have been determined in sediment cores collected from the Arthur Kill, Hackensack

River, and Passaic River in northern New Jersey. These rivers are in industrialized areas near former

creosote wood-preserving facilities that operated through the 1960s and 1970s. Temporal distributions

were determined in each core based on the activities of the radionuclides 210Pb and 137Cs. Sediments at

depths corresponding to the years 1978 and 1964 contained total PAHs at concentrations of 1.71 mg/kg

(ppm) for 1978, and not detected to 35.7 mg/kg for 1964 (Huntley et al. 1993). In a study of Eagle

Harbor, an estuarine bay of the Puget Sound in which sediments were contaminated with creosote from a

wood treatment facility, total PAHs were detected at concentrations as high as 6,461 mg/kg (Swartz et al.

1989).

In the vertical profile of sediments in a seep area at the base of a hill where PAHs emerged after being

transported approximately 400 meters in ground water from a buried subsurface coal tar source,

naphthalene was detected at 2–45 ppm (Madsen et al. 1996).
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6. POTENTIAL FOR HUMAN EXPOSURE

6.4.4 Other Environmental Media

Since wood and coal tar creosotes are complex mixtures, techniques for relating apparent

bioaccumulation or biomagnification in food chains to human health concerns are not well defined. Fish

or shellfish directly exposed to coal tar creosote wastes will be tainted by offensive odors and tastes. 

Extracts of shellfish taken from the wharf of the biological station in St. Andrews and from

Passamaquoddy Bay (both in New Brunswick, Canada) indicated contamination with creosote oil (Zitko

1975). Concentrations of creosote oil found were as follows:

Shellfish Location

Concentration,

μg/g lipid

mussel Biological Station 1,046

periwinkle Biological Station

Passamaquoddy Bay

3,254

459

whelk Biological Station

Passamaquoddy Bay

354

202

clam Passamaquoddy Bay 459

The biological station's wharf had been periodically repaired using lumber treated with coal tar creosote;

no other sources of coal tar creosote in the vicinity of the Passamaquoddy Bay sampling site were known. 

The author suggested that the differences in creosote oil concentration in periwinkles and whelks

collected in the same localities may indicate that PAHs are not bioaccumulated. However, in an estuarine

environment near a Pensacola, Florida, creosote-contaminated wood-preservation facility site, a native

mollusc (T. haemstoma) and a nonnative mollusc (C. virginica) both exhibited bioaccumulation of

fluorene, pyrene, and phenanthrene at up to 10 times greater than observed in controls (Elder and Dresler

1988). 

Additionally, a study at a creosote spill near Lake Pontchartrain in Louisiana, provided some indications

that biomagnification through food chains leading to humans can take place. This study documented the

bioaccumulation of creosote-derived PAH fractions in the marsh clam Rungia cuneata (DeLeon et al.

1988). With total PAH levels in the ambient water #25 ppb, caged clams introduced to an area near a

major creosote spill showed tissue concentrations of benzopyrenes up to 600 ppb after 4 weeks of

exposure. This clam is a major food item for crustaceans such as the blue crab that are part of commercial

fisheries in the Lake Pontchartrain area. 
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6. POTENTIAL FOR HUMAN EXPOSURE

Creosote-treated wood such as marine pilings may be left in the environment for many years. The USDA

reported that residual creosote in marine pilings after 25, 40, and 59 years of service ranged from 280 to

380 kg/m3

 (HSDB 2000). 

6.5 GENERAL POPULATION AND OCCUPATIONAL EXPOSURE

Potential sources of non-occupational human exposure to creosote include contact with creosote-treated

wood products (e.g., railroad ties used for landscaping), incineration of creosote-treated scrap lumber, and

contact with contaminated environmental media at hazardous waste sites (e.g., ingestion of contaminated

ground water). At the Koppers Company, Inc. NPL site in Texarkana, Texas, where a creosote wood

treatment facility existed for 51 years prior to being converted to a residential area and an industrial site

(sand and gravel company), a study by the Texas Department of Health found an increased incidence of

skin rashes in residents who had dermal contact with soil at the site (Agency for Toxic Substances and

Disease Registry 1994).

Risk of exposure to creosote constituents through contact with contaminated ground water will vary with

the individual chemicals involved as well as with the mix of chemicals present at any one time and the

environmental conditions. Physical and chemical properties of the compounds, including solubility and

molecular weight, will affect distance which a contaminant plume may travel from the source, as well as

its susceptibility to biodegradation or sorption (King and Barker 1999). The environment in which

contamination occurs is also of importance since natural attenuation of chemical compounds may be

dependent on whether oxidizing or reducing conditions are present. In an investigation of natural attenuation of contaminant plumes from an emplaced coal tar creosote source, King et al. (1999) observed

greater and more rapid decreases in plume mass for some compounds, such as phenol, m-xylene, and

carbazole, while the dibenzofuran plume mass and extent remained relatively constant, and the plume

mass and travel distance from the source for naphthalene and 1-methylnaphthalene increased throughout

the 4-year study. Therefore, potential for exposure to creosote constituents present in ground water will

differ from location to location and over time. 

Direct exposure of homeowners to wood treatment products containing creosote should be limited, since

EPA has restricted the sale and use of such products to certified applicators. Industrial sources have noted

that there have been no reports or instances of health effects allegations in the last 20 years (ending in

1996), except for rare reports of skin irritation resulting from public contact with creosote-treated wood.
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6. POTENTIAL FOR HUMAN EXPOSURE

Another potential source of nonoccupational exposure is the therapeutic use of coal tar shampoos for antidandruff therapy, coal tar ointments for treatment of eczematous dermatitis, and mineral coal tar for the

treatment of psoriasis. Adsorption of PAHs may occur through the skin, lungs, and gastrointestinal tract

(Strickland et al. 1996). van Schooten et al. (1994) measured the urinary excretion of a specific PAH

metabolite, 1-hydroxypyrene, to assess the internal dose of PAH after acute dermal application of coal tar

shampoo. The shampoo selected for the experiment had a PAH concentration of 2,840 mg/kg, including

pyrene (285 mg/kg) and benzopyrene (56 mg/kg). In other brands, the concentrations were at least

100 times lower. A single use of the coal tar shampoo resulted in increased 1-hydroxypyrene excretion in

all participants. The mean increase of totally excreted 1-hydroxypyrene on day 1 was 10 times the preexperiment background values. On day 2, the mean increase was 5 times. Interindividual variation was

considerable, with a variation in the first day increase of between 3 and 20 times. The 1-hydroxypyrene

values observed in coke oven workers are similar to the values obtained on day 1 after a single treatment

with coal tar shampoo (0.4–8.3 μmol/mol creatinine) (van Schooten et al. 1994). However, exposure

levels determined using the 1-hydroxypyrene biomarker may be affected by the time of measurement

following exposure (Viau and Vyskocil 1995). Viau and Vyskocil observed maximum excretions of

1-hydroxypyrene in urine a few hours after exposure to pyrene in a coal tar-based shampoo or following

dermal contact with either creosote or pyrene. 

Occupational exposure to PAHs and other constituents of creosote may occur in several industries where

workers are exposed to coal tar creosote, coal tar, coal tar pitch volatiles, or products containing creosote. 

Such occupations include jobs in the wood preserving industry, railroad work (installation and removal of

crossties), treated lumber installation work involving structures such as fences or bridges, electric utility

work involving treated poles, coke oven work, jobs in the rubber industry or tire plants, road paving

work, roofing work, chimney cleaning, aluminum smelting work, iron foundry work, steel plant work,

and site remediation work involving creosote-contaminated environmental media.

Individuals working in the wood-preserving industry comprise the largest portion of the population

potentially exposed to coal tar creosote. Workers employed at creosote pressure-treatment facilities may

be exposed by direct dermal contact or by inhalation of volatilized components. Potential exposure to

coal tar creosote in these plants is minimized by the use of closed systems for receiving, transferring,

mixing, storing, and applying the mixture to wood products. Similarly, dermal exposure from the

handling of freshly treated wood is minimized by the use of highly mechanized processes. Exposure via

inhalation, however, is more likely to occur. For example, worker exposure may be significant during

opening of treatment cylinder doors and cylinder cleaning operations (EPA 1981b). Inhalation and
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6. POTENTIAL FOR HUMAN EXPOSURE

A Special Review of a currently registered pesticide may be initiated by EPA when validated data indicate that

certain types of toxicity (e.g., carcinogenicity, developmental toxicity, acute effects) exist for humans or for

non-target plant or animal species. A formal process exists for notifying registrants and other interested parties,

requesting further data regarding the pesticide in question, analyzing and reporting risks and benefits, and

requesting public review. The final regulatory decision may be implemented over a period of time or it may be

imposed immediately as an emergency action based solely on the EPA's finding of immediate danger to human

health or the environment.

dermal exposure are also more likely in plants using nonpressure treatment methods such as thermal and

dip treatments in open tanks. An estimated 100 workers were involved in commercial thermal and dip

treatment operations in the late 1970s. Some of these workers experienced consistently high inhalation

exposures (USDA 1980). Other historical nonpressure treatment exposures included an estimated

50,000 individuals (e.g., homeowners, farmers, landscapers) who applied creosote in noncommercial

brush, dip, spray, and soak treatments (EPA 1981a). Dermal contact and inhalation may have resulted in

exposure to high concentrations of creosote components for these individuals, but the exposures were

usually of intermittent frequency (USDA 1980). However, designation of creosote products as restricted

use pesticides by EPA in 1986 has probably decreased the number of individuals potentially exposed in

these nonpressure wood treatment applications (EPA 1986b).

In 1996, there were 25,000 workers employed in 75–100 domestic wood treatment plants using coal tar

creosote. As a result of the use of engineering controls and personal protective equipment (e.g.,

respiratory protection and impervious gloves) required in the 1986 settlement of the EPA Special Review

process,1

 airborne exposures to creosote components in the workplace are generally below the OSHA

permissible exposure limit (PEL) of 0.2 mg benzene soluble particulates per m3

 air (Rivers 1990).

However, prior to the consistent use of these controls by industry, workers were potentially exposed to

higher airborne concentrations of creosote constituents. For example, the concentrations of creosote (i.e.,

coal tar pitch volatiles) components in 3- to 8-hour personal air samples, taken over a 2-day period at a

railroad tie treatment facility in Somerville, Texas, were found to range from 0.003 to 1.211 mg/m3

(NIOSH 1980b). Another industrial hygiene survey of worker exposure to creosote at a wood-treatment

facility in Tacoma, Washington, showed coal tar pitch volatiles in personal air samples ranging from

<0.0004 to 0.112 mg/m3

 (NIOSH 1981b). The higher concentrations were found at the end of the

treatment process when the cylinder was opened. NIOSH investigated creosote exposure among dock

builders in Brooklyn, New York, in 1980. Employees were reported to have substantial direct skin

contact with creosote. Breathing zone concentrations of the cyclohexane extractable fraction of the coal

tar pitch volatiles ranged from 0 to 0.059 mg/m3

 of air (NIOSH 1981a). Comprehensive studies of worker
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6. POTENTIAL FOR HUMAN EXPOSURE

exposure to creosote in wood treatment plants have been conducted by Koppers Company, alone and in

conjunction with NIOSH (Markel et al. 1977; SRI 1993). Data from these studies indicated that, on the

average, employee exposure to particulate polycyclic organic materials (PPOM) was within the

permissible level of 0.2 mg/m3

 recommended by NIOSH for coal tar pitch volatiles. The only

components that could be reliably measured in the vapor-phase fractions collected were naphthalene,

methylnaphthalene, and acenaphthene. The concentrations of these chemicals ranged from 0.54 to

2.0 mg/m3

. Fluorene and phenanthrene-anthracene were detected in trace quantities, but were not

quantifiable. Benzene-soluble particulates (PPOM) ranged from 0.02 to 0.10 mg/m3. The World Health

Organization reported that air concentrations of creosote-derived PAHs were 0.05–650 μg/m3

 at a wood

treatment plant where railway sleepers were treated with creosote; the main creosote constituents detected

were naphthalene, fluorene, and phenanthrene (HSDB 2000). At a second plant, where a coal tar solution

was used to treat railway sleepers and telephone poles, PAHs were detected in the air at 0.004–11 mg/m3

(HSDB 2000). 

A gravimetric analytical method has been used in most of these workplace monitoring studies. This

method involves the collection of airborne particulates on glass fiber filters and subsequent extraction by

solvents, such as benzene or cyclohexane. The extracted fraction of the particulate matter is determined

by weighing. As a result of two significant shortcomings of this method, the inability to identify

constituents of the airborne particulates and to sample vapor phase components, EPA (1981a) concluded

that definitive information was not available on the identity of airborne components of creosote in

workplace atmospheres. EPA (1981a) also stated that quantitative estimates of dermal exposures were

not available for treatment plant workers. Quantitative inhalation or dermal exposure data for workers

applying creosote in nonpressure treatment scenarios and for downstream workers who install, handle, or

contact treated wood products were also unavailable. An industrial hygiene survey of wood treatment

facilities conducted in Finland revealed that vapor phase components were an important source of worker

exposure. Vapors were collected on XAD-2 resin (recovery 82–102%) and analyzed by gas

chromatography (GC). PAHs were collected on glass fiber filters and analyzed with high-pressure liquid

chromatography (HPLC) using a fluorescence detector. Most of the airborne contaminants in worker

breathing zones were in the vapor phase, with naphthalene the main component, averaging 52% of the

total concentration; the proportion of particulate PAHs to total concentration of vapors was <0.5–3.7%. 

The major components in the vapors have acute toxicity potential but are not as tumorigenic or mutagenic

as the less volatile PAHs (Heikkilä et al. 1987). A recent study by Becker et al. (1999) demonstrated the

feasibility of quantifying thiaarenes (sulfur-containing polycyclic aromatic hydrocarbons). Using GC
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6. POTENTIAL FOR HUMAN EXPOSURE

with atomic emission detection, these authors measured thiaarene concentrations of 0.4–19.0 μg/m3 in the

personal air space of workers at an aluminum reduction plant who were exposed to coal tar pitch volatiles.

Exposure to coal tar creosote may also occur during installation of treated poles, during inspection and

maintenance operations, and through casual contact (USDA 1980). One of the major end point uses of

creosote is treatment of railroad cross ties. Since cross ties are installed mechanically by railroad

companies, workers generally have minimal dermal exposure in this process. Exposure via inhalation,

however, is considered to be moderate and consistent during this type of installation procedure. In other

situations, cross ties may be installed manually, in which case, there is consistent moderate to high

exposure via skin contact as well as by inhalation. The amount of exposure via skin contact ranges from

low to high depending on whether workers wear protective clothing. Skin contact is considered minimal

for railroad personnel who inspect ties in use, as well as for the general public who may have casual

contact with creosote-treated cross ties. In instances where crossties are used for landscaping purposes,

contractors involved in the sale and installation of freshly treated ties experience consistent moderate

inhalation exposure and minimal to occasionally high dermal exposure.

Installation of treated lumber and timbers in structures such as bridges, piers, retaining walls, fences, and

barns involves a significant amount of manual contact. Likewise, the installation of switch ties, cross

planks, crossarms, block flooring, and fence posts is usually done manually. In these situations, human

exposure via inhalation is considered moderate while exposure via skin contact may vary from minimal to

high depending on the type of protective equipment used (USDA 1980).

Exposure of individuals installing treated fence posts, lumber, and timbers via inhalation of creosote

volatiles (e.g., acenaphthene and naphthalene) can also occur when freshly treated materials are handled

under calm, hot, sunny conditions (USDA 1980). Exposure may be even greater during warmer months

when ambient temperatures are higher. Acenaphthene, fluorene, phenanthrene, anthracene, and

fluoranthene were observed to undergo more volatilization from creosote-treated wood at 30 EC than at

4 EC (Gevao and Jones 1998).

The risk of direct dermal contact is particularly high for workers installing treated poles. Activities such

as attaching fittings often preclude the use of protective gloves, and as a result of creosote bleeding from

the treated poles, the potential for dermal contact of workers performing maintenance operations persists

for years after installation (Henningsson 1983).
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6. POTENTIAL FOR HUMAN EXPOSURE

Individuals employed in industries that manufacture and process creosote or products containing creosote

may be exposed to the highest concentrations of this compound. The National Occupational Exposure

Survey (NOES), conducted by NIOSH from 1981 to 1983, estimated that 241 workers employed at

3 facilities were potentially exposed to creosote in the United States (NOES 1990). The NOES database

does not contain information on the frequency, concentration, or duration of exposure; the survey

provides only estimates of workers potentially exposed to chemicals in the workplace. 

Rubber processing workers at a tire plant in Poland who were occupationally exposed to coal tar pitch

volatiles were found to have been exposed to excessive (>0.2 mg/m3

) levels of PAHs, including

benzo[a]pyrene (Rogaczewska and Ligocka 1994). Measurements of benzo[a]pyrene were generally in

the range of <4–142 ng/m3

, but were as high as 3,470–6,060 ng/m3 for workers who weighed the raw

materials. 

In an investigation of the effect of decreased dermal exposure to creosote on the internal dose of PAHs in

workers at a creosote wood impregnation plant, the use of Tyvek coveralls worn beneath outer workclothes decreased the internal dose of pyrene (Van Rooij et al. 1993b). Workers not wearing the overalls

had total pyrene skin contamination of 47–1,510 μg/day and had urinary levels of 1-hydroxypyrene of

6.6 μg. For dermally protected workers, dermal pyrene contamination was approximately 35% less than

that of the unprotected workers and urinary levels of 1-hydroxypyrene were 3.2 μg. The low level of

efficacy was attributed to uncovered skin areas (face, wrists, ankles). Volatile pyrene in the breathingzone air was measured at 0.3–3.0 μg/m3

. The authors determined that for creosote workers, the level of

dermal exposure to PAHs is the main determinant of the internal exposure dose; 15 times more pyrene

was absorbed through dermal uptake than through respiratory uptake. Data from earlier studies indicate

that the daily skin contamination with pyrene was higher for creosote workers (median of 350 μg)

compared with that measured for coke oven workers (70 μg) and road pavers (117 μg); for aluminum

workers, a pyrene level of 395 μg was measured (Van Rooij et al. 1993b).

Previously, the only information on biological indicators of exposure to coal tar found in the available

literature involved a study of 1-hydroxypyrene in the urine of a creosote wood-treatment plant worker

(Jongeneelen et al. 1985). The pyrene metabolite, 1-hydroxypyrene, is now more commonly used as a

biological indicator to assess total PAH exposure in several industries as well as for nonoccupational uses

of coal-tar based products (Malkin et al. 1996; Strickland et al. 1996). Elovaara et al. (1995) studied

inhalation and dermal exposure to naphthalene and 10 large PAHs in creosote impregnation plant

workers. Air concentrations of the compounds were measured and compared with measurements of
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6. POTENTIAL FOR HUMAN EXPOSURE

urinary 1-hydroxypyrene. Urinary concentrations, due to high dermal exposures were high

(16–120 μmol/mol creatine) even in the morning, were lower in postshift measurements (19–85 μmol/mol

creatine) and then were highest in the evening (27–122 μmol/mol creatine), indicating that time of

sampling is important. The authors concluded that the biomarker was useful in determining exposure to

3- to 6-ring PAHs, but not to naphthalene volatiles.

Jongeneelen (1992) related urinary concentrations of 1-hydroxypyrene for coke oven workers exposed to

fumes containing PAHs to measured levels of coal tar pitch volatiles in order to equate the biological

indicator data with lung cancer relative risk levels determined using epidemiological data obtained from

U.S. and European coke plants. A urinary concentration of 2.3 μmol/mol creatine was equated with the

threshold limit value (TLV) (ACGIH) of 0.2 mg/m3

 for coal tar pitch volatiles, and consequently with the

relative risk for lung cancer of approximately 1.3 for a group of exposed workers. Although an empirical

relationship between the biomarker 1-hydroxypyrene and relative cancer risk in an exposed group may be

determined, because creosote constituents vary from source to source, and because the carcinogenic PAH

fraction and the routes of exposure will also vary, the health risks related to exposure to coal tar creosote

versus coal tar pitch volatiles versus coal tar will differ between exposed groups such as creosote and

coke oven workers (Viau et al. 1995). Viau et al. (1995) did conclude, however, that PAHs from

background environmental contamination and from smoking could be excluded from consideration of

urinary excretion of 1-hydroxypyrene within a certain group of workers.

Coal-handling workers at a coke oven who were exposed to coal-tar sludge (67% coal tar) through dermal

contact had increased urinary 1-hydroxypyrene concentrations following work shifts (Malkin et al. 1996). 

Urinary concentrations of the biomarker increased from a preshift mean of 1.00 μmol/mol creatine to a

postshift level of 1.7 μmol/mol creatine. The increases were attributed to dermal exposure, as exposure to

volatile pyrene was determined to be minimal.

A review paper of studies using the concentration in urine of 1-hydroxypyrene as a biomarker of PAH

exposure included levels reported in various studies (Strickland et al. 1996). The respective pre- and

postshift urinary excretion levels of 1-hydroxypyrene for coke oven workers were 0.89 and

2.47 μmol/mol creatine; for asphalt pavers, respective levels were 1.35 and 1.76 μmol/mol creatine.

Other biomarkers used to determine exposure to the creosote include urinary concentrations of

1-naphthol, 2-naphthol, and 1-pyrenol. Naphthalene is the main volatile present in creosote vapors. For

workers exposed to creosote volatiles during tar distillation, Bieniek (1997) measured volatile
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6. POTENTIAL FOR HUMAN EXPOSURE

concentrations of 0.77 mg/m3 for naphthalene, 0.016 mg/m3 for 1-naphthol, and 0.012 mg/m3 for

2-naphthol; corresponding urinary concentrations of 693.1 and 264.4 μmol/mol creatine were measured

for 1- and 2-naphthol, respectively. 

For workers exposed to creosote by chiseling coal tar pitch layer or by handling creosote-impregnated

wood, exposure to total PAHs and 4- to 6-ring PAHs was 50 times higher for the worker exposed to the

coal tar pitch layer while exposure to volatile naphthalene was >6 times higher for the wood handlers

(Heikkilä et al. 1995). Total PAHs and 4- to 6-ring PAHs were measured at 440 and 290 μg/m3

,

respectively, in the work area of the chiseler. Urinary concentrations of 1-pyrenol were 2–4 times higher

for the chiseler compared with the wood handlers. Volatile naphthalene was measured at 1,000 μg/m3

 in

the work area of the wood handlers and 160 μg/m3

 in the work area of the chiseler. Urinary

concentrations of 1-naphthol were 15–20 times higher for the wood handlers as compared with the

chiseler.

Workers in a creosote railroad tie impregnation plant exposed to 1.5 mg/m3

 naphthalene, 5.9 μg/m3

particulate PAH, and 1.4 μg/m3 4- to 6-ring PAHs were measured for the urinary biomarker 1-naphthol

(Heikkilä et al. 1997). Postshift urinary concentrations were a mean of 20.5 μmol/L; urinary

concentrations in occupationally nonexposed male smokers were below the detection limit of

0.07 μmol/L. The authors concluded that 1-naphthol was a good biomarker for determining exposure to

volatile naphthalene from creosote, but was not a good indicator of inhalation or dermal exposure to

PAHs from creosote. 

Polycyclic aromatic hydrocarbons are capable of forming adducts with DNA in cells. Exposure to PAHs

from creosote were measured in the personal work areas of coke oven workers in the Czech Republic

(Lewtas et al. 1997). Measured levels of DNA adducts in white blood cells of a nonoccupationally

exposed population were well correlated with the low to moderate environmental exposures. The DNA

adducts of the coke oven workers who were exposed to carcinogenic PAHs at levels of

<5–>200,000 ng/m3

 (<0.005–>200 μg/m3) did not correlate well with the exposure levels. These authors

concluded that various mechanisms were responsible for the lower DNA-binding potency at the higher

exposure levels, precluding the use of a linear model for dose-response extrapolation in risk assessment.
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6. POTENTIAL FOR HUMAN EXPOSURE

6.6 EXPOSURES OF CHILDREN

This section focuses on exposures from conception to maturity at 18 years in humans. Differences from

adults in susceptibility to hazardous substances are discussed in 3.7 Children’s Susceptibility.

Children are not small adults. A child’s exposure may differ from an adult’s exposure in many ways. 

Children drink more fluids, eat more food, breathe more air per kilogram of body weight, and have a

larger skin surface in proportion to their body volume. A child’s diet often differs from that of adults. 

The developing human’s source of nutrition changes with age: from placental nourishment to breast milk

or formula to the diet of older children who eat more of certain types of foods than adults. A child’s

behavior and lifestyle also influence exposure. Children crawl on the floor, put things in their mouths,

sometimes eat inappropriate things (such as dirt or paint chips), and spend more time outdoors. Children

also are closer to the ground, and they do not use the judgment of adults to avoid hazards (NRC 1993).

Children are exposed to creosote via the same routes that adults are, including inhalation of contaminated

air, ingestion of ground water used as a source of drinking water, and dermal contact with contaminated

soil or products treated with coal tar creosote. Additionally, small children are more likely than adults to

be in close contact with yard dirt or playground dirt, lawns, and indoor (carpet) dust. Creosote residues

bound to soil or dust particles in carpets or on bare floors may present an exposure route for infants and

toddlers through dermal contact and oral ingestion. Children are known to participate in frequent handto-mouth activity and to have a tendency to put foreign objects into their mouths. As a result of this

behavior, children may ingest creosote present in soil and dust or through direct transfer of the chemical

from their skin to their mouths. Children are lower to the ground than adults and something which may

exist at arm or hand level for an adult may be at mouth level for a child. Because of behavior such as

putting their mouths on objects or chewing on objects, children may be exposed to coal tar creosote

through oral ingestion of the chemical through chewing on treated wood, such as fences, bridge, or pier

railings. Adsorption of PAHs may occur through the skin, lungs, and gastrointestinal tract. However,

exposure to certain levels of creosote constituents does not mean that the compounds will be bioavailable

at those levels. No U.S. data were found on exposure or body burden measurements made on children. 

Coal tar creosote is widely used for the preservation and water-proofing of wood which is used for utility

poles, railroad ties, log homes, fence posts, barns, bridges, piers, and marine pilings. Creosote is also

used in roofing and road paving; is used and/or produced in coke oven operations, and in the aluminum,

iron, and steel industries; and is used therapeutically in coal-tar based shampoos, as a treatment for
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6. POTENTIAL FOR HUMAN EXPOSURE

psoriasis and eczema, and as a treatment for intestinal ailments. Prior to its designation as a Restricted

Use Pesticide in 1986, it was available for home and farm use. 

Children are likely to play in or near areas where adults would be less likely to venture, such as areas with

no trespassing signs, in creeks, on the ground, in the dirt, in ditches near where utility poles are present,

and on or near railroad tracks. Additionally, children are likely to collect and bring home found pieces of

wood for use in building clubhouses or treehouses. Because coal tar creosote is used to preserve utility

poles and railroad ties, playing near utility (telephone or electrical) poles and near or on railroad tracks

may pose a risk of exposure to children. Children are subject to inhalation exposure, which may be of

increased risk during warmer months when volatilization of PAHs may be higher. Gevao and Jones

(1998) observed greater volatilization of acenaphthene, fluorene, phenanthrene, anthracene, and

fluoranthene from creosote-treated wood at 30 EC than at 4 EC. However, if the creosote constituents

have leached downward from the treated wood and are present in the soil surrounding the utility poles or

railroad tracks, volatilization from the soil surface is not as likely, as the majority of the coal tar creosote

would be bound to the soil particles. In that case, and in the case of direct contact with treated poles or

railroad ties, children are more likely to be exposed dermally and through oral ingestion which may occur

when they put unwashed hands in their mouths. No U.S. data were found documenting significant

exposure to children through such means as ingested soil or dust particles. 

Children may be exposed to coal tar creosote when playing near abandoned hazardous waste sites or if

their parents are occupationally exposed to creosote-contaminated soil through involvement with site

remediation or clean-up procedures and bring soil-bound contamination into the home on work clothes or

footwear, despite preventative procedures which may be in place at the work site. Creosote constituents

have been measured in the surface soil at levels as high as 15,680 ppm (PAHs) at the site of an old wood

preservation facility in Slidell, Louisiana, that was destroyed by fire (Acharya and Ives 1994). At an

abandoned wood treatment facility in Conroe, Texas, PAH constituents of creosote have been detected in

the 0.7- to 1.8-foot soil depth at maximum concentrations of 3.7 ppm for naphthalene, 3.4 ppm for

methylnaphthalene, 3.8 ppm for dibenzofuran, 4.2 ppm for fluorene, and 2.2 ppm for anthracene

(Bendient et al. 1984). At the Koppers Company, Inc. NPL site in Texarkana, Texas, where a creosote

wood treatment facility existed for 51 years prior to being converted to a residential area and an industrial

site (sand and gravel company), creosote-derived pyrene, fluoranthene, phenanthrene, and anthracene

(base/neutral compounds) were measured in surface and subsurface soils at levels ranging from

nondetectable to 1,000 ppm (Agency for Toxic Substances and Disease Registry 1994). 
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6. POTENTIAL FOR HUMAN EXPOSURE

Although biodegradation of creosote in soil, on treated wood, in waste water effluent, and in aquatic

environments has been observed, the process may only serve to reduce the total amount of creosote

present. While the phenolic and LMW PAHs are degraded, the HMW PAHs that have been shown to

resist biological attack may persist. Thus, it is possible that children exposed to the creosote constituents

remaining in soil or other media following some biodegradation may be exposed to the more toxic

components of creosote. However, the presence of creosote components in soil does not mean that the

soil-bound compounds will be bioavailable if ingested. In a study of PAHs and their metabolites in the

blood, feces, and urine of rats, the authors observed that rats that were orally exposed to contaminated

soils showed significantly higher excretion of unchanged 1-OH-pyrene and benzo[a]pyrene in feces, and

significantly lower excretion of 1-OH pyrene in both feces and urine, than did rats that were dosed with

the pure compounds, indicating that the ingested soil-bound compounds were less available in the body

for metabolism (van Schooten et al. 1997). Similar results were observed in a study of mice that ingested

soil-bound coal tar (Koganti et al. 1998). In that study, the bioavailability of PAHs from soil-bound coal

tar was estimated to be 9–75% less (based on 1-OH-pyrene excreted in urine) than that observed in mice

dosed with an organic extract of the soil; estimates of PAH bioavailability based on chemical-DNA

adduct formation ranged from nondetectable to 76%. Other authors have observed differences in

bioavailability of soil-bound creosote constituents between types of soil. Goon et al. (1991) observed

higher oral bioavailability of soil-bound benzo[a]pyrene with sand soil versus clay soil. The clay fraction

of soil is more chemically and physically reactive than the sand fraction, allowing for greater adsorption. 

In the same study, the authors also observed, however, that the oral bioavailability of the compounds in

soil remained at a similar level for the first 30 days following contamination, but decreased by 6 months

following the initial contamination.

Children may be exposed to creosote constituents brought into the home by parents or other household

members who are occupationally exposed. Creosote residues may be present on clothing items and shoes

of workers employed in industries where creosote-derived products are used or produced, and utility

company workers who are in contact with treated wood. Exposure to children may occur through dermal

contact with contaminated items. Because children are likely to be in close contact with carpet or floors,

transfer of contaminated dirt from work shoes to carpeting provides a means of exposure. Respiratory

exposure from contact with occupationally exposed workers is not likely to be significant. 

A potential source of exposure in infants is the presence of creosote constituents in breast milk. The

hydrocarbons found in coal tar creosote are lipophilic substances and, as such, may potentially be found

in breast milk, although this has not been assessed. No data were found in the available literature on the
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6. POTENTIAL FOR HUMAN EXPOSURE

presence of creosote constituents in breast milk. It has been determined that creosote-derived PAHs may

cross the placenta (Agency for Toxic Substances and Disease Registry 1993a). For more information on

the health effects of PAHs, the reader is referred to the ATSDR Toxicological Profile for Polycyclic

Aromatic Hydrocarbons (Agency for Toxic Substances and Disease Registry 1995).

Data were not available in the literature on the weight-adjusted intake of creosote by children. In one

documented case, creosote fumes caused methemoglobinemia in an infant, leading to temporary hypoxia

and cyanosis (Dean et al. 1992).

Data were not available in the literature on the dietary exposure of creosote to children. Based on the

bioaccumulation of creosote constituents in fish and other aquatic organisms, and the potential for uptake

or contamination in plant food sources, dietary exposure is theoretically possible, but is unlikely to be

significant. An exception to this may be in residential areas such as that built on the old Koppers

Company, Inc. site. Homegrown produce grown in contaminated soils may provide a significant source

of exposure to children. The drinking of chaparral tea may result in oral exposure to wood creosote. 

Case reports of people who have drunk chapparal tea indicate kidney damage as a likely outcome

(Gordon et al. 1995).

6.7 POPULATIONS WITH POTENTIALLY HIGH EXPOSURES

Individuals living in the vicinity of hazardous waste sites and abandoned wood-treatment plants

contaminated with coal tar creosote may experience higher levels of exposure than the rest of the general

population. These environmental exposures generally are at a lower dose but of longer duration than the

occupational exposures.

Individuals who apply coal tar creosote directly to wood, including farmers, carpenters, and homeowners

who come in contact with creosote-treated wood products, are believed to be exposed to the highest levels

of creosote components via inhalation and dermal contact. It has been estimated that historically about

4,000 workers may have been routinely exposed and up to 50,000 people may have been intermittently

exposed to coal tar creosote through its application as a preservative to wood products (USDA 1980). 

The size of this population may have decreased since EPA restricted the use of creosote to certified

applicators.
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6. POTENTIAL FOR HUMAN EXPOSURE

Other individuals who are potentially exposed to coal tar creosote, coal tar, coal tar pitch volatiles, or

products containing creosote include coke oven workers, rubber industry or tire plant workers, road

paving workers, roofers, chimney cleaners, aluminum smelting workers, iron foundry workers, steel plant

workers, and site remediation workers who are involved with creosote-contaminated soils or water. 

Whether from bioaccumulation or from direct exposure, fish and shellfish may accumulate creosote

constituents at concentrations high enough to prompt public health officials to issue consumption

advisories. As of September 1994, creosote was involved in the two fish consumption advisories listed

below (EPA 1995):
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6. POTENTIAL FOR HUMAN EXPOSURE

State Waterbody Geographic Extent

Louisiana Bayou Bonfouca 7 miles

Oregon Willamette River 1,000 foot radius from McCormack and

Baxter wood treatment site

6.8 ADEQUACY OF THE DATABASE

Section 104(I)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the

Administrator of EPA and agencies and programs of the Public Health Service) to assess whether

adequate information on the health effects of creosote is available. Where adequate information is not

available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the

initiation of a program of research designed to determine the health effects (and techniques for developing

methods to determine such health effects) of creosote.

The following categories of possible data needs have been identified by a joint team of scientists from

ATSDR, NTP, and EPA. They are defined as substance-specific informational needs that if met would

reduce the uncertainties of human health assessment. This definition should not be interpreted to mean

that all data needs discussed in this section must be filled. In the future, the identified data needs will be

evaluated and prioritized, and a substance-specific research agenda will be proposed. 

6.8.1 Identification of Data Needs

Physical and Chemical Properties. Limited physical property data, such as boiling point and

density (see Table 4-2), are available for the coal tar creosote mixture. Additional physical and chemical

property data, such as water solubility, vapor pressure, Koc, and Henry's law constant values would be

useful in order to predict the partitioning and transformation of coal tar creosote components in air, water,

and soil. These values are currently not available because their determination is complicated by the fact

that creosote is a mixture of variable composition. However, data on vapor pressure, water solubility,

etc., are available for individual components of creosote, and these can be used to estimate the behavior of

creosote. 
CREOSOTE 275

6. POTENTIAL FOR HUMAN EXPOSURE

Production, Import/Export, Use, Release, and Disposal. Manufacturing methods are well

described in the literature. Production figures are limited because of the confidential nature of this

business information. Uses of creosote, both coal tar and beechwood, are well described. Since the use

of coal tar creosote as a wood preservative has been restricted, the potential of the population to be

exposed is greatly diminished. The major releases of creosote resulting from treatment processes at

wood-preserving plants are known, but the levels are not well quantified. Current production, release,

and disposal information would assist in identifying the levels of creosote present in the environment and,

thus, populations potentially exposed as a result of these processes. Creosote sludge from production

processes can be treated and disposed on-site with proper groundwater monitoring. Creosote can no

longer be disposed in hazardous waste landfills unless treated to EPA specified standards. Creosotetreated wood used in industrial applications can be burned in an industrial incinerator or boiler; however,

treated wood used in domestic or farm applications should be buried rather than incinerated.

According to the Emergency Planning and Community Right-to-Know Act of 1986, 42 U.S.C. 

Section 11023, industries are required to submit substance release and off-site transfer information to the

EPA. The TRI, which contains this information for 1999, became available in 2001. This database will

be updated yearly and should provide a list of industrial production facilities and emissions.

Environmental Fate. The limited information available regarding transport and partitioning of

creosote components among environmental compartments indicates mobility of water soluble PAHs,

phenol, and heterocyclic constituents of the mixture in water; sorption of PAH components in soils; and

bioconcentration of creosote-derived PAHs by terrestrial and aquatic organisms. In an examination of the

partitioning of coal tar-derived PAHs into ground water and the usefulness of a computer model to

simulate such, Lee et al. (1992) found that theoretically “ideal” behavior was observed for the individual

compounds and that the model was useful in estimating concentrations in ground water. This finding

indicates that, although coal tar is a complex mixture of compounds with varying physical and chemical

properties, the fate of the individual compounds may be modeled as if they were present as single

contaminants. Additional studies on the behavior of the transport of the individual components of

creosote when present as a mixture may be necessary. Biotransformation appears to be the most

important degradation process in soils and aquatic environments. Additional data on the transport of

volatile creosote components in the atmosphere and the partitioning of creosote released to surface waters

and soils would be useful. Quantitative data on the rates of biotransformation in soils, surface water, and

ground water under aerobic and anaerobic conditions would also be useful. Data on the degradation rates

or relative persistence of the HMW PAHs would be particularly useful since these components of
CREOSOTE 276

6. POTENTIAL FOR HUMAN EXPOSURE

creosote are among the more toxic fraction, and are less soluble and less readily degraded than the LMW

PAHs. The importance of other transformation processes, such as photolysis, photooxidation, and

hydrolysis, in relation to biotransformation and rates of transport between media, should also be defined. 

These data would be useful to help define potential pathways of human exposure and to estimate ambient

concentrations of creosote components in environmental media.

Bioavailability from Environmental Media. Very limited information was found in the available

literature regarding the uptake of creosote components by living organisms from contaminated water and

soil at hazardous waste sites. Studies have been done with persistent constituents (e.g., PAHs) which

show that plant uptake from soils is limited (Agency for Toxic Substances and Disease Registry 1995;

Gile et al. 1982), whereas bioconcentration in aquatic organisms from contaminated surface waters has

been demonstrated. Data from human and animal studies indicate that creosote components are absorbed

following ingestion or inhalation, or after dermal contact with the mixture. Additional data on the

bioavailability of creosote components following ingestion or inhalation of creosote-contaminated soils

would be helpful. Of particular importance are data on the bioavailability of the HMW PAHs that may

persist in soil and are resistant to many bioremediation techniques.

Food Chain Bioaccumulation. Very limited information was found in the available literature

regarding the biomagnification of creosote-derived compounds among food chain trophic levels. Many

aquatic organisms are able to rapidly metabolize and eliminate PAHs, the major constituents of the

commercial mixture (Eisler 1987). However, the marsh clam Rungia cuneata, which is a major food item

for crustaceans such as the blue crab that are part of commercial fisheries, showed tissue concentrations of

benzopyrenes up to 600 ppb after 4 weeks of exposure to creosote after a major spill; total PAH levels in

the ambient water were #25 ppb (DeLeon et al. 1988). Additional studies are needed to determine

whether this bioaccumulation indeed moves up the trophic chain to pose human exposure concerns. Also,

vegetables and other produce grown in or around deposits of creosote wastes may uptake or be

contaminated by creosote constituents through adsorption to roots or surfaces. Since these materials will

be hard to remove through washing or other food preparation processes, consumption of these may

provide a route for exposure. Additional data are needed on the ability of agricultural plants to uptake

creosote constituents.

EPA (1993) has issued Fish Sampling and Analysis Guidance that provides an overview of the issues

involved in considering fish consumption advisories for PAHs. Since PAHs may be derived from
CREOSOTE 277

6. POTENTIAL FOR HUMAN EXPOSURE

creosote or other sources such as the combustion of petroleum products, state-issued advisories for PAHs

should also be examined to see if creosote-derived sources are at issue. 

Exposure Levels in Environmental Media. Limited information is available regarding ambient

concentrations of creosote-derived PAHs in soils (Davis et al. 1993; EPA 1987b; HazDat 2002) and no

data are available regarding atmospheric concentrations of creosote components. Very limited

information is available on concentrations of component compounds in surface waters (DeLeon et al.

1988) and sediments (Madsen et al. 1993, 1996), including those receiving wood treatment plant

effluents. Data are still lacking for contaminated media in the vicinity of hazardous waste sites. These

data would be useful to estimate the exposure of populations coming into contact with components of the

mixture through inhalation of contaminated air, consumption of contaminated surface water or ground

water, or direct dermal contact with environmental media.

Reliable monitoring data for the levels of creosote in contaminated media at hazardous waste sites are

needed so that the information obtained on levels of creosote in the environment can be used in

combination with the known body burden of creosote to assess the potential risk of adverse health effects

in populations living in the vicinity of hazardous waste sites.

Exposure Levels in Humans. A population exists that is potentially exposed to creosote through

contact with contaminated media at hazardous waste sites and with treated wood products. A second

potentially exposed workforce population exists at wood treatment facilities and in other industries in

which creosote-derived products are produced or used. Currently, no information exists that demonstrates

tissue levels of any components of the mixture in these populations. Although exposure is now estimated

in occupationally exposed workers using urinary concentrations of biomarkers, such as 1-hydroxypyrene,

actual exposure levels are harder to determine. Estimates of human exposure to creosote constituents, or

body burdens of creosote components, are complicated by the lack of information on exposure to creosote

constituents and levels of creosote-derived components in the environment. Collecting information on

tissue levels of creosote components in humans would be necessary to examine the relationship between

levels of creosote-derived compounds in the environment, human tissue levels, and subsequent

development of health effects. This information is necessary for assessing the need to conduct health

studies on these populations.
CREOSOTE 278

6. POTENTIAL FOR HUMAN EXPOSURE

Exposures of Children. Data on the exposure levels and body burden measurements of creosote

constituents in children are needed to determine the risks associated with exposure. Because small

children are likely to engage in hand-to-mouth activity (with unwashed hands) and to be in close contact

with dirt, lawns, and indoor (carpet) dust, and because creosote residues bound to soil or dust particles in

carpets or on bare floors, may present an exposure route for infants and toddlers through dermal contact

and oral ingestion, bioavailability from soil data are necessary. Bioavailability data are also necessary to

determine the amount of contaminant that children may be exposed to through dermal contact with treated

wood, such as may occur when children play on railroad tracks. Data on the bioavailability of creosote

constituents from treated wood are also necessary because through behaviors such as putting their mouths

on objects or chewing on objects, children may be exposed to creosote through oral ingestion of the

chemical through chewing on treated wood, such as fences, bridge, or pier railings. 

Data are also necessary on whether children are different from adults in their weight-adjusted intake of

creosote compounds. Creosote compounds may be present in dietary sources such as fish or food grown

in or near contaminated soils. While data on the oral bioavailability of some soil-bound components of

creosote are available, it is necessary to determine the exposure contribution of such sources to children

and to determine the contribution to body burden in children.

Data are necessary on the number of children (<18 years of age) who may be occupationally exposed to

creosote and on the levels of exposure they may experience. It is possible that some workers in industries

such as tire plants or those involved in roofing or road paving may be exposed to creosote in their daily

tasks. Information on this is may be important in assessing whether occupational exposure in children is

similar to the levels observed for all occupationally exposed workers. 

Child health data needs relating to susceptibility are discussed in 3.12.2 Identification of Data Needs:

Children’s Susceptibility.

Exposure Registries. No exposure registries for creosote were located. This substance is not

currently one of the compounds for which a subregistry has been established in the National Exposure

Registry. The substance will be considered in the future when chemical selection is made for

subregistries to be established. The information that is amassed in the National Exposure Registry

facilitates the epidemiological research needed to assess adverse health outcomes that may be related to

exposure to this substance.
CREOSOTE 279

6. POTENTIAL FOR HUMAN EXPOSURE

6.8.2 Ongoing Studies

A search of federally funded research in progress (FEDRIP 2000) revealed several studies that are

discussed in this section. Creosote is currently subject to a Federal Insecticide, Fungicide, and

Rodenticide Act (FIFRA) registration standard and data call-in by EPA. In addition, the Creosote

Council II is planning to conduct a research program that includes testing for worker exposure and

protection.

Remedial investigation/feasibility studies being conducted at the 46 NPL sites where creosote has been

found and at the numerous creosote-contaminated Resource Conservation and Recovery Act (RCRA)

corrective action sites should provide data on concentrations of the mixture in contaminated media in the

vicinity of hazardous waste sites. For example, creosote constituents have been found in surface water

impoundments and soil samples taken near wood treatment facility sites in Colorado, Louisiana, Texas,

and Montana.

The Cornell University Superfund Basic Research and Educational Pilot Program was (1992) established

with the aim to conduct research on the bioavailability and impact of hazardous substances in health and

ecological risk, specifically as related to exposure, neurological, and immunological effects; and the

remediation of sites containing polychlorinated biphenyls (PCBs), PAHs, and heavy metals. Relevant

areas of study include biodegradation of non-aqueous phase liquids (NAPLs), kinetic controls on

environmental fate in soil and aquifers, sequestration in soil and its effects on bioavailability, and

microscale parameters modeling macroscale fate in soil. A current study led by Dr. Madsen concerns the

determination of factors leading to the persistence of creosote-derived PAHs (naphthalene and

phenanthrene) in fresh water sediments at a field site. 

The USDA is sponsoring a study by researchers led by Dr. Lee at Purdue University on the interaction of

organic chemicals, including coal tar, with soils. Researchers are investigating and modeling the abiotic

processes controlling the mobility and bioavailability of organic compounds in soil. They will be

determining the adsorption of and release rates of PAHs from a coal tar/soil waste matrix.

The U.S. Geological Survey is investigating the fate and transport of immiscible contaminants, including

coal tar and creosote wastes, in subsurface ground water. Models will be developed to simulate and

predict the migration of slightly soluble, highly volatile immiscible contaminants in the field. These

models will eventually aid in the design of control and abatement techniques. 
CREOSOTE 280

6. POTENTIAL FOR HUMAN EXPOSURE

Researchers at Brown University (Dr. Suuberg principal investigator) are conducting a study funded by

OSTI to determine the vapor pressures and heats of vaporization of heavy, primary coal tars. The

researchers are attempting to provide needed physical property data by means of direct measurements of

the vapor pressures of coal tar fractions. They are also attempting to determine vapor pressures using

well-established techniques and modifications of those techniques.

Data from field and laboratory studies of creosote-contaminated ground water are being analyzed by the

U.S. Geological Survey to determine the transformation pathways of selected organic compounds, assess

the relative importance of physical, chemical, biochemical, and microbial processes in the transformation

of these compounds under ambient conditions, and study relevant biotransformation processes occurring

in the subsurface ground water. 

The National Science Foundation is sponsoring a study led by Dr. Richard Bartha of Rutgers University

on the multisubstrate biodegradation kinetics of PAHs from creosote, coal tar, and diesel fuel. The

relative biodegradabilities and substrate interactions of PAHs in sole and multi-substrate systems will be

determined and related to dissolution kinetics processes governing bioavailability. An integrated

mathematical model of the behavior of PAHs in NAPL-contaminated soils will be developed and

validated. 

The National Science Foundation is sponsoring a study by Princeton University (Dr. Catherine Peters,

principal investigator) regarding the chemical, physical, and microbiological processes governing the

behavior of mixtures of PAHs in NAPL-contaminated soils. 

Dr. Luthy and co-workers at Carnegie-Mellon University, in a study sponsored by Department of Energy,

are investigating the physicochemical and biochemical solubilization and mineralization of coal tarderived PAHs. The study will address the rate-controlling processes for microbial degradation of the

PAHs in both the environment and in waste water treatment processes; the kinetics of solute

solubilization and rates of mineralization will be determined. The possible synergistic interactions

between PAH-degrading bacteria and biosurfactant/emulsifier-producing bacteria will also be

investigated. The results of the research should be applicable to both remediation of coal-tar

contaminated soils in the environment and treatment systems for coal conversion process effluents. 

EPA is sponsoring a study led by Dr. Mahaffey of the Ecova Corporation to develop an in situ process

that will enhance the rate and efficiency of the biodegradation of hydrophobic organic chemicals at
CREOSOTE 281

6. POTENTIAL FOR HUMAN EXPOSURE

military installations and Superfund sites. Research activities will focus on the identification of chemical

or biological emulsifiers (surfactants) that will enhance the bioavailability of petrogenic waste (including

creosote and coal tars), and thus enhance their biodegradation. 

Researchers at Tienzyme, Inc. (B.W. Bogan, principal investigator) in State College, Pennsylvania, are

investigating the use of surfactant- or surfactant/lipid-based formulations to enhance the removal of

HMW PAHs from creosote- and tar-contaminated soils by bioremediation involving white-rot fungi. 

The USDA is sponsoring several studies on creosote. Dr. Chow, Dr. Retner, and co-workers at the

University of Illinois are investigating the effects of accelerated aging on the rate of biodegradation of

creosote-treated red oak ties by common oak decay fungi. The effects of natural weathering on the rate of

biodegradation of creosote-treated ties selected from tracks located in the Midwest will be examined. 

Computer models will compare the rates of biodegradation results of naturally weathered ties and ties

exposed to accelerated aging processes.

Researchers at Mississippi State University (Dr. Borazjini, principal investigator) are investigating the in

situ bioremediation of creosote and PCP contaminated water in an attempt to develop a rapid biological

technique for the cleanup of ground water using oxygen, surfactants, cofactors, and micronutrients. 

Surfactants will be evaluated for their abilities to enhance the bioremediation of wood-preserving process

waste water containing high concentrations of PCP, PAHs, oil, and grease.

Dr. Choong and other researchers at Louisiana State University are investigating the recycling of utility

poles for use in engineered wood products. Creosote in the poles will be removed using organic

extractants and steam, and the poles will be evaluated to determine their residual decay resistance and to

determine the effect of residual creosote on the physical, mechanical, and gluing properties of the used

utility poles. The study will include the reduction of the poles into smaller sized, defect-free wood

materials for the production of engineered woods, as well as the determination of the effect of joint

designs on the strength properties of the wood laminated composites made from the pieces of the poles.
CREOSOTE 282

7. ANALYTICAL METHODS

The purpose of this chapter is to describe the analytical methods that are available for detecting,

measuring, and/or monitoring creosote, its metabolites, and other biomarkers of exposure and effect to

creosote. The intent is not to provide an exhaustive list of analytical methods. Rather, the intention is to

identify well-established methods that are used as the standard methods of analysis. Many of the

analytical methods used for environmental samples are the methods approved by federal agencies and

organizations such as EPA and the National Institute for Occupational Safety and Health (NIOSH). Other

methods presented in this chapter are those that are approved by groups such as the Association of

Official Analytical Chemists (AOAC) and the American Public Health Association (APHA). 

Additionally, analytical methods are included that modify previously used methods to obtain lower

detection limits and/or to improve accuracy and precision.

The analytical methods used to quantify creosote and related mixtures in biological and environmental

samples are summarized below. As noted in Chapter 4, coal-derived mixtures (creosote, pitch, tar) are

chemically very similar; the methods used for their analysis are directed to the primary components of

these mixtures. In most cases uncovered through a search of the recent literature, the methods used for

coal-derived mixtures are based on analysis of high-pressure liquid chromatography (HPLC) with

ultraviolet (UV) absorbance detection to nondestructively separate these compounds for collection and

characterization.

The high resolving power of capillary gas chromatography (GC) is required for the successful analysis of

coal-derived materials, since these mixtures can contain hundreds of components with very similar

chemical properties. Guillen et al. (1992) and Blanco et al. (1992) have demonstrated the full power of

capillary GC using both mass spectrometry (MS) and flame ionization detection (FID) for analyzing coal

tar. Specific applications for biological and environmental analyses are described below.

7.1 BIOLOGICAL MATERIALS

The levels of creosote in biological materials can be estimated by measuring the PAH content in

biological samples. Methods include GC/FID, GC/MS, and HPLC. Synchronous luminescence

spectroscopy (SLS), 32P-postlabeling, and immunoassay techniques, i.e., enzyme linked immunosorbent

assays (ELISA) and ultrasensitive enzyme radio immunoassay (USERIA), are methods currently being

developed to detect and quantify ultratrace levels of PAH adducts bound covalently to macromolecules
CREOSOTE 283

7. ANALYTICAL METHODS

(e.g., DNA). Table 7-1 lists the available analytical methods for determining creosote/coal tar-derived

PAH components in biological samples. GC/MS and HPLC have been employed to detect creosotederived PAH complexes at ppt (pg/g) levels in human tissues, including adipose tissue, blood, and urine

(Liao et al. 1988; Obana et al. 1981). The detection and quantification of trace levels of PAHs in

biological tissues involves extensive and rigorous clean-up procedures including Florisil, silica, and

alumina column chromatography (Liao et al. 1988; Obana et al. 1981).

There is considerable evidence, both in vitro and in vivo, that PAHs are enzymatically converted to highly

reactive metabolites that bind covalently to macromolecules such as DNA, thereby causing carcinogenesis

and mutagenesis in mammalian systems. Thus, benzo[a]pyrene (a procarcinogenic PAH and the most

thoroughly studied one) is converted by specific cellular enzymes to the syn- and anti-isomers of 7β,

8δ-dihydroxy-(9δ, 10δ)-epoxy-7,8,9,10-tetrahydro-benzo[a]pyrene (B[a]PDE) and binds covalently to

DNA, resulting in formation of the putative B[a]PDE-DNA adduct (Autrup and Seremet 1986; Harris et

al. 1985; Haugen et al. 1986; Santella et al. 1995).

In an analysis of B[a]P and coal tar pitch volatiles in workplace air conducted by Ny et al. (1993), urine

samples were analyzed for the pyrene metabolite 1-hydroxypyrene, and a high correlation between levels

of this biomarker and PAH air levels was observed. Analyses were also conducted by HPLC with

fluorescence detection. Tolos et al. (1990) reported results of 1-hydroxypyrene urinalysis for aluminum

reduction plant workers, and showed a strong positive correlation between the compound and

17 environmental PAHs. This work verified the choice by earlier researchers (Jongeneelen et al. 1988) of

the pyrene metabolite as a useful marker of exposure to PAHs. Elovaara et al. (1995) also demonstrated

the usefulness of 1-hydroxypyrene as a biomarker for exposure to naphthalene and 10 other PAHs for

creosote impregnation plant workers. Particulate PAHs were Soxhlet extracted with cyclohexane and

analyzed by HPLC with fluorescence detection. 

The ELISA technique has been employed for detecting antibodies in serum bound to B[a]PDE-DNA

adducts. The USERIA method involves measuring the immunological response of B[a]PDE-DNA in the

presence of rabbit anti-serum, alkaline phosphatase enzyme, and radiolabeled para nitrophenyl phosphate

(PNPP). The radioactivity of the hydrolyzed tritiated PNPP is measured by a scintillation counter. Both

ELISA and USERIA methods have been employed to detect PAH-DNA adducts at 10-15 mol levels in the

blood and tissues of humans occupationally exposed to PAH (Amin et al. 1982; Harris et al. 1985; 
CREOSOTE 284

7. ANALYTICAL METHODS

Table 7-1. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH 

Components in Biological Samples

Form

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit Percent

recovery Reference

Coal tar

creosote,

Coal tar

Adipose

tissues

Benzene/hexane

extraction of

adipose tissue;

addition of

Na2SO4; cleanup

with Florisil

column; elution of

PAHs with 8%

benzene in

hexane, sample

concentration.

GC/MS 5–50 ng/g 52–95%

recovery

Liao et al.

1988

Coal tar

creosote

Liver

homogentate

Extraction of

homogenate with

ethyl acetate;

water removal

(Na2SO4),

concentration.

HPLC No data No data Amin et al.

1982

Saponification of

minced tissue,

extraction with

hexane; clean up

by solvent

partition,

concentration;

purification by

silica/alumina

chromatography;

concentration of

eluent.

HPLC 0.006–0.46 ng/g No data Obana 

et al. 1981

Coal tar

creosote

Blood Separation of

white cells;

isolation of DNA

by standard

Rnase and phenol

treatment.

ELISA 1x10-15 mol

BPDE per μg

DNA

No data Perera 

et al. 1988
CREOSOTE 285

7. ANALYTICAL METHODS

Table 7-1. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH 

Components in Biological Samples (continued)

Form

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Coal tar

creosote,

Coal tar

Isolation of PAHDNA adduct from

white cells;

digestion of

adduct with

radiolabeled

(

32P)ATP;

radiolabeled

adduct resolution

by TLC.

32P-postlabeling

0.3x10-15 mol

BPDE per μg

DNA

No data Phillips 

et al. 1988

Coal tar

creosote

Separation of

lymphocyte cells

and isolation of

BPDE-DNA

adduct by

standard

treatments.

ELISA or

USERIA

and SLS

0.006–0.23x

10-15 mol BPDE

per μg DNA

No data Harris et

al. 1985

Coal tar

creosote

Urine Animal dosing

with radiolabeled

B[a]P; collection

of urine, addition

of MeOH; c-18

Sep-Pak column

cleanup; elution

with aqueous

MeOH.

HPLC 5x10-12 mol 

7-BPDE-Gua

per μg of

labeled B[a]P

No data Autrup and

Seremet

1986

Coal tar

creosote,

Coal tar

pitch

Coal tar

Hydrolysis of

conjugates

enzymatically;

isolation of

1-pyrenol using

SPE column.

HPLC/Fl 0.45 nmol/L No data Tolos et al.

1990

Coal tar

creosote,

Coal tar

pitch

Hydrolysis of

conjugates

enzymatically;

isolation of

1-pyrenol using

SPE column

HPLC/Fl 10 nmol/L 84–88% Ny et al.

1993

BPDE benzo[a]pyrene diol epoxide; B[a]P = benzo[a]pyrene; DMSO = dimethyl sulfoxide; ELISA = enzyme linked

immunosorbent assay; Fl = fluorescence; Gua = guanine; GC/MS = gas chromatography/mass spectrometry;

HPLC = high-performance liquid chromatography; NADP+

 = oxidized nicotinamide adenosine dinucleotide;

SLS = synchronous luminescence spectroscopy; SPE = solid phase extraction; USERIA = ultra-sensitive enzyme

radioimmunoassay
CREOSOTE 286

7. ANALYTICAL METHODS

Haugen et al. 1986; Newman et al. 1988; Perera et al. 1988). The 32P-postlabeling method involves a

5'

-labeling of DNA adducts that have been digested with nuclease P1 enzyme system to

3'

-mononucleotides. Adducts present in the digest that were resistant to nuclease P1 were thus labeled

with 32P, while unmodified nucleotides were not. The digested DNA adducts are separated by thin-layer

chromatography (TLC) and quantified by scintillation counting. A detection limit of 0.3x10-15 mol of

PAH adduct per μg of DNA (less than one adduct in 107

 nucleotides) has been achieved (Philips et al.

1988).

7.2 ENVIRONMENTAL SAMPLES

As with biological samples, the PAH component fraction is most often used as an indicator of creosote

contamination of environmental media. For example, screening for total PAHs is often used at hazardous

waste sites when creosote contamination is suspected. The PAH fraction (neutral) is used in these

analyses because it is more persistent than the acidic or basic fractions, which tend to be more mobile and

biodegradable. The methods used to measure total PAHs can also be used to detect the nitrogen, oxygen,

and sulfur heterocyclic components of the mixture. Table 7-2 lists the available analytical methods for

determining creosote/coal tar-derived PAH components in environmental samples.

The efficacy of supercritical fluid extraction was demonstrated to be a promising technique for coal tar

pitch (Camel et al. 1993). Extraction procedures for coal tar pitch volatiles on air sampling filters have

been compared by Hekmat et al. (1994). Methylene chloride was shown to be superior as an extracting

solvent to cyclohexane. For coal tar pitch volatiles collected on poly(tetrafluoroethylene) filters or glass

fiber filters and extracted with benzene, cyclohexane, or dichloromethane, Hekmat et al. (1994) found that

the highest recoveries were achieved with collection on poly(tetrafluoroethylene) filters, desorption with

dichloromethane, and analysis using spectrophotometry (UV quantification). Cyclohexane was not found

to be a suitable substitute for benzene. These authors also concluded that spectrophotometric methods

were superior to gravimetric methods of measurement of coal tar pitch volatiles. 

Hale and Aneiro (1997) reviewed recent progress made in improving analytical techniques for

determining components of creosote in environmental media. The multiple extraction and purification

steps required prior to chromatographic analysis is problematic in that compounds may be lost through

volatilization or transformed through photodegradation. More efficient extraction procedures include

supercritical fluid extraction, accelerated solvent, and microwave, and solid-phase extraction. Newer 
CREOSOTE 287

7. ANALYTICAL METHODS

Table 7-2. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH

Components in Environmental Samples

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Wooden

sleepers

(railroad

crossties) in

playground

Extraction of sample

with ether; filtration

through anhydrous

sodium sulfate and

evaporation of

solvent;

acid/base/neutral

liquid-liquid partition.

GC/MS 1–3 ng/sample No data Rotard and

Mailahn

1987

Coal tar

creosote

Dissolution of

sample in

cyclohexane and

extraction with 90%

ethanol; evaporation

of extract to

dryness; dissolution

of residue in

cyclohexane,

extraction with

nitromethane;

evaporation of

extract to dryness

and dissolution of

residue with small

amount of benzene.

GC 10 ppm No data Lijinsky 

et al. 1963

Dissolution of

sample in methylene

chloride at a

concentration of

.10% (w/w).

GC No data No data Nestler

1974a

River

sediments

Digestion of wet

sediment sample in

boiling EtOH/KOH;

extraction of

hydrocarbons into

cyclohexane; extract

concentration and

Florisil column

cleanup; elution of

PAH complex with

50% methylene

chloride/hexane;

concentration of

sample.

HPLC No data No data Black 1982
CREOSOTE 288

7. ANALYTICAL METHODS

Table 7-2. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH

Components in Environmental Samples (continued)

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Contaminated

groundwater

Filtration through

prebaked glass-fiber

filters to remove

suspended

sediments; cleanup

with bonded-phase

extraction column;

elution of organics

from column with

acetonitrile followed

by methylene

chloride; water

removal (Na2SO4);

concentration by

nitrogen blow-down.

GC/MS 50 μg/L 95% Rostad 

et al. 1984

Groundwater pH to 12. Extraction

with CH2Cl2. Drying

and concentration of

organic phase

(containing neutral

and bases). 

Adjustment of

aqueous phase pH

to 7 and extraction;

then to pH 2 and

extraction. Both

extracts derivatized

to TMS

esters/ethers.

GC/FlD 100 ppb >90% for

PAHs;

.30–50%

for

phenols; 

.>70% for

bases

Mueller 

et al. 1991

Impregnated

wood

(workplace)

Heating of sample at

60 EC in a chamber;

cleanup with XAD-2

column; extraction

with ether. 

Collection of heated

sample on a

prewashed

(cyclohexane) glass

fiber filter; extraction

of sample with

cyclohexane and

evaporation to

dryness; dissolution

of residue in

acetonitrile/water

(85/15).

GC/MS

HPLC

0.07–0 μg/L

using ITMS (α, β,

and sulfate) 

8 ng/m3

116–128%

No data

Heikkilä et

al. 1987
CREOSOTE 289

7. ANALYTICAL METHODS

Table 7-2. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH

Components in Environmental Samples (continued)

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Creosote

treated wood

Heating of sample in

injection port of GC.

GC No data No data Lorenz and

Gjovik 1972

Gas and

particulate

matter

(workplace)

Pumping sample

through a glass fiber

filter-XAD-2

adsorbent sampling

system; extraction

with ether in

ultrasonic bath;

concentration of

extract and dilution

with acetonitrile.

HPLC 0.005–2.5 mg/m3 87–102% Andersson 

et al. 1983

Breathing

zone air

(workplace)

Pumping air through

Teflon filters and

sorbent tubes. 

Extraction of

particulate and

tubes with benzene. 

Concentration of

extracts.

GC 0.05 mg/sample No data Tolos et al.

1990

Breathing

zone air

(workplace)

No information. HPLC/Fl No data No data Rogaczews

ka and

Ligocka

1991

Breathing

zone air

(workplace)

Pumping air through

filters and XAD

resin. Extraction of

both with benzene.

Concentration.

HPLC/UV-Fl No data No data Ny et al.

1993

Creosote Dissolution in

cyclohexane;

washing with H2SO4;

neutralization of acid

fraction and

extraction with

cyclo-hexane;

alumina column

cleanup.

HPLC/UV or

GC/MS

No data No data Galceran et

al. 1994
CREOSOTE 290

7. ANALYTICAL METHODS

Table 7-2. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH

Components in Environmental Samples (continued)

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Water and

sediment

Extraction (Soxhlet

for sediment only) of

PAHs with

methylene chloride.

HPLC/

spectrofluorometric 

detection

No data Water -

74.4±

7.8% to

103±

1.1%;

Sediment -

71.3±

2.9% to

105±

3.1%

Bestari et al.

1998

Creosotetreated woodSoxhlet extraction of

PAHs with

dichloromethane;

concentration of

extracts and

cleanup on silica

column eluted with

hexane; drying with

anhydrous sodium

sulfate; extraction in

series with hexane,

hexane: DCM

(60:40); elution with

hexane: DCM

(60:40).

GC/FID No data HMW

PAHs -

104±0.9%

LMW 

PAHs -

84±5%

Gevao and

Jones 1998

Sediment

pore water

and elutriate

Drying with

anhydrous sodium

sulfate; Soxhlet

extraction with

acetone:hexane

(59:41); concentration of extract;

cleanup on silica

column eluted in

series with hexane

and dichloromethane; concentration and

redissolution in

hexane.

GC/FID 2–5 ng/g No data Hyötyläinen

and Oikari

1999b
CREOSOTE 291

7. ANALYTICAL METHODS

Table 7-2. Analytical Methods for Determining Creosote/Coal Tar-Derived PAH

Components in Environmental Samples (continued)

Sample

matrix

Preparation

method

Analytical

method

Sample

detection limit

Percent

recovery Reference

Coal tar pitch

volatiles on

glass filters

Soxhlet extraction

with dichloromethane; cleanup

on silica columns

eluted with

cyclohexane;

concentration;

HPLC separation

using backflush. 

GC/Sselective

AED

4 ng/m3 Cleanup

recoveries

were

estimated

at

97–100%

Becker et al.

1999

AED = atomic emission detection; Fl = fluorescence; FID = flame ionization detection; GC = gas chromatography;

HMW = high molecular weight; HPLC = high-performance liquid chromatography; LMW = low molecular weight;

MS = mass spectrometry; PAH = polycyclic aromatic hydrocarbon; UV = ultraviolet
CREOSOTE 292

7. ANALYTICAL METHODS

methods also include on-line purification and coupling of extraction and chromatography. These authors

found that MS use has increased, especially since ion traps and mass selective detectors have become

more available. Other increasingly common methods are HPLC with fluorescence and diode array UV;

and C-, S-, and N-selective GC detectors. The use of HPLC with fluorescence detection allows for a

lower limit of detection for some PAHs than does GC/FID. 

GC/FID or GC/MS are the most widely employed analytical techniques for the determination of coalderived PAHs in contaminated ground water, railroad cross ties, and impregnated wood (Gevao and Jones

1998; Heikkilä et al. 1987; King and Barker 1999; Lijinski et al. 1963; Lorenz and Gjovik 1972; Nestler

1974a; Rostad et al. 1984; Rotard and Mailahn 1987). GC/FID is one of the methods recommended by

EPA for detection of PAHs in waste water and solid waste (EPA 1986c). GC/FID was utilized by

Bieniek (1997) to determine the breathing-zone air concentration of naphthalene in a coking plant. 

Hyötyäinen and Oikari (1999b) utilized GC/FID to determine PAHs in sediment pore water and elutriates. 

Heikkilä et al. (1987; 1997), employed GC/MS to determine creosote levels in workplace air from

impregnated wood. Detection limits of 10x10-6 to 50x10-6 g of creosote per m3

 of sample and recoveries

of 82 and 102% were achieved. Heikkilä and co-workers measured the components of PAHs with

reverse-phase HPLC using fluorescence detection. A similar study was conducted by Heikkilä et al.

(1995) for a worker exposed to coal tar pitch. For the detection of creosote vapors, naphthalene was used

as an indicator since it constitutes about 18% by weight of total PAHs in creosote (Andersson et al. 1983;

Heikkilä et al. 1987). Rotard and Mailahn (1987) used a modified sample extraction procedure to identify

various components of creosote extracts in railroad cross ties. The procedure involved the separation of

compounds by functional group using acid, base, and neutral conditions. Detected compounds included

phenanthrene, anthracene, and naphthalene (neutral extractions), quinoline, and isoquinoline (basic

extraction), cresols, and phenols (acidic extraction). Mohammed et al. (1998) used GC/MS to determine

creosote-derived PAHs in aquifer materials. Recent literature has shown that GC with (sulfur selective)

atomic emission detection (CG/AED) is successful in determining the thiaarene fraction of total PAHs in

the atmosphere without prior separation of the thiaarenes from the PAHs (Becker et al. 1999). 

Grimmer et al. (1997) developed a technique using GC/MS for simultaneously determining 25 urinary

metabolites as a measure for exposure to individual PAHs. Samples are treated enzymatically with

glucuronidase and arylsulfatase and extracted with benzene or toluene; the extract is then divided and one

part is treated with diazomethane to convert phenols into methylethers and the other part is used to

convert dihydrodiols into phenols. Following further purification, individual metabolites are determined
CREOSOTE 293

7. ANALYTICAL METHODS

using GC/MS. The detection limit for various compounds is approximately 0.01 ng. Inter-individual

variation was significant. These authors determined that the correlation between inhaled PAHs to their

urinary metabolites will vary with the individual, but appeared to be linear for an individual.

Rostad et al. (1984) developed a method for the isolation and detection of creosote in contaminated

ground water. This method involved passage of the sample through a small column containing a solidbonded phase sorbent, which retained the organic compounds. The authors indicated that this method is

simple, faster, and cheaper to perform than the acid/base/neutral extraction procedure. It effectively

isolated all organic compounds from contaminated ground water regardless of polarity, functional group,

or water solubility in one step, thereby minimizing hazardous exposure to sample.

A study on the spatial and temporal distribution of PAHs from various sources (wood-preserving

facilities, refineries, chemical manufacturers, etc.) was reported by Huntley et al. (1995). The

concentrations of PAHs were shown to increase with sediment depth from analysis of core samples. 

Samples were analyzed using EPA Method 8310 (GC/MS).

HPLC with fluorescence detection has been used to identify coal-derived PAHs in river sediments (Black

1982). Andersson et al. (1983) employed an Amberlite XAD-2 adsorbent for isolating organic

compounds from gas and particulate matter in a creosote impregnating plant. Good sample recoveries

and detection limits were achieved. HPLC, with either fluorescence or UV detection, is an EPArecommended method for the analysis of both solid and liquid hazardous waste (EPA 1986c). At present,

HPLC cannot achieve the high resolution capability of capillary GC. HPLC, however, does offer some

advantages for the determination of coal-derived PAHs in environmental samples. HPLC offers a variety

of stationary phases capable of providing unique selectivity for the separation of PAH components and/or

isomers that are often difficult to separate by GC. In addition, UV absorption and fluorescence detection

provide sensitive and selective detection of PAHs. Rogaczeska and Ligocka (1991) reported results of a

study of occupational exposure to coal tar pitch volatiles, including benzo[a]pyrene (B[a]P), by measuring

B[a]P in air using HPLC with fluorescence detection. 

An acid partition and alumina column clean-up procedures were used to analyze for several acridines

(HPLC/UV) in creosote by Galceran et al. (1994). HPLC with fluorescence detection was used for

analysis of the PAH components from a coal tar sample (NIST SRM 1597) as reported in a review article

by Wise et al. (1993). Since fluorescence detection affords more selectivity than UV absorbance

detection, less clean-up is required for certain sample types. This study also showed the utility of a multidimensional approach to PAH analysis from complex samples. This methodology involves use of normal
CREOSOTE 294

7. ANALYTICAL METHODS

phase liquid chromatography (LC) to separate PAH fractions, which can then be analyzed by reverse

phase LC with fluorescence. Coal tar pitch has also been analyzed using planar chromatography as an

initial fractionation technique (Herod and Kandiyoti 1995). The resultant fractions were analyzed either

directly on the silica by MS, or were extracted from the silica for further fractionation using size

exclusion chromatography. The approach yielded structural information not readily available from direct

characterization of the original mixture.

7.3 ADEQUACY OF THE DATABASE

Section 104(I)(5) of CERCLA, as amended, directs the Administrator of ATSDR (in consultation with the

Administrator of EPA and agencies and programs of the Public Health Service) to assess whether

adequate information on the health effects of creosote is available. Where adequate information is not

available, ATSDR, in conjunction with the National Toxicology Program (NTP), is required to assure the

initiation of a program of research designed to determine the health effects (and techniques for developing

methods to determine such health effects) of creosote. 

The following categories of possible data needs have been identified by a joint team of scientists from

ATSDR, NTP, and EPA. They are defined as substance-specific informational needs that if met would

reduce the uncertainties of human health assessment. This definition should not be interpreted to mean

that all data needs discussed in this section must be filled. In the future, the identified data needs will be

evaluated and prioritized, and a substance-specific research agenda will be proposed. 

7.3.1 Identification of Data Needs

Methods for Determining Biomarkers of Exposure and Effect. Wood creosote and coalderived tars are complex mixtures of organic compounds. Virtually all potential human and ecological

exposures in the natural environment are limited to the coal-derived tars and not wood creosote, which is

used medicinally. Sensitive methods exist for measuring components of the coal-derived mixtures in

biological media. Most of these methods involve detection of PAHs, the predominant components of

creosote, and their metabolites (Amin et al. 1982; Harris et al. 1985; Haugen et al. 1986; Newman et al.
CREOSOTE 295

7. ANALYTICAL METHODS

1988; Ny et al. 1993; Perera et al. 1988; Tolos et al. 1990). These analytical methods can reliably detect

trace levels of PAHs in human tissues and body fluids, making them sensitive enough to measure

background levels in the population, as well as levels at which biological effects might occur. PAHs,

however, are not unique to creosote exposure. Analytical methods currently exist which are sensitive and

selective enough to measure possibly unique or unusual components of creosote, and are capable of

yielding a unique "fingerprint" for the mixture. These would be useful in monitoring exposures that

might occur in work environments and near hazardous waste sites where creosote has been detected. 

Although these capabilities exist, they have not been applied except in the case of the pyrene biomarker

discussed earlier.

The analytical methods for measuring PAHs and their metabolites in biological tissues and fluids are

sensitive enough to measure levels at which health effects might occur, as well as background levels in

the population. Methods also exist for measuring PAH-DNA adducts (Harris et al. 1985; Phillips et al.

1988), and research efforts are underway to develop methods that will detect ultratrace levels of these

adducts in biological media. The increased sensitivity may allow correlation between levels of these

adducts and observed health effects of PAH exposure related to coal products. There is also a need for

methods to quantitatively correlate monitored levels of various PAHs in biological tissues or fluids to

toxic effects in humans. Methods dependent on monitoring PAHs, however, are not specific for coalderived products exposure. Methods sensitive and selective enough to detect a unique component or

group of components making up the mixture would allow a more accurate assessment of the health effects

associated with exposure to monitored levels of creosote and tars. The use of 1-pyrenol as illustrated

above is an example of such an approach. Additional methods, targeting the detection of unique

components of coal tar, coal tar creosote, and coal tar pitch in biological samples, would facilitate

detection of exposure to these mixtures. 

Methods for Determining Parent Compounds and Degradation Products in Environmental

Media. Reliable and sensitive methods are available for measuring PAHs from creosote and tars in soil

or sediments (Black 1982), water (Mueller et al. 1991; Rostad et al. 1984), air (Ny et al. 1993;

Rogaczewska and Ligocka 1991; Tolos et al. 1990), and other environmental media. Exposure to such

materials is most likely to occur in industrial settings where coal-derived tars are manufactured or used. 

Creosote-contaminated water and soil are a concern in areas near hazardous waste sites and other areas

where creosote might be concentrated. The analytical methods available are accurate and sensitive

enough to quantitatively detect PAHs from creosote and tars in these and other environmental media, and

are effective for estimating creosote levels in media known to be contaminated with this substance. There

is a lack of sensitive and reliable methods for detecting and measuring creosote and coal tar degradation
CREOSOTE 296

7. ANALYTICAL METHODS

products in environmental media. Development of such methods would allow assessment of the potential

exposure to these products.

The minimal use of wood creosote for other than medicinal purposes probably argues against a pressing

need for analytical methods for environmental monitoring of this substance. The rather short half-life of

phenolic substances under most environmental conditions increases the difficulty of developing such

assay methods.

7.3.2 Ongoing Studies

No ongoing studies concerning techniques for measuring and determining creosote in biological and

environmental samples were reported.

CREOSOTE 298

8. REGULATIONS AND ADVISORIES

The international, national, and state regulations and guidelines regarding coal tars, coal tar pitch, and

creosote in air, water, and other media are summarized in Table 8-1. ATSDR has derived no MRLs for

any of the creosotes, in part because creosote is a mixture that can vary in chemical components and

concentrations. No EPA reference concentration or reference dose exists for the compound.

The EPA has determined that creosote is a class B1 carcinogen (probable human carcinogen) (IRIS 2001). 

A potency factor was not provided in IRIS. IARC classifies creosote as Group 2A (probably carcinogenic

to humans) and coal tars as Group 1 (carcinogenic to humans) (IARC 2001). The National Toxicology

Program classifies coal tar (coke oven emissions, coal tar, coal tar pitch, and creosotes) as a known

human carcinogen (NTP 1998).

Coal tar creosote is on the list of chemicals appearing in "The Emergency Planning and Community

Right-to-Know Act of 1986" (EPCRA) (EPA 1987b). Section 313 of Title III of EPCRA requires owners

and operators of certain facilities that manufacture, import, process, or otherwise use the chemicals on this

list to report annually their release of those chemicals to any environmental media.

OSHA requires employers of workers who are occupationally exposed to coal tar pitch volatiles to

institute engineering controls and work practices to reduce employee exposure to, and maintain employee

exposure at or below permissible exposure limits (PEL). The employer must use engineering and work

practice controls, if feasible, to reduce exposure to or below an 8-hour time-weighted average (TWA) of

0.2 mg/m3

. Respirators must be provided and used during the time period necessary to install or

implement feasible engineering and work practice controls (OSHA 1999a).
CREOSOTE 299

8. REGULATIONS AND ADVISORIES

Table 8-1. Regulations and Guidelines Applicable to Coal Tar Creosote, 

Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles

Agency Description Information Reference

INTERNATIONAL

Guidelines:

IARC Carcinogenicity classification

Creosotes

Coal-tars

Group 2Aa

Group 1b

IARC 2001

NATIONAL

Regulations and

Guidelines:

a. Air:

ACGIH TWA—coal tar pitch volatilesc 0.2 mg/m3 ACGIH 2001

NIOSH REL—coal tar pitch volatilesd

IDLH

0.1 mg/m3

80 mg/m3

NIOSH 2001

OSHA 8-Hour TWA for general

industry—coal tar pitch volatilese

0.2 mg/m3 OSHA 2001b

29CFR1910.1000

Table Z-1

8-Hour TWA for construction

industry—coal tar pitch volatilese

0.2 mg/m3 OSHA 2001a

29CFR1926.55

8-Hour TWA for shipyard

industry—coal tar pitch volatilese

0.2 mg/m3 OSHA 2001c

29CFR1915.1000

b. Water No data

c. Food

ATF Denaturant authorized for

denatured spirits—coal tar

ATF 2001

27CFR21.151

FDA Active ingredient for the control of

dandruff, seborrheic dermatitis, and

psoriasis—coal tar

0.5–5% FDA 2001a

21CFR358.710

Synthetic flavoring substance and

adjuvants—beechwood creosote

Used in the minimum

quantity required to

produce their

intended effect, and

in accordance with all

principles of good

manufacturing

practice

FDA 2001d

21CFR172.515
CREOSOTE 300

8. REGULATIONS AND ADVISORIES

Table 8-1. Regulations and Guidelines Applicable to Coal Tar Creosote, 

Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles (continued)

Agency Description Information Reference

NATIONAL (cont.)

FDA Based on evidence currently

available, there are inadequate

data to establish general

recognition of the safety and

effectiveness of these ingredients

for the specified uses

Coal tar

Beechwood creosote

Creosote (beechwood) and

creosote

Creosote (beechwood), oral and

topical

Topical acne drug

products and diaper

rash drug products

Expectorant drug

products

Poison ivy, oak, and 

sumac drug products

Nasal decongestant

drug products

FDA 2001b

21CFR310.545

Drugs, recommended warning and

caution statements—creosote

External use

Douche preparations

Caution—do not

apply to large areas

of the body

Warning—use of

solutions stronger

than recommended

may result in severe

local irritation, burns,

or serious poisoning;

do not use more than

twice weekly

FDA 2001c

21CFR369.20

d. Other

ACGIH Carcinogenicity classification—coal

tar pitch volatilesc A1f

ACGIH 2001

EPA RfC

RfD

Carcinogenicity

classification—creosote

No data

No data

B1g

IRIS 2001
CREOSOTE 301

8. REGULATIONS AND ADVISORIES

Table 8-1. Regulations and Guidelines Applicable to Coal Tar Creosote, 

Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles (continued)

Agency Description Information Reference

NATIONAL (cont.)

EPA CERCLA Section 102 and RCRA

Section 3001 reportable

quantity—creosote and coal tar

1 pound EPA 2001b

40CFR302.4

Identification and listing of

hazardous waste—creosote

identified as a toxic waste

U051 EPA 2001c

40CFR261.33

Toxic chemical release reporting:

Community right-to-know; effective

date—creosote

01/01/90 EPA 2001d

40CFR372.65

TSD facilities; Henry’s law constant

less than 0.1 atm m3

/mol—creosote

EPA 2001a

40CFR265

Appendix VI

NTP Carcinogenicity classification—coal

tar and coal tar aerosols

Known to be a

human carcinogen

NTP 1998

STATE

Regulations and

Guidelines:

No data

a

Group 2A: Probably carcinogenic to humans

b

Group 1: Carcinogenic to humans

c

Coal tar pitch volatiles: benzene soluble aerosol

d

Coal tar pitch volatiles: cyclohexane-extractable fraction e

Coal tar pitch volatiles: benzene soluble fraction, anthracene, benzo[a]pyrene, phenanthrene, acridine, chrysene,

pyrene

f

A1: Confirmed human carcinogen

g

B1: Probable human carcinogen

ACGIH = American Conference of Governmental Industrial Hygienists; ATF = Alcohol, Tobacco, and Firearms;

CERCLA = Comprehensive Environmental Response Compensation and Liability Act; CFR = Code of Federal

Regulations; EPA = Environmental Protection Agency; FDA = Food and Drug Administration; IARC = International

Agency for Research on Cancer; IDLH = immediately dangerous to life or health; IRIS = Integrated Risk

Information System; NIOSH = National Institute for Occupational Safety and Health; NTP = National Toxicological

Program; OSHA = Occupational Safety and Health Administration; RCRA = Resource Conservation and Recovery

Act; REL = recommended exposure limit; RfC = inhalation reference concentration; RfD = oral reference dose;

TSD = transport, storage, and disposal; TWA = time-weighted average
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CREOSOTE 348

10. GLOSSARY

Absorption—The taking up of liquids by solids, or of gases by solids or liquids.

Acute Exposure—Exposure to a chemical for a duration of 14 days or less, as specified in the

Toxicological Profiles.

Adsorption—The adhesion in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the

surfaces of solid bodies or liquids with which they are in contact.

Adsorption Coefficient (Koc)—The ratio of the amount of a chemical adsorbed per unit weight of

organic carbon in the soil or sediment to the concentration of the chemical in solution at equilibrium.

Adsorption Ratio (Kd)—The amount of a chemical adsorbed by a sediment or soil (i.e., the solid phase)

divided by the amount of chemical in the solution phase, which is in equilibrium with the solid phase, at a

fixed solid/solution ratio. It is generally expressed in micrograms of chemical sorbed per gram of soil or

sediment.

Benchmark Dose (BMD)—Usually defined as the lower confidence limit on the dose that produces a

specified magnitude of changes in a specified adverse response. For example, a BMD10 would be the

dose at the 95% lower confidence limit on a 10% response, and the benchmark response (BMR) would be

10%. The BMD is determined by modeling the dose response curve in the region of the dose response

relationship where biologically observable data are feasible. 

Benchmark Dose Model—A statistical dose-response model applied to either experimental toxicological

or epidemiological data to calculate a BMD.

Bioconcentration Factor (BCF)—The quotient of the concentration of a chemical in aquatic organisms

at a specific time or during a discrete time period of exposure divided by the concentration in the

surrounding water at the same time or during the same period.

Biomarkers—Broadly defined as indicators signaling events in biologic systems or samples. They have

been classified as markers of exposure, markers of effect, and markers of susceptibility.

Cancer Effect Level (CEL)—The lowest dose of chemical in a study, or group of studies, that produces

significant increases in the incidence of cancer (or tumors) between the exposed population and its

appropriate control.

Carcinogen—A chemical capable of inducing cancer.

Case-Control Study—A type of epidemiological study which examines the relationship between a

particular outcome (disease or condition) and a variety of potential causative agents (such as toxic

chemicals). In a case-controlled study, a group of people with a specified and well-defined outcome is

identified and compared to a similar group of people without outcome.

Case Report—Describes a single individual with a particular disease or exposure. These may suggest

some potential topics for scientific research but are not actual research studies.
CREOSOTE 349

10. GLOSSARY

Case Series—Describes the experience of a small number of individuals with the same disease or

exposure. These may suggest potential topics for scientific research but are not actual research studies.

Ceiling Value—A concentration of a substance that should not be exceeded, even instantaneously.

Chronic Exposure—Exposure to a chemical for 365 days or more, as specified in the Toxicological

Profiles.

Cohort Study—A type of epidemiological study of a specific group or groups of people who have had a

common insult (e.g., exposure to an agent suspected of causing disease or a common disease) and are

followed forward from exposure to outcome. At least one exposed group is compared to one unexposed

group.

Cross-sectional Study—A type of epidemiological study of a group or groups which examines the

relationship between exposure and outcome to a chemical or to chemicals at one point in time.

Data Needs—Substance-specific informational needs that if met would reduce the uncertainties of human

health assessment.

Developmental Toxicity—The occurrence of adverse effects on the developing organism that may result

from exposure to a chemical prior to conception (either parent), during prenatal development, or

postnatally to the time of sexual maturation. Adverse developmental effects may be detected at any point

in the life span of the organism.

Dose-Response Relationship—The quantitative relationship between the amount of exposure to a

toxicant and the incidence of the adverse effects.

Embryotoxicity and Fetotoxicity—Any toxic effect on the conceptus as a result of prenatal exposure to

a chemical; the distinguishing feature between the two terms is the stage of development during which the

insult occurs. The terms, as used here, include malformations and variations, altered growth, and in utero

death.

Environmental Protection Agency (EPA) Health Advisory—An estimate of acceptable drinking water

levels for a chemical substance based on health effects information. A health advisory is not a legally

enforceable federal standard, but serves as technical guidance to assist federal, state, and local officials.

Epidemiology—Refers to the investigation of factors that determine the frequency and distribution of

disease or other health-related conditions within a defined human population during a specified period. 

Genotoxicity—A specific adverse effect on the genome of living cells that, upon the duplication of

affected cells, can be expressed as a mutagenic, clastogenic or carcinogenic event because of specific

alteration of the molecular structure of the genome.

Half-life—A measure of rate for the time required to eliminate one half of a quantity of a chemical from

the body or environmental media.

Heterocyclic—A molecular configuration in which one of the atoms in a ring is not a carbon atom. 

Heterocyclic oxygen refers to a ring in which the non-carbon atom is oxygen. Other elements such as

nitrogen and sulfur are frequently found in heterocyclic rings.
CREOSOTE 350

10. GLOSSARY

Immediately Dangerous to Life or Health (IDLH)—The maximum environmental concentration of a

contaminant from which one could escape within 30 minutes without any escape-impairing symptoms or

irreversible health effects.

Incidence—The ratio of individuals in a population who develop a specified condition to the total

number of individuals in that population who could have developed that condition in a specified time

period. 

Intermediate Exposure—Exposure to a chemical for a duration of 15–364 days, as specified in the

Toxicological Profiles.

Immunologic Toxicity—The occurrence of adverse effects on the immune system that may result from

exposure to environmental agents such as chemicals.

Immunological Effects—Functional changes in the immune response.

In Vitro—Isolated from the living organism and artificially maintained, as in a test tube.

In Vivo—Occurring within the living organism.

Lethal Concentration(LO) (LCLO)—The lowest concentration of a chemical in air which has been

reported to have caused death in humans or animals.

Lethal Concentration(50) (LC50)—A calculated concentration of a chemical in air to which exposure for a

specific length of time is expected to cause death in 50% of a defined experimental animal population.

Lethal Dose(LO) (LDLO)—The lowest dose of a chemical introduced by a route other than inhalation that

has been reported to have caused death in humans or animals.

Lethal Dose(50) (LD50)—The dose of a chemical which has been calculated to cause death in 50% of a

defined experimental animal population.

Lethal Time(50) (LT50)—A calculated period of time within which a specific concentration of a chemical

is expected to cause death in 50% of a defined experimental animal population.

Lowest-Observed-Adverse-Effect Level (LOAEL)—The lowest exposure level of chemical in a study,

or group of studies, that produces statistically or biologically significant increases in frequency or severity

of adverse effects between the exposed population and its appropriate control.

Lymphoreticular Effects—Represent morphological effects involving lymphatic tissues such as the

lymph nodes, spleen, and thymus.

Malformations—Permanent structural changes that may adversely affect survival, development, or

function.

Minimal Risk Level (MRL)—An estimate of daily human exposure to a hazardous substance that is

likely to be without an appreciable risk of adverse noncancer health effects over a specified route and

duration of exposure.
CREOSOTE 351

10. GLOSSARY

Modifying Factor (MF)—A value (greater than zero) that is applied to the derivation of a minimal risk

level (MRL) to reflect additional concerns about the database that are not covered by the uncertainty

factors. The default value for a MF is 1.

Morbidity—State of being diseased; morbidity rate is the incidence or prevalence of disease in a specific

population.

Mortality—Death; mortality rate is a measure of the number of deaths in a population during a specified 

interval of time.

Mutagen—A substance that causes mutations. A mutation is a change in the DNA sequence of a cell’s

DNA. Mutations can lead to birth defects, miscarriages, or cancer.

Necropsy—The gross examination of the organs and tissues of a dead body to determine the cause of

death or pathological conditions.

Neurotoxicity—The occurrence of adverse effects on the nervous system following exposure to a

chemical.

No-Observed-Adverse-Effect Level (NOAEL)—The dose of a chemical at which there were no

statistically or biologically significant increases in frequency or severity of adverse effects seen between

the exposed population and its appropriate control. Effects may be produced at this dose, but they are not

considered to be adverse.

Octanol-Water Partition Coefficient (Kow)—The equilibrium ratio of the concentrations of a chemical

in n-octanol and water, in dilute solution.

Odds Ratio (OR)—A means of measuring the association between an exposure (such as toxic substances

and a disease or condition) which represents the best estimate of relative risk (risk as a ratio of the

incidence among subjects exposed to a particular risk factor divided by the incidence among subjects who

were not exposed to the risk factor). An odds ratio of greater than 1 is considered to indicate greater risk

of disease in the exposed group compared to the unexposed.

Organophosphate or Organophosphorus Compound—A phosphorus containing organic compound

and especially a pesticide that acts by inhibiting cholinesterase.

Permissible Exposure Limit (PEL)—An Occupational Safety and Health Administration (OSHA)

allowable exposure level in workplace air averaged over an 8-hour shift of a 40-hour workweek.

Pesticide—General classification of chemicals specifically developed and produced for use in the control

of agricultural and public health pests.

Pharmacokinetics—The science of quantitatively predicting the fate (disposition) of an exogenous

substance in an organism. Utilizing computational techniques, it provides the means of studying the

absorption, distribution, metabolism and excretion of chemicals by the body.
CREOSOTE 352

10. GLOSSARY

Pharmacokinetic Model—A set of equations that can be used to describe the time course of a parent

chemical or metabolite in an animal system. There are two types of pharmacokinetic models: data-based

and physiologically-based. A data-based model divides the animal system into a series of compartments

which, in general, do not represent real, identifiable anatomic regions of the body whereby the

physiologically-based model compartments represent real anatomic regions of the body.

Physiologically Based Pharmacodynamic (PBPD) Model—A type of physiologically-based doseresponse model which quantitatively describes the relationship between target tissue dose and toxic end

points. These models advance the importance of physiologically based models in that they clearly

describe the biological effect (response) produced by the system following exposure to an exogenous

substance. 

Physiologically Based Pharmacokinetic (PBPK) Model—Comprised of a series of compartments

representing organs or tissue groups with realistic weights and blood flows. These models require a

variety of physiological information: tissue volumes, blood flow rates to tissues, cardiac output, alveolar

ventilation rates and, possibly membrane permeabilities. The models also utilize biochemical information

such as air/blood partition coefficients, and metabolic parameters. PBPK models are also called

biologically based tissue dosimetry models.

Prevalence—The number of cases of a disease or condition in a population at one point in time. 

Prospective Study—A type of cohort study in which the pertinent observations are made on events

occurring after the start of the study. A group is followed over time.

q1*—The upper-bound estimate of the low-dose slope of the dose-response curve as determined by the

multistage procedure. The q1* can be used to calculate an estimate of carcinogenic potency, the

incremental excess cancer risk per unit of exposure (usually μg/L for water, mg/kg/day for food, and

μg/m3

 for air).

Recommended Exposure Limit (REL)—A National Institute for Occupational Safety and Health

(NIOSH) time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour

workweek.

Reference Concentration (RfC)—An estimate (with uncertainty spanning perhaps an order of

magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups)

that is likely to be without an appreciable risk of deleterious noncancer health effects during a lifetime. 

The inhalation reference concentration is for continuous inhalation exposures and is appropriately

expressed in units of mg/m3 or ppm.

Reference Dose (RfD)—An estimate (with uncertainty spanning perhaps an order of magnitude) of the

daily exposure of the human population to a potential hazard that is likely to be without risk of deleterious

effects during a lifetime. The RfD is operationally derived from the no-observed-adverse-effect level

(NOAEL-from animal and human studies) by a consistent application of uncertainty factors that reflect

various types of data used to estimate RfDs and an additional modifying factor, which is based on a

professional judgment of the entire database on the chemical. The RfDs are not applicable to

nonthreshold effects such as cancer.
CREOSOTE 353

10. GLOSSARY

Reportable Quantity (RQ)—The quantity of a hazardous substance that is considered reportable under

the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Reportable

quantities are (1) 1 pound or greater or (2) for selected substances, an amount established by regulation

either under CERCLA or under Section 311 of the Clean Water Act. Quantities are measured over a

24-hour period.

Reproductive Toxicity—The occurrence of adverse effects on the reproductive system that may result

from exposure to a chemical. The toxicity may be directed to the reproductive organs and/or the related

endocrine system. The manifestation of such toxicity may be noted as alterations in sexual behavior,

fertility, pregnancy outcomes, or modifications in other functions that are dependent on the integrity of

this system.

Retrospective Study—A type of cohort study based on a group of persons known to have been exposed

at some time in the past. Data are collected from routinely recorded events, up to the time the study is

undertaken. Retrospective studies are limited to causal factors that can be ascertained from existing

records and/or examining survivors of the cohort.

Risk—The possibility or chance that some adverse effect will result from a given exposure to a chemical.

Risk Factor—An aspect of personal behavior or lifestyle, an environmental exposure, or an inborn or

inherited characteristic, that is associated with an increased occurrence of disease or other health-related

event or condition.

Risk Ratio—The ratio of the risk among persons with specific risk factors compared to the risk among

persons without risk factors. A risk ratio greater than 1 indicates greater risk of disease in the exposed

group compared to the unexposed.

Short-Term Exposure Limit (STEL)—The American Conference of Governmental Industrial

Hygienists (ACGIH) maximum concentration to which workers can be exposed for up to 15 min

continually. No more than four excursions are allowed per day, and there must be at least 60 min

between exposure periods. The daily Threshold Limit Value - Time Weighted Average (TLV-TWA) may

not be exceeded.

Target Organ Toxicity—This term covers a broad range of adverse effects on target organs or

physiological systems (e.g., renal, cardiovascular) extending from those arising through a single limited

exposure to those assumed over a lifetime of exposure to a chemical.

Teratogen—A chemical that causes structural defects that affect the development of an organism.

Threshold Limit Value (TLV)—An American Conference of Governmental Industrial Hygienists

(ACGIH) concentration of a substance to which most workers can be exposed without adverse effect. 

The TLV may be expressed as a Time Weighted Average (TWA), as a Short-Term Exposure Limit

(STEL), or as a ceiling limit (CL).

Time-Weighted Average (TWA)—An allowable exposure concentration averaged over a normal 8-hour

workday or 40-hour workweek.

Toxic Dose(50) (TD50)—A calculated dose of a chemical, introduced by a route other than inhalation,

which is expected to cause a specific toxic effect in 50% of a defined experimental animal population.
CREOSOTE 354

10. GLOSSARY

Toxicokinetic—The study of the absorption, distribution and elimination of toxic compounds in the

living organism.

Uncertainty Factor (UF)—A factor used in operationally deriving the Minimal Risk Level (MRL) or

Reference Dose (RfD) or Reference Concentration (RfC) from experimental data. UFs are intended to

account for (1) the variation in sensitivity among the members of the human population, (2) the

uncertainty in extrapolating animal data to the case of human, (3) the uncertainty in extrapolating from

data obtained in a study that is of less than lifetime exposure, and (4) the uncertainty in using lowestobserved-adverse-effect level (LOAEL) data rather than no-observed-adverse-effect level (NOAEL) data. 

A default for each individual UF is 10; if complete certainty in data exists, a value of one can be used;

however a reduced UF of three may be used on a case-by-case basis, three being the approximate

logarithmic average of 10 and 1.

Xenobiotic—Any chemical that is foreign to the biological system.

CREOSOTE A-1

APPENDIX A

ATSDR MINIMAL RISK LEVEL AND WORKSHEETS

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) [42 U.S.C.

9601 et seq.], as amended by the Superfund Amendments and Reauthorization Act (SARA) [Pub. L.

99–499], requires that the Agency for Toxic Substances and Disease Registry (ATSDR) develop jointly

with the U.S. Environmental Protection Agency (EPA), in order of priority, a list of hazardous substances

most commonly found at facilities on the CERCLA National Priorities List (NPL); prepare toxicological

profiles for each substance included on the priority list of hazardous substances; and assure the initiation

of a research program to fill identified data needs associated with the substances.

The toxicological profiles include an examination, summary, and interpretation of available toxicological

information and epidemiologic evaluations of a hazardous substance. During the development of

toxicological profiles, Minimal Risk Levels (MRLs) are derived when reliable and sufficient data exist to

identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration for a

given route of exposure. An MRL is an estimate of the daily human exposure to a hazardous substance

that is likely to be without appreciable risk of adverse noncancer health effects over a specified duration

of exposure. MRLs are based on noncancer health effects only and are not based on a consideration of

cancer effects. These substance-specific estimates, which are intended to serve as screening levels, are

used by ATSDR health assessors to identify contaminants and potential health effects that may be of

concern at hazardous waste sites. It is important to note that MRLs are not intended to define clean-up or

action levels.

MRLs are derived for hazardous substances using the no-observed-adverse-effect level/uncertainty factor

approach. They are below levels that might cause adverse health effects in the people most sensitive to

such chemical-induced effects. MRLs are derived for acute (1–14 days), intermediate (15–364 days), and

chronic (365 days and longer) durations and for the oral and inhalation routes of exposure. Currently,

MRLs for the dermal route of exposure are not derived because ATSDR has not yet identified a method

suitable for this route of exposure. MRLs are generally based on the most sensitive chemical-induced end

point considered to be of relevance to humans. Serious health effects (such as irreparable damage to the

liver or kidneys, or birth defects) are not used as a basis for establishing MRLs. Exposure to a level

above the MRL does not mean that adverse health effects will occur.
CREOSOTE A-2

APPENDIX A

MRLs are intended only to serve as a screening tool to help public health professionals decide where to

look more closely. They may also be viewed as a mechanism to identify those hazardous waste sites that

are not expected to cause adverse health effects. Most MRLs contain a degree of uncertainty because of

the lack of precise toxicological information on the people who might be most sensitive (e.g., infants,

elderly, nutritionally or immunologically compromised) to the effects of hazardous substances. ATSDR

uses a conservative (i.e., protective) approach to address this uncertainty consistent with the public health

principle of prevention. Although human data are preferred, MRLs often must be based on animal studies

because relevant human studies are lacking. In the absence of evidence to the contrary, ATSDR assumes

that humans are more sensitive to the effects of hazardous substance than animals and that certain persons

may be particularly sensitive. Thus, the resulting MRL may be as much as a hundredfold below levels

that have been shown to be nontoxic in laboratory animals.

Proposed MRLs undergo a rigorous review process: Health Effects/MRL Workgroup reviews within the

Division of Toxicology, expert panel peer reviews, and agencywide MRL Workgroup reviews, with

participation from other federal agencies and comments from the public. They are subject to change as

new information becomes available concomitant with updating the toxicological profiles. Thus, MRLs in

the most recent toxicological profiles supersede previously published levels. For additional information

regarding MRLs, please contact the Division of Toxicology, Agency for Toxic Substances and Disease

Registry, 1600 Clifton Road, Mailstop E-29, Atlanta, Georgia 30333.
CREOSOTE B-1

APPENDIX B

USER'S GUIDE

Chapter 1

Public Health Statement

This chapter of the profile is a health effects summary written in non-technical language. Its intended

audience is the general public especially people living in the vicinity of a hazardous waste site or

chemical release. If the Public Health Statement were removed from the rest of the document, it would

still communicate to the lay public essential information about the chemical.

The major headings in the Public Health Statement are useful to find specific topics of concern. The

topics are written in a question and answer format. The answer to each question includes a sentence that

will direct the reader to chapters in the profile that will provide more information on the given topic.

Chapter 2

Relevance to Public Health

This chapter provides a health effects summary based on evaluations of existing toxicologic,

epidemiologic, and toxicokinetic information. This summary is designed to present interpretive,

weight-of-evidence discussions for human health end points by addressing the following questions.

1. What effects are known to occur in humans?

2. What effects observed in animals are likely to be of concern to humans?

3. What exposure conditions are likely to be of concern to humans, especially around hazardous

waste sites?

The chapter covers end points in the same order they appear within the Discussion of Health Effects by

Route of Exposure section, by route (inhalation, oral, dermal) and within route by effect. Human data are

presented first, then animal data. Both are organized by duration (acute, intermediate, chronic). In vitro

data and data from parenteral routes (intramuscular, intravenous, subcutaneous, etc.) are also considered

in this chapter. If data are located in the scientific literature, a table of genotoxicity information is

included.

The carcinogenic potential of the profiled substance is qualitatively evaluated, when appropriate, using

existing toxicokinetic, genotoxic, and carcinogenic data. ATSDR does not currently assess cancer

potency or perform cancer risk assessments. Minimal risk levels (MRLs) for noncancer end points (if

derived) and the end points from which they were derived are indicated and discussed.

Limitations to existing scientific literature that prevent a satisfactory evaluation of the relevance to public

health are identified in the Chapter 3 Data Needs section.
CREOSOTE B-2

APPENDIX B

Interpretation of Minimal Risk Levels

Where sufficient toxicologic information is available, we have derived minimal risk levels (MRLs) for

inhalation and oral routes of entry at each duration of exposure (acute, intermediate, and chronic). These

MRLs are not meant to support regulatory action; but to acquaint health professionals with exposure

levels at which adverse health effects are not expected to occur in humans. They should help physicians

and public health officials determine the safety of a community living near a chemical emission, given the

concentration of a contaminant in air or the estimated daily dose in water. MRLs are based largely on

toxicological studies in animals and on reports of human occupational exposure.

MRL users should be familiar with the toxicologic information on which the number is based. Chapter 2,

"Relevance to Public Health," contains basic information known about the substance. Other sections such

as Chapter 3 Section 3.9, "Interactions with Other Substances,” and Section 3.10, "Populations that are

Unusually Susceptible" provide important supplemental information.

MRL users should also understand the MRL derivation methodology. MRLs are derived using a

modified version of the risk assessment methodology the Environmental Protection Agency (EPA)

provides (Barnes and Dourson 1988) to determine reference doses for lifetime exposure (RfDs). 

To derive an MRL, ATSDR generally selects the most sensitive end point which, in its best judgement,

represents the most sensitive human health effect for a given exposure route and duration. ATSDR

cannot make this judgement or derive an MRL unless information (quantitative or qualitative) is available

for all potential systemic, neurological, and developmental effects. If this information and reliable

quantitative data on the chosen end point are available, ATSDR derives an MRL using the most sensitive

species (when information from multiple species is available) with the highest NOAEL that does not

exceed any adverse effect levels. When a NOAEL is not available, a lowest-observed-adverse-effect

level (LOAEL) can be used to derive an MRL, and an uncertainty factor (UF) of 10 must be employed. 

Additional uncertainty factors of 10 must be used both for human variability to protect sensitive

subpopulations (people who are most susceptible to the health effects caused by the substance) and for

interspecies variability (extrapolation from animals to humans). In deriving an MRL, these individual

uncertainty factors are multiplied together. The product is then divided into the inhalation concentration

or oral dosage selected from the study. Uncertainty factors used in developing a substance-specific MRL

are provided in the footnotes of the LSE Tables.

Chapter 3

Health Effects

Tables and Figures for Levels of Significant Exposure (LSE)

Tables (3-1, 3-2, and 3-3) and figures (3-1 and 3-2) are used to summarize health effects and illustrate

graphically levels of exposure associated with those effects. These levels cover health effects observed at

increasing dose concentrations and durations, differences in response by species, minimal risk levels

(MRLs) to humans for noncancer end points, and EPA's estimated range associated with an upper- bound

individual lifetime cancer risk of 1 in 10,000 to 1 in 10,000,000. Use the LSE tables and figures for a

quick review of the health effects and to locate data for a specific exposure scenario. The LSE tables and

figures should always be used in conjunction with the text. All entries in these tables and figures

represent studies that provide reliable, quantitative estimates of No-Observed-Adverse-Effect Levels

(NOAELs), Lowest-Observed-Adverse-Effect Levels (LOAELs), or Cancer Effect Levels (CELs).
CREOSOTE B-3

APPENDIX B

The legends presented below demonstrate the application of these tables and figures. Representative

examples of LSE Table 3-1 and Figure 3-1 are shown. The numbers in the left column of the legends

correspond to the numbers in the example table and figure.

LEGEND

See LSE Table 3-1

(1) Route of Exposure One of the first considerations when reviewing the toxicity of a substance using

these tables and figures should be the relevant and appropriate route of exposure. When sufficient

data exists, three LSE tables and two LSE figures are presented in the document. The three LSE

tables present data on the three principal routes of exposure, i.e., inhalation, oral, and dermal (LSE

Table 3-1, 3-2, and 3-3, respectively). LSE figures are limited to the inhalation (LSE Figure 3-1)

and oral (LSE Figure 3-2) routes. Not all substances will have data on each route of exposure and

will not therefore have all five of the tables and figures.

(2) Exposure Period Three exposure periods - acute (less than 15 days), intermediate (15–364 days),

and chronic (365 days or more) are presented within each relevant route of exposure. In this

example, an inhalation study of intermediate exposure duration is reported. For quick reference to

health effects occurring from a known length of exposure, locate the applicable exposure period

within the LSE table and figure.

(3) Health Effect The major categories of health effects included in LSE tables and figures are death,

systemic, immunological, neurological, developmental, reproductive, and cancer. NOAELs and

LOAELs can be reported in the tables and figures for all effects but cancer. Systemic effects are

further defined in the "System" column of the LSE table (see key number 18).

(4) Key to Figure Each key number in the LSE table links study information to one or more data points

using the same key number in the corresponding LSE figure. In this example, the study represented

by key number 18 has been used to derive a NOAEL and a Less Serious LOAEL (also see the 2

"18r" data points in Figure 3-1).

(5) Species The test species, whether animal or human, are identified in this column. Chapter 2,

"Relevance to Public Health," covers the relevance of animal data to human toxicity and

Section 3.4, "Toxicokinetics," contains any available information on comparative toxicokinetics. 

Although NOAELs and LOAELs are species specific, the levels are extrapolated to equivalent

human doses to derive an MRL.

(6) Exposure Frequency/Duration The duration of the study and the weekly and daily exposure

regimen are provided in this column. This permits comparison of NOAELs and LOAELs from

different studies. In this case (key number 18), rats were exposed to 1,1,2,2-tetrachloroethane via

inhalation for 6 hours per day, 5 days per week, for 3 weeks. For a more complete review of the

dosing regimen refer to the appropriate sections of the text or the original reference paper, i.e.,

Nitschke et al. 1981.

(7) System This column further defines the systemic effects. These systems include: respiratory,

cardiovascular, gastrointestinal, hematological, musculoskeletal, hepatic, renal, and dermal/ocular. 

"Other" refers to any systemic effect (e.g., a decrease in body weight) not covered in these systems. 

In the example of key number 18, 1 systemic effect (respiratory) was investigated.
CREOSOTE B-4

APPENDIX B

(8) NOAEL A No-Observed-Adverse-Effect Level (NOAEL) is the highest exposure level at which no

harmful effects were seen in the organ system studied. Key number 18 reports a NOAEL of 3 ppm

for the respiratory system which was used to derive an intermediate exposure, inhalation MRL of

0.005 ppm (see footnote "b").

(9) LOAEL A Lowest-Observed-Adverse-Effect Level (LOAEL) is the lowest dose used in the study

that caused a harmful health effect. LOAELs have been classified into "Less Serious" and

"Serious" effects. These distinctions help readers identify the levels of exposure at which adverse

health effects first appear and the gradation of effects with increasing dose. A brief description of

the specific end point used to quantify the adverse effect accompanies the LOAEL. The respiratory

effect reported in key number 18 (hyperplasia) is a Less serious LOAEL of 10 ppm. MRLs are not

derived from Serious LOAELs.

(10) Reference The complete reference citation is given in Chapter 9 of the profile.

(11) CEL A Cancer Effect Level (CEL) is the lowest exposure level associated with the onset of

carcinogenesis in experimental or epidemiologic studies. CELs are always considered serious

effects. The LSE tables and figures do not contain NOAELs for cancer, but the text may report

doses not causing measurable cancer increases.

(12) Footnotes Explanations of abbreviations or reference notes for data in the LSE tables are found in

the footnotes. Footnote "b" indicates the NOAEL of 3 ppm in key number 18 was used to derive an

MRL of 0.005 ppm.

LEGEND

See Figure 3-1

LSE figures graphically illustrate the data presented in the corresponding LSE tables. Figures help the

reader quickly compare health effects according to exposure concentrations for particular exposure

periods.

(13) Exposure Period The same exposure periods appear as in the LSE table. In this example, health

effects observed within the intermediate and chronic exposure periods are illustrated.

(14) Health Effect These are the categories of health effects for which reliable quantitative data exists. 

The same health effects appear in the LSE table.

(15) Levels of Exposure concentrations or doses for each health effect in the LSE tables are graphically

displayed in the LSE figures. Exposure concentration or dose is measured on the log scale "y" axis. 

Inhalation exposure is reported in mg/m3

 or ppm and oral exposure is reported in mg/kg/day.

(16) NOAEL In this example, 18r NOAEL is the critical end point for which an intermediate inhalation

exposure MRL is based. As you can see from the LSE figure key, the open-circle symbol indicates

to a NOAEL for the test species-rat. The key number 18 corresponds to the entry in the LSE table. 

The dashed descending arrow indicates the extrapolation from the exposure level of 3 ppm (see

entry 18 in the Table) to the MRL of 0.005 ppm (see footnote "b" in the LSE table).

(17) CEL Key number 38r is 1 of 3 studies for which Cancer Effect Levels were derived. The diamond

symbol refers to a Cancer Effect Level for the test species-mouse. The number 38 corresponds to

the entry in the LSE table.
CREOSOTE B-5

APPENDIX B

(18) Estimated Upper-Bound Human Cancer Risk Levels This is the range associated with the

upper-bound for lifetime cancer risk of 1 in 10,000 to 1 in 10,000,000. These risk levels are

derived from the EPA's Human Health Assessment Group's upper-bound estimates of the slope of

the cancer dose response curve at low dose levels (q1*).

(19) Key to LSE Figure The Key explains the abbreviations and symbols used in the figure.
CREOSOTE B-6

APPENDIX B

SAMPLE

1 6 Table 3-1. Levels of Significant Exposure to [Chemical x] – Inhalation

Key tofigurea Species

Exposurefrequency/duration System

NOAEL(ppm)

LOAEL (effect)

Reference Less serious (ppm) Serious (ppm)

2 6 INTERMEDIATE EXPOSURE

5 6 7 8 9 10

3 6 Systemic 9 9 9 99 9

4 6 18 Rat 13 wk

5 d/wk6 hr/d

Resp 3b 10 (hyperplasia) Nitschke et al.

1981

CHRONIC EXPOSURE

11

Cancer 938 Rat 18 mo

5 d/wk7 hr/d

20 (CEL, multiple

organs)

Wong et al. 1982

39 Rat 89–104 wk

5 d/wk6 hr/d

10 (CEL, lung tumors,

nasal tumors)

NTP 1982

40 Mouse 79–103 wk

5 d/wk6 hr/d

10 (CEL, lung tumors,

hemangiosarcomas)

NTP 1982

a The number corresponds to entries in Figure 3-1.

12 6 b Used to derive an intermediate inhalation Minimal Risk Level (MRL) of 5 x 10-3 ppm; dose adjusted for intermittent exposure and divided by an uncertainty factor of 100 (10 for extrapolation from animal to humans, 10 for human variability).
CREOSOTE B-7

APPENDIX B
CREOSOTE B-8

APPENDIX B
CREOSOTE C-1

APPENDIX C

ACRONYMS, ABBREVIATIONS, AND SYMBOLS

ACOEM American College of Occupational and Environmental Medicine

ACGIH American Conference of Governmental Industrial Hygienists

ADI acceptable daily intake

ADME absorption, distribution, metabolism, and excretion

AED atomic emission detection

AOEC Association of Occupational and Environmental Clinics

AFID alkali flame ionization detector

AFOSH Air Force Office of Safety and Health

ALT alanine aminotransferase

AML acute myeloid leukemia

AOAC Association of Official Analytical Chemists

AP alkaline phosphatase

APHA American Public Health Association

AST aspartate aminotranferase

atm atmosphere

ATSDR Agency for Toxic Substances and Disease Registry

AWQC Ambient Water Quality Criteria

BAT best available technology

BCF bioconcentration factor

BEI Biological Exposure Index

BSC Board of Scientific Counselors

C centigrade

CAA Clean Air Act

CAG Cancer Assessment Group of the U.S. Environmental Protection Agency

CAS Chemical Abstract Services

CDC Centers for Disease Control and Prevention

CEL cancer effect level

CELDS Computer-Environmental Legislative Data System

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations

Ci curie

CI confidence interval

CL ceiling limit value

CLP Contract Laboratory Program

cm centimeter

CML chronic myeloid leukemia

CPSC Consumer Products Safety Commission

CWA Clean Water Act

DHEW Department of Health, Education, and Welfare

DHHS Department of Health and Human Services

DNA deoxyribonucleic acid

DOD Department of Defense

DOE Department of Energy

DOL Department of Labor

DOT Department of Transportation
CREOSOTE C-2

APPENDIX C

DOT/UN/ Department of Transportation/United Nations/

 NA/IMCO North America/International Maritime Dangerous Goods Code

DWEL drinking water exposure level

ECD electron capture detection

ECG/EKG electrocardiogram

EEG electroencephalogram

EEGL Emergency Exposure Guidance Level

EPA Environmental Protection Agency

F Fahrenheit

F1 first-filial generation

FAO Food and Agricultural Organization of the United Nations

FDA Food and Drug Administration

FEMA Federal Emergency Management Agency

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FPD flame photometric detection

fpm feet per minute

FR Federal Register

FSH follicle stimulating hormone

g gram

GC gas chromatography

gd gestational day

GLC gas liquid chromatography

GPC gel permeation chromatography

HPLC high-performance liquid chromatography

HRGC high resolution gas chromatography

HSDB Hazardous Substance Data Bank 

IARC International Agency for Research on Cancer

IDLH immediately dangerous to life and health

ILO International Labor Organization

IRIS Integrated Risk Information System 

Kd adsorption ratio

kg kilogram

Koc organic carbon partition coefficient

Kow octanol-water partition coefficient

L liter

LC liquid chromatography

LCLo lethal concentration, low

LC50 lethal concentration, 50% kill

LDLo lethal dose, low

LD50 lethal dose, 50% kill

LDH lactic dehydrogenase

LH luteinizing hormone

LT50 lethal time, 50% kill

LOAEL lowest-observed-adverse-effect level

LSE Levels of Significant Exposure

m meter

MA trans,trans-muconic acid

MAL maximum allowable level

mCi millicurie

MCL maximum contaminant level

MCLG maximum contaminant level goal
CREOSOTE C-3

APPENDIX C

MFO mixed function oxidase

mg milligram

MGP manufactured gas plant

mL milliliter

mm millimeter

mmHg millimeters of mercury

mmol millimole

mppcf millions of particles per cubic foot

MRL Minimal Risk Level

MS mass spectrometry

NAAQS National Ambient Air Quality Standard

NAS National Academy of Science

NATICH National Air Toxics Information Clearinghouse

NATO North Atlantic Treaty Organization

NCE normochromatic erythrocytes

NCEH National Center for Environmental Health

NCI National Cancer Institute

ND not detected

NFPA National Fire Protection Association

ng nanogram

NIEHS National Institute of Environmental Health Sciences

NIOSH National Institute for Occupational Safety and Health

NIOSHTIC NIOSH's Computerized Information Retrieval System

NLM National Library of Medicine

nm nanometer

NHANES National Health and Nutrition Examination Survey

nmol nanomole

NOAEL no-observed-adverse-effect level

NOES National Occupational Exposure Survey

NOHS National Occupational Hazard Survey

NPD nitrogen phosphorus detection

NPDES National Pollutant Discharge Elimination System

NPL National Priorities List

NR not reported

NRC National Research Council

NS not specified

NSPS New Source Performance Standards

NTIS National Technical Information Service

NTP National Toxicology Program

ODW Office of Drinking Water, EPA

OERR Office of Emergency and Remedial Response, EPA

OHM/TADS Oil and Hazardous Materials/Technical Assistance Data System

OPP Office of Pesticide Programs, EPA

OPPTS Office of Prevention, Pesticides and Toxic Substances, EPA

OPPT Office of Pollution Prevention and Toxics, EPA

OR odds ratio

OSHA Occupational Safety and Health Administration

OSW Office of Solid Waste, EPA

OW Office of Water

OWRS Office of Water Regulations and Standards, EPA

PAH polycyclic aromatic hydrocarbon
CREOSOTE C-4

APPENDIX C

PBPD physiologically based pharmacodynamic 

PBPK physiologically based pharmacokinetic 

PCE polychromatic erythrocytes

PEL permissible exposure limit

PID photo ionization detector

pg picogram

pmol picomole

PHS Public Health Service

PMR proportionate mortality ratio

ppb parts per billion

ppm parts per million

ppt parts per trillion

PSNS pretreatment standards for new sources

RBC red blood cell

REL recommended exposure level/limit

RfC reference concentration

RfD reference dose

RNA ribonucleic acid

RTECS Registry of Toxic Effects of Chemical Substances

RQ reportable quantity

SARA Superfund Amendments and Reauthorization Act

SCE sister chromatid exchange

SGOT serum glutamic oxaloacetic transaminase

SGPT serum glutamic pyruvic transaminase

SIC standard industrial classification

SIM selected ion monitoring

SMCL secondary maximum contaminant level

SMR standardized mortality ratio

SNARL suggested no adverse response level

SPEGL Short-Term Public Emergency Guidance Level

STEL short term exposure limit

STORET Storage and Retrieval

TD50 toxic dose, 50% specific toxic effect

TLV threshold limit value

TOC total organic carbon

TPQ threshold planning quantity

TRI Toxics Release Inventory

TSCA Toxic Substances Control Act

TWA time-weighted average

UF uncertainty factor

U.S. United States

USDA United States Department of Agriculture

USGS United States Geological Survey

VOC volatile organic compound

WBC white blood cell

WHO World Health Organization

> greater than $ greater than or equal to

= equal to
CREOSOTE C-5

APPENDIX C

< less than # less than or equal to

% percent α alpha β beta γ gamma δ delta

μm micrometer

μg microgram q1* cancer slope factor

– negative

+ positive

(+) weakly positive result

(–) weakly negative result

CREOSOTE D-1

APPENDIX D

INDEX

acute dermal exposure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

adenocarcinoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 107, 108

adipose tissue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164, 284, 285

adrenal gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

adrenal glands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 51, 56, 58, 98, 104, 105, 124, 134, 135, 188, 190

adsorption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263, 271, 273, 277, 280

aerobic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255-257, 276

AHH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161, 162, 167, 172, 173, 184, 186, 192, 199, 200

air . . . . . . . . . . . . . . . 2-4, 6-9, 14, 15, 44, 52, 53, 63, 126, 130, 141, 156, 157, 168, 172, 174, 175, 191, 202, 223, 225, 231, 244,

 246-248, 250, 254, 258, 265, 266, 268, 270, 271, 275, 278, 284, 287, 290, 293, 294, 297-299

alanine aminotransferase (see ALT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

ALT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92, 94, 95

ambient air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126, 254

anaerobic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255, 276

aryl hydrocarbon hydroxylase (see AHH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

aspartate aminotransferase (see AST) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

AST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50, 92, 94

bioaccumulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 202, 253, 258, 261, 262, 273, 274, 277

bioavailability ........................................................................ 255, 273, 277, 279-282

bioconcentration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253, 276, 277

bioconcentration factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253

biodegradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255-257, 262, 272, 280-282

biomagnification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19, 261, 262, 277

biomarker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195, 196, 211, 212, 215, 263, 268-270, 284, 296

birth weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57, 134

blood . . . . . . . . . . . . . . . . . . . . . . . 13, 47-49, 89-91, 93, 95, 96, 121, 122, 132, 147, 148, 151, 152, 158, 160, 162, 163, 165, 167,

169, 184, 191, 195, 197, 211, 270, 272, 284, 285

body weight effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45, 54, 87, 98, 113, 131

breast cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108-110, 188

breast milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9, 12, 163, 173, 184, 185, 195, 270, 273

cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9, 11, 20, 22, 28, 42-44, 58-64, 107-112, 124, 127, 136-139, 147, 159, 186, 188,

191, 193, 198, 199, 201, 207, 208, 211, 219, 220, 258, 268, 269, 301

carcinogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 22, 24, 112, 211, 298, 301

carcinogenic . . . . . . . . . . . . . . . . . 8, 22, 24, 27-29, 64, 108, 138-140, 144-147, 186, 198, 199, 208, 247, 255, 269, 270, 298, 301

carcinogenicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 24, 108, 110, 139, 185, 186, 208, 212, 265, 299-301

carcinoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63, 64, 132, 136, 140, 141, 200

cardiovascular effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47, 48, 89, 120, 121

chloracne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52, 127

chromosomal abnormalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

crustaceans ..................................................................................... 262, 277

deoxyribonucleic acid (see DNA) ................................................................... 152, 154

dermal effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-23, 52, 53, 87, 98, 124, 127, 128, 211

DNA . . . . . . . . . . . . . . . . . . . . . . . . . 99, 147-154, 159-161, 165, 167, 173, 196, 197, 201, 208, 211, 212, 270, 273, 284-287, 296

endocrine effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51, 97, 113, 124

EROD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

estrogen receptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188

estrogenic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 105, 188, 189

ethoxyresorufin-O-deethylase (see EROD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

FDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 299-301

FEDRIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214, 280

fetus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9, 190, 192, 200

fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 12, 19, 20, 253, 258, 261, 273, 274, 278, 279

fish consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274, 278

Food and Drug Administration (see FDA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 301

friable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

gastrointestinal effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48, 89, 90, 121
CREOSOTE D-2

APPENDIX D

general population . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5, 21, 42, 52, 133, 137, 138, 195, 200, 262, 274

groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4, 6, 7, 19, 46, 53, 120, 238, 243, 248, 249, 257, 259, 276, 289

half-life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195, 254, 297

hematological effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49, 91, 121

Henry’s law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253, 301

hepatic effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21, 50, 92, 122, 198

hydrolysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277, 286

hydroxyl radical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

IgG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

immune system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

immunoglobulin G (see IgG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

immunological effects ........................................................................ 132, 210, 280

Integrated Risk Information System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

kidney . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 8, 20, 22, 43, 51, 56, 58, 87, 96, 97, 107, 123, 134, 135, 152, 192, 199, 205, 274

lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251, 257, 262

LD50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64, 85, 86, 91, 112, 205

leukemia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22, 43, 58, 85

liver . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 8, 20, 21, 50, 56, 58, 60, 87, 92-96, 104, 105, 111, 122, 134, 135, 149, 151, 152, 159,

162-165, 167, 169, 170, 172, 183, 184, 188, 193-195, 199, 205, 208, 285

lung . . . . . . . . . . . . . . . . . . . . . . 8, 22, 23, 42-47, 57, 58, 60-63, 88, 105, 106, 110, 111, 135, 139, 143, 144, 149-152, 157, 158,

162-165, 184, 195, 205, 208, 209, 268

lymph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 146

lymphatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

lymphoreticular effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54, 101, 102, 131, 132

marine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234, 247, 249, 257, 258, 262, 271

milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7, 9, 12, 163, 173, 184, 185, 195, 270, 273

Minimal Risk Levels (see MRL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 28

MRL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 24, 206, 207

MRLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23, 25, 28, 298

musculoskeletal effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45, 206, 207

National Institute for Occupational Safety and Health (see NIOSH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

National Occupational Exposure Survey (see NOES) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

National Priorities List (see NPL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 17, 46, 241, 243

neoplastic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108, 136

neurobehavioral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

NHL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

NIOSH . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 29, 30, 52, 53, 126-128, 130, 132, 172, 210, 218-220, 224, 265, 267, 283, 299, 301

nitrophenol ................................................................................. 167, 169, 170

NOAEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 45, 87, 101-105, 107, 113

NOAELs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 28

NOES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

non-Hodgkin's lymphoma (see NHL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

no-observed-adverse-effect levels (see NOAEL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

NPL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 17, 46, 53, 120, 241-244, 247-251, 255, 259, 260, 262, 272, 280

ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52, 53, 126

ocular effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53, 130

odds ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

particulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156, 157, 174, 175, 254, 265, 266, 270, 284, 290, 294

particulates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251, 265, 266

partition coefficients .......................................................................... 223, 225, 231

PBPD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

PBPK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180-183, 191, 214

pharmacodynamic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180, 181

pharmacokinetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155, 180-183, 206-209, 212, 213

photolysis .................................................................................. 252, 255, 277

physiologically based pharmacodynamic (see PBPD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

physiologically based pharmacokinetic (see PBPK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180, 183

playground equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9, 12

protective gloves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156, 174, 267

public health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, 8, 14, 17, 20, 27, 28, 187, 203, 274, 275, 283, 295

RCRA ..................................................................................... 238, 280, 301
CREOSOTE D-3

APPENDIX D

reference dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298, 301

regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15, 25, 298-301

renal effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 50, 51, 96, 122, 123

Resource Conservation and Recovery Act (see RCRA) ............................................... 238, 280, 301

Restricted-use pesticide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 12, 15

salivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

salmon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249, 252

sediment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238, 244, 250-252, 255-257, 259-261, 288, 291, 293, 294

selenium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

serum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21, 50, 92-96, 132, 148, 158, 165, 169, 284

SMR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43, 60

soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10, 14, 22, 46, 53, 57, 108, 120, 128, 129, 176, 201, 244, 248-253, 255-257, 259,

260, 262, 271-273, 275, 277, 279, 280, 297

solubility .................................................... 158, 164, 184, 223, 225, 231, 251, 255, 262, 275, 294

Standardized mortality ratio (see SMR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Superfund . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251, 252, 255, 257, 280, 282

surface water ........................................................ 244, 247-250, 255, 256, 259, 276, 278, 280

thyroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 51, 97

time-weighted average (see TWA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59, 298, 301

toxicokinetic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27, 155

Toxics Release Inventory (see TRI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234, 244

transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52, 184, 186, 187, 201, 250, 251, 258, 276, 277, 280, 301

TRI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234, 238, 244, 246, 248-250, 276

tumors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20, 22, 44, 63, 64, 108-111, 126, 129, 140-147, 162, 185, 186, 205, 208

TWA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59, 298, 299, 301

U.S. Department of Agriculture (see USDA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244

USDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244, 247, 248, 256, 258, 262, 264, 266, 267, 274, 280, 282

vapor phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157, 175, 254, 266

vapor pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223, 225, 231, 275

volatility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256

volatilization ..................................................... 244, 247, 250, 252, 253, 256, 267, 271, 272, 287

water . . . . . . . . . . . . 2-8, 10, 12, 14, 19, 90, 108, 109, 125, 158, 159, 164, 165, 169, 177, 184, 185, 188, 191, 196, 201, 202, 206,

207, 211, 223-225, 231, 234, 238, 244-252, 255-257, 259-263, 271, 272, 274-278, 280-282,

285, 289, 291, 293, 294, 297-299