# HAZARDOUS WASTE CHARACTERISTICS SCOPING STUDY

U.S. Environmental Protection Agency Office of Solid Waste

November 15, 1996i 

# TABLE OF CONTENTS Page
EXECUTIVE SUMMARY

................................................................... ES-1 CHAPTER 1. INTRODUCTION

............................................................ 1-1

1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study

. . 1-1
1.2 Regulatory Background

................................................. 1-2
1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics

..... 1-4 Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management

. 1-4 Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste Management 1-4 Step 3: Review the Existing Characteristics

................................ 1-4 Step 4: Identify Gaps Associated with Non-TC Chemicals

.................... 1-6 Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and Large-Scale Environmental Problems

............................... 1-6 Step 6: Review State Expansions of TC and State Listings

.................... 1-7 Step 7: Evaluate the Industries and Waste Management Practices Associated with Potential Gaps

................................................. 1-7 Step 8: Assess Regulatory Programs' Coverage of Potential Gaps

............... 1-8 Step 9: Present Integrated Evaluation of Nature and Extent of Potential Gaps

..... 1-8
1.4 Report Outline

........................................................ 1-8 CHAPTER 2. RELEASES FROM NON-HAZARDOUS INDUSTRIAL WASTE MANAGEMENT UNITS 2-1
2.1 Methodology

.......................................................... 2-1
2.1.1 Criteria For Selecting Releases

.................................... 2-1
2.1.2 Approach For Identifying Releases

................................. 2-3 2.1.2.1 State Industrial D Programs

................................ 2-3 2.1.2.2 State Superfund Programs

................................. 2-5 2.1.2.3 Federal Superfund Program

................................ 2-6 2.1.2.4 Construction and Demolition (C&D) Landfill Report

............ 2-6
2.1.3 Release Profile Preparation

....................................... 2-7
2.2 Results

............................................................... 2-8 2.2.1 Number of Cases By State

........................................ 2-8 2.2.2 Number of Cases By Industry

..................................... 2-10 2.2.3 Number of Cases By Type of Waste Management Unit

................. 2-11

# TABLE OF CONTENTS(Continued)
Page

ii 2.2.4 Type of Media Affected

.......................................... 2-12 2.2.5 Types of Contaminants Released

................................... 2-13
2.3 Major Limitations

...................................................... 2-17 CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS 3-1
3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics

............ 3-1 3.1.1 Statutory and Regulatory Framework

............................... 3-1 3.1.2 Risks Associated with Physical Hazards

............................. 3-3 3.1.3 Acute Toxic Hazards to Humans

................................... 3-4 3.1.4 Chronic Toxicity Risks to Humans

................................. 3-4 3.1.5 Risks to Non-Human Receptors

................................... 3-5 3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management 3-6
3.2 Ignitability Characteristic

................................................ 3-8 3.2.1 Definition of Ignitability

......................................... 3-8 3.2.2 Potential Gaps Related to Definition of Ignitability

.................... 3-9 3.2.3 Potential Gaps Related to Ignitability Test Methods

...................... 3-12
3.3 Corrosivity

........................................................... 3-12 3.3.1 Definition of Corrosivity

......................................... 3-12 3.3.2 Potential Gaps Related to Definition of Corrosivity

.................... 3-13 3.3.3 Potential Gaps Related to Corrosivity Test Methods

................... 3-16
3.4 Reactivity

............................................................ 3-16 3.4.1 Definition of Reactivity

.......................................... 3-16 3.4.2 Potential Gaps Related to Definition of Reactivity

..................... 3-17 3.4.3 Potential Gaps Related to Reactivity Test Methods

.................... 3-19

# TABLE OF CONTENTS(Continued)
Page

iii 3.5 Potential Gaps Associated with the Toxicity Characteristic

..................... 3-19 3.5.1 Definition of Toxicity Characteristic

................................ 3-19 3.5.2 Changes in Groundwater Pathway Analysis

.......................... 3-21 3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes

......... 3-27 3.5.4 Potential Risks from Surface Water Exposures

....................... 3-33 3.5.5 Potential Indirect Pathway Risks from TC Analytes

.................... 3-35 3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes

......... 3-38 3.5.7 Potential Risks to Ecological Receptors from TC Analytes

.............. 3-38
3.6 Potential Gaps Associated with TCLP

...................................... 3-39 3.6.1 TCLP Background

.............................................. 3-39 3.6.2 Limitations of the TCLP

......................................... 3-42 CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH NON-TC CHEMICALS

................ 4-1

4.1 Overview of Methodology

............................................... 4-1 Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents

. 4-1 Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents

. 4-1 Step 3: Apply Hazard-Based Screening Criteria

............................. 4-3 Step 4: Review Relevant Multipathway Risk Modeling Results

................. 4-3 Step 5: Identify Potential Acute Hazards

.................................... 4-3 Step 6: Summarize Findings

............................................. 4-3
4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes

..... 4-3
4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern 4-7 4.3.1 Approach to Identifying Potentially Hazardous Chemicals

.............. 4-7 4.3.2 Screening Approach

............................................ 4-9 4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial Waste Constituents

............................................. 4-12

# TABLE OF CONTENTS(Continued)
Page

iv 4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste Constituents

................................................... 4-15 4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents

...... 4-20
4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents 4-20 4.4.1 Combine the Lists

.............................................. 4-20 4.4.2 Screen Combined List Against Single Criteria

........................ 4-25 4.4.3 Screen Combined List Against Multiple Parameters

................... 4-33
4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste Constituents

.......................................................... 4-34
4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial Waste Constituents

..................................................... 4-35
4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps

. 4-40 CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH NATURAL RESOURCE DAMAGES AND LARGE-SCALE ENVIRONMENTAL

PROBLEMS

................................................................ 5-1
5.1 Damage to Groundwater Resources

........................................ 5-1
5.2 Damage to Local Air Quality from Odors

................................... 5-2
5.3 Large-Scale Environmental Problems

...................................... 5-4 5.3.1 Air Deposition to the Great Waters

................................. 5-4 5.3.2 Airborne Particulates

............................................ 5-6 5.3.3 Global Climate Change

.......................................... 5-7 5.3.4 Potential Damages from Endocrine Disruptors

........................ 5-9 5.3.5 Red Tides

..................................................... 5-13 5.3.6 Stratospheric Ozone Depletion

.................................... 5-14 5.3.7 Tropospheric Ozone and Photochemical Air Pollution

................. 5-15 5.3.8 Water Pollution

................................................ 5-15 CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY CHARACTERISTIC AND LISTINGS

. . 6-1

6.1 State Expanded Toxicity Characteristics

.................................... 6-1 6.2 State Only Listings

..................................................... 6-2

6.3 State Restrictions on Exemptions

.......................................... 6-5 6.4 Summary

............................................................. 6-6

# TABLE OF CONTENTS(Continued)
Page

v CHAPTER 7. SUMMARY OF POTENTIAL GAPS

........................................... 7-1

7.1 Organization of the Analysis of Potential Gaps

............................... 7-1 7.2 Summary of Potential Gaps

.............................................. 7-2 CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF INDUSTRY AND WASTE MANAGEMENT METHODS 8-1
8.1 Data Sources and Major Limitations

....................................... 8-1
8.2 Potential Gaps as a Function of Industry/Waste Source

......................... 8-3 8.2.1 Non-Hazardous Industrial Waste Generation by Industry

............... 8-3 8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste Releases 8-5 8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry

..... 8-8 8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible NonHazardous Industrial Waste Constituents

............................ 8-18
8.3 Potential Gaps as a Function of Management Practices

......................... 8-21 8.3.1 Waste Management Practices by Waste Type and Industry

.............. 8-21 8.3.2 Management Practices Seen in the Release Descriptions

................ 8-24 8.3.3 Potential Hazards Associated with Use Constituting Disposal

............ 8-29 8.3.4 Potential Hazards Associated with Other Management Practices

......... 8-31 CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED BY EXISTING REGULATIONS

.... 9-1

9.1 RCRA Programs

....................................................... 9-1 9.1.1 Hazardous Waste Programs

......................................... 9-1 9.1.2 Subtitle D

....................................................... 9-3
9.2 Medium-Specific Regulations

............................................ 9-3 9.2.1 Clean Water Act

.................................................. 9-4 9.2.2 Safe Drinking Water Act

........................................... 9-7 9.2.3 Clean Air Act Amendments

......................................... 9-10

9.3 Federal Insecticide, Fungicide, and Rodenticide Act

........................... 9-13
9.4 Toxic Substance Control Act

............................................. 9-15
9.5 Pollution Prevention

.................................................... 9-15
9.6 Occupational Safety and Health Act

........................................ 9-16

# TABLE OF CONTENTS(Continued)
Page

vi 9.7 Hazardous Materials Transportation Act

.................................... 9-16
9.8 Summary

............................................................. 9-19 CHAPTER 10. SUMMARY EVALUATION OF NATURE AND EXTENT OF POTENTIAL GAPS

. . 10-1

10.1 Overview of the Evaluation of Potential Gaps

................................ 10-1 10.1.1 Objectives of the Gaps Analysis

................................... 10-1 10.1.2 Criteria Used for Evaluating Gaps

................................. 10-1
10.2 Findings of the Evaluation

............................................... 10-3 10.2.1 Potential Gaps Associated with the ICR Characteristics

................ 10-3 10.2.2 Potential Gaps Associated with TC Analytes

......................... 10-8 10.2.3 Potential Gaps Associated with Non-TC Waste Constituents

............ 10-14 10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental Problems

..................................................... 10-22 10.2.5 Gaps Associated with State TC Expansions and Listings

................. 10-25 10.2.6 Major Data Gaps and Uncertainties

.................................. 10-26
10.3 Framework for Determining an Appropriate Course of Action

................... 10-27 10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze Key Issues and Fill Major Data Deficiencies

......................... 10-27 10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps 10-27vii 

# LIST OF EXHIBITS Page
Exhibit 1-1 Scoping Study Approach

........................................................ 1-5
Exhibit 2-1 Number of Release Descriptions By State

.......................................... 2-9 Exhibit 2-2 Number of Management Units & Volume of Waste Managed On-Site, by State (1985)

...... 2-9 Exhibit 2-3 Number of Case Studies by Industry (SIC)

.......................................... 2-10 Exhibit 2-4 Number of Case Studies By Waste Management Unit

................................. 2-12 Exhibit 2-5 TC Contaminants Detected in Case Studies

......................................... 2-14 Exhibit 2-6 Contaminants with SMCLs Detected in Case Studies

................................. 2-15 Exhibit 2-7 Other Contaminants Detected in At Least Three Case Studies

........................... 2-16 Exhibit 2-8 Most Common Constituents By Industry

............................................ 2-18
Exhibit 3-1 Risks Potentially Associated with Non-Hazardous Industrial Waste Management

........... 3-7 Exhibit 3-2 Materials Formerly Classified by DOT as Combustible Liquids (which generally are not

RCRA ignitable)

.............................................................. 3-11 Exhibit 3-3 Other Definitions of Reactivity

................................................... 3-18 Exhibit 3-4 TC Constituents and Regulatory Levels (mg/l)

....................................... 3-20 Exhibit 3-5 Comparison of TC Regulatory Concentrations and HWIR-Waste Proposed Exit/Leech Levels

. 3-25 Exhibit 3-6 Summary of Inhalation Pathway Screening Methods, Input Data, and Models Used for

Bounding Risk Analysis

........................................................ 3-29 Exhibit 3-7 Emission Fraction for Air Releases of Volatile TC Analytes

............................ 3-30 Exhibit 3-8 Inhalation Pathway Risks for TC Analytes and Their Dependence on Fate and Transport

Properties

.................................................................... 3-32 Exhibit 3-9 Major Fate and Transport Parameters for TC Analytes

................................ 3-36 Exhibit 3-10 Ratios of TC Leachate Regulatory Levels to Ambient Water Quality Criteria for Aquatic

Life

......................................................................... 3-40
Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential Gaps in the

TC Characteristics

............................................................. 4-2 Exhibit 4-2 Known Non-Hazardous Industrial Waste Constituents Found in Case Studies, ISDB, Listings

Documents, and Effluent Guidelines by Chemical Class

............................... 4-6 Exhibit 4-3 Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents

.............. 4-8 Exhibit 4-4 Criteria Considered for Screening Non-Hazardous Industrial Waste Constituents

........... 4-10 Exhibit 4-5 Toxicity Screening Results for Possible Non-Hazardous Industrial Waste Constituents

....... 4-13
Exhibit 4-6 Persistence and Bioconcentration/Bioaccumulation Screening Results for Possible NonHazardous Industrial Waste Constituents

........................................... 4-16 Exhibit 4-7 Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating Possible NonHazardous Industrial Waste Constituents Against TRI Release Volumes

.................. 4-17 Exhibit 4-8 Possible Non-Hazardous Industrial Waste

# LIST OF EXHIBITS(Continued) Page

viii Constituents by Chemical Class

.................................................. 4-21 Exhibit 4-9 Screening of Known Non-Hazardous Industrial Waste Constituents Against TRI Release

Volumes

..................................................................... 4-22 Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents

.... 4-26 Exhibit 4-11 Potential Endocrine Disruptors

................................................... 4-27 Exhibit 4-12 TRI Releases and Non-Confidential TSCA Production Volume Data for the Known and Possible NonHazardous Industrial Waste Constituents

........................................... 4-28 Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Summary Potential of Known and

Possible Non-Hazardous Industrial Waste Constituents

................................ 4-29 Exhibit 4-14 LNAPL/DNAPL Formation Potential of Known and Possible Non-Hazardous Industrial Waste

Constituents

.................................................................. 4-32 Exhibit 4-15 Multiple Screening Criteria Applied to Known and Possible Non-Hazardous Industrial Waste

Constituents

.................................................................. 4-34 Exhibit 4-16 Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous Industrial

Waste Constituents

............................................................ 4-36 Exhibit 4-17 Potential Acute Hazards Associated with Known and Possible Non-Hazardous Industrial

Waste Constituents

............................................................ 4-39 Exhibit 4-18 Potential Gaps in the Hazardous Waste Characteristics Identified Based on the Hazardous

Properties of Known and Possible Non-Hazardous Industrial Waste Constituents

........... 4-41
Exhibit 5-1 Constituents/Properties with SMCLs Found in Release Descriptions

..................... 5-2 Exhibit 5-2 Chemicals from Release Descriptions with Low Odor Thresholds

....................... 5-3 Exhibit 5-3 Initial List of Large-Scale Environmental Problems

................................... 5-4 Exhibit 5-4 U.S. Sources of Air Pollutants of Concern for Great Waters

............................ 5-5
Exhibit 6-1 State Toxicity Characteristics: Additional Constituents and More Stringent Regulatory

Levels

....................................................................... 6-3 Exhibit 6-2 State Toxicity Criteria Applied to Whole Waste (Representative Sample)

................. 6-4
Exhibit 7-1 Summary of Potential Gaps in the Hazardous Waste Characteristics

...................... 7-2

# LIST OF EXHIBITS(Continued) Page

ix Exhibit 8-1 Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group

......... 8-4 Exhibit 8-2 Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels in the Release

Descriptions for Non-Hazardous Waste Management

................................. 8-6 Exhibit 8-3 Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in Release

Descriptions

.................................................................. 8-7 Exhibit 8-4 Most Frequently Occurring Constituents in the Release Descriptions

..................... 8-9 Exhibit 8-5 Occurrence of Waste Constituents by Industry Group

................................. 8-11 Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry

.............. 8-19 Exhibit 8-7 Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in 1985

..... 8-22 Exhibit 8-8 Active Non-Hazardous Industrial Waste Management Units in 1985 by Major Industry Group 8-23 Exhibit 8-9 Non-Hazardous Industrial Waste Management by Industry and Waste Type from TSDR and ISDB 8-25 Exhibit 8-10 Waste Management Unit Types in the Release Descriptions

............................ 8-30 Exhibit 9-1 TC Constituents with Effluent Limits Established under CWA

.......................... 9-5 Exhibit 9-2 CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial Waste

Constituents

.................................................................. 9-6 Exhibit 9-3 CWA Coverage of Industries Represented in Release Descriptions

...................... 9-7 Exhibit 9-4 TC Constituents with SDWA MCL Levels

.......................................... 9-8 Exhibit 9-5 MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern in Groundwater

Pathways

.................................................................... 9-9 Exhibit 9-6 TC Constituents Designated as HAPs under CAA

.................................... 9-11 Exhibit 9-7 CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents

........... 9-12 Exhibit 9-8 CAA Coverage of Industries Represented in Release Descriptions

....................... 9-13 Exhibit 9-9 Status of Pesticides That are TC Analytes or Known Non-Hazardous Industrial Waste

Constituents

.................................................................. 9-14 Exhibit 9-10 TC Constituents with Established OSHA PELs

...................................... 9-17 Exhibit 9-11 OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents

........... 9-18 Exhibit 9-12 Potential Gaps and Potential Non-RCRA Regulatory Control

........................... 9-19

# LIST OF EXHIBITS(Continued) Page

x Exhibit 10-1 Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR)

Characteristics

................................................................ 10-4 Exhibit 10-2 Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

.... 10-9 Exhibit 10-3 Evaluation of Potential Gaps Associated with Non-TC Chemicals

....................... 10-15 Exhibit 10-4 Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems

. . 10-24

# HAZARDOUS WASTE CHARACTERISTICS SCOPING STUDY: EXECUTIVE SUMMARY

U.S. Environmental Protection Agency Office of Solid Waste

November 15, 1996

### Page ES-1 

# EXECUTIVE SUMMARY

The U.S. Environmental Protection Agency (EPA), Office of Solid Waste has investigated potential gaps in the current hazardous waste characteristics promulgated under the federal Resource Conservation and Recovery Act (RCRA). This report, the Hazardous Waste Characteristics Scoping Study, presents the findings of that investigation. THE SCOPING STUDY: AN EARLY STEP This study is a first step for the Agency in fulfilling a long-standing goal to review the adequacy and appropriateness of the hazardous characteristics. The study also fulfills an obligation in a consent decree with the Environmental Defense Fund (EDF). The study is by design a scoping study and, therefore, does not conclusively identify particular chemical classes for regulation, or fundamental flaws in the overall regulatory framework requiring immediate regulatory action. However, the study does identify several key areas that merit further analysis due to the significant potential for improving hazardous waste management practices and protection to health and the environment. Thus, the scoping study provides a catalogue of potential gaps in the hazardous waste characteristics. The Agency considers that this study is one very critical component of a broader array of efforts underway to review and improve the RCRA program, to ensure that regulation is appropriate to the degree of risk posed by hazardous wastes and waste management practices. Efforts involve both regulatory and de-regulatory actions, as appropriate for specific wastes and waste management practices. STUDY PROCESS AND FINDINGS Review of Current Characteristics The review of the current characteristic regulations evaluated the protectiveness of the characteristics against the risks they were intended to address and also risks they were not specifically intended to address. For example, EPA evaluated risks that are now addressed by the Toxicity Characteristic (TC), e.g., direct ingestion of groundwater, by considering new groundwater modeling techniques that have been in use since the promulgation of the current TC levels, as well as any changes to the toxicity values on which the original levels were based. In addition, EPA evaluated risks from other exposure pathways and to ecological receptors, which are both risks not intended to be protected by the original TC. The review of the current TC regulatory levels suggests that: (1) further analysis of the current TC regulatory levels should be conducted using new groundwater modeling techniques, as well as considering changes to toxicity values for specific constituents; and (2) non-groundwater pathways and ecological receptors--not currently addressed by TC provisions--may be of potential concern.The study included some screening analyses of

### Page ES-2



### potential air releases from surface impoundments and land application units. The Agency found that inhalation risk levels for a significant number of current TC constituents at the fenceline (under certain exposure conditions) exceeded the allowable risk levels upon which the TC is based. Waste piles and land application units may be of special concern for ecological receptors due to surface runoff.Thirteen TC constituents have regulatory levels that are 10,000 or more times higher than Ambient Water Quality Criteria concentrations, with four of these being at least 100,000 times higher, suggesting that the level of protectiveness of the TC may not be very high for ecological receptors. The study also identifies the need to examine a broader array of leaching procedures, in addition to the Toxicity Characteristic Leaching Procedure (TCLP), to better predict environmental releases from various waste types and waste management conditions.Notable examples are the inability of the TCLP to predict significant releases under highly alkaline conditions or to media other than groundwater, or to serve as a leaching procedure for oily wastes. The most obvious potential gap identified for the ignitability and reactivity characteristics is the reference to outdated DOT regulations.Other potential gaps identified for these characteristics include the exclusion of combustible liquids and lack of specific test methods for non-liquids for ignitability; exclusion of corrosive solids, not addressing corrosion of non-steel materials and solubilization of non-metals, and whether pH limits are adequately protective for corrosivity; and, an overly-broad definition and lack of specific test methods for reactivity. Releases from Non-Hazardous Industrial Waste Facilities The Agency identified actual releases of non-hazardous waste constituents as one means of finding potential problem constituents and management activities. EPA reviewed data on non-hazardous industrial waste management activities that was readily available from state monitoring and compliance files. The Agency focused on wastes that are not currently regulated as hazardous (by virtue of being listed or exhibiting a characteristic) to identify releases potentially causing human health or environmental damages. The Agency considered three major factors in judging whether a release was an appropriate case study for this evaluation. A release had to meet all three of the following criteria to be included: (1) The source of contamination had to be a waste management unit or other intended final disposal area that received only non-hazardous industrial waste; (2) A release from a waste management unit must have caused contamination at levels of potential concern (constituent-specific concentrations that exceed federal standards or state guidelines or regulations); and, (3) Documented evidence must be available to support the exceedences referred to in (2). EPA found 112 environmental release case studies in 12 states with readily available (and not necessarily representative) data on non-hazardous waste management units. The

### Page ES-3



### releases were found from facilities in 15 (2-digit) Standard Industry Classification (SIC)industries. The top four categories were: SIC 49: Electric, Gas, and Sanitary Services (refuseside only); SIC 26: Paper & Allied Products; SIC 28: Chemical & Allied Products; and, SIC 20: Food & Kindred Products. Over 90 percent of the releases were from landfills or surface impoundments and nearly all (98 percent) involved groundwater contamination.This is most likely because groundwater monitoring is the most common method for detecting releases from waste management units. Many of the chemical constituents most commonly detected above a regulatory levelare already addressed in the current TC, even though the release occurred from nonhazardous waste management.The 20 constituents most commonly detected above a regulatory level are inorganics.The constituents that exceeded state groundwater protection standards or health-based federal drinking water standards most frequently were lead, chromium, cadmium, benzene, arsenic and nitrates. All of these, with the exception of nitrates, are current TC constituents. Organic constituents, both TC and non-TC, were also identified in the case studies, however, they were detected less frequently than the inorganic toxicity characteristic constituents. This collection of release descriptions is not statistically representative of problem industries nor intended to identify particular problem facilities.The Agency believes thatthe case studies are indicative of the type of releases associated with the management of nonhazardous wastes in the types of facilities identified. The Agency also believes that information on releases from past waste management practices is useful in demonstrating the potential for human health or environmental damage. Non-TC Chemical Constituents In reviewing chemicals and chemical classes not currently regulated by the TC, EPA found in excess of 100 constituents that potentially occur in waste and may pose significant risks.EPA reviewed 37 regulatory or advisory lists of chemicals to identify possible constituents of non-hazardous wastes. EPA also compiled a list of chemicals which are “known” to be constituents of non-hazardous wastes because they were identified in the environmental release case studies or other Agency data sources on non-hazardous industrial wastes. EPA screened these chemicals and narrowed the list to possible constituents of non-hazardous waste that, by virtue of their toxicity, fate and transport properties, or exposure potential, could pose significant risks to human health and/or the environment.These chemicals were both inorganics and organics, and include volatiles, nonvolatile organics, PAHs and pesticides.Because of the large number of constituents identified as candidates and the limited time available for the scoping study, no risk analyses were conducted. However, it may be a reasonable next step to assess the potential risks for a subset of these constituents.

### Page ES-4



### Natural Resource Damages/Large-Scale Environmental ProblemsThe Agency examined the potential for broad environmental impacts from nonhazardous waste management.These impacts may include damages to natural resources which diminish the value and usability of a resource without threatening human health, as well as possible contributions to regional and global environmental problems. With respect to groundwater contamination, over 80 percent of the facilities identified in the case studies discussed earlier had releases exceeding secondary drinking water standards (non-health based standards).These releases were identified because exceedence of secondary standards may reduce the useability and, therefore, the value of the groundwater. Iron, chloride, sulfate and manganese were among the most frequently detected constituents exceeding secondary standards. In reviewing air deposition of toxic constituents to great waters, the Agency found a number of TC constituents, as well as some other chemicals identified in the study. However, it was not possible to assess the importance of waste to air deposition of toxics to the great waters. State-Only Hazardous Waste Regulations Some states have adopted hazardous waste identification rules that are broader or more stringent than federal RCRA Subtitle C regulations. These expansions reflect state judgements about gaps in the federal program.Data on hazardous waste regulations from eight states, California, Michigan, New Hampshire, Oregon, Rhode Island, Texas, Washington, and New Jersey were considered. Several states regulate additional constituents beyond the TC list ( 25 for California, 9 for Michigan, and 1 for Washington). California also applies a more aggressive leaching test, the waste extraction test (WET) to wastes. California also has a test for combinations of hazardous constituents, in which a combined concentration of the listed constituents cannot exceed 0.001 percent as a total in the waste. Four states also apply acute toxicity values (LD50 or LC50) for human or ecological toxicity to the whole waste. NEXT STEPS The potential gaps and areas of health and environmental concern identified here will require further, more detailed examination before regulatory action can be undertaken. For example, the study highlights risks to ecological receptors and possible inhalation risks to humans as potential gaps, as well as further evaluation of the adequacy of the TCLP. These topics were found to be potential gaps in more than one area of the study and will likely be specific areas of further investigation. Following release of this report, the Agency will engage in a variety of outreach activities in identifying appropriate next steps. While the Agency considers this a final report, comments from interested members of the public are solicited and will be used to help identify and structure follow-on activities. As noted above, revisions to the characteristics program will likely, in the long run, involve both regulatory and de-regulatory activities.Page 1-1 

### Agreement for Hazardous Waste Characteristics Scoping Study The Administrator shall perform a study of potential gaps in the coverage of the existing hazardous waste characteristics. The purpose of the study is to investigate if there are gaps in coverage, and the nature and extent of the gaps identified. The potential gaps in coverage to be addressed in the study [shall] incorporate both waste management practices and possible impacts to human health and the environment. With respect to waste management practices, the study shall, at a minimum, address releases from non-hazardous waste surface impoundments; waste piles; land treatment units; landfills; and various forms of use constituting disposal such as road application, dust suppression or use in a product applied to the land. Human health and environmental impacts to be addressed by the study shall include, but not be limited to: (a) impacts via non-groundwater exposure pathways, both direct and indirect, to human and ecological receptors; (b) impacts via the groundwater pathway to ecological receptors; (c) the potential for formation of non-aqueous phase liquids in groundwater; and (d) impacts via the groundwater pathway to human receptors caused by releases of toxic constituents not included in the current toxicity characteristic, such as EPA-classified carcinogens, priority pollutants identified in the Clean Water Act, and solvents used for purposes other than degreasing. The Administrator shall complete the study by November 15, 1996, and shall provide the plaintiff with two copies of the study immediately upon completion. Environmental Defense Fund, Inc. v. Browner, Civ. No. 89-0598, order granting stipulated motion of EDF and EPA for amendment of consent decree. May 17, 1996, pp. 18-19. 

# CHAPTER 1. INTRODUCTION

The U.S. Environmental Protection Agency (EPA), Office of Solid Waste has investigated potential gaps in the current hazardous waste characteristics promulgated under the federal Resource Conservation and Recovery Act (RCRA). This report, the Hazardous Waste Characteristics Scoping Study, presents the findings of that investigation. Chapter 1 presents background information on the Scoping Study as follows:

Section 1.1 describes the purpose and scope of the Scoping Study; Section 1.2 discusses relevant aspects of the RCRA hazardous waste and non-hazardous waste programs; Section 1.3 summarizes the methodology used to prepare the Scoping Study; and Section 1.4 outlines the remaining chapters and appendices of the Study. 1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study As stipulated under an amended consent decree with the Environmental Defense Fund (EDF) (presented in the text box below), the Agency has investigated potential gaps in the coverage of the existing RCRA hazardous waste characteristics. The purpose of this Study is to identify potential gaps in coverage and to investigate the nature and extent of such gaps. Based on the results of the Study, EPA will seek input from interested parties and determine the appropriate course of action to further address any significant potential gaps identified in the Study. 1.2 Regulatory Background45Federal Register 33084, May 19, 1980. 1
58Federal Register

46049, August 31, 1993. 2
55Federal Register

26987, June 29, 1990. 3
58Federal Register

46049, August 31, 1993. 4

Page 1-2 

### This report focuses on wastes that are not currently regulated as hazardous (by virtue of being listed or exhibiting a characteristic). Industrial wastes are classified either as "hazardous waste" and managed under Subtitle C of the Resource Conservation and Recovery Act (RCRA) or as "non-hazardous waste" and managed under Subtitle D of RCRA, primarily under state programs. In the context of this report, the term "non-hazardous industrial waste" broadly refers to waste that is neither municipal solid waste, special waste, nor considered a hazardous waste under Subtitle C of RCRA. A brief description of the Agency's hazardous and non-hazardous waste classification systems is provided below. Subtitle C of RCRA, as amended, establishes a federal program for the comprehensive regulation of hazardous waste. Section 1004(7) of RCRA defines hazardous waste as "a solid waste, or a combination of solid wastes, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may: (a) cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed." Under RCRA Section 3001, EPA is charged with defining which solid wastes are hazardous by identifying the characteristics of hazardous waste and listing particular hazardous wastes. Current hazardous waste characteristics are ignitability, corrosivity, reactivity, and toxicity. The Agency's definitions of ignitability and reactivity have not changed materially since their adoption in 1980.1 

### The Agency's definition for corrosivity was last revised in 1993. The Agency's current definition of toxicity was 2 

### promulgated in 1990, replacing the Extraction Procedure (EP) leach test with the Toxicity Characteristic Leaching 3 

### Procedure (TCLP) and adding 25 organic chemicals to the list of toxic constituents of concern and establishing their regulatory levels. The Agency's definition of toxicity was last revised in 1993; however, this revision did 4 

### not alter the framework for defining this characteristic. A solid waste is classified as listed hazardous waste if it is named on one of the following four lists developed by EPA:

Nonspecific source or F wastes(40 CFR 261.31). These are generic wastes, commonly produced by manufacturing and industrial processes. Examples include spent halogenated solvents used in degreasing and wastewater treatment sludge from electroplating processes as well as dioxin wastes, most of which are "acutely hazardous" wastes due to the danger they present to human health or the environment. Specific source or K wastes(40 CFR 261.32). This list consists of wastes from specifically identified industries such as wood preserving, petroleum refining, andPage 1-3 

### organic chemical manufacturing. These wastes typically include sludges, still bottoms, wastewaters, spent catalysts, and residues. Discarded commercial chemical products or P and U wastes(40 CFR 261.33(e) and (f)). The third and fourth lists consist of specific commercial chemical products and manufacturing chemical intermediates. They include chemicals such as chloroform and creosote, acids such as sulfuric acid and hydrochloric acid, and pesticides such as DDT and kepone. Disposal of non-hazardous solid waste is regulated under Subtitle D of RCRA. Subtitle D wastes include municipal solid waste, special waste, and industrial waste.

Municipal solid wasteincludes household and commercial solid waste. Household waste is defined as any solid waste (including garbage, trash, and sanitary waste in septic tanks) derived from households (including single and multiple residences, hotels and motels, bunkhouses, ranger stations, crew quarters, campgrounds, picnic grounds, and day-use recreation areas) (40 CFR 258.2). Commercial waste refers to all types of solidwaste generated by stores, offices, restaurants, warehouses, and other nonmanufacturing activities, excluding residential and industrial wastes (40 CFR 258.2). Special waste, as used in this document, refers to oil and gas exploration and production waste, fossil fuel combustion wastes, cement kiln dust, and solid waste from the extraction, beneficiation, and processing of ores and minerals (40 CFR 261.4).
Non-hazardous industrial wasterefers to solid waste generated by manufacturing or industrial processes that is not a hazardous waste regulated under Subtitle C of RCRA or a special waste (40 CFR 258.2). Under Subtitle D, the management of non-hazardous industrial waste in land-based units must comply with 40 CFR Part 257, which establishes minimum federal standards for the management and siting of land-based units. Individual states are responsible for implementing 40 CFR Part 257 under their own authority. They have adopted statutory and regulatory frameworks for management of non-hazardous industrial wastes. These requirements vary widely from one state to another in terms of their design and operating requirements, monitoring requirements, and other management requirements such as recordkeeping, closure, post-closure care, and financial responsibility. Even within a given state, the non-hazardous industrial waste requirements may vary from facility to facility depending on the characteristics of the wastes managed and the environmental setting of the waste management unit. The Agency is currently developing "voluntary guidelines" for non-hazardous industrial waste management to better ensure that this waste is managed in a manner that is protective of human health and the environment. 1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics As shown in Exhibit 1-1, the general approach EPA used to perform the Scoping Study has nine steps. Each of these steps is discussed below. Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management The Agency conducted detailed investigations to identify specific instances of environmentalcontamination resulting from the management of non-hazardous industrial wastes. These case studies provide realworld information on releases of these wastes into the environment, the chemicals released and their concentrations, and the waste management practices and industries involved. The preliminary findings of suchPage 1-4



### research were presented in a draft report entitled "Hazardous Waste Characteristics Scoping Study: Environmental Release Descriptions" (September 24, 1996). EPA held a public meeting on October 10, 1996 to explain and obtain comments on the draft report. EPA has considered and, where appropriate, incorporated these comments in preparing this Scoping Study. Chapter 2 summarizes these investigations and Appendix A presents the individual environmental release descriptions. Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste ManagementThis step identifies categories of risks to human health and the environment that may result from nonhazardous industrial waste management. The underlying premise of this step is that a gap in the hazardous waste characteristics is any significant risk to human health or the environment associated with non-hazardous industrial waste management that could be, but is not, addressed by the current characteristics. Thus, this assessment deals with both:

Hazards that the current hazardous waste characteristics were intended to address, namely physical hazards such as fire and explosion and toxic groundwater contamination near waste management facilities; and Hazards that the characteristics were not intended to address, such as non-groundwater pathway exposures to toxins, damages to ecological receptors, and natural resource damages. EPA identified risks by types of receptors, types of toxic effects and physical hazards, exposure pathways, and time and spatial scales, as described in Section 3.1. The search for potential risks used broad definitions of risk and adverse effects and addressed all aspects of non-hazardous industrial waste management, without any prejudgment as to the likelihood that a risk was significant, whether it could be best addressed by the characteristics, or whether it was already addressed by other regulations. The results of this risk classification step were used in identifying and evaluating potential gaps, as described below. Step 3: Review the Existing Characteristics The identification of potential gaps continues with a review of the existing definitions of the characteristics. This step is next for two reasons. First, limitations in the characteristics' effectiveness in reducing the risks they were intended to address may constitute important potential gaps. When the characteristics were promulgated, the Agency identified physical hazards and acute toxic hazards during transport and disposal activities and chronic exposure to groundwater contaminated with wastePage 1-5



### Insert Exhibit 1-1 Scoping Study ApproachPage 1-6



### constituents as being among the most important waste management risks. Reducing these risks remains an important goal of the characteristics. Second, this analysis lays the groundwork for evaluating other potential gaps. Step 3 begins by examining the definitions and test methods of the ignitability, corrosivity, and reactivity (ICR) characteristics, which are essentially unchanged since they were promulgated in 1980. EPA reviewed the assumptions and approaches used to develop these characteristics and compared the characteristics to approaches taken to controlling similar hazards under other federal and state regulatory schemes. Step 3 also examines the definition of the toxicity characteristic (TC), which was designed to protect against human health risks from exposure to hazardous waste constituents released to groundwater. EPA reviewed new information on the toxicity, fate, and transport of the TC constituents and improvements in groundwater modeling since the TC was revised in 1990. The Agency also examined the potential risks from TC constituents through inhalation, surface water, and indirect pathways and to ecological receptors. Chapter 3 describes these analyses. Step 4: Identify Gaps Associated with Non-TC Chemicals Potential gaps in the hazardous characteristics from non-TC chemicals are identified by, first, identifying two groups of constituents:

"Known" non-hazardous industrial waste constituents:constituents "known" to be present in non-hazardous industrial wastes, based on the data gathered in the environmental release descriptions in Step 2, EPA's 1987 Telephone Screening Survey of non-hazardous industrial waste management facilities, EPA effluent guideline development documents, and recent hazardous waste listing determinations. "Possible" non-hazardous industrial waste constituents:constituents on various regulatory or advisory lists, which were screened for their toxicity, fate, and transport properties and for a proxy of their occurrence in non-hazardous industrial waste, using available environmental release data from the 1994 Toxics Release Inventory. Then, these two lists of constituents are evaluated and compared and chemicals are classified by physical properties, chemical composition, use, and origin. Finally, potential gaps were identified by applying multiple hazard-based screening criteria to specific chemicals and chemical classes. Chapter 4 describes these analyses. Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and Large-Scale Environmental Problems As discussed above, steps 3 and 4 respectively examine potential gaps inherent in the current hazardous waste characteristics and associated with adverse human health or localized ecological effects from constituents not addressed by the toxicity characteristic. Step 5 addresses a third set of risks associated with non-hazardous industrial waste management: damages to natural resources that may not have direct human health or ecological effects, and large-scale environmental problems. The specific risks addressed are:

Pollution of groundwater by constituents that diminish the value and usability of the resource without threatening human health; Air pollution through odors that harm the quality of life but may not have severe health effects; andPage 1-7 

### Large-scale environmental problems, including air deposition to the Great Waters, damages from endocrine disruptors and airborne particulates, global climate change, red tides, stratospheric ozone depletion, tropospheric ozone and photochemical air pollution and water pollution. Chapter 5 presents these analyses. Step 6: Review State Expansions of TC and State Listings Several states have expanded their hazardous waste management programs to regulate as hazardous certain wastes or waste constituents that are not hazardous under the federal program. Step 6 examines how states have expanded their toxicity characteristics and have listed as hazardous certain wastes that are not listed under the federal program. (Step 3 examines how states have regulated additional wastes by expanding their ICR characteristics.) These expansions beyond the federal hazardous waste identification rules reflect state judgments about gaps in the federal hazardous waste program and thereby constitute potential gaps that may merit further investigation. Chapter 6 presents this analysis. (Chapter 7 summarizes the potential gaps identified in Chapters 3 through 6.) Step 7: Evaluate the Industries and Waste Management Practices Associated with Potential Gaps The evaluation of potential gaps asks two basic questions: (1) What do the qualitative and quantitative indicators of risk show about the potential gaps? and (2) To what extent are the risks associated with the potential gaps addressed by other regulations? Steps 7, 8, and 9 address these questions. Step 7 addresses aspects of the first question. Specifically, it assesses the following:

The amount of non-hazardous industrial wastes generated by various industries; The frequency with which various chemicals were detected or reported in releases from various industries; The management methods associated with the major non-hazardous industrial waste generators; andThe management practices associated with documented environmental releases of nonhazardous industrial wastes. Because of data limitations, EPA could not evaluate all potential gaps against all of these criteria. Instead, this step focuses principally on the potential gaps identified in Steps 3 and 4. Chapter 8 presents this analysis. Step 8: Assess Regulatory Programs' Coverage of Potential Gaps The second major issue in evaluating potential gaps is the extent to which the risks are controlled by existing regulatory or other environmental programs. As noted above, risk-related gaps were identified solely in terms of their relationship to non-hazardous industrial waste management, and not with regard to whether they might be controlled under regulatory or other programs. Chapter 9 discusses how major federal and state regulatory programs may address some of the risks represented by the potential gaps. To the extent that they are already addressed or could be addressed more effectively by programs other than the hazardous waste regulations, the potential gaps may not merit further attention by the RCRA Subtitle C program. Step 9: Present Integrated Evaluation of Nature and Extent of Potential GapsPage 1-8 

### In the final step of the methodology, which is presented in Chapter 10, EPA integrates and summarizes all of the lines of evidence relating to particular potential gaps in the hazardous waste characteristics. The summary is presented in the form of several tables. This section also reviews the major data gaps and uncertainties of the analysis. 1.4 Report Outline This Scoping Study is organized in the same order as the methodology outlined above. Chapter 2 characterizes releases from non-hazardous industrial waste management; Chapter 3 categorizes risks associated with potential gaps in the characteristics and

reviews the existing characteristics to identify potential gaps; Chapter 4 identifies potential gaps associated with non-TC chemicals; Chapter 5 identifies potential gaps associated with certain natural resource damages and

large-scale environmental problems; Chapter 6 identifies potential gaps in the characteristics by reviewing how selected states

have expanded the TC and listed wastes that are not listed as hazardous under the federal program; Chapter 7 summarizes the potential gaps identified in Chapters 3 through 6; Chapter 8 evaluates the extent of the risks presented by potential gaps; Chapter 9 discusses how major federal and state regulatory programs address the risks

represented by the potential gaps; and Chapter 10 presents an integrated summary evaluation of the nature and extent of potential

gaps and the associated major analytical limitations and describes the framework that the Agency will apply in developing a plan for addressing potential gaps in the hazardous waste characteristics identified in this Study. The Study also includes several appendices. Appendix A describes the individual environmental releases summarized in Chapter 2. Appendix B discusses several data sources used to identify environmental releases that were not successful in finding releases meeting EPA's stringent selection criteria. Appendix C provides a detailed comparison of the ICR characteristics to related approaches under other federal and state programs. Finally, a separate background document contains detailed information and analysis that supplements the screening-level risk analysis presented in Chapter 3 and the identification of "possible" non-hazardous industrial waste constituents in Chapter 4.Page 1-9



### CHAPTER 1. INTRODUCTION

........................................................ 1-1
1.1 Purpose and Requirements of the Hazardous Waste Characteristics Scoping Study

.... 1-1
1.2 Regulatory Background

................................................... 1-2
1.3 Approach for Studying Potential Gaps in the Hazardous Waste Characteristics

....... 1-4 Step 1: Characterize Releases from Non-Hazardous Industrial Waste Management

... 1-4 Step 2: Categorize Risks Associated with Non-Hazardous Industrial Waste Management1-4 Step 3: Review the Existing Characteristics

................................... 1-4 Step 4: Identify Gaps Associated with Non-TC Chemicals

....................... 1-6 Step 5: Identify Potential Gaps Associated with Certain Natural Resource Damages and Large-Scale Environmental Problems

................................. 1-6 Step 6: Review State Expansions of TC and State Listings

....................... 1-7 Step 7: Evaluate the Industries and Waste Management Practices Associated with Potential Gaps

.................................................... 1-7 Step 8: Assess Regulatory Programs' Coverage of Potential Gaps

................. 1-8 Step 9: Present Integrated Evaluation of Nature and Extent of Potential Gaps

........ 1-8
1.4 Report Outline

.......................................................... 1-8Page 1-10



### Exhibit 1-1 Scoping Study Approach

.................................................. 1-5Page 2-1



# CHAPTER 2. RELEASES FROM NON-HAZARDOUS

INDUSTRIAL WASTE MANAGEMENT UNITS

This chapter presents the methodology and results of the Agency's efforts to identify contamination resulting from the management of non-hazardous industrial wastes. The Agency prepared a draft report entitled "Hazardous Waste Characteristics Scoping Study: Environmental Release Descriptions" which was released for public comment on September 25, 1996 (see 61Federal Register 50295). This chapter summarizes the revised report, incorporating relevant comments on the draft report. This chapter is composed of three sections: Section 2.1 discusses the criteria, information sources, and methodology used to select releases to include in the report; Section 2.2 summarizes the release descriptions and presents findings of the study; and Section 2.3 presents the major limitations of the study. The environmental release descriptions described in this chapter are presented in Appendix A of this Scoping Study. 2.1 Methodology Based on 1985 data, 7.6 billion tons of non-hazardous industrial waste are generated and managed on-site annually by 17 major industries in the United States. Despite this large volume of non-hazardous industrial waste, EPA has few data concerning the releases, human health impacts, or environmental damages caused by such wastes. To identify such releases for purposes of the Scoping Study, the Agency reviewed readily available information from a wide variety of data sources. The purpose of this review was not to estimate risks posed, but rather to characterize releases due to non-hazardous industrial waste management practices. This section discusses the criteria and methodology used to select releases. 2.1.1 Criteria For Selecting Releases The Agency considered three major factors in judging whether a release is an appropriate case study for this report. To be included, a release had to meet all three of the criteria described below:
1. Source of Release.The source of contamination had to be a waste management unit that received only non-hazardous industrial waste. Releases were excluded if:

a. Evidence suggested that the management unit also received municipal solid waste, special waste, or RCRA hazardous waste. Many facilities manage municipal, hazardous, and special wastes in the same waste management units as non-hazardous industrial waste. Releases from such units were not included in this report.
b. The source of contamination could not be attributable solely to a non-hazardous industrial waste management unit. Releases were excluded where contamination (1) was detected at or near the facility, but the source of contamination was unknown; (2) wasSMCLs are based on aesthetic considerations (e.g., taste and odor) and are not federally enforceable. 1

Page 2-2



### not from a waste management unit (e.g., was a product spill); or (3) was from a combination of non-hazardous industrial waste unit(s) and municipal, special, or hazardous waste unit(s).

c. The source of contamination was industrial wastewater discharges that are point source discharges regulated under Section 402 of the Clean Water Act, as amended.
d. The management method employed would be illegal in most states today. (Facilities were included if management practices would be legal today, even if no longer employed at a particular facility.)
2. Evidence of Damage.For purposes of the study, "damage" is considered to be a release exceeding one of the levels described below. All exceedences were examined for purposes of this scoping study. Exceedences may not actually represent significant risks. To be included in the Study, a release from a waste management unit must have caused contamination at levels of potential concern for that contaminated medium. Levels of potential concern used for this criterion were often based on federal or state drinking water standards for groundwater contamination and exceedences of background concentrations for soil contamination. Federal drinking water standards include maximum contaminant levels (MCLs) and secondary maximum contaminant levels (SMCLs) . State drinking water standards, which are often stricter than the federal standards,

1 

### also were considered. Releases were not included if contaminant concentrations were above background concentrations but below levels of potential concern. If at least one contaminant was detected at concentrations above a federal or state standard, then data were collected and presented for all contaminants detected at that site.
3. Test of Proof.Documented evidence must prove that a damage or danger from a non-hazardous industrial waste management unit has occurred. Evidence was accepted if it met one or more of the following three tests:

a. Scientific investigation. Damages were found to exist as part of the findings of a scientific study. Such studies include both extensive formal investigations (e.g., in support of litigation or a state enforcement action) and the results of technical tests (e.g., monitoring of wells);
b. Administrative ruling. Damages were found to exist through a formal administrative ruling, such as the conclusions of a site report by a field inspector, or through existence of an enforcement action that cited specific health or environmental dangers; and/or

c. Court decision. Damages were found to exist through a ruling of a court of law or through an out-of-court settlement. 2.1.2 Approach For Identifying Releases"Issue Paper: Potential Damage Cases From On-Site Disposal of Non-Hazardous Industrial Waste," August 1995. 2"Damage Cases: On-Site Disposal of Non-Hazardous Industrial Waste," September 1995. 3

Page 2-3 

### Public Involvement In the limited time available for preparing this Scoping Study, the Agency implemented a number of measures to involve the public in this aspect of the data collection effort. Specifically, the Agency contacted the States and facilities identified in the release descriptions to solicit comments on draft versions of the release descriptions. Concurrently, the Agency released a draft version of its "Hazardous Waste Characteristics Scoping Study: Environmental Release Description" report to the public for comment and review on September 25, 1996 (see 61 Federal Register

50295). This report was made available through the RCRA Information Center and the internet via EPA's web page. Next, the Agency conducted a public meeting on October 10, 1996 in Arlington, Virginia to solicit comments on the draft report. Finally, the Agency released a draft version of the individual release descriptions to the public for comment and review on October 29, 1996 (see 61Federal Register 55800). The Agency investigated eight major data sources to identify potential releases:

State Industrial D programs; State Superfund programs; Federal Superfund program; Draft EPA report on construction and demolition waste landfills; Federal RCRA corrective action program; Other federal and state data sources; Newspapers; and Other literature searches.
EPA identified 112 facilities with environmental releases from 4 of the 8 data sources. As a result, this section summarizes the methodologies used to investigate only the four sources that resulted in case studies. Detailed descriptions of the other four methodologies are presented in Appendix B. Draft release descriptions were sent to facility owners/managers for data verification before inclusion in this final report. 2.1.2.1 State Industrial D Programs As specified under RCRA Subtitle D, states are the primary regulators of non-hazardous solid waste, also known as Subtitle D waste. EPA's role is largely limited to establishing guidelines for the development and implementation of state plans, providing technical assistance, and approving plans that comply with these requirements. States are responsible for developing and implementing their own plans. EPA identified states with potential case studies, then reviewed the state files for those potential case studies. The Agency is currently preparing voluntary guidelines on management standards for non-hazardous industrial wastes. As part of this effort, in 1995, the Agency contacted representatives from every state in thecontinental United States and asked them to identify known or potential environmental damages caused by nonhazardous industrial waste management units. The Agency visited and reviewed state files at four of the five 2 

### states that reported the largest number of potential case studies, California, Texas, North Carolina, New Mexico, and Wisconsin, and prepared a report summarizing the results of the visits. The Agency did not visit California 3 

### because, at the time, California was preparing a comprehensive report on its Solid Waste Assessment Test (SWAT) program, which included detailed information on environmental releases at non-hazardous industrial waste disposal sites.California Code of Regulations, Title 23, Section 13273. 4

Page 2-4 12 States Included in Analysis California North Carolina Florida Pennsylvania Louisiana Tennessee Michigan Texas New Mexico Virginia New York Wisconsin 

### For the Scoping Study, the Agency chose to investigate seven additional states based on the reported numbers of potential case studies for these States. Overall, the Agency focused its review of non-hazardous industrial waste data on 12 of the 16 states that indicated having at least 10 potential case studies. The Agency limited its review to these 12 states due to significant time constraints associated with the Scoping Study. As the first step in identifying relevant releases or case studies, the Agency contacted the states by telephone to discuss the requirements and purpose of the release descriptions. For states that housed their files regionally, the Agency contacted each regional office with potential case studies. After scheduling appointments to review the state files, the Agency visited states to review and collect information about the specific releases of non-hazardous industrial wastes into the environment at concentrations of concern. The Agency did not visit California. During these trips, the Agency reviewed readily available documentation on each potential case study and collected documentation for only those releases that appeared to meet all three of the criteria described in Section 3.1.1. Over 80 percent of the facilities identified as potential case studies were excluded from further review, primarily because the facilities co-disposed non-hazardous industrial waste with municipal, hazardous, or special waste, or because the environmental damages discovered at the facility could not be directly linked to a non-hazardous industrial waste management unit. On an as-needed basis, EPA also made follow-up contact with state personnel most knowledgeable about particular sites to obtain additional relevant information. To ensure that facility-specific information was accurately compiled and presented, the Agency contacted the states and facilities by telephone to ask them to review the draft release descriptions prepared for this report. The Agency sent each state and facility their release descriptions, asked for their written comments on the descriptions, and incorporated relevant comments. Review of California's Industrial D Data.In 1984, the California State legislature passed a law that required testing of water and air media at all solid waste disposal sites. The law also required California's 4 

### State Water Resource Control Board to rank all solid waste disposal sites in groups of 150 each, according to the threat these facilities or sites may pose to water quality. California's legislation requires site operators to submit a water quality "solid waste assessment test" (SWAT) report presenting the following information:

An analysis of the surface and groundwater on, under, and within one mile of the solid waste disposal site to provide a reliable indication of whether there is any leakage of hazardous waste constituents; and A chemical characterization of the soil-pore liquid in those areas that are likely to be affected if the solid waste disposal site is leaking, as compared to geologically similar areas near the solid waste disposal site that are known to not have been affected by leakage or waste discharge. To expedite the review of California's Industrial D data, the Agency obtained a copy of California's Solid Waste Assessment Test database. The Agency reviewed the database to identify those facilities believed to manage only non-hazardous industrial waste and found to have leaked waste constituents outside the limits of the wasteEnvironmental Law Institute, "An Analysis of State Superfund Programs: 50-State Study, 1993 Update," prepared for U.S. 5 Environmental Protection Agency's Office of Emergency and Remedial Response, December 1993.

Page 2-5 Industrial D Case Studies Satisfying Criteria for

Inclusion in the Scoping Study California 29 Florida 6 Wisconsin 20 New York 6 Tennessee 9 North Carolina 6 Louisiana 7 Michigan 4 New Mexico 7 Virginia 3 Texas 6 Pennsylvania 1

State Superfund Programs with 1,000 Sites California New York Illinois Ohio Indiana Pennsylvania Massachusetts Tennessee Michigan Texas Missouri Wisconsin New Jersey
= State had readily available information. 

### management unit at levels above California or federal regulatory standards. California's waste classification system was used to identify facilities believed to manage only non-hazardous industrial waste.
The review of Industrial D data from 12 states identified a total of 104 releases that met the Agency's selection criteria. Hundreds of potential cases were reviewed to identify these releases. 2.1.2.2 State Superfund Programs
Abandoned or uncontrolled hazardous substance sites not addressed by the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) program may be subject to remediation under the state Superfund programs. EPA believes that some of these sites may be contaminated with industrial wastes that would not be hazardous under the current RCRA Subtitle C requirements. To expedite the process of identifying relevant sites and to cover the largest possible percentage of state Superfund sites, the Agency focused on the states with the largest programs. These states were identified according to the Environmental Law Institute's 1993Analysis of State Superfund Programs

. In July 1996, the Agency 5 

### identified and contacted 13 states listed as having at least 1,000 state Superfund sites. Personnel from each of the 13 states were asked whether they produce publicly available summaries of their state Superfund programs. The Agency obtained the most recent annual state Superfund reports for Missouri, New Jersey, New York, and Texas and obtained a printout of California's database for review. Due to the significant time constraints associated with its analysis, the Agency did not pursue information from other states, which lacked detailed, readily available information on their Superfund program. Short published site descriptions for nearly 1,000 state Superfund sites from 5 states, California, Missouri, New Jersey, New York, and Texas, were reviewed to identify potential case studies that meet the Agency's selection criteria. A total of 60 sites were identified as potential case studies. The Agency contacted the five states by telephone to discuss the availability of existing information on those 60 sites. Two states (New York and Texas) indicated that they had additional information readily available for review. The Agency visited these states' Superfund offices to review and the additional information. The Agency identified one case study from New York as meeting all of the selection criteria. 2.1.2.3 Federal Superfund ProgramConditionally exempt small quantitygenerators (CESQGs) are defined as generators of less than 100 kilograms per month of 6 hazardous waste. See 40 CFR 261.5.
Page 2-6 

### The Agency investigated several CERCLA data sources to identify releases relevant to the Scoping Study. The vast majority of the CERCLA sites were not expected to meet the Agency's selection criteria for two reasons. First, the majority of the sites are contaminated with RCRA hazardous wastes or with releases or spills from products. These sites will not meet the Agency's selection criteria for source of release. Second, most of the CERCLA sites contaminated with non-hazardous industrial wastes are also expected to be contaminated with hazardous wastes. Therefore, it is unlikely that a non-hazardous industrial waste management unit will be identified as the source of the release at a CERCLA site. Due in part to the large number (over 1,300) of CERCLA National Priority List (NPL) sites and the relatively small number of sites likely to meet the Agency's three release selection criteria, the Agency attempted to identify potential case study sites through telephone discussions with Regional EPA Superfund personnel and Regional members of the National Association of Remedial Project Managers and the National On-Scene Coordinator Association. Although the Regional Contacts agreed that the Agency should be able to identify at least a few case studies from the CERCLA program, they often were unable to identify specific sites. EPA Superfund staff in Region 4, however, identified two sites apparently meeting the Agency's selection criteria. The Agency visited Region 4's Superfund office and reviewed and copied the relevant files for these two sites. One of the two sites met the Agency's selection criteria. The following federal Superfund data sources were also reviewed; however no releases meeting the Agency's selection criteria were identified:

Record of Decision (ROD) database; CERCLA Natural Resource Damage Claims; CERCLA Characterization Database; and Exposure assessments performed by the Agency for Toxic Substances and Disease Registry (ATSDR). 2.1.2.4 Construction and Demolition (C&D) Landfill Report On May 18, 1995, EPA's Office of Solid Waste published a draft report entitledDamage Cases: Construction and Demolition Waste Landfills. The report, prepared in support of EPA's rulemaking (60Federal Register 30963, June 12, 1995) on conditionally exempt small quantity generators (CESQG), presents information on environmental 6 

### releases from construction and demolition (C&D) waste landfills, which receive materials generated from the construction or destruction of structures such as buildings, roads, and bridges. One purpose of the report was to determine whether the disposal of C&D waste in landfills has threatened or damaged human health or the environment. The May 1995 report used three criteria to select potential C&D waste landfill damage cases. The landfill received predominantly C&D waste, with or without CESQG waste mixed in. C&D landfills known to have received significant quantities of municipal, industrial, or hazardous wastes were excluded. The use of the site as a C&D landfill had to be the only potential source of the observed contamination. Sites located near other potential sources of the contamination such as underground storage tanks were excluded.Page 2-7 

### There was documented evidence of groundwater contamination, surface water contamination, or ecological damage at the site. "Contamination" was defined as an increase in chemical constituent concentrations above background or an exceedence of an applicable regulatory standard or criterion attributable to releases from the site. In preparing the May 1995 report, the Agency searched for C&D landfills meeting these criteria using four information sources: existing studies of C&D landfills, materials available through the federal Superfund program, representatives of EPA Regions, and representatives of state and county environmental agencies. The Agency identified 11 environmental releases in the May 1995 report. Although one of the Agency's criteria, as listed above, was to eliminate C&D landfills that receivedsignificant quantities of municipal or hazardous wastes, 5 of the 11 landfills received municipal, special, or hazardous wastes. Therefore, for purposes of this report, the Agency eliminated these five C&D landfill cases. Eliminating the landfills that managed even small quantities of municipal, special, or hazardous waste, ensures that the reported damages were caused by the non-hazardous industrial wastes, thereby meeting the Agency's selection criteria for the source of the release. 2.1.3 Release Profile Preparation The release profiles presented in Appendix A to the Scoping Study were prepared using a standard format. This format is discussed below. Because the release profiles were prepared under significant time constraints using readily available data, detailed descriptions of the facility, wastes, and waste management practices could not be developed. The data often provided only a brief description of the facility and focused primarily on the results of the environmental sampling conducted at the facility.

"Facility Overview" discusses the facility's operations, how long the facility was or has been in operation, the location of the facility, surrounding land uses, the geologic and hydrogeologic conditions at the facility, and other environmental characteristics, provided this information was available.

"Media Affected" identifies whether the damages are associated with groundwater, surface water, soil, and/or ecological receptors.

"Wastes and Waste Management Practices" discusses the type(s) of wastes generated at the facility and the practices employed to manage the wastes including descriptions of the individual waste management units and groundwater monitoring practices, provided this information was available.

"Extent of Contamination" discusses the groundwater contamination, surface water contamination, and/or soil contamination at the site. Constituents detected in groundwater or surface water above background levels are identified and compared to applicable state and federal standards. The maximum detected concentration for all tested constituents are given. In reporting exceedences of state or federal standards, EPA attempted to exclude constituents whose upgradient or background concentrations were as high as those in downgradient wells.

"Corrective Actions/Regulatory Actions" discusses any corrective or regulatory actions that have been recommended, planned, or taken at the site.

"Source" simply identifies the information source(s) used to prepare the release profiles. The main source of information was the facility-specific files located in state offices.Page 2-8



### 2.2 Results This section discusses the findings of the review of release data. It begins by summarizing the 112 documented release descriptions using the following five categories:

Number of cases by state; Number of cases by industry; Number of cases by type of waste management method; Type of media affected; and Type and level of contaminants. Later chapters of this report also present these and additional release description data. 2.2.1 Number of Cases By State The 112 releases described in this chapter were found in 12 states. Because this report is a Scoping Study, these case studies were not intended to be geographically or statistically representative of the number of known or potential releases of non-hazardous industrial wastes identified by the Agency. Although these case studies are not statistically or geographically representative, they do illustrate the type of releases that have occurred from non-hazardous industrial waste management units in various parts of the country, as shown in Exhibit 2-1. The case studies were selected based on the availability of data. Due to the limited time available to collect data, the Agency largely focused its efforts on the states with the most available data on releases from non-hazardous industrial waste management units. This process identified releases in most areas of the nation, except the northwest, northern mountain states, and midwest. The states in these regions either were unable to identify any or identified few potential case studies in the Agency's 1995 efforts to estimate the number of potential releases from non-hazardous industrial waste management units by state.Page 2-9 

### Exhibit 2-1 Number of Release Descriptions By State

The available data on facilities that manage non-hazardous industrial waste indicate that the states addressed in this report manage some of the largest volumes of non-hazardous industrial waste. Also, seven of the 12 states represented in this report are among the 10 states with the largest number of on-site non-hazardous industrial waste management units in 1985. Exhibit 2-2 identifies the number Exhibit 2-2 Number of Management Units & Volume of Waste Managed On-Site, by State (1985) Rank by Number of 1985 Volume Waste Number of Management Units i n Managed Number of Release Units State 1985 (Million tons/yr.) Descriptions a a 

### 1 California 2,150 570 29 2 Texas 1,900 590 6 3 Wisconsin 1,720 60 22 4 Pennsylvania 1,475 940 1 5 Georgia 1,080 220 None 6 Illinois 1,005 265 None 7 Ohio 960 155 None 8 Vermont 940 5 None 9 Louisiana 890 170 7 10 North Carolina 855 240 6

### Exhibit 2-2 (continued) Number of Management Units & Volume of Waste Managed On-Site, by State (1985) Rank by Number of 1985 Volume Waste Number of Management Units i n Managed Number of Release Units State 1985 (Million tons/yr.) Descriptions a a

Page 2-10 

### 12 Virginia 800 150 6 13 Michigan 785 210 4 14 New York 740 30 8 15 Florida 740 310 7 21 Tennessee 510 245 9 41 New Mexico 140 10 7 Source: "Telephone Screening Survey," U.S. Environmental Protection Agency, 1987. a


### of on-site management units and the volume of waste managed on-site in states. (See Chapter 8 for further discussion of waste generation by industry.) 2.2.2 Number of Cases By Industry The releases documented in this report were from facilities in 15 2-digit Standard Industry Classification (SIC) codes. (Industry data are presented at the two-digit level because more specific classification were not readily available for many facilities.) Over 31 percent of the cases involve Electric, Gas, and Sanitary Services facilities (SIC 49). All of these facilities are in the refuse system sector (SIC 4953). The top four SIC codes are SIC 49: Electric, Gas, and Sanitary Services, SIC 26: Paper & Allied Products, SIC 28: Chemical & Allied Products, and SIC 20: Food & Kindred Products. These four industry groups represent nearly 75 percent of the releases studied or evaluated in this report. Exhibit 2-3 identifies the number of cases by industry.
Exhibit 2-3 Number of Case Studies by Industry (SIC)
Electric, Gas, & Sanitary Services (49) 35 (31%) Paper & Allied Products (26) 27 (24%) Chemical & Allied Products (28) 11 (10%) Food & Kindred Products (20) 10 (9%) Primary Metal Industries (33) 6 (5%) Nonmetallic Minerals, Except Fuels (14) 4 (4%) Petroleum & Coal Products (29) 4 (4%) Fabricated Metal Products (34) 3 (3%) Transportation Equipment (37) 3 (3%)

### Exhibit 2-3 (continued) Number of Case Studies by Industry (SIC)

U.S. Environmental Protection Agency, Office of Solid Waste, "Non-Hazardous Waste Management:Priority Industries," draft, 7 July 1993. U.S. Environmental Protection Agency, Office of Solid Waste, "State Requirements for Non-Hazardous Industrial Waste Managemen t 8 Facilities, September 1995.

Page 2-11 

### Agricultural Production - Livestock (02) 2 (2%) Electronic & Other Electric Equipment (36) 2 (2%) Stone, Clay, & Glass Products (32) 2 (2%) Apparel & Other Textile Products (23) 1 (1%) Instruments & Related Products (38) 1 (1%) Industrial Machinery & Equipment (35) 1 (1%)

These findings are generally consistent with the Agency's previous finding that four industries, Paper and Allied Products (SIC 26), Chemicals and Allied Products (SIC 28), Petroleum Refining & Related Industries (SIC 29), and Primary Metal Industries (SIC 33), generated more than 68 percent of the 7.6 billion tons of Industrial D waste managed on-site in 1985. Although these case studies were identified based on available data and other selection 7 

### criteria, the number of cases identified per industry and the volume of waste generated per industry appear to be positively correlated.
2.2.3 Number of Cases By Type of Waste Management Unit Four major types of land-based treatment and storage units were identified in the case studies: landfills, surface impoundments, land application units, and waste piles. Exhibit 2-4 presents the number of case studies by waste management unit. Several cases studies discuss more than one unit, therefore, the total number of units is higher than the total number of case studies. Approximately 93 percent of the case studies involved landfills and/or surface impoundments. This finding may partly reflect the greater regulatory attention these units receive from the states, rather than necessarily imply that these units have more frequent releases than other types of waste management units. Over 90 percent of the landfills and 80 percent of the surface impoundmentsincluded in the case studies are unlined and over 70 percent of the units are no longer being used to manage nonhazardous industrial wastes. All 50 states have developed regulations for surface impoundments. Approximately 90, 46, and 18 percent of the states have developed regulations specifically for landfills, land application units, and waste piles, respectively. The large number of surface impoundments identified in this report is consistent with a finding of

8

### EPA's 1987 Telephone Screening Survey that slightly more than half of the facilities that generate and manage onsite non-hazardous industrial waste managed their wastes in"State Regulation of Waste Piles, EI Digest Industrial and Hazardous Waste Management," April 1996, pages 16 to 21. 9"Nonhazardous Industrial Surface Impoundments: State Regulations and the Environmental Ma rketplace," Environmental 10 Information, Ltd., 1996, pages 3 to 7. "State Requirementsfor Nonhazardous Waste Land Application Units, EI Digest Industrial and Hazardous Waste Management," Ma y 11 1996.

Page 2-12 

### Exhibit 2-4 Number of Case Studies By Waste Management Unit

Landfill 73 Surface Impoundment 31 Land Application Unit 12 Waste Pile 4

on-site surface impoundments. The 1987 survey also indicated that 35 percent of the facilities managed their wastes on-site in waste piles, 19 percent in landfills, and 18 percent in land application units. Many states apply their non-hazardous industrial waste regulations on a site-by-site basis and, therefore, not all facilities in a state are subject to the same data collection and recordkeeping requirements. One recent report indicates that even states with waste pile regulations do not appear to be actively enforcing control, monitoring, and closure requirements, which may partly explain the small number of release descriptions for waste piles.9 

### The large number of landfills and surface impoundments in the release descriptions appears consistent with the type of management units used by the primary industries included in this report. Reportedly, the food processing industry has the largest number of non-hazardous industrial waste surface impoundments and land application units. Other major industries identified in this report with a large number of surface impoundments 10,11 

### and landfills include the paper, electric power, chemical, mining, and metal finishing industries.
2.2.4 Type of Media Affected Nearly 98 percent of the case studies involved groundwater contamination. Approximately 31 percent of the case studies involved contamination of surface water or soil. No case studies had documented damages from releases to the air and nearly 30 percent of the case studies affected multiple media. The predominance of groundwater contamination is consistent with the use of groundwater monitoring as the most common method of detecting releases from waste management units. Surface water is not as routinely monitored as groundwater. Surface water sampling is seldom conducted at a facility until a release is identified. Soil sampling is conducted much less frequently than groundwater monitoring, and like surface water sampling, is seldom conducted until a release has been identified. Few states regulate air emissions from non-hazardous industrial waste management units. Thus, it is not surprising that no cases of damage from releases to the air were documented in the case studies collected for this report.Page 2-13 

### 2.2.5 Types of Contaminants Released The number of and types of contaminants routinely analyzed for in groundwater and other types of samples varies among states and facilities. Although most facilities included in the case studies were monitored for a wide range of constituents, the 20 constituents most commonly detected to exceed regulatory levels were inorganics. Approximately 50 constituents were detected three or more times, and 70 constituents were detected fewer than three times. Exhibit 2-5 identifies all of the TC constituents that were detected in the case studies, Exhibit 2-6 presents all of the constituents with SMCLs that were identified in the case studies, and Exhibit 2-7 identifies the other constituents that were detected in at least three case studies. The exhibits also identify the number of cases where each constituent was detected, the number of times the constituent was detected above at least one regulatory level, the regulatory levels, the average maximum and the highest maximum detected concentration identified in the case studies, and the range of the ratio of the highest detected constituent concentrations to regulatory standards. Note, only constituents with regulatory standards are included in Exhibits 2-5, 2-6, and 2-7. Many inorganic constituents were elevated in groundwater monitoring wells. Constituents that exceeded state groundwater protection standards or federal drinking water standards most frequently were:

Iron (49 detections) Cadmium (17 detections) Chloride (32 detections) Benzene (16 detections) Manganese (34 detections) Arsenic (15 detections) Sulfate (29 detections) Zinc (13 detections) Lead (22 detections) Aluminum (12 detections) Chromium (21 detections) Nitrate (12 detections) Six of the constituents identified above (iron, chloride, manganese, sulfate, zinc, and aluminum) have drinking water standards that are based only on SMCLs. A total of 25 TC constituents have been detected in the release descriptions. Exhibit 2-5 identifies 20 ofthe 25 TC constituents detected. Five TC constituents (2,4,6-trichlorophenol, 2,4-dinitrotoluene, o-cresol, pcresol, and methyl ethyl ketone) were not included in Exhibit 2-5 because there were no federal or state standards established for them. All but 2 of the 20 TC constituents identified in Exhibit 2-5 (carbon tetrachloride, 1,4- dichlorobenzene) were detected above a federal or state standard. The majority (85 percent) of the TC constituents detected above a federal or state standard exceeded the standards by at least 1 time, 60 percent exceeded by 10 times, 50 percent exceeded by 100 times, 20 percent exceeded by 1,000 times, 10 percent exceeded by 10,000 times, and none exceeded by at least 100,000 times. The average maximum detected concentrations for five of the TC constituents (arsenic, benzene, selenium, vinyl chloride, and lindane) exceeded the TCPage 2-14 

### Exhibit 2-5 TC Contaminants Detected in Case Studies

Constituent (mg/l) Constituents Standards (mg/l) (mg/l) (mg/l) Standards

TC Level With

Detected Federal/ State Concentration Federal/State Case Studies Concentrations Abov e Detected Concentration to Case Studies with Ratio of Highest Detected Average Maximu m Detected Range of Highest Maximu m Federal/State Detected Standards Concentration
Lead 5 37 22 0.0015 - 0.05 1.3 28 560 - 18,667 Chromium 5 36 21 0.01 - 0.1 2.3 58 580 - 5,800 Arsenic 5 29 15 0.005 - 0.05 28.4 595 11,900 - 119,000 Cadmium 1 28 17 0.0004 - 0.005 0.2 3 600 - 7,500 Barium 100 28 11 0.2 - 2 31.1 630 315 - 3,150 Benzene 0.5 23 16 0.0005 - 0.001 1.4 15 15,000 - 30,000 Mercury 0.2 19 6 0.0002 - 0.002 0.002 0.007 3.5 - 35 Selenium 1 18 6 0.01 - 0.05 2.2 27 540 - 2,700 Trichloroethylene 0.5 15 7 0.0005 - 0.005 0.03 0.14 28 - 280 Vinyl chloride 0.2 13 6 0.0002 - 0.002 2.9 8.6 4,300 - 43,000 Silver 5 12 3 0.01 - 0.1 0.006 0.01 0.1 - 1 Chlorobenzene 100 9 2 0.05 0.025 0.05 1 Chloroform 6 8 2 0.0006 - 0.08 0.11 0.4 105 - 667 Tetrachloroethylene 0.7 7 3 0.005 0.0085 0.026 5 1,4-Dichlorobenzene 7.5 5 0 0.015 - 0.075 0.017 0.035 0.5 - 2.3 Carbon tetrachloride 0.5 4 0 0.005 0.0017 0.004 0.8 Pentachlorophenol 100 2 2 0.001 0.036 0.063 63 Lindane 0.4 2 2 0.0002 0.66 1.2 6,000 1,2-Dichloroethane 0.5 2 2 0.005 0.016 0.02 4 Heptachlor 0.008 1 1 0.0004 0.002 0.002 5Page 2-15 

### Exhibit 2-6 Contaminants with SMCLs Detected in Case Studies

Constituent/ Property Constituents Standards Standards (mg /l) (mg/l) (mg/l) Standards Case Studies With Concentrations Abov e Range of Concentration to Detected Federal/State Federal/State Federal/State

Case Studies with Ratioof the Highest Detected Detected Average Maximum Highest Maximum Detected Detected Concentration Concentration pH 66 24 6.5 - 8.5 5.4 12.4 1.5 - 1.9 (unitless) (unitless) (unitless) Iron 54 49 0.15 - 0.3 244 4,400 14,667 - 29,333 Chloride 52 32 125 - 250 1,825 37,200 149 - 297 Sulfate 50 29 125 - 500 2,273 26,000 52 - 208 Total dissolved 48 30 500 - 1,000 7,033 98,164 98 - 196 solids Manganese 39 34 0.0025 - 0.3 10 97 323 - 3,880 Zinc 33 13 0.05 - 5 20 262 52 - 5,240 Copper 17 2 0.13 - 1.3 0.15 0.9 0.7 - 7 Aluminum 12 12 0.05 - 0.2 235 1,933 9,665 - 38,660 Fluorides 12 4 0.44 - 4 12 98 25 - 223Page 2-16 

### Exhibit 2-7 Other Contaminants Detected in At Least Three Case Studies

Constituent Constituents Standards Standards (mg /l) (mg/l) (mg/l) Standards Case Studies With Concentrations Abov e Range of Concentration to Detected Federal/State Federal/State Federal/State

Case Studies with Ratioof the Highest Detected Detected Average Maximum Highest Maximum Detected Detected Concentration Concentration
Sodium 40 8 20 -160 1,292 15,600 98 - 780 Nitrate 33 12 2 - 10 46 560 56 - 280 Magnesium 32 3 35 - 420 140 1,495 4 - 43 Toluene 20 7 0.07 - 1 0.62 6.7 7 - 96 Phenol 18 10 0.001 - 1.2 6.3 60 50 - 60,000 Ammonia 16 2 2 55.3 410 205 Nickel 14 4 0.08 - 0.1 0.1 0.5 5 - 6.3 Nitrite 11 9 1 18.9 64 64 Xylenes 10 1 0.124 - 10 2 4.8 0.5 - 39 1,1-Dichloroethane 10 0 0.7 0.18 1 1 Acetone 9 1 0.7 1.4 10.6 15 Nitrogen 8 0 2 - 10 8.1 57.6 6 - 29 Dichloromethane 7 4 0.005 - 0.015 0.6 4 267 - 800 Ethylbenzene 7 3 0.14 - 0.7 0.3 0.9 1.3 - 6.4 Vanadium 7 0 0.014 0.1 0.4 31 cis-1,2- 7 3 0.07 0.081 0.24 3 Dichloroethylene Beryllium 7 6 0.004 - 1.1 0.25 1.7 2 - 425 Cyanide 6 2 0.04 - 0.2 0.09 0.4 2 - 10 Boron 6 1 2.9 40.4 82 28 Cobalt 5 0 0.005 0.083 0.16 32 Naphthalene 5 1 0.008 3.3 14.2 1,775 Antimony 5 4 0.006 0.67 3 500 trans-1,2- 4 1 0.01 0.0016 0.052 5 Dichloroethylene Thallium 4 2 0.002 0.0048 0.01 5Page 2-17



### regulatory levels established for these constituents and the highest maximum detected concentrations for over half of the identified TC constituents exceed TC regulatory levels. All SMCLs or similar state standards, except those for foaming agents, color, odor, and corrosivity, were violated by one or more release descriptions. As shown in Exhibit 2-6, the majority (90 percent) of the SMCL constituents exceeded the standards by at least 1 time, 80 percent exceeded by 10 times, 40 percent exceeded by 100 times, 20 percent exceeded by 1,000 times, 10 percent exceeded by 10,000 times, and none exceeded by at least 100,000 times. (Because silver has both a TC level and an SMCL, it is included in Exhibit 2-5 with the other TC constituents.) SMCLs are based on aesthetic considerations (e.g., taste and odor) and are not federally enforceable. Therefore, exceedences of the SMCLs do not necessarily indicate a potential danger to human health or the environment. Sixteen of the case studies (14 percent) were identified based only on an exceedence of an SMCL. This type of contamination is discussed further in Chapter 5. Exhibit 2-7 identifies 24 other constituents that were detected in the release descriptions. All but four of the constituents in Exhibit 2-7 (1,1- dichloroethane, nitrogen, vanadium, and cobalt) were detected above a federal or state regulatory level. Half (50 percent) of these other constituents exceeded one of the standards by at least 10 times, 13 percent exceeded by 100 times, 4 percent exceeded by 1,000 times, and none exceeded by at least 10,000 times. Constituents managed in landfills were detected in samples nearly three times more frequently than constituents managed in surface impoundments. All of the constituents presented in Exhibits 2-5, 2-6, and 2-7 are associated with wastes managed in landfills. Approximately 81 percent of the constituents are associated with both landfills and surface impoundments, 33 percent are associated with landfills, surface impoundments, and land application units, 33 percent are associated with landfills, surface impoundments, and waste piles, and 12 percent are associated with all 4 waste management units. The constituents that are associated only with landfills are antimony, beryllium, boron, cobalt, cyanides, silver, and thallium. Exhibit 2-8 identifies the 10 constituents for each of the 6 industries that were identified most frequently in the case studies. As the exhibit illustrates, inorganics are the most commonly detected chemicals. The commonly detected constituents are chloride, pH, iron, lead, total dissolved solids, manganese, sulfate, magnesium, zinc, and arsenic.
2.3 Major Limitations The findings presented in this chapter must be interpreted with care for several reasons, including the limited time available to collect data, potentially unrepresentative data, and the Agency's stringent release selection criteria. Each of these major limitations is discussed in detail below. Data were collected under significant time constraints. The significant amount of data included in this chapter were collected and analyzed over a four-month period. During this time the Agency reviewed previously collected data, readily available databases, and reports; identified and contacted appropriate state and federal personnel; visited state and EPA Regional offices; reviewed facility files; prepared case study summaries; developed a database to analyze the data; performed QA/QC on the data; sent draft case studies to states and facilities for review; prepared a draft report for public review; andPage 2-18



### incorporated comments into the report, as appropriate. Due to the time constraints of the consent decree, the Agency had to carefully prioritize its efforts and, in doing so,Page 2-19 

### Exhibit 2-8 Most Common Constituents By Industry

Industrial

Classification Code Number of Case Studies in Which the (SIC) Constituent Constituent Was Detected Refuse Systems (495) pH 19 * 

### Iron 14 * 

### Manganese 13

* 

### Sulfate 13

* 

### Lead 12 Chloride 11

* 

### Magnesium 10 Nitrate 10 Total dissolved solids 10 * 

### Trichloroethylene 10 Paper & Allied Products (26) pH 22 * 

### Chloride 21

* 

### Iron 21 * 

### Sulfate 20

* 

### Sodium 15 Calcium carbonate 12 Calcium 11 Magnesium 11 Zinc 11 Total dissolved solids 10 * 

### Chemical & Allied Products (28) Benzene 7 Chromium 7 Iron 7 * 

### Lead 6 Manganese 6

* 

### Sulfate 6

*

### Exhibit 2-8 (continued) Most Common Constituents By Industry

Industrial

Classification Code Number of Case Studies in Which the (SIC) Constituent Constituent Was Detected

Page 2-20 

### Chemical & Allied Products (28) Total dissolved solids 6 (Cont.) * 

### Zinc 6 Arsenic 5 Chloride 5

* 

### Food & Kindred Products (20) Nitrite 6 Nitrate 5 Nitrogen 5 pH 4 * 

### Total dissolved solids 4 * 

### Total filterable residue 4 Calcium 3 Chloride 3

* 

### Magnesium 3 Sodium 3 Non-Metallic Minerals, Except Arsenic 4 Fuels (14) Iron 4 * 

### Lead 4 Manganese 4

* 

### pH 4 * 

### Cadmium 3 Chloride 3

* 

### Copper 3 Nickel 3 Potassium 3

### Exhibit 2-8 (continued) Most Common Constituents By Industry

Industrial

Classification Code Number of Case Studies in Which the (SIC) Constituent Constituent Was Detected

Page 2-21 

### Primary Metal Industries (33) Lead 4 Chromium 3 Aluminum 2 Arsenic 2 Barium 2 Cadmium 2 Chloride 2

* 

### Mercury 2 Nickel 2 Zinc 2
Constituents with Secondary Maximum Contaminants. *



### may have eliminated or missed a number of potential case studies that could have been included in the report if additional data were available and/or additional time was spent collecting and reviewing data. Data may be unrepresentative and/or out-of-date. In this report, the Agency did not attempt to estimate the proportion of non-hazardous management facilities currently experiencing constituent releases. Due primarily to the limited time available for data collection and analysis, the Agency relied upon readily available data. The Agency did not perform any new sampling or collect new data from facilities managing non-hazardous industrial wastes. Nor did the Agency perform a comprehensive review of previously collected state and federal data for all non-hazardous industrial waste management facilities. State file reviews were conducted in one to three days per state and were limited to those states that indicated having files of release incidents that met the Agency's selection criteria. Although the collection of release descriptions is not statistically representative in any way, these cases are indicative of the type of releases associated with the management of non-hazardous industrial waste. Because only readily available data were analyzed, the data may not reflect current waste generation and management practices at the particular facility. Environmental contamination resulting from waste disposal practices may take many years to become evident; some releases described in this report occurred over 20 years ago. The documented releases may have resulted from particular waste generation and disposal practices or other conditions that no longer exist. Specifically, process feedstocks, processing operations, waste characteristics, and/or waste management practices may have changed. Facilities may no longer manage their wastes in unlined units or in environmentally sensitive areas. Therefore, releases associated with a waste do not necessarily demonstrate that current waste management practices or regulations need to change. Conversely, the failure of a site toPage 2-22



### exhibit documented damages at present does not necessarily suggest that waste management has not or will not cause damage. The Agency, however, believes that information on dangers posed by past waste management practices is useful in demonstrating the potential for human health or environmental damages. The extent to which the findings can be used to draw conclusions concerning the relative performance of waste management practices among states or across industry sectors is also severely limited by variations in recordkeeping, monitoring, and other state requirements. Recordkeeping and monitoring procedures vary significantly among the states. Several states have complete and up-to-date central enforcement or monitoring records on facilities that generate and manage non-hazardous industrial wastes. Where states have such records, information on releases may be readily available. Thus, states with the most complete and accessible monitoring information on non-hazardous industrial wastes may appear to have more releases than states with less centralized information management programs. Stringent selection criteria. The Agency developed stringent selection criteria to help focus its data collection efforts and to avoid any misrepresentation of release incidents. By focusing solely on releases clearly associated with non-hazardous industrial waste management units, the Agency excluded numerous release incidents caused by accidental releases and spills of products. Although these incidents may have been caused by hazardous constituents similar to those managed in non-hazardous industrial waste management units, and may pose similar hazards, the Agency did not analyze these cases, largely because of the inability of RCRA to prevent product releases. The Agency also excluded release incidents that could not be linked to specific facilities. Thus, cases of groundwater and surface water contamination caused by multiple facilities were excluded because the source of the releases could not be associated with specific facilities or waste management units. The Agency also excluded numerous release incidents associated with facilities that manage hazardous, municipal, or special wastes in addition to non-hazardous industrial waste. Facilities that manage hazardous, municipal, or special wastes frequently co-dispose of their non-hazardous industrial wastes in the same or adjacent waste management units. Due to the close proximity of these different units, sampling results generallycannot identify the specific unit associated with the release. Thus, the Agency excluded cases where nonhazardous industrial waste was managed in the same or adjacent waste management units as hazardous, municipal, or special wastes, because the source of the release could not clearly be associated with the non-hazardous industrial waste.Page 2-23



### CHAPTER 2. RELEASES FROM NON-HAZARDOUS INDUSTRIAL WASTE MANAGEMENT UNITS 2-1
2.1 Methodology

..................................................... 2-1
2.1.1 Criteria For Selecting Releases

................................ 2-1
2.1.2 Approach For Identifying Releases

............................. 2-3 2.1.2.1 State Industrial D Programs

............................ 2-3 2.1.2.2 State Superfund Programs

............................. 2-5 2.1.2.3 Federal Superfund Program

............................ 2-6 2.1.2.4 Construction and Demolition (C&D) Landfill Report

....... 2-6
2.1.3 Release Profile Preparation

................................... 2-7
2.2 Results

.......................................................... 2-8
2.2.1 Number of Cases By State

................................... 2-8 2.2.2 Number of Cases By Industry

................................ 2-10 2.2.3 Number of Cases By Type of Waste Management Unit

........... 2-11 2.2.4 Type of Media Affected

.................................... 2-12 2.2.5 Types of Contaminants Released

............................. 2-13
2.3 Major Limitations

................................................ 2-17Page 2-24



### Exhibit 2-1 Number of Release Descriptions By State

..................................... 2-9
Exhibit 2-2 Number of Management Units & Volume of Waste Managed On-Site, by State (1985) 2-9
Exhibit 2-3 Number of Case Studies by Industry (SIC)

................................... 2-10
Exhibit 2-4 Number of Case Studies By Waste Management Unit

.......................... 2-12
Exhibit 2-5 TC Contaminants Detected in Case Studies

.................................. 2-14
Exhibit 2-6 Contaminants with SMCLs Detected in Case Studies

........................... 2-15
Exhibit 2-7 Other Contaminants Detected in At Least Three Case Studies

.................... 2-16
Exhibit 2-8 Most Common Constituents By Industry

..................................... 2-18Page 3-1



# CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS

This chapter examines how well the existing hazardous waste characteristics address the types of risk they were intended to address, that is, their target risks. It also addresses certain other or non-target risks that are closely associated with the definitions of the hazardous characteristics. This evaluation of potential gaps begins by examining the characteristics' definitions and test methods. This approach is used for two reasons. First, limitations in the characteristics' effectiveness in reducing their target risks may themselves constitute important potential gaps. When the characteristics were promulgated, the Agency identified physical hazards and acute toxic hazards during transport and disposal activities, along with chronic exposure to groundwater contaminated with specific waste constituents, as being among the most important waste management risks. Reducing these risks remains an important goal of the characteristics. Second, this analysis lays the groundwork for evaluating other potential gaps. Specifically, risk-based screening methods are used to evaluate non-target risks from non-ground-water pathways associated with the toxicity characteristic (TC) analytes. The findings of that analyses are used to identify potential gaps associated with a wider universe of known and possible non-hazardous industrial waste constituents, as discussed in Chapter 4. This chapter revisits many of the assumptions and approaches used to develop the existing hazardous waste characteristics. The ignitability, corrosivity, and reactivity (ICR) characteristics are essentially unchanged since their initial promulgation in 1980. The TC characteristic was revised in 1990, but has not changed materially since then. Potential gaps in these characteristics may be identified if the state of knowledge about risks addressed by the characteristics has improved since the characteristics were promulgated; risks that were not specifically addressed may now be identified as more important, such as risks from releases to surface water, inhalation, and indirect pathways and ecological risks. In addition, the tests used to identify wastes with hazardous characteristics do not reliably identify all of the risks the characteristics were intended to address. The following sections address these issues. Section 3.1 reviews the statutory and regulatory language related to the types of risks the hazardous waste characteristics were intended to address and discusses the major categories of waste management risks addressed and not addressed by the current characteristics. Sections 3.2 through 3.4 discuss potential gaps associated with the ignitability, corrosivity, and reactivity characteristics, respectively. In addition, a detailed comparison of the ICR characteristics can be found in Appendix C. Section 3.5 discusses the potential gaps associated with the toxicity characteristic, including updated risk information on the TC analytes. Section 3.6 evaluates the toxicity characteristic leaching procedure (TCLP) as a predictor of constituent releases and potential risk. 3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics 3.1.1 Statutory and Regulatory Framework The RCRA hazardous waste characteristics are a vital part of the comprehensive program of hazardous waste management established by Subtitle C of RCRA, as amended. Three provisions of the RCRA statute are particularly relevant to identifying and expanding the hazardous waste characteristics (and listing hazardous wastes).

First, Section 1004(7) defines hazardous waste as "a solid waste, or combination of solid wastes, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may (A) cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (B) pose a substantial present or potential hazard to human health or the45Federal Register 33108-33110, May 19, 1980. 1

Page 3-2



### environment when improperly treated, stored, transported, or disposed of, or otherwise managed." This definition indicates the general types of risks that the hazardous waste management regulations are meant to address. Second, Section 3001(a) requires EPA to "develop and promulgate criteria for identifying the characteristics of hazardous waste, and for listing hazardous wastes, . . . taking into account toxicity, persistence, and degradability in nature, potential for accumulation in tissue, and other related factors such as flammability, corrosiveness, and other hazardous characteristics. Such criteria shall be revised from time to time as may be appropriate." Third, Section 3001(b) requires EPA to "promulgate regulations identifying the characteristics of hazardous waste, and listing particular hazardous wastes, . . . which shall be based on the criteria promulgated under [Section 3001(a)] and shall be revised from time to time thereafter as may be appropriate." The Section also requires EPA to "identify or list those hazardous wastes which shall be subject to the [hazardous waste regulations] solely because of the presence in such wastes of certain constituents (such as identified carcinogens, mutagens, or teratogens) at levels in excess of levels which endanger human health." In response to the mandate of Section 3001(a), EPA promulgated two sets of criteria for identifying the characteristics of hazardous waste in 40 CFR 261.10(a). The first set of criteria reflects the statutory definition of hazardous waste and the types of risks that the characteristics are intended to address: "(1) The solid waste may (i) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (ii) pose a substantial present or potential hazard to human health or the environment when it is improperly treated, stored, transported, disposed, or otherwise managed." The second set of criteria considers implementation factors: "(2) The characteristic can be (i) measured by an available standardized test method which is reasonably within the capability of generators of solid waste or private sector laboratories that are available to serve generators of solid waste; or (ii) reasonably detected by generators of solid waste through their knowledge of their waste." As stated in the May 19, 1980, final rule, EPA adopted the second set of criteria because the primary responsibility for determining whether wastes exhibit a characteristic rests with generators, for whom standard and available testing protocols are essential. This Scoping Study addresses these criteria for the current 1Page 3-3



### characteristics in only a general way. The Agency, however, will carefully consider these factors when deciding the appropriate course of action for addressing any potential gaps in coverage that are identified in this Study. The following sections review the nature of the risks to human health and environment potentially posed by non-hazardous industrial waste management. These risks are associated with physical hazards, acute toxic hazards to humans, chronic toxic hazards to humans, risk to non-human receptors, and other hazards. In the discussion below, risks addressed by the hazardous waste characteristics are distinguished from those risks not directly or adequately addressed. The purpose of this section is to develop a preliminary list of possible gaps in the characteristics. At this stage, few judgments are made as to the nature and severity of any potential gaps. Instead, the remainder of this Report investigates these potential gaps. 3.1.2 Risks Associated with Physical Hazards Physical hazards include agents that cause direct physical harm such as thermal burns, wounds, contusions, or eye injuries, in contrast to agents causing harm through chemical burns or toxic effects. These hazards are controlled primarily through the ignitability, corrosivity, and reactivity (ICR) characteristics. EPA patterned these characteristics after similar regulations promulgated by the U.S. Department of Transportation, the National Fire Protection Association, and other organizations. The ICR characteristics are intended primarily to protect waste management and transportation workers against hazards often associated with hazardous materials. These hazards include flammability, explosivity, and the propensity to react violently with other wastes, corrode containers, and directly injure skin and eyes during transport or management activities. In addition, these characteristics are intended to prevent the facilitated release and transport of hazardous waste constituents. For example, the corrosivity test is designed, in part, to identify wastes that, because of their acidity or basicity, may facilitate the solubilization of metals from wastes. This solubilization increases the potential impact of metals in groundwater, thereby increasing the likelihood of risks to human health via contaminated groundwater. For the purposes of this Scoping Study, the question is: What physical risks may arise from the management of non-hazardous industrial wastes that are currently not covered by the characteristics? Several potentially significant physical risks are not effectively addressed by the hazardous characteristics. Some of the potential gaps arise from specific definitions of the ICR characteristics. These potential gaps, which are discussed in more detail in Sections 3.2 through 3.4, include:

The lack of coverage of corrosive solids; The decision not to address liquids with moderate flash points;55Federal Register 11809, March 29, 1990. 2

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### Limitations in the test procedures prescribed for reactivity; and Potential limitations of pH as an adequate indicator of corrosivity. These issues relate to protecting waste management and transportation workers from physical injuries, except where explosions or fire might release toxic particulates that could harm nearby residents. Physical hazards to residents near management facilities are not considered, based on the assumption that the general public has limited access to non-hazardous industrial waste management facilities. Other physical concerns relate to facilitated pollutant transport. For example, the corrosivity characteristic was not intended to address corrosion to liners or any materials other than steel or to prevent facilitated transport of organic chemicals through solubilization in discarded solvents. EPA considered, and decided to omit, a “solvent override” provision in the 1990 TC rule that would have classified as hazardous wastes with more than a specified concentration of hazardous organic solvents. The Agency, however, left open the possibility that such a provision could be reconsidered if additional data warrant it. A related issue is the 2 

### potential formation of dense and light non-aqueous phase liquids (DNAPLs and LNAPLs). They are a potential concern both because they may facilitate pollutant transport and they have the potential for damaging groundwater resources and generating high remediation costs. Section 4.4 discusses the issue of DNAPL and LNAPL formation. 3.1.3 Acute Toxic Hazards to Humans The hazardous waste characteristics address some potential health risks from acute exposures to toxic chemicals. They limit the potential for release of toxic chemicals during transportation, storage, treatment, and disposal and resulting from fires, explosions, or violent reactions. There are no specific quantitative benchmarks that define acceptable acute exposure limits, however. The main focus of the ICR characteristics is onprotecting workers, although the general public is implicitly protected under the assumption that protecting onsite workers would protect more distant resident populations as well. Sections 3.2 through 3.4 discuss potential gaps in the ICR characteristics. The characteristics were not intended to protect against other acute systemic toxicity hazards. Direct contact with a waste, in theory, could result in the absorption of an acutely toxic dose of a waste constituent from a non-corrosive waste. The Agency, however, considered this scenario to be highly improbable for non-hazardous industrial waste mismanagement. Similarly, acute exposures via contaminated surface or groundwater are possible, but were considered much less likely to be important than chronic toxicity under most circumstances. Because the TC focuses on the groundwater pathway, with the attendant long-term transport and dilution of pollutants, EPA assumed that chronic exposures would be dominant in determining the potential for adverse health effects. Section 3.5.6 discusses the potential for acute adverse effects of exposure to the TC analytes and Section 4.6 addresses acute risks from non-TC constituents. 3.1.4 Chronic Toxicity Risks to Humans As noted above, EPA intended the TC to be the major vehicle for controlling chronic health risks, although the reactivity and corrosivity characteristics also were intended to prevent releases that facilitate exposure to waste constituents. Although RCRA Section 3001 identifies a range of types of toxic effects of concern (toxicity, carcinogenicity, mutagenicity, and teratogenicity), the implementation of the TC is limited to 40 chemicals for which toxicity and groundwater fate and transport data were available when the Agency revised the characteristic in 1990. In addition, the levels of protectiveness achieved by the TC leachate concentration standards were determined using fate and transport models and assumptions that were current at the time. To the extent that thePage 3-5



### toxicity data and groundwater fate and transport models have changed or improved in the six years since the TC was promulgated, its expected level of protectiveness may also have changed. Section 3.5 discusses in detail potential gaps associated with the level of protectiveness of the TC in light of recent advances in toxicology and groundwater modeling. The TC was not intended to address several potentially important risks. These risks have been identified as significant contributors to risks from some hazardous waste constituents and management technologies, and might apply to non-hazardous industrial waste management as well. Probably the most important risks potentially not directly addressed by the TC are associated with exposure pathways other than groundwater. The TC did not attempt to address these risks because groundwater was thought to be the dominant risk pathway for waste management. Upon re-examining potential non-hazardous industrial waste management and mismanagement scenarios, however, EPA recognizes that other pathways also may be important. One pathway not directly addressed by the TC is the direct inhalation of volatile or particulate-bound waste constituents to air from waste management units during normal operation or after closure. Such exposures to on-site workers and off-site receptors through direct inhalation may be significant for some constituents. Other potentially important pathways include the surface water pathway and “indirect” pathways arising from air releases (e.g., air deposition to crops), runoff, and the discharge of contaminated groundwater to surface water. Also, bioaccumulation of certain contaminants in aquatic and/or terrestrial food chains could result in human exposures through the consumption of contaminated fish, shellfish, livestock, and game animals. In Section 3.5, a screening-level risk assessment and other information clarify the significance of these pathways for the TC analytes. Chapter 4 extends the screening-level analysis to non-TC constituents. 3.1.5 Risks to Non-Human Receptors Neither the TC nor the ICR characteristics were established specifically to reduce risks to non-human receptors. Such risk reduction, to the extent that it occurs, is a byproduct of the control of human health risks. For example, by preventing pollutant releases from fires and explosions or reducing pollutant transport, the characteristics protect the environment as well as human health. The quantitatively-defined levels of protection incorporated into the TC leachate concentration limits were based on human toxicity considerations; they do not consider toxicity to non-human receptors. While the exposure levels accepted as protective of human health may be generally protective of wildlife populations, notable exceptions arise both from the ecotoxicological properties of some chemicals and from differences between human and non-human receptor exposure patterns. The question therefore can be asked: To what extent is the TC protective of ecological receptors? As in the case of human health risks, the TC does not directly protect against risks from chemicals not on the TC list. Similarly, it is not clear how protective the existing TC levels are for the various exposure pathways that are most important for aquatic and terrestrial receptors. In the case of ecological receptors, as is the case for human health, both direct and indirect exposure pathways may be significant. These issues are addressed in more detail in Section 3.5 and Chapter 4 of this report.Page 3-6 

### 3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management In establishing the existing hazardous waste characteristics, the Agency focused exclusively on human health risks directly associated with local effects of accidents and on chemical contamination of the environment in the near vicinity of the management units. In Chapter 5 of this study, EPA has taken a broader view, and has expanded the scope of the risk identification to include risks other than those originally considered, even indirectly, in establishing the hazardous waste characteristics. These additional categories of risks include damages to natural resources and contributions to large-scale environmental problems. Non-hazardous industrial waste management has the potential to adversely affect the value or utility of natural resources, such as wetlands, groundwater, and air, without posing human health risks. For example, releases from non-hazardous industrial waste management units have polluted previously usable groundwater with constituents generally not considered toxic, such as iron, manganese, chloride, and total dissolved solids. The regulatory criteria violated by these releases, such as Secondary Maximum Concentration Levels (SMCLs) developed under the Safe Drinking Water Act, are not directly health-related, but relate instead to the aesthetic properties or usability of the water. Therefore, even though no health risk is predicted, the water is rendered unusable and the environment is thereby damaged. Similarly, odor from non-hazardous industrial waste management may be seen as an air resource damage, reducing the quality of life for affected individuals, even in the absence of direct health effects. The last category of risks are associated with the possible contribution of non-hazardous industrial waste management to large-scale environmental problems, including:

Air deposition to the Great Waters; Damages from airborne particulates; Global climate change; Potential damages from endocrine disruptors; Red tides; Stratospheric ozone depletion; Tropospheric ozone and photochemical air pollution; and Water pollution. The possible relationship between non-hazardous industrial waste management and these risks is less clear than for the previously identified risks. As summarized in Exhibit 3-1, Section 3.1 has presented an intentionally broad inventory of potential risks to human health and the environment associated with the management of non-hazardous industrial wastes not currently identified as hazardous. This list provides a catalogue of risks for evaluation against the existing characteristics in the rest of this chapter and the following chapters.Page 3-7



### Exhibit 3-1. Risks Potentially Associated with Non-Hazardous Industrial Waste Management

Types of Risks By Characteristics Risks Not Intended to be Addressed by Characteristics

RisksIntended to be Addresse d
Physical Hazards Burns and injuries to waste Physical injuries to the general public

management and Facilitated transport of organics from solubilization transportation workers DNAPL/LNAPL generation from fire, explosions, and violent reactions Skin, eye injury from direct contact with corrosive substances (workers) Facilitated transport of chemicals (primarily inorganics) in groundwater Acute Toxicity Adverse effects from Inhalation of toxic gases and particulates by public Risks to Humans inhalation of toxic gases Acute health risks from other exposure pathways (direct contact,

and particulates (workers) ingestion of contaminated water or food) Chronic Toxicity Risks of cancer and non- Chronic health risks to workers Risks to Humans cancer effects from Chronic risks from exposures to non-TC chemicals (public and

consumption of groundwater workers) contaminated by TC Chronic risks associated with non-groundwater pathways: constituents (public) -- inhalation of volatilized materials and particulates other than those released from fire or explosion -- ingestion of surface water contaminated by runoff or groundwater discharge -- risks to public from direct contact with waste, contaminated soil, and in direct pathways (ingestion of contaminated crops, fish, game) Risks from specific types of toxins: -- reproductive toxins -- endocrine disruptors Toxic Risks to

-- Aquatic toxicity Nonhuman Receptors Toxicity to terrestrial organisms Sediment toxicity Bioaccumulation/biomagnification Groundwater exposure Other Risks

-- Damages to groundwater, surface water, and air affecting their usability or qualityNon-hazardous industrial waste management contribution to largescale environmental problems, such as air deposition to the Great Waters, damages from airborne particulates, global climate change, potential damages from endocrine disruptors, red tides, stratospheric ozone depletion, tropospheric ozone and photochemical air pollution, and water pollution.Page 3-8 Potential Ignitability Gaps Excludes DOT Combustible Liquids (liquids with flash point above 140 but below 200 degrees Fahrenheit) Excludes Aqueous Flammable Liquids (alcohol solutions of concentrations < 24 percent) that are capable of flashing, but not supporting combustion References outdated DOT Regulations No test methods for non-liquids 

### 3.2 Ignitability Characteristic This section describes potential gaps related to the definition of the RCRA ignitability characteristic and its test methods. The basic approach taken in identifying potential gaps for ignitability as well as for corrosivity and reactivity was to review the original 1980 rulemaking record and to compare the characteristic to approaches taken to controlling similar hazards under other regulatory schemes, including the U.S. Department of Transportation's (DOT's) hazardous materials regulations, the U.S. Occupational Safety and Health Administration's (OSHA's) worker health hazards standards, and state hazardous waste management standards. 3.2.1 Definition of Ignitability The ignitability characteristic is intended to “identify wastes capable of causing fires during routine transportation, storage and disposal, and wastes capable of exacerbating a fire once started." These risks include generally recognized fire hazards to waste management and transportation workers, such as burns and inhalation smoke or fumes, and the potential generation and facilitated transport in air of toxic particulates and fumes that could harm the general public. According to 40 CFR 261.21, a solid waste exhibits the characteristic of ignitability if a representative sample of the waste has any of the following properties:

Is a liquid, other than an aqueous solution containing less than 24 percent alcohol by volume and has flash point less than 60 C (140 F), as determined by: o o



### -- A Pensky-Martens Closed Cup Tester, using the test method specified in ASTM Standard D-93-79 or D-93-80 (incorporated by reference, see § 260.11),

-- A Setaflash Closed Cup Tester, using the test method specified in ASTM standard D-3278-78 (incorporated by reference, see § 260.11), or

-- An equivalent test method approved by the Administrator under procedures set forth in §§ 260.20 and 260.21; Is not a liquid and is capable, under standard temperature and pressure, of causing fire through friction, absorption of moisture or spontaneous chemical changes and, when ignited, burns so vigorously and persistently that it creates a hazard; Is an ignitable compressed gas as defined in 49 CFR 173.300 and as determined by the test methods described in that regulation or equivalent test methods approved by the Administrator under §§ 260.20 and 260.21; or Is an oxidizer as defined in 49 CFR 173.151. 3.2.2 Potential Gaps Related to Definition of IgnitabilityU.S. Environmental Protection Agency, Office of Solid Waste,Background Document: Resource Conservation and Recovery Act, 3 Subtitle C -- Identification and Listing of Hazardous Wastes, Section 261.21-Characteristics of Ignitability, May 2, 1980, p. 10-11.

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### Liquids with flash point at or above 140 F not covered.The RCRA ignitability characteristic includes liquid wastes with flash point less than 60 C (140 F). When promulgating the original characteristic, EPA o o 

### acknowledged choosing a definition for ignitable liquid wastes that excluded some potential wastes that would meet the definition of hazardous materials under DOT regulations. The DOT definition offlammable liquidincludes liquids with flash point not more than 60.5 C (141 F), or any material in liquid phase with a flash point at or above 37.8 C (100 F) that is intentionally heated and offered for transportation or transported at or above its flash point in a bulk packaging. The DOT definition ofcombustible liquidincludes liquids with flash point above 60.5 C (141 F) and below 93 C (200 F). Thus, the RCRA ignitability characteristic covers wastes that would be classified as DOT flammable liquids, but not DOT combustible liquids. Consistent with DOT regulations, OSHA includes such "combustible" liquids in its definition ofhealth hazard, and Rhode Island regulates them as hazardous wastes. In a background document supporting the promulgation of the original characteristics, EPA stated that 3 

### the RCRA ignitability flash point limit of 140 F reflects conditions likely to be encountered during routine waste o 

### management. In support of this conclusion, the Agency referenced seven studies documenting temperatures and conditions at waste management units. The information available to the Agency at the time was limited, however. Furthermore, two of these studies reported temperatures of greater than 140F. One study reported temperatures of o 

### approximately 160 F near the surface of a landfill, noting that aerobic conditions near the surface of landfills o 

### often result in relatively high temperatures. Data are still limited regarding whether temperatures greater than 140F are encountered during non- o 

### hazardous industrial waste management, in what situations and how frequently this occurs, and what maximum temperatures are reached (particularly in hotter regions of the nation). One relevant issue is whether temperatures exceeding 140F may be encountered during mismanagement (as opposed to routine waste management). o 

### Examples of possible mismanagement scenarios for ignitable wastes include:

Wastes stored in closed, heat-containing facilities (e.g., metal sheds, upper floor warehouse spaces, or metal trucks) in hot climates and/or sunlight; and Wastes mixed in waste management units in a manner that might generate heat through chemical reactions, especially in the presence of hot climate or sunlight. No information is readily available regarding the universe of "combustible" industrial wastes currently being managed as non-hazardous. Nevertheless, some liquid materials with flash points generally in this range can be identified, as shown in Exhibit 3-2. Examples include certain alcohols, low molecular weight esters, ethylene glycol ethers, kerosene, jet fuels, certain petroleum byproducts, many "tints and paints," and individual chemicals including benzaldehyde, benzonitrile, and bromobenzene. If these materials are disposed of or are present in wastes, the wastes may be combustible, in spite of not being hazardous by the ignitability characteristic. In addition, mixtures of materials of differing flash points may fall into this category. Exclusion for aqueous liquids containing less than 24 percent alcohol may warrant reexamination.At the time of the original rulemaking, some commenters argued that liquid wastes such as wine and some latex paints that exhibit low flash points because of their alcohol content do not sustain combustion because of the high percentage of water and therefore should not be designated as characteristically hazardous waste. EPA agreed and excluded from the ignitability characteristic aqueous solutions containing less than 24 percent of alcohol by volume. A45Federal Register 33108. 4

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### similar exclusion is found in DOT regulations. EPA stated that it hoped "to undertake further study to determine whether another exclusion limit is more appropriate and to evaluate tests which might be capable of identifying wastes which exhibit this phenomenon." EPA also intended to evaluate possible supplemental test methods to 4 

### evaluate flammability hazards for these types of wastes. The exclusion for aqueous liquids containing alcohol has caused confusion during implementation and enforcement concerning whether it applies only to ethanol or more broadly to all alcohols. The exclusion also focuses on aqueous alcohol solutions, rather than on the underlying target of liquids with low flash points that do not sustain combustion. (Tests for sustained combustion are now available: ASTM has methods D-4206 and D-4207.) In addition, the rationale that certain liquids should not be considered ignitable if they do not sustain combustion may not be valid where an excluded aqueous solution could flash and ignite a co-managed non-hazardous waste that would sustain combustion.Page 3-11



### "Adhesive" Ethylhexaldehyde Exhibit 3-2 Materials Formerly Classified by DOT as Combustible Liquids

(which generally are not RCRA ignitable)

Source: Suspect Chemicals Handbook, 1988. n.o.s. = not otherwise specified. Note: Current DOT Hazardous Materials Table in 49 CFR 172.101 does not distinguish combustible liquids from flammable liquids. The above list was taken from a 1987 version of DOT regulations that classified some materials as combustible liquids. This list is intended to provide examples of materials "that may be combustible (i.e., liquids with 141 F < flash point < 200F)." o oBackground Document, supra footnote 2, p. 14. 5
45Federal Register

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### References to DOT regulations are outdated.The ignitability characteristic refers to a DOT definition of ignitable compressed gas (49 CFR 173.300) that has been withdrawn. Current DOT regulations at 49 CFR 173.115 defineflammable gas, which is any material that is a gas at 20 C (68 F) or less and 101.3 kPa (kilopascals equal to 14.7 pounds per square inch) of pressure. The complete definition includes any material that has a boiling point of 20 C (68 F) or less at 101.3 kPa (14.7 psi)) that (1) is ignitable at 101.3 kPa (14.7 psi) when in a mixture of 13 percent or less by volume with air; or (2) has a flammable range at 101.3 kPa (14.7 psi) with air of at least 12 percent regardless of the lower limit. Likewise, the termoxidizer is no longer defined at 49 CFR 173.151. It is now found at 49 CFR 173.127. These out-of-date citations constitute a potential gap because they may cause regulatory confusion and misinterpretation and thereby may impede efficient and effective compliance and enforcement. 3.2.3 Potential Gaps Related to Ignitability Test Methods No test method is specified for non-liquids.The ignitability characteristic does not specify a testmethod for non-liquid wastes. In a background document supporting the original rulemaking, EPA stated that nonliquid wastes may present a hazard by virtue of their capacity to ignite and burn as a result of friction, moisture absorption, or spontaneous reaction under the normal temperatures and pressures encountered in waste management.5 

### The Agency noted that such wastes are akin to reactive wastes and can directly injure workers or others as a result of fire, induced explosions, or induced generation of toxic gases at almost any point in the waste management process. Examples of potential ignitable non-liquid wastes include soils highly contaminated with gasoline or other ignitable substances and sorbents used to cleanup spills of ignitable substances. In explaining the final rulemaking, the Agency stated that, although "EPA would have preferred providing a test method for identifying ignitable solids, it has determined . . . that there are no test methods capable of accurately identifying the small class of ignitable solids to which its regulation is directed. EPA is presently working with the Department of Transportation and other organizations to correct this deficiency." Since then, 6 

### EPA has identified a test method that may be suitable for identifying ignitable solids. Method 1030 ("Ignitability of Solids") has been proposed for inclusion in the Third Edition of the EPA test methods manual "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods," EPA Publication SW-846. The method is 7 

### appropriate for pastes, granular materials, solids that can be cut into strips, and powdery substances. 3.3 Corrosivity 3.3.1 Definition of Corrosivity According to 40 CFR 261.22, a solid waste exhibits the characteristic of corrosivity if a representative sample of the waste has either of the following properties:

Is aqueous and has a pH less than or equal to 2 or greater than or equal to 12.5, as determined by a pH meter using Method 9040 in "Test Methods for the Evaluation of Solid Waste, Physical/Chemical Methods," incorporated by reference in § 260.11; orPage 3-13 Potential Corrosivity Gaps Excludes corrosive non-liquids pH limits may not effectively protect against some types of injury Corrosion to materials other than steel is not directly addressed Solubilization of non-metals (e.g., by organic solvents) is not addressed Excludes irritants and sensitizers pH test methods may not accurately predict hazards 

### Is a liquid and corrodes steel (SAE 1020) at a rate greater than 6.35 mm (0.250 inch) per year at a test temperature of 55 C (130 F) as determined by the test method specified in o o 

### NACE (National Association of Corrosion Engineers) Standard TM-01-69 as standardized in "Test Methods for the Evaluation of Solid Waste, Physical/Chemical Methods," EPA Publication SW-846, as incorporated by reference in § 260.11. The first part of this definition encompasses wastes exhibiting low or high pH, which “can cause harm to human tissue, promote the migration of toxic contaminants from other wastes, react dangerously with other wastes, and harm aquatic life.” Specifically, the Agency identified skin and eye damage to transporters who are directly exposed to the waste as a primary focus of this characteristic. The pH limits also were intended to address the potential solubilization of heavy metals allowing migration to groundwater, reactions with incompatible wastes resulting in fires, explosions, generation of flammable or toxic gases, generation of pressure inside vessels, and the dispersal of toxic vapors, mists, and particulates. The other part of the corrosivity characteristic relates to the corrosivity of waste to steel containers. The Agency identified this aspect of corrosivity as a hazard because “wastes capable of corroding metal can escape from the containers in which they are segregated and liberate other wastes.” The consequences of liberating wastes from containers during transportation or storage include harm from direct contact, violent reactions, and the release of waste components to the environment. 3.3.2 Potential Gaps Related to Definition of Corrosivity Non-liquids are not covered.The current RCRA corrosivity characteristic is limited to liquids. Other regulatory programs, however, also cover corrosive non-liquids. For example:

DOT regulates corrosive liquids and solids as hazardous materials;
The OSHA definition of health hazard includes all corrosives regardless of physical form;
The Basel Convention definitions of hazardous materials are not limited to liquids; and At least four states (California, New Hampshire, Rhode Island, and Washington) include non-aqueous wastes in their definitions of corrosivity. New Hampshire and Rhode Island specifically include corrosive gases as well as corrosive solids. The states that include non-liquids in their corrosivity characteristics specify mixing the non-aqueous waste with water and then testing for pH. The rationale for this approach is that the waste is likely to come into contact with water during land-based management. In addition, EPA has developed Method 9045 (Soil and Waste pH), which can be used to test some corrosive solid wastes. Finally, Method 1120 (Dermal Corrosion) may be applied to solids, liquids, and emulsions (see additional discussion below under "potential gaps related to corrosivity test methods").U.S. Environmental Protection Agency, Office of Solid Waste,Background Document: Resource Conservation and Recovery Act, 8 Subtitle C-Identification and Listing of Hazardous Wastes, Section 261.22-Characteristic of Corrosivity, May 2, 1980, p. 5. Id., pp. 9-10. 9
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### pH limits may not cover some hazards.EPA originally proposed pH limits of 12.0 or greater and 3.0 or less, and a majority of commenters argued that these limits were too stringent. The commenters argued that the limit of 12.0 or greater would regulate as hazardous many lime-stabilized wastes and sludges, thereby discouraging use of a valuable treatment technique, and that the pH limit of 3.0 or less would regulate a number of substances generally thought to be innocuous (e.g., cola drinks) and many industrial wastewaters prior to neutralization. EPA agreed with these commenters and promulgated pH limits of 12.5 or greater and 2.0 or less in the 1980 final rule. The more stringent proposed pH limits were based on studies of eye tissue damage. These studies indicated that pH extremes above 11.5 and below 2.5 generally are not tolerated by human corneal tissue. EPA decided that 8 

### basing pH limits on eye tissue damage was unnecessarily conservative. Thus, eye damage is a hazard not fully addressed by the corrosivity characteristic. The corrosivity characteristic also was intended to prevent harm to ecological receptors caused by the release of hazardous wastes with high- or low-pH. In discussing aquatic life in the original background document,9 

### EPA noted that the optimum pH range for freshwater fish is 6.5 to 9.0 and that an increase or decrease of 2 pH units beyond the optimum range causes severe effects. Levels of pH of 11.0 or greater and 3.5 or less are fatal to all species of fish. EPA also noted that altering surface water pH can reduce the productivity of food organisms essential to fish and wildlife. The pH limits of the corrosivity characteristic (2.0 and 12.5) are well beyond the safe range for aquatic life, but wastes presumably would be significantly diluted before the point of exposure to aquatic life. EPA did not conduct a risk assessment of such potential hazards (e.g., modeling the pathway of waste released to surface water and exposure to aquatic life) and thus it is not known under what circumstances high- or low-pH wastes could cause harm to aquatic receptors. Corrosion of materials other than steel is not directly addressed.In the second part of the corrosivity characteristic, EPA uses steel corrosion as an indicator of corrosivity. EPA adopted this aspect of corrosivity because "wastes capable of corroding metal can escape from the containers in which they are segregated and liberate other wastes." EPA adopted DOT's corrosion standard, noting that the rate at which a waste corrodes a 10 

### material commonly used in container construction (low carbon steel) is a suitable measure of its hazardousness.Ibid, p. 6. 11
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### The reliance on the steel corrosion rate may create a potential gap if there are plausible mismanagement scenarios where wastes are stored, transported, or disposed in containers made from materials more easily corroded than low carbon steel (e.g., plastic by organic solvents) or are disposed in solid waste management units lined with materials such as clay or synthetics. Also, there may be a potential gap in the characteristic if waste management scenarios result in conditions where wastes are subject to higher temperatures than the 130F test o 

### temperature. Solubilization of hazardous constituents.The corrosivity characteristic also was intended to address the potential for high- and low-pH materials to solubilize potentially toxic waste constituents. EPA offers the example that a drop in pH from 4.0 to 2.0 increases the solubility of red mercury oxide or chromium hydroxide in water approximately 100 times. The general concern is for inorganic ions that may be converted to more soluble 11 

### species. This characteristic does not address the potential solubilization of organic constituents by organic liquids such as solvents, nor does it address the formation of non-aqueous phase liquids (NAPLs) by such materials. EPA considered including a solvents "override" in the TC characteristic, but did not do so. The 12 

### solvents override would have caused wastes with high concentrations of solvents to be classified as hazardous on the basis of potential NAPL formation. The issue of NAPL formation is discussed in more detail in Chapter 5. Lack of coverage of sensitizers and irritants.At least two types of materials that may pose potential hazards to humans through direct contact are not included in the corrosivity characteristic or any other characteristic: irritants and sensitizers. OSHA includes irritants in its definition ofhealth hazard and definesirritant

as a material that is not corrosive, but which causes a reversible inflammatory effect on living tissue by chemical action at the site of contact. A chemical is a skin irritant if, when tested on the intact skin of albino rabbits by the methods of 16 CFR 1500.41 for four hours exposure or by other appropriate techniques, it results in an empirical score of five or more. A chemical is an eye irritant if so determined under the procedure listed in 16 CFR 1500.42 or other appropriate techniques. (See 29 CFR 1910.1200.)
OSHA also includes sensitizers in its definition of health hazard. Asensitizer is defined as a material that causes a substantial proportion of exposed people or animals to develop an allergic reaction in normal tissue after repeated exposure to the chemical. (See 29 CFR 1910.1200.) This analysis did not identify any specific non-hazardous industrial wastes that are irritants or sensitizers. Irritants and sensitizers, however, are common categories of materials and these properties are often identified in laboratory testing of materials. A major issue regarding this potential gap is whether any irritants and/or sensitizers pose a hazard in wastes that reaches the statutory level of hazard intended to be covered by RCRA Subtitle C.45Federal Register 33109. 13

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### 3.3.3 Potential Gaps Related to Corrosivity Test Methods Use of pH as an indicator has limitations.EPA chose pH as a measure of corrosivity because "wastes exhibiting low or high pH can cause harm to human tissue, promote the migration of toxic contaminants from other wastes, react dangerously with other wastes, and harm aquatic life." The ability of some substances to damage 13 

### human tissue, however, may not be adequately indicated by a pH measurement. Other regulatory and advisory bodies (e.g., DOT, OSHA, Basel Convention) use criteria based on full thickness destruction of human skin. Since the original rulemaking in 1980, Method 1120 (Dermal Corrosion) has been developed commercially. The dermal corrosion assay system is anin vitrotest method which determines the corrosive potential of a substance toward human skin. It can be used to test liquids (aqueous or non-aqueous), solids (water soluble or insoluble), and emulsions. Method 1120 is essentially the same method that DOT uses. It replaced previous tests (e.g., Draize test) that used live animals with a test that uses a proprietary synthetic pig collagen material. 3.4 Reactivity 3.4.1 Definition of Reactivity The reactivity characteristic is “intended to identify wastes, which because of their extreme instability and tendency to react violently or explode, pose a problem at all stages of the waste management process.” This characteristic was intended to reduce physical risks to transportation and disposal workers and to avoid incidents that could result in the release of toxic constituents into the air consequent to an explosion or violent reaction. 40 CFR 261.23 states that a solid waste exhibits the characteristic of reactivity if a representative sample of the waste has any of the following properties:

Is normally unstable and readily undergoes violent change without detonating; Reacts violently with water; Forms potentially explosive mixtures with water; When mixed with water, generates toxic gases, vapor, or fumes in a quantity sufficient to present a danger to human health or the environment; Is a cyanide or sulfide bearing waste which, when exposed to pH conditions between 2 and 12.5 can generate toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment; Is capable of detonation or explosive reaction if it is subjected to a strong initiating source or if heated under confinement;45Federal Register 33109. 14
45Federal Register

33110. 15

Page 3-17 Potential Reactivity Gaps Broad, non-specific definitions References outdated DOT regulations No test methods specified 

### Is readily capable of detonation or explosive decomposition or reaction at standard temperature and pressure; or Is a forbidden explosive as defined in 49 CFR 173.51, or a Class A explosive as defined in 49 CFR 173.53 or a Class B explosive as defined in 49 CFR 173.88. 3.4.2 Potential Gaps Related to Definition of Reactivity The Definition is broad and lacks specificity.In discussing the reactivity characteristic in the 1980 final rule, EPA stated that "the definition was intended to identify wastes which, because of their extreme instability and tendency to react violently or explode, pose a problem at all stages of the waste management process." EPA noted that 14 

### the reactivity characteristic encompasses a diverse class of physical properties and effects and overlaps somewhat with the ignitability characteristic. Some commenters argued that the definition was vague. They advocated using a quantitative definition accompanied by testing protocol(s). EPA responded that "the prose definition should provide generators with sufficient guidance to enable them to determine whether their wastes are reactive." EPA argued that most 15 

### generators whose wastes are dangerous because they are reactive are well aware of this property and such wastes usually are generated from reactive feedstocks and/or processes producing reactive products or intermediates. EPA further stated that problems posed by reactivity appeared to be confined to a fairly narrow category of wastes. Theoretically, the reactivity characteristic could be clarified and made consistent with other programs (especially DOT) by developing more specific definitions of general terms such as "normally unstable," "violent change," "potentially explosive," "reacts violently with water," "readily capable of detonation," and so forth. Other programs include more specific definitions. For example, as shown in Exhibit 3-3, DOT has adopted definitions ofspontaneously combustible materialanddangerouswhen wet material, which could be used to clarify the RCRA characteristic. Specifically, DOT identifies an ignition time and violent reaction rate. Likewise, OSHA definespyrophoric, unstable reactive, andwater reactive, specifying reactive conditions such as shocks, pressure, and temperature which define the characteristic. The Basel Convention also defines similar terms. References to DOT regulations are outdated.Forbidden explosive are no longer defined in 49 CFR 173.51. The current DOT regulations define forbidden explosives at 49 CFR 173.54. Other explosives are defined at 49 CFR 173.50. 49 CFR 173.88 no longer exists.Page 3-18 

### Exhibit 3-3 Other Definitions of Reactivity

DOT(49 CFR 173.124) Spontaneously combustible materialis a pyrophoric material, that is a liquid or solid that, even in small quantities and without an external ignition source, can ignite within five minutes after coming in contact with air.
Aself-heating materialis a material that, when in contact with air and without an energy supply, is liable to self-heat.
Adangerous when wet materialis a material that, by contact with water, is liable to become spontaneously flammable or to give off flammable or toxic gas at a rate greater than 1 liter per kilogram of the material, per hour. OSHA(29 CFR 1910.1200) Apyrophoric chemicalis a chemical that will ignite spontaneously in air at a temperature of 130 C or below.
Anunstable reactive chemicalis a chemical that in the pure state, or as produced or transported, will vigorously polymerize, decompose, condense, or will become self-reactive under conditions of shocks, pressure or temperature.
Awater reactive chemicalis a chemical that reacts with water to release a gas that is either flammable or presents a health hazard. Basel Convention Characteristic
Anexplosiveis a solid or liquid capable by chemical reaction of producing gas at such a temperature and pressure and at such speed as to cause damage to the surroundings. Substances or wastes liable to spontaneous combustionare liable to spontaneous heating under normal conditions encountered in transport, or to heating upon contact with air, and being then liable to catch on fire. Substances or wastes which, in contact with water, emit flammable gasesare substances or wastes, which by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities. Substances or wastes that cause liberation of toxic gases in contact with air or water are substances or wastes that, by interaction with air or water, are liable to give off toxic gases in dangerous quantities. Organic peroxidesare organic substances or wastes which contain the bivalent O-O structure are thermally unstable substances which may undergo exothermic self-accelerating decomposition.45Federal Register 33110, May 19, 1980. 16
55Federal Register

11801, March 29, 1990. In finalizing the revised toxicity characteristic, however, the Agency used a 17 generic DAF of 100 in a subsurface fate and transport model to set the regulatory levels.

Page 3-19 

### 3.4.3 Potential Gaps Related to Reactivity Test Methods Reactivity characteristic lacks test method(s).When the Agency promulgated the reactivity characteristic in 1980, no available tests were identified for use in defining the reactivity characteristic because: They were too restrictive and were confined to measuring how one specific aspect of

reactivity correlates with a specific initiating condition or stress. Testing the reactivity of a sample does not necessarily reflect reactivity of the waste, because reactivity varies with properties including mass and surface area. Most available tests required subjective interpretation of results. Existing methods were not developed for testing wastes. Although EPA has identified a test method (Method 9010) for reactive sulfide and/or cyanide bearing wastes, the Agency has not identified suitable test methods to fully define the reactivity characteristic. 3.5 Potential Gaps Associated with the Toxicity Characteristic 3.5.1 Definition of Toxicity Characteristic The toxicity characteristic was designed by EPA to reduce risks to public health from chronic exposures to groundwater contamination caused by releases of toxic waste constituents. The Agency found “persuasive evidence that the contamination of groundwater through the leaching of waste contaminants from land disposed wastes is one of the most prevalent pathways by which toxic waste constituents migrate to the environment.” The legislative 16 

### history of RCRA and EPA’s case studies of damages from hazardous waste management were cited as support for focusing the toxicity characteristic exclusively on groundwater pathway risks. EPA originally listed 14 contaminants as part of the toxicity characteristic. Subsequently, EPA added another 26 substances to the list, as shown in Exhibit 3-4. These 40 TC chemicals were selected because:

The chemicals were included on the 40 CFR Part 261 Appendix VIII list of hazardous waste constituents that have been “shown to have toxic, carcinogenic, mutagenic, or teratogenic effects,” and Appropriate chronic toxicity information had been developed and adequate fate and transport data were available to allow the modeling of groundwater fate and transport for each constituent.17Page 3-20



### Arsenic 5.0 Hexachlorobenzene 0.013 Exhibit 3-4 TC Constituents and Regulatory Levels (mg/l)

Source: 40 CFR 261.24.
Thus, EPA found these chemicals to be among those posing the greatest risk to humans from chronic groundwater exposure. The remainder of Section 3.5 evaluates the TC in five steps: Section 3.5.2 examines whether new data on the toxicity and persistence of TC analytes and updated groundwater transport modeling techniques would result in allowable TC leachate concentrations different from those established in 1990. Section 3.5.3 presents screening-level exposure and risk modeling methods and results that are used to evaluate whether the current TC chemicals could pose risks to human health and environmental receptors through the inhalation pathway. Sections 3.5.4 and 3.5.5 evaluate potential risks from TC chemicals to human health through surface water pathways and indirect pathways, respectively. These risks are evaluated by comparing toxicity and fate and transport values to defined risk-related criteria, both singly and in combination, and by reviewing the results of the Agency's multipathway risk modeling for the analytes that was performed as part of the proposed Hazardous Waste Identification Rule (HWIR-Waste) development.Page 3-21 

### Sections 3.5.6 and 3.5.7 evaluate the potential for acute adverse health effects of exposures to TC analytes and potential risks to ecological receptors from TC analytes, respectively. 3.5.2 Changes in Groundwater Pathway Analysis This section of the Scoping Study explores two issues related to the current TC regulatory levels: (1) whether new toxicity data indicate a potential need to revise the regulatory levels; and (2) whether, in light of recent developments in groundwater modeling techniques, the current dilution and attenuation factor (DAF) value of 100 still provides a reliable basis for assuring that human health is protected against risks from groundwater exposures to TC chemicals. Revisions to MCLs and Toxicity Criteria The toxicological bases for the establishment of TC analyte regulatory levels were chronic toxicological and health-based regulatory criteria that were current at the time of promulgation. These included Safe Drinking Water Act Maximum Contaminant Levels (MCLs), Reference Doses (RfDs), and Risk-Specific Doses (RSDs) based on ingestion pathway Cancer Slope Factors (CSFs). For almost all of the TC analytes, these values have not changed since 1990. The few changes have included:

A reduction in the RfD for p-cresol by a factor of ten and the withdrawal of the MCL of 50 ug/l for lead and its replacement with an Action Level of 15 ug/l. For cresol and lead, the reductions in RfDs and promulgation of Action Levels indicate that the toxicological evaluation of these chemicals has changed such that the TC regulatory levels may be less protective than was originally intended. The changes for both of these analytes were an order of magnitude or less. The withdrawal of the MCL for silver, with its replacement by an SMCL at the same value. This change simply means that the critical toxic effect for silver (argyria, which is the collection of dark pigment in the skin and mucous membranes) has been downgraded from a health effect to a cosmetic effect. In addition, the RfD for pentachlorophenol has been reduced from 2 mg/l to 3x10 mg/l. -2 

### More importantly, since the TC was revised, the Agency has promulgated a cancer slope factor for this compound, which is a suspect human carcinogen. Thus, the critical toxic endpoint has been changed from non-cancer to cancer induction. The promulgation of the Cancer Slope Factor implies that a much lower TC regulatory level (about 1000 times lower) would be needed to achieve the same level of protection against cancer risks as originally intended when the TC was promulgated.A detailed discussion of the groundwater modeling approach used by EPA in support of the TC rule can be found at 55Federal 18 Register 11816, March 29, 1990.
Ibid at 11827. 19A detailed discussion of the EPACMTP model can be found in U.S. Environmental Protection Agency, Office of Solid Waste, 20 EPACMTP Background Document, 1995; andEPACMTP Background Document for Metals, Volume 1: Methodology, 1995.

Page 3-22 

### Advances in Groundwater Modeling To develop the existing TC regulatory levels, the Agency used the EPAMCL model to estimate the likely extent of dilution after the release of waste constituents from waste management units during their transport to the nearest drinking water wells. These calculations were conducted for municipal solid waste landfills and 18 

### Subtitle D surface impoundments, taking into account the geochemical properties of the constituents, the size and configuration of the units, the vadose zone and groundwater regimes beneath the units, and the distribution of distances in the downgradient direction to the nearest drinking water well. Groundwater regimes were defined using distributions of transport parameter values typical of conditions throughout the United States. Receptor wells were assumed to be in the groundwater plume at a distribution of distances derived from a Subtitle D facility survey. Simulation methods were used to derive estimates of dilution-attenuation factors (DAFs) for each constituent and each type of waste management unit. After reviewing the results, the Agency elected to calculate acceptable leachate concentrations (regulatory levels) for each TC analyte using a single DAF value of 100. In 19 

### other words, the threshold leachate concentration of each analyte above which wastes would be identified as TC hazardous was set equal to allowable drinking water concentration or other benchmark (10 cancer risk or Hazard -5 

### Quotient (HQ) = 1.0) for the analytes multiplied by 100. Since the TC was promulgated, the Agency has continued to use the same general approach to evaluate the groundwater transport of pollutants in developing RCRA regulations. The exact techniques used in this modeling, however, have changed significantly. In recent rulemakings, the Agency has used an updated version of the EPAMCL model, known as EPACMTP, to derive constituent-specific DAFs for a wide range of pollutant releases from hazardous and non-hazardous waste management units. This model employs many of the same basic transport algorithms as the EPAMCL, with several important differences, including the following:20



### The EPACMTP model uses a detailed metals speciation model (MINTEQA) to estimate leachate concentrations from wastes of defined ionic composition, whereas the EPAMCL model did not employ such a model; The EPACMTP, unlike EPAMCL, can model the adsorbtion to soil and transformation of organic waste constituents by hydrolysis into more toxic (or less toxic) transformation products; The EPACMTP directly simulates the interface between the saturated and vadose zones; The EPACMTP model can simulate groundwater mounding under management units, whereas the EPAMCL could not; and The EPACMTP model provides more flexibility in modeling finite, versus infinite, source terms.U.S. Environmental Protection Agency, Office of Solid Waste,Technical Support Document for the Hazardous Waste 21 Identification Rule: Risk Assessment for Human and Ecological Receptors, August 1995. U.S. Environmental Protection Agency, Office of Solid Waste,Regulatory Impact Analysis of the Supplemental Proposed Rule 22 Applying to Phase IV Land Disposal Restrictions to Newly Identified Mineral Processing Wastes, December 1995.

Page 3-23 

### Recent applications of the model also used somewhat different assumptions regarding waste and facility characteristics, hydrogeological regimes, climatology, and receptor locations than those used in the development of the TC. Therefore, it is not possible, except in a very general way, to simply compare the DAF value used in establishing the TC allowable leachate concentrations with the constituent-specific DAF values for the same constituents derived in the subsequent analyses. In addition, DAF values derived for metals using the EPACMTP vary with the initial concentration of the constituent in the waste, because the model incorporates saturable binding and transport phenomena. In contrast, the DAFs derived using the EPAMCL model are concentration-invariant under most conditions. Recently, EPA has employed the EPACMTP model in two major regulatory development efforts. EPA applied the model in its development of proposed risk-based exit levels for the Proposed Hazardous Waste Identification Rule for Process Waste (HWIR-Waste). In that 21 

### analysis, EPACMTP was used to back-calculate concentrations of constituents in wastes and in waste leachate corresponding to specific risk levels through groundwater exposures. The Agency is currently revising the proposed HWIR-Waste exit level groundwater risk modeling methods in response to comments from the Science Advisory Board and from other technical reviewers. Thus, the results of this modeling presented in this Scoping Study should be regarded as preliminary. In the Phase IV LDR regulatory development effort for mineral processing wastes, the model was used to derive constituent-specific DAFs for mineral processing wastes disposed of in surface impoundments and waste piles. The DAFs were then used to derive 22 

### groundwater pathway risk estimates for exposure to waste constituents. The results of these analyses have been used to evaluate the extent to which changes in modeling techniques may have affected the assessment of groundwater fate and transport relative to the assessment used to derive the TC regulatory concentrations. As noted previously, a simple comparison of DAF values and/or calculated risk levels from the different modeling efforts is not possible without further analysis since the more recent modeling employs different groundwater transport models and different assumptions regarding facility characteristics, groundwater regimes, and receptor locations. In the case of the mineral processing risk assessment, for example, DAF values were derived specifically for facility sizes representative of the mineral processing industry, rather than Subtitle D management units. In addition, groundwater modeling was performed using climatologic data primarily from drier regions where many mineral processing facilities are located. While Subtitle D facilities were used to calculate releases for the HWIR-Waste proposal, the receptor wells were assumed to be distributed uniformly in the downgradient direction, instead of being confined to the plume. More importantly, the proposed exit levels were derived using a carcinogenic risk target of 10 , rather than 10 , and -6 -5 

### the 90th percentile, rather than the 85th percentile, estimates of risk were used. Using the 90th instead of 85th percentile of the risk output results in estimating higher risks for a given receptor for a given constituent concentration and in more stringent (lower) exit levels. Thus, the proposed HWIR-Waste risk calculations, especially for carcinogens, are substantially more conservative in several important respects than those used to derive the TC regulatory levels.In one of these cases (for endrin), however, the limiting risk, is ecological, rather than human health. 23

Page 3-24 

### In the mineral processing risk assessment, DAF values were derived for eight of the TC analyte metals. For waste piles, the DAF values for the majority of the TC metals were considerably higher than 100, the highest value being 1x10 for lead. Barium, with a DAF value of 54, was the only metal for which the mineral processing waste

30 

### pile DAF was less than the value of 100 used in the derivation of the TC regulatory concentrations. These results imply that the DAF value of 100 used in the TC derivation remains conservative for most metals when compared to values derived for this population of facilities. The situation is different, however, if the DAF values derived for mineral processingsurface impoundmentsare used as a basis for comparison. In this case, the majority of the DAF values for the TC metals were less than 100. This finding suggests that the DAF value of 100 used to derive the TC regulatory levels may not provide adequate protection against groundwater risks from surface impoundments, which are the most frequent management type employed for non-hazardous industrial wastes. The large difference in DAF values for the two types of management units can be explained partly in terms of the comparative aridity of the locations for which DAFs were calculated. Where little moisture was available to drive transport from the waste piles through the vadose zone, DAF values tended to be high. In contrast, the surface impoundments provided a water supply that drove transport through the vadose zone into groundwater. The extent to which this effect would be seen in moister regions of the country is not clear. The HWIR-Waste proposed groundwater exit level calculations for the TC analytes are summarized in Exhibit 3-5, and compared to the TC regulatory levels. The majority of the exit levels are considerably lower (more stringent) than the corresponding TC regulatory levels. In 4 cases, the TC levels are comparable to or less than the exit level. For 9 analytes, the ratio of the TC regulatory level to the exit level is between 1 and 10. For 12

23 

### analytes, this ratio is between 10 and 100; for 5 analytes, the ratio is between 100 and 1,000; and for 6 analytes, the ratio is greater than 1,000. This distribution confirms that, generally, the assumptions and modeling approaches used to derive the HWIR-Waste proposed exit levels lead to somewhat more conservative or more protective results than those used to derive the TC regulatory levels. This conclusion holds true, even taking into account that the cancer risk target is 10-fold lower for setting some of the proposed exit levels than was used for setting the TC levels. For all but a few of the carcinogens among the TC analytes, the proposed exit levels are far more than 10 times lower than the corresponding TC regulatory levels. Thus, some other factors account for a significant proportion of the conservatism in these calculations.Page 3-25 

### Exhibit 3-5 Comparison of TC Regulatory Concentrations and HWIR-Waste Proposed Exit/Leach Levels

Analyte mg/l Level, mg/l Level (mg/l) Level

Chronic Toxicit y HWIR-Waste Regulatory Leve l Reference Level, TC Regulatory Groundwater Exi t to Exit/Leach

a a b Ratio of

Arsenic 0.05 5 0.000148 33784 Barium 1 100 15.5 6.5 Benzene 0.005 0.5 0.0054 92.6 Cadmium 0.01 1 0.11 9.1 Carbon tetrachloride 0.005 0.5 0.00161 311 Chlordane 0.0003 0.03 0.000163 184 Chlorobenzene 1 100 1.33 75.2 Chloroform 0.06 6 0.017 353 Chromium 0.05 5 0.476 10.5 Cresol, m- 2 200 3.2 62.5 Cresol, o- 2 200 3.2 62.5 Cresol, p- 2 200 0.32 625 Dichlorobenzene, 1,4- 0.075 7.5 0.0108 694 Dichloroethane, 1,2- 0.005 0.5 0.00006 8333 Dichloroethylene, 1,1- 0.007 0.7 0.00018 3889 2,4-D 0.1 10 0.6 16.7 Dinitrotoluene, 2,4- 0.0005 0.13 0.112 1.2 Endrin 0.0002 0.02 32 0.000625 Heptachlor 0.00008 0.008 No value 30 Heptachlor epoxide 0.00008 0.008 0.45 0.0178 Hexachloro-1,3-butadiene 0.005 0.5 0.00691 72.4 Hexachlorobenzene 0.0002 0.13 0.000113 1150 Lindane 0.004 0.4 0.693 0.577 Hexachloroethane 0.03 3 0.033 90.9 Lead 0.05 5 11.6 0.4Page 3-26 

### Exhibit 3-5 (continued) Comparison of TC Regulatory Concentrations and HWIR-Waste Proposed Exit/Leach Levels

Analyte MCL or HBL Level, mg/l ExitLevel (mg/l) Level a TC Regulatory HWIR-Waste Lowes t to Exit/Leach

a b Ratio of

Regulatory Leve

l

Mercury 0.002 0.2 0.138 1.4 Methoxychlor 0.1 10 No value

-- Methyl ethyl ketone 2 200 30 6.7 Nitrobenzene 0.02 2 0.032 62.5 Pentachlorophenol 1 100 0.00041 243902 Pyridine 0.04 5 0.06 83.3 Selenium 0.01 1 0.357 2.8 Silver 0.05 5 No value

-- Tetrachloroethylene 0.007 0.7 0.68 1.0 Toxaphene 0.005 0.5 0.11 4.5 Trichloroethylene 0.005 0.5 0.0128 39 Trichlorophenol, 2,4,5- 4 400 4.2 95.2 Trichlorophenol, 2,4,6- 0.02 2 0.0152 132 Silvex 0.01 1 0.48 2.1 Vinyl chloride 0.002 0.2 0.00006 3333

Notes: 55Federal Register

11804, March 29, 1990. a 60 Federal Register 66424-66432, December 21, 1995. b



### Some of this conservatism may be due to differences in modeling assumptions, rather than modifications in modeling techniques. For example:

The HWIR-Waste proposed exit levels were derived to be protective of 90th percentile receptors, while the TC levels were set to be protective of 85th percentile receptors. As shown in Exhibit 3-5, some HWIR-Waste proposed exit levels were driven by exposure pathways other than groundwater. The proposed HWIR-Waste exit levels and the TC regulatory levels were designed for different purposes. The TC levels are designed to provide a method for identifyingPage 3-27 

### wastes that would otherwise be non-hazardous, while the proposed HWIR-Waste exit levels would relieve wastes previously identified as hazardous from stringent regulatory control. These issues are discussed in more detail in Sections 3.5.3 and 3.5.4. Other differences in modeling assumptions, such as the retention of constituents in waste management (loss terms) in TC modeling only and the differences in the assumed location of wells relative to the contamination source, influence the results in the other direction. Summary.Based on the preceding analyses, only general conclusions can be drawn about whether there are any significant gaps in the TC associated with the specific regulatory levels set for individual constituents. The wide range in the mineral processing DAF values illustrates the high degree of variability associated with specific groundwater modeling assumptions, and does not necessarily indicate whether the DAFs should be considered less or more protective than when they were originally derived. The HWIR-Waste proposed exit level calculations, on the other hand, suggest that the application of more recent modeling techniques might result in more conservative transport calculations. Some, but not all, of this greater level of protectiveness reflects a policy decision by the Agency regarding what proportion of receptors should be protected to the target risk level. In addition, advances in modeling techniques and differences in specific input assumptions also affect the differences in the apparent levels of protectiveness. 3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes This section investigates the general level of protectiveness of the allowable TC concentrations against direct inhalation, a risk that the TC was not specifically intended to protect against. EPA analyzed this issue by performing screening-level risk calculations for long-term air releases of the TC constituents from Subtitle D facilities. EPA used the CHEMDAT8 model using facility characteristic parameters for surface impoundments and land application units (LAUs). Release estimates for all of the organic TC analytes were developed for two scenarios. In the first scenario, releases were estimated from the same “high-end” surface

impoundments and LAUs that were modeled in the proposed HWIR-Waste exit level modeling. The second scenario modeled releases from the "central tendency" impoundments and LAUs, which were considerable smaller and shallower than the high-end units. In both release scenarios, the concentrations of the organic TC analytes were assumed to be at the TC regulatory level for liquid wastes in surface impoundments and at 20 times the TC levels for nonwastewaters in land application units. The latter assumption roughly estimates the maximum concentration of the TC analyte that could be present without the waste being hazardous, assuming efficient leaching using the TCLP. For analytes that do not leach well, this approach may underestimate exposure concentrations and risks associated with air releases from non-hazardous industrial wastes, since nonwastewaters with high concentrations of constituents would not beidentified as hazardous by the TCLP. Average releases to air were calculated for an assumed 40-year facility lifespan under both scenarios. The basic approach and input assumptions used in the modeling are summarized in Exhibit 3-6. The organic TC analytes for which releases were modeled vary widely in molecular weight, vapor pressure, Henry’s Law constant, and other physical properties that affect releases to air. Thus, the extent of release of these chemicals to air from land disposal facilities might be expected to differ widely. This is true to some extent; but, as can be seen in Exhibit 3-7, the estimated release of these compounds from land application units and surface impoundments over the expected facility life-span varies only moderately. In the case of the high-endRelease from surface impoundments were estimated on an annual basis, rather than on a facility life-time basis because 24 these units receive a constant and continuous flow of wastes throughout the facility life, with liquid flowing out of the unit after an assumed dwell time. In contrast, once a waste is added to an LAU, it is assumed to remain in the facility to volatilize throughout the facility life-span.

Page 3-28 

### land application units, between approximately 7 percent and 100 percent of the chemicals entering the units are released to the air over the facility life. The average proportion of the analytes released from these units was 81.6 percent, and the calculated releases were greater than 95 percent for two-thirds of the organic TC analytes. The results were similar for the central tendency LAU. Releases ranged from 27 to 100 percent of the analytes, and the average proportion released was 96.3 percent. The explanation for the predicted higher proportional releases from the central tendency LAU is not clear, but may be related to the shallower tilling depth assumed for the central tendency unit (0.2 compared to 0.3 meters). The proportions of the TC analytes released from surface impoundments are shown in the final two columns of Exhibit 3-7. The releases ranged from 6 to 77 percent of the applied total per year for the high-end impoundment, with an average release of 55.5 percent per year. Proportionate releases were again higher from the 24 

### central tendency unit, ranging from 15 percent to 88 percent, with an average of 71.2 percent released annually. Similar to the situation for the LAUs, the higher proportional releases from the central tendency unit may be due to its considerably shallower depth (2 meters) compared to the high-end unit (7 meters). The limited impact of a chemical's Henry's Law constant on air releases is somewhat surprising in light of the broad spectrum of solubility and vapor pressure reflected in the chemicals modeled. Perhaps it can best be understood as indicating that, in the long run (a year or more), a high proportion of any of these organic chemicals placed in uncovered land management units will be released to the air, provided other removal pathways are not important. In actual practice, some land application units are covered to some extent, and other removal processes, such as leaching, biological and chemical degradation, and binding to soil or sediment, compete to reduce air emissions significantly. EPA calculated chronic risks from inhalation pathway exposures for all organic TC analytes. To calculate exposure concentrations, EPA multiplied release estimates by the long-term fenceline dispersion coefficients used in the proposed HWIR-Waste exit level calculations for the high-end and central tendency surface impoundments and LAU releases. The fenceline dispersion coefficients are used to represent the nearest credible residential exposure locations, in keeping with the proposed HWIR-Waste risk methodology. Exposure durations are assumed to be 30 years in the high-end exposure release and exposure scenario, and 9 years in the central tendency scenario.Page 3-29

Modeling Procedures Estimate release proportions at TC regulatory concentrations Estimate exposure concentrations using fenceline dispersion coefficients from HWIR-Waste modela Estimate risks using IRIS and HEAST toxicity values (RfCs and Unit Risk values) Subtitle D Surface Impoundment from Proposed HWIR-Waste Risk Analysis
HIGH-END CENTRAL TENDENCY 40,000 square meters 2,000 square meters 40-year lifespan 40-year lifespan Depth 7 meters Depth 2 meters "Generic" Land Application Unit from Proposed HWIR-Waste Risk Analysis
HIGH-END CENTRAL TENDENCY 900,000 square meters 61,000 square meters 40-year lifespan 40-year lifespan Tilling depth 0.3 meters Tilling depth 0.2 meters Long-Term Release Values Estimated over facility life using CHEMDAT8 model Modeled at TC concentrations for surface impoundments Modeled at 20 times TC concentrations for land application units Assumed persistence in management units (except vinyl chloride) Chronic Exposure Durations High-end exposure duration = 30 years Central tendency exposure duration = 9 years Chemicals Modeled All organic TC analytes Differ by seven orders of magnitude in Henry's Law constant Have molecular weight from 30 to 410 Are rapidly degrading to very persistent

Technical Support document for the Hazardous Waste Identification Rule: Risk Assessment for Human and Ecological a Receptors, US. Environmental Protection Agency, Office of Solid Waste, August 1995. 

### Exhibit 3-6 Summary of Inhalation Pathway Screening Methods, Input Data, and Models Used for Bounding Risk AnalysisPage 3-30 

### Exhibit 3-7 Emission Fraction for Air Releases of Volatile TC Analytes

TC Analyte kH Tendency High-End Tendency High-End Fraction Emitted From: Land Application Unit Surface Impoundment Central Central
Benzene 5.5x10 0.9984 0.9984 0.8661 0.7451 -3 Carbon tetrachloride 2.9x10 0.9984 0.9984 0.8578 0.7318 -2 Chlordane 6.7x10 0.9984 0.6301 0.6649 0.4413 -5 Chlorobenzene 4.4x10 0.9984 0.9984 0.8564 0.7294 -3 Chloroform 4.0x10 0.9984 0.9984 0.8676 0.7475 -3 m-Cresol 8.8x10 0.8228 0.2225 0.2093 0.0858 -7 o-Cresol 1.6x10 0.9749 0.3384 0.3651 0.1713 -6 p-Cresol 8.2x10 0.8249 0.2233 0.2105 0.0864 -7 Cresol

-- 0.9678 0.3256 0.3550 0.1648 2,4-D 4.5x10 0.9984 0.6866 0.6970 0.4722 -6 1,4 Dichlorobenzene 2.8x10 0.9984 0.9984 0.8483 0.7163 -3 1,2 Dichloroethane 1.3x10 0.9984 0.9984 0.8659 0.7443 -3 1,1 Dichloroethylene 2.5x10 0.9984 0.9984 0.8769 0.7631 -2 2,4 Dinitrotoluene 1.5x10 0.9984 0.9417 0.7280 0.5151 -7 Endrin 1.2x10 0.2696 0.0674 0.1466 0.0575 -6 Heptachlor 5.9x10 0.9984 0.9984 0.8160 0.6662 -4 Heptachlor epoxide 8.3x10 0.9983 0.5730 0.6558 0.4287 -6 Hexachlorobenzene 7.5x10 0.9984 0.9984 0.8211 0.6744 -4 Hexachloro-1,3-butadiene 2.4x10 0.9984 0.9984 0.8261 0.6824 -2 Hexachloroethane 3.6x10 0.9984 0.9984 0.8335 0.6928 -3 Lindane 3.4x10 0.9984 0.9984 0.8246 0.6793 -6 Methoxychlor 6.3x10 0.9984 0.9979 0.7759 0.6038 -6 Methyl ethyl ketone 3.6x10 0.9984 0.9984 0.8526 0.7174 -5 Nitrobenzene 2.1x10 0.9984 0.9689 0.7851 0.5981 -5 Pentachlorophenol 1.4x10 0.9984 0.9983 0.8021 0.6379 -5 Pyridine 7.0x10 0.9984 0.9822 0.7827 0.5975 -3 Tetrachloroethylene 1.7x10 0.9984 0.9984 0.8519 0.7224 -2 Toxaphene 3.4x10 0.9984 0.9984 0.7891 0.6282 -6 Trichloroethylene 1.1x10 0.9984 0.9984 0.8604 0.7359 -2 2,4,5 Trichlorophenol 4.4x10 0.9979 0.4889 0.5733 0.3339 -6 2,4,6 Trichlorophenol 4.1x10 0.9984 0.7077 0.6830 0.4571 -6 2,4,5-TP (Silvex) 1.3x10 0.9984 0.9984 0.8203 0.6735 -8 Vinyl chloride 8.4x10 0.9984 0.9984 0.8829 0.7733 -2The risks are greater from the high-end surface impoundment than from the central tendency surface impoundment, despite the 25 lower proportionate releases from the former units, because the total mass disposed in the high-end unit and the total mass released are much greater. This result also occurs for the LAUs.

Page 3-31 

### Exhibit 3-8 summarizes the results of the screening-level risk estimation for the TC analytes having inhalation pathway toxicity values in IRIS or HEAST (as discussed below). The first eight columns of the results indicate whether the estimated lifetime cancer risk associated with managing the analytes at the TC (or the TC multiplied by 20) concentrations in the various management units would be greater than 10 or if the inhalation -5 

### pathway hazard quotient (HQ) would exceed 1.0. These risk threshold values are the same as those used in developing the TC analyte concentrations for groundwater exposures. For the 16 TC analytes with IRIS Unit Risk values, inhalation pathway cancer risks greater than 10 are not predicted for any of the TC analytes released from -5 

### the central tendency surface impoundment. In contrast, cancer risks above 10 are predicted for 12 of these -5 

### analytes released from the high-end impoundment. None of these analytes released from the central tendency LAU 25 

### would result in an inhalation pathway risk greater than 10 . Releases of four analytes (chloroform, 1,4- -5 

### dichlorobenzene, 1,1-dichloroethylene, hexachlorobenzene, and toxaphene) from the high-end LAU would result in risks above this level. Of the four TC organics with inhalation RfCs, hazard quotients greater than 1.0 were calculated for three analytes (chlorobenzene, methyl ethyl ketone, and nitrobenzene) released from the central tendency surface impoundment. When releases are modeled from high-end impoundments, the one additional chemical (1,4- dichlorobenzene) also has an HQ greater than 1.0. Exactly the same pattern is seen for LAUs. These results indicate that, under assumptions of no degradation or release to other pathways, the cancer risks and non-cancer hazard indices associated with management of some of the organic TC analytes may be above levels of concern previously used in amending the TC. These risks may be overestimated if significant amounts of pollutants in waste are released through other pathways or are degraded biologically or chemically. For this reason, EPA used the proposed HWIR-Waste database to identify the TC analytes that are persistent in soil or water. As shown in the last two columns of Exhibit 3-8, most of the organic analytes that exceed the air risk targets under the assumption of no degradation are, in fact, not very persistent in either soil or water. Using a cutoff value for degradation rate constants of 0.5 year , -1 

### which corresponds to a half-life in soil or water of about 17 months, only 3 of the organic TC analytes are expected to be very persistent. The relatively short half-lives in water or soil may reduce the potential concern for inhalation pathway risks associated with the other TC analytes to the same extent. These results illustrate the need for more detailed, site-specific modeling of all of the transport and degradation processes. Risks were calculated in this analysis for only those TC analytes having inhalation pathway toxicity values (Reference Concentrations or Unit Risk values) in IRIS. If instead inhalation pathway toxicity values were derived for the rest of the TC analytes from ingestion pathway values and used in similar risk calculations, the number of chemicals for which cancer risks and particularly non-cancer risks would exceed levels of regulatory concern would be much higher. These results have not been included in Exhibit 3-8 because EPA considers the level of uncertainty associated with such procedures to be unacceptably high.

### Page 3-32Exhibit 3-8. Inhalation Pathway Risks for TC Analytes and Their Dependence on Fate and Transport PropertiesTC AnalyteCancer Risk Exceeds 10-5HQ Exceeds 1.0Persistentin WateraPersistentin SoilSurface ImpoundmentLandfillSurface ImpoundmentLandfillCentral TendencyHigh-EndCentral TendencyHigh-EndCentral TendencyHigh-EndCentral TendencyHigh-EndBenzene--------NDNDNDND----Carbon tetrachloride--1.50E-04----NDNDNDND----Chlordane--1.34E-04----NDNDNDNDX*X*ChlorobenzeneNDNDNDND2.55E+039.99E+045.74E+022.06E+04----Chloroform--2.82E-03--5.69E-04NDNDNDND----1,4 DichlorobenzeneNDNDNDND--1.84E+02--3.87E+01----1,2 Dichloroethane--2.65E-04--NDNDNDNDND----1,1 Dichloroethylene--7.31E-04--1.44E-04NDNDNDND----Heptachlor--1.90E-04----NDNDNDND----Heptachlor epoxide--2.44E-04----NDNDNDNDXXHexachlorobenzene--1.10E-03--2.47E-04NDNDNDNDXXHexachloro-1,3-butadiene--2.06E-04----NDNDNDND----Hexachloroethane--2.28E-04----NDNDNDND----Methyl ethyl ketoneNDNDNDND1.02E+023.93E+032.30E+018.25E+02----NitrobenzeneNDNDNDND4.67E+021.64E+041.15E+024.00E+03----Tetrachloroethylene--------NDNDNDND----Toxaphene--2.75E-03--6.60E-04NDNDNDNDNDNDTrichloroethylene--------NDNDNDND----2,4,6 Trichlorophenol--------NDNDNDND----Vinyl chloride--3.56E-04----NDNDNDND----Notes:Degradation rate constant for soil or water less than 0.5 yr.a-1*For surface impoundments only; does not exceed at landfills.X=Yes.--=Risk or hazard is below threshold.ND=No Data.Such releases are likely to be controlled by permit requirements for surface water discharges and through facility design 26 regulations.


### Page 3-33 Evaluation of the proposed HWIR-Waste exit level calculations for the TC analytes confirms the potential concern for nongroundwater pathways. For some of the TC analytes, the HWIR-Waste proposed exit level calculations indicated that non-groundwater pathways are significant. Findings include the following:

For 9 of the TC analytes, pathways other than human groundwater exposure drove the establishment of proposed exit levels.For six of the analytes, ingestion of contaminated milk or vegetables was the highestrisk exposure pathways. For one of the pollutants, the driving non-groundwater exposure pathway was direct inhalation. For two analytes, ecological risks rather than health risks drove the derivation of proposed exit levels. In all of these cases, the initial release was to air through volatilization. These indirect pathway risks will be discussed in more detail in the following sections. 3.5.4 Potential Risks from Surface Water Exposures This section investigates the general level of protectiveness of the TC regulatory levels against surface water exposures, a risk that the TC was not specifically intended to address. Waste constituents could be released to surface water from land management units through several mechanisms:

Discharge of groundwater contaminated by leachate from waste management units; Transport of waste constituents to surface water bodies by runoff and overland transport of wastes released from the management unit; Direct releases through overland runoff of liquid wastes from surface impoundments;26 

### and Volatilization of constituents from land-based units, followed by deposition onto surface water or onto soil that eventually finds its way into surface water bodies. The surface water exposure pathways of potential significance for humans include direct consumptive use (i.e., ingestion and dermal contact with domestic water) and dermal contact and incidental ingestion of the surface water associated with recreational exposures. If the contaminants are persistent in sediment, dermal contact and incidental ingestion of small amounts of sediment also are possible exposure pathways. All of these release and exposure pathways have been analyzed in the development of hazardous waste management regulations and in other contexts. The experience gained in these exercises has led the Agency to a number of general conclusions regarding the importance of surface water exposures for human health risks:Preliminary Report on Factors Important to Identifying Risk-Based Entry Characteristics: Analysis of Hazardous Waste 27 Identification Risk Models, Ogden Environmental and Engineering Services, August 1996

. 

### Page 3-34 For common waste management practices, surface water exposure cannot be automatically ruled out as insignificant in comparison to groundwater, inhalation, and other indirect pathways. The significance of surface water releases depends heavily on the management practices employed by a facility and the specific interactions between surface water and groundwater at the facility. Generally, groundwater discharge significantly affects surface water quality only where groundwater constitutes a significant proportion of the total surface water in a water body. This pathway may be important for very large management units that generate large amounts of leachate, but usually significant surface water quality impacts are limited to relatively small streams adjacent to management units and to on-site or adjacent ponds derived mainly from leachate. Exposure to volatile contaminants in surface water is generally limited because these contaminants are depleted rapidly from surface water through volatilization. Air releases from surface water may themselves be significant from a health standpoint. Usually, however, volatilization from the management unit itself dominates, unless the unit is covered. Incidental ingestion and dermal contact with contaminated sediment tend not to be significant exposure pathways for humans, because of their infrequency and the relatively small amounts of contaminated sediment contacted (but see below). Indirect pathway exposures may be of concern, however. The contaminants that persist in sediment and have a high capacity to bioaccumulate and bioconcentrate are often the most significant contributors to human health risks. This capacity may overcome the high dilution factors often associated with releases to surface water. These persistent pollutants most often reach human receptors through the consumption of contaminated fish or shellfish. In evaluating the potential risks associated with proposed HWIR-Waste chemicals, EPA identified contaminants for which surface water pathways were of potential concern. Whether or not the surface water pathway was a concern depended on the waste treatment scenario. For wastewaters managed in surface impoundments, surfacewater was not a human health risk for any of the TC analytes. All of the proposed exit levels driving nongroundwater pathways for humans were associated with volatilization followed by deposition on soil and did not involve surface water. For nonwastewaters disposed in land application units and waste piles, however, more than 50 percent of the proposed exit levels for the HWIR-Waste constituents are driven by pathways involving surface water exposures. The driving (highest-risk) pathways were approximately equally divided among the contaminants 27 

### between overland runoff followed by fish uptake, and overland runoff followed by surface water ingestion. These results must be interpreted cautiously. The analysis of the proposed HWIR-Waste exit levels cited above gives only a comparative, not an absolute, indication of the importance of the surface water exposure pathways for waste piles and land application units. The proposed exit levels calculated for these types of units are generally higher than those associated with surface impoundments, for example, indicating that the magnitude of the risksThe Koc is the organic carbon binding coefficient; the Kd is the soil-water dissociation constant. 28


### Page 3-35 from wastes piles and land application units are, in general, lower than those associated with surface impoundments. Summary. The preceding analysis has explored the possibility that significant risks to health or the environment may be associated with exposures through surface water pathways. While a number of theoretical arguments suggest that such releases might be important under only a relatively narrow range of conditions, the proposed HWIR-waste modeling results indicate that these pathways may well be significant for some TC analytes disposed as non-hazardous industrial wastes. The possibility that the surface water releases and exposures represent a potential gap in the TC, especially for persistent and bioaccumulative chemicals, cannot be ruled out. 3.5.5 Potential Indirect Pathway Risks from TC Analytes "Indirect" pathways are any pathways involving more than one environmental medium (e.g., groundwater, air, surface water, soil, sediment, and biota) between the release and the exposed receptor. The initial release may be to any medium. Indirect exposure pathways often, but not always, involve uptake of environmental contaminants by living organisms, which, in turn, are consumed by human or other receptors. Some of the pathways discussed in the previous sections, such as groundwater releases to surface water, are, strictly speaking, indirect. This section, however, emphasizes pathways involving potential long-range transport of persistent pollutants and pathways involving biota (crops, fish, or livestock) prior to human exposures. Persistence, properties facilitating physical transport, and the potential to bioaccumulate in the environment are critical in the indirect pathways, and the physical/chemical and environmental fate properties of constituents significantly determine their movement through such pathways. Exhibit 3-9 summarizes some important physical, chemical, and environmental fate properties of the TC analytes relating to persistence, partitioning behavior between environmental media, and bioaccumulation. For each parameter, the exhibit compares each constituent's value to a criterion or cutoff value that roughly indicates whether the parameter will strongly influence the transport and partitioning of the chemical in the environment in a multipathway analysis. The derivation of these criteria are discussed in more detail in Section 4.3.2. The first column identifies TC analytes with a high Koc (high Kd for metals), generally indicating a 28 

### propensity to bind to soils. A high value means that chemicals will leach only slowly to soil, but would bind to particulates if they were released through runoff or into the air. Essentially all of the chemicals with Koc values above 10,000 are pesticides. In addition, the majority of the TC metals would be expected to bind to some extent to particulates.

### Page 3-36 Exhibit 3-9 Major Fate and Transport Parameters for TC Analytes

TC Analyte Koc/Kd > Constant > 10 in Air RateConstant Plants > 3.5 Factor > Fish BCF/BAF > at m-m/mol > 0.15 yr. < 0.5/yr. (ug/g)/(ug/g) 7.8x10 day/kg 1000 l/kg Henry's Law Half-life Degradation for Forage Biotransfer

- 10,000 ml /g 5 3 Soil/Water Plant-SoilBFC Beef

-4 1,1-Dichloroethene 1,2-Dichloroethane 1,4-Dichlorobenzene 2,4,5-TP (Silvex) 2,4,5-Trichlorophenol 2,4,6-Trichlorophenol 2,4-D 2,4-Dinitrotoluene Arsenic Barium Benzene Cadmium Carbon tetrachloride Chlordane Chlorobenzene Chloroform ChromiumCresol, mCresol, oCresol, pEndrin Heptachlor Heptachlor epoxide Hexachloro-1,3-butadiene Hexachlorobenzene Hexachloroethane Lead Lindane Mercury Methoxychlor Methyl ethyl ketone Nitrobenzene Pentachlorophenol Pyridine Selenium Silver Tetrachloroethylene Toxaphene Trichloroethylene Vinyl chlorideAs noted previously, kH is the ratio of a chemical's vapor pressure to its water solubility. 29


### Page 3-37 The next column on Exhibit 3-9 shows the Henry's Law constants (kH) for the TC analytes, with values 29 

### above 10 generally indicating a moderate to high capacity to volatilize from soil-water systems, which may be the

-5 

### first step in an indirect exposure pathway. About half (19) of the TC analytes have kH values above 10 . As -5 

### discussed in Section 3.5.3, variations in Henry's Law constants did not strongly effect the predicted long-term release of the TC analytes from surface impoundments and waste piles. Short-term releases, however, may be much more dependent on this parameter. The next two columns address the persistence of TC analytes in soils, water, and air. Data in these two columns summarize information from the proposed HWIR-Waste database on the estimated half-life of chemicals in air and the overall degradation rate constants in soils and surface water. Four of the TC analytes are identified as having long half-lives in air and 12 are persistent (have low degradation rate constants) in soil and/or surface water. The air half-life values must be interpreted cautiously, as the proposed HWIR-Waste database contains this information on only about 20 chemicals. Metals and many high-Koc organics would also be expected to have long half-lives in air if they were bound to particulates. As discussed earlier, the TC analytes with long half-lives in soil/water systems include primarily the metals and chlorinated pesticides. The final three columns of Exhibit 3-9 consider the propensity of TC analytes to bioaccumulate in aquatic and terrestrial ecosystems. The plant-soil bioconcentration factor (BCF) is an estimate of the typical ratio of the concentration of a constituent in soil to the concentration in a particular kind of plant (in this case, forage plants consumed by beef and dairy cattle). Similarly, the beef biotransfer factor is an estimated typical ratio of the concentrations of pollutants in the diet of beef cattle to the resultant concentrations in edible tissue. Finally, the BCF and bioaccumulation factor (BAF) values for fish represent the typical ratios of pollutant concentrations in surface water to that in fish tissue, considering only water exposures or considering all pathways, respectively. (These value tend to be quite similar for most chemicals.) Although the exhibit indicates that several constituents may bioaccumulate from soil to forage plants, in reality, only 2,4,5- trichloropropionic acid (Silvex) has a very high bioconcentration potential. The value of the forage biotransfer factor for this pesticide is five orders of magnitude greater than for any other chemical (greater than 10 ). 6 

### Generally the same chemicals have high beef biotransfer factors, fish BCFs, and BAFs, with barium, mercury, and lindane bioconcentrating only in aquatic systems, and arsenic, chromium, selenium, and silver being significant for the beef exposure pathways alone. Summary. These single comparisons indicate the significant potential for many TC analytes to be transported through multiple media to reach the ultimate receptors. The data in Exhibits 3-8 and 3-9 show that the chlorinated pesticides (i.e., chlordane, endrin, heptachlor, heptachlor epoxide, hexachlorobenzene, methoxychlor, pentachlorophenol, and toxaphene), chloroform, and hexachloro-1,3-butadiene have the potential to participate in indirect exposure pathways and have non-groundwater pathways as their driving pathways. In addition, several high-toxicity and persistent metals, such as mercury, arsenic, and lead, also are of potential concern.

### Page 3-38 3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes The TC was originally established based on the need to protect individuals from adverse health effects due to chronic exposures to the TC constituents consumed in groundwater. This approach to protecting against groundwater exposure risks is conservative because the relatively long time scale involved in groundwater transport to receptors, under most reasonable assumptions, means that limiting concentrations in any time period to the low chronic risk-based levels also will protect against short-term adverse effects. Short transient exposures to high levels of groundwater contaminants are extremely uncommon. Before the concentration of a pollutant reaches the relatively high level required to cause acute effects, it generally will have exceeded the allowable chronic exposure level for a long period of time. This relationship may not apply to exposure through pathways not involving slow releases to groundwater. For example, the rapid evaporation of volatile chemicals from a ruptured container, the catastrophic release due to overtopping of a surface impoundment, or runoff erosion from an extreme storm event have the potential to result in short-term acute exposures to humans and environmental receptors. For this reason, EPA has evaluated the potential level of protectiveness of the TC against acute exposures. EPA evaluated the potential for adverse effects associated with acute volatilization of chemicals from land management units. The approach was analogous to the screening-level risk modeling for chronic exposure, except that the short-term releases were calculated andexposure concentrations were compared to short-term exposure standards. This analysis indicates that the shortterm concentrations of all of the volatile TC analytes calculated at the fenceline were far below applicable short-term exposure standards (in this case, occupational exposure standards). This simple modeling does not unconditionally eliminate the possibility of adverse effects from acute exposures to the TC analytes. Unusual release events, such as fires, or explosions, could result in higher exposures than calculated assuming simple volatilization. In addition, high winds or other events could result in high concentrations of particle-bound metals and other non-volatile analytes. The potential for these kinds of release events strongly depends on specific waste characteristics, site conditions, and management practices. 3.5.7 Potential Risks to Ecological Receptors from TC Analytes Risks to non-human receptors are the final category of risks evaluated by EPA. Like the inhalation, surface water, and indirect pathway risks, they were not expressly factored into the derivation of the regulatory levels for the TC analytes. While a substantial number of the TC chemicals are toxic to ecological receptors, the protection of ecological receptors was not a specific concern in the rulemaking. This section discusses potential gaps in the TC characteristic associated with harm to ecological receptors. Many of the same factors that contribute to potential risks for human receptors also contribute to potential risks for ecological receptors. Generally, harm to environmental receptors requires release of chemicals from containment and transport to sensitive receptors without extensive degradation or extreme dilution, just as in the case of human health risks. Thus, the physical properties of chemicals that contribute to persistence and transport in the environment, as shown in Exhibit 3-9, are indicators of potentially significant risks for ecological receptors. The fact that most of the persistent chemicals with high bioconcentration potentials are also pesticides, which are toxic to certain plants, insects, or other animals, adds to the potential risks. The degree of protection of ecological receptors afforded by the TC leachate concentrations does not appear very high for many of the most toxic pesticides. Exhibit 3-10 compares the TC regulatory levels to two basic measures of potential aquatic toxicity, the acute and chronic Ambient Water Quality Criteria (AWQC) for the45Federal Register 33110, May 19, 1980. 30
51Federal Register

21648, June 13, 1986. 31


### Page 3-39 protection of aquatic life. It shows that, for many analytes, the allowable leachate concentrations are many orders of magnitude above the corresponding AWQC. The shaded boxes in the table identify TC analytes with regulatory levels greater than 1,000 times the AWQC. The chemicals falling into this category again include the chlorinated pesticides, chlorobenzene, lead, mercury, silver, and 2,4,5-trichlorophenol. This ratio indicates that if the TC analytes were released from wastes to groundwater and from there discharged to surface water, a dilution of at least 1,000-fold would be required to reduce the concentration to levels not harmful to aquatic biota. Such a scenario may be unlikely, however, because, as noted above, these chemicals tend to bind strongly to soil and do not move readily in groundwater. (As is discussed in more detail in Chapter 2, however, some of these chemicals were found ingroundwater at concentrations above health-based levels in the descriptions of environmental releases from nonhazardous industrial waste management units.) In a more likely scenario, the high ecotoxicity of these chemicals means that runoff transport of particulate wastes at concentrations not considered hazardous under the TC could cause adverse effects in water bodies near management units. As noted above, the concern for runoff exposures is borne out to some extent by the proposed HWIR-Waste modeling, where proposed exit levels are driven by this pathway for disposal in waste piles and land application units. In the case of silver and endrin (two of the chemicals in shaded boxes in Exhibit 3- 10), the proposed exit levels were driven by runoff releases to surface water. Summary. Based on these findings, it appears that the level of protectiveness of the TC is not very high for some non-human receptors. At a minimum, the ecotoxicity parameters suggest a potential concern associated with the aquatic toxicity of chlorinated pesticides, as well as a few other chemicals. The severity of these potential gaps is addressed in more detail in later chapters. 3.6 Potential Gaps Associated with TCLP This section reviews the technical basis for the Toxicity Characteristic Leaching Procedure (TCLP) and discusses potential problems associated with its use based on a brief review of available literature and data. Specifically, this section focuses on whether the TCLP fails to accurately predict releases from identified classes of wastes into groundwater and non-groundwater pathways. 3.6.1 TCLP Background In 1980, prior to development of the TCLP, the Agency adopted the Extraction Procedure (EP) to identify wastes likely to leach hazardous concentrations of particular toxic constituents into the groundwater under conditions of improper management. In 1986, the Agency proposed a modified leaching procedure, the TCLP, to 30 

### replace the EP. The Agency promulgated the final rule on the

31

### Page 3-40 Exhibit 3-10 Ratios of TC Leachate Regulatory Levels to Ambient Water Quality Criteria for Aquatic Lifea

Chemical (mg/l) (ug/l) to AWQC

Acute Chronic Freshwater AWQC Concentration (ug/l) TC TC Leachate Ratio of TC

Regulatory

Leve l Concentration Regulatory Leve l

Arsenic 850 190 5 5000 26 Barium

-- -- 100 100000 NA Benzene 5300

-- 0.5 500 0.09b Cadmium 3.9 1.1 1 1000 909 Carbon tetrachloride 35200

-- 0.5 500 0.01 Chlordane 2.4 0.0043 0.03 30 6.98E+04 Chlorobenzene 250 50 100 100000 2.00E+04 1,4 Dichlorobenzene 250 50 7.5 7500 150 Chloroform 28900 1240 6 6000 4.8 Chromium 1700 210 5 5000 24 Chromium VI 16 11

--- 5000 455 o-Cresol

-- -- 200 200000 NA m-Cresol

-- -- 200 200000 NA p-Cresol

-- -- 200 200000 NA Cresol

-- -- 200 200000 NA 2,4-D

-- -- 10 10000 NA 1,2-Dichloroethane 118000 20000 0.5 500 0.025 1,1 Dichloroethylene

-- -- 0.7 700 NA 2,4-Dinitrotoluene 330 230 0.13 130 0.57 Endrin 0.18 0.0023 0.02 20 8.70E+04 Heptachlor 0.52 0.0038 0.008 8 2.11E+04 Heptachlor epoxide 0.52 0.0038 0.008 8 2.11E+04 Hexachlorobenzene 6 3.68 0.13 130 35

### Page 3-41 Exhibit 3-10 (continued) Ratios of TC Leachate Regulatory Levels to Ambient Water Quality Criteria for Aquatic Life

Chemical (mg/l) (ug/l) to AWQC

Acute Chronic Freshwater AWQC Concentration (ug/l) TC TC Leachate Ratio of TC

Regulatory

Leve l Concentration Regulatory Leve l
Hexachloro-1,3-butadiene 90 9.3 0.5 500 54 Hexachloroethane 980 540 3 3000 5.6 Lead 82 3.2 5 5000 1.56E+04 Lindane 2 0.08 0.4 400 5.00E+04 Mercury 2.4 0.012 0.2 200 1.67E+05 Methoxychlor

-- 0.03 10 10000 3.33E+06 Methyl ethyl ketone

-- -- 200 200000 NA Nitrobenzene 27000

-- 2 2000 0.07a Pentachlorophenol 20 13 100 100000 7.69E+04 Pyridine

-- -- 5 5000 NA Selenium 20 5 1 1000 200 Silver 4.1 0.12 5 5000 4.17E+05 2,4,5-TP (Silvex)

-- -- 1 1000 NA Tetrachloroethylene 5280 840 0.7 700 0.83 Toxaphene 0.73 0.0002 0.5 500 2.50E+07 Trichloroethylene 45000 21900 0.5 500 0.02 2,4,5-Trichlorophenol 100 63 400 400000 6.35E+04 2,4,6-Trichlorophenol

-- 970 2 2000 2.1 Vinyl chloride

-- -- 0.2 200 NA

Notes: Shaded rows indicate that the ratio of the TC regulatory level to the AWQC for the analyte exceeds 1,000. a Indicates ratio is to acute AWQC. b55Federal Register 11827, March 29, 1990. 32Note that the majority of these data were collected from on-site groundwater monitoring wells and not from drinking water 33 wells, and therefore actual risks likely are lower than would be indicated by these data. Lester Sotsky, Arnold & Porter, “ Reynolds MetalCompany’s Gum Springs Facility,” Memorandum to Steven Silverman, U.S. EPA, 34 September 26, 1996.


### Page 3-42 application of the TCLP in 1990. In finalizing the TCLP, the Agency intended to improve the leachate test 32 

### procedure and eliminate some of the analytical difficulties involved in the EP. The TCLP is used to quantify the extractability of certain hazardous constituents from solid waste under a defined set of laboratory conditions. This test is used to evaluate the leaching of TCmetals, volatile and semivolatile organic compounds, and pesticides from wastes. In principle, this procedure simulates the leaching of constituents into groundwater under conditions found in a municipal solid waste (MSW) landfill. The TCLP, however, does not simulate the release of contaminants to non-groundwater pathways. The TCLP is most commonly used by EPA and state agencies to evaluate the leaching potential of wastes, and for determining toxicity. The TCLP is promulgated in Appendix II of 40 CFR Part 261.24(a) and has been designated as EPA Method 1311 in "Test Methods for Evaluating Solid Waste, Physical/Chemical Methods - SW-846." In the TCLP, liquid wastes (those containing less than 0.5 percent dry solid material) are "extracted" by filtering the wastes through a 0.6 to 0.8 μ glass fiber filter. Non-liquid samples (those containing greater than or equal to 0.5 percent dry solid material) are:

Reduced to a particle size of less than 9.5 mm (liquid, if any, is separated from the solid phase) and extracted with an acetate buffer solution with either a pH of 5 or an acetic acid solution with a pH of 3, depending on the alkalinity of the waste (wastes with a pH of 5 and above are extracted with the acetic acid solution); A liquid-to-solid ratio of 20:1 is used for an extraction period of 18 hours; and The leachate is filtered and combined with the liquid portion of the wastes, if necessary. Contaminant analyses then are conducted on the extracts of the liquids and non-liquids. 3.6.2 Limitations of the TCLP The Agency reviewed TC constituent and concentration data collected on releases from the non-hazardous industrial waste management units discussed in Chapter 2 (see Exhibit 2-5). These data show that, of the 15 TC constituents detected in at least three case studies, eight are present in groundwater at levels much higher than their TC levels. If the wastes passed the TCLP before being placed in the management units, this could indicate 33 

### that the TCLP underestimated the long-term releases for certain classes of wastes. One of the major limitations of these data, however, is that they may not reflect current waste analysis or management practices. For example, some data represent releases from waste disposal that occurred prior to implementation of the TCLP, and thus some of the releases that exceed TC levels could be due to problems with other extraction procedures or to the lack of any testing procedure. Nevertheless, some site data (not reported in Chapter 2) exists that may represent problems with the TCLP. For example, the kiln residues from the treatment of spent aluminum potliners at one facility are disposed in a monofill as non-hazardous wastes. EPA approved a delisting petition for the kiln 34Note, however, that this list of issues is not meant to be comprehensive. Other issues, such asthe potential overestimation 35 of the dilution simulated by the TCLP, may need further study. van der Sloot, H.A., G.J. de Groot, and J. Wijkstra, "Leaching Characteristics of Construction Materials and Stabilization 36 Products Containing Waste Materials," in P.L. Cote and T.M. Gilliam, eds.,Environmental Aspects of Stabilization and Solidification of Hazardous and Radioactive Wastes, ASTM STP 1033, American Society for Testing and Materials, Philadelphia, Pennsylvania, 1989; and Willis, et al., "When the TCLP Is Not Enough: Leaching Tests for Solidification/Stabilization Technologies," Hazardous Materials Controls/Superfund 1991, Proceedings of the 12th National Conference, Hazardous Materials Control Research Institute, pp. 385-388, December 3-5, 1991.


### Page 3-43 residue waste based on TCLP data that showed the target constituents in the TCLP extract to be below treatment standards (which, for the TC constituents, are lower than the TC regulatory levels). When the leachate from the monofill was analyzed, however, levels of arsenic were found to be higher than its TC level. Other hazardous constituents, including cyanide and fluoride, were also found at levels higher than those predicted by the TCLP. Several technical and practical issues have been raised by the regulated community and others regarding the applicability of the TCLP for identifying hazardous waste. A number of comments were submitted to the Agency in response to the June 13, 1986 proposal to replace the EP with the TCLP. The Agency responded to the comments in the final rule, but also decided to continue to address commenters concerns and further evaluate modifications to the TCLP. The Agency stated that further improvements in the TCLP will be proposed as they are developed. Subsequent to that rulemaking, additional concerns have been raised by commenters during later rulemakings (e.g., rules addressing newly listed or identified wastes). Some of the key issues regarding the TCLP identified from these comments on various rulemakings and from other sources are outlined below.35 

### TCLP underestimates leachate from some high alkaline wastes or environments. The high alkalinity of some wastes may make the TCLP an inappropriate predictor of leachate composition. For example, the addition of acid during the TCLP might not reduce the pH of high alkaline waste to the same level as would occur over time in the environment. Thus, long-term leachate concentrations of constituents that are insoluble at higher pH ranges maybe underestimated in the TCLP leachate compared to the actual leachate from the industrial landfills where a longterm acid environment (e.g., from acidic rain water) is present. Some toxic metal constituents are more mobile at both the higherandthe lower pH ranges. For example, studies show that leaching of metals such as cadmium, chromium, and lead typically is limited when the pH is in the range of about 8 or 9, but can increase significantly when the pH either increases or decreases. Thus, if a waste 36 

### is highly alkaline (e.g., pH >11) and the TCLP acidic leaching medium lowers the pH to only about 8 or 9, then the concentrations of these metals in the TCLP leachate could be significantly lower than would occur from either a highly alkaline or a highly acidic environment (depending on a number of factors, such as characteristics of any co-disposed wastes, type of treatment, and characteristics of the soil and rain water)."Preliminary Proposal to Require the TCLP in Lieu of the Waste Extraction Test," Memorandum to James Carlisle, Department 37 of Toxics Substances Control, California EPA, from Jon Marshack, California Regional Water Quality Control Board, December 18, 1995; and U.S. Environmental Protection Agency,Technical Background Document and Response to Comments - Identification and Listing of Hazardous Waste - Method 1311 - TCLP, F-90-TCF-S0004, April 1989.
Ibid

. 38
61Federal Register

2338, January 25, 1996. 39U.S. Environmental Protection Agency, "Performance Testing of Method 1312 QA Support for RCRA Testing," p. III, June 1989. 40


### Page 3-44 Multiple Extraction Procedure (MEP)
The MEP involves an initial extraction with acetic acid and at least eight subsequent extractions with a synthetic acid rain solution (sulfuric/nitric acid adjusted to pH 3). The MEP is intended to simulate 1,000 years of freeze and thaw cycles and prolonged exposure to a leaching medium. One advantage of the MEP over the TCLP is that the MEP gradually removes excess alkalinity in the waste. Thus, the leaching behavior of metal contaminants can be evaluated as a function of decreasing pH, where the solubility of most metals increases. Currently, the MEP is used in the Agency's de-listing program. Several commenters to the June 13, 1986 TCLP proposal expressed concern regarding the application of the TCLP to alkaline wastes. They noted that no high alkaline wastes were included in the development of the TCLP and, therefore, no conclusions could be made concerning the actual behavior of these wastes. The MEP, described in the text box, is one test that the Agency and others use that may better simulate the long-term leaching behavior of such wastes. TCLP underestimates the leachate concentrations from oily wastes and some paint wastes. Several reports indicate that oily and some paint wastes tend to clog the filters used to separate the extract from the solids prior to analysis, resulting in under-reporting of the extractable constituent concentrations. Several 37 

### commenters on the June 13, 1986 TCLP proposal noted that, in the development of the TCLP, the Agency tested only 11 wastes. These commenters argued that increasing the

38 

### variety of wastes (to include oily wastes, organic chemical wastes, and municipal wastes) and the number of extractions performed could refine the TCLP and enhance its accuracy. TCLP may not accurately mimic conditions commonly found in non-hazardous industrial waste disposal. As discussed in the 1980 final EP rule, several commenters responding to the proposed use of the EP for evaluating the leaching of hazardous constituents argued that the co-disposal assumption is not applicable to wastes that arenever co-disposed with municipal solid wastes and thus do not leach at the aggressive rates characteristic of codisposal situations. Thus, the commenters stated, the leachate procedure does not simulate the conditions found in industrial waste monofills. In response, the Agency stated that most wastes, even those that are unlikely to be disposed in a municipal landfill, are likely to come into contact with some form of acidic leaching medium during their management histories or could otherwise encounter environments that could cause the wastes to leach comparable levels of toxic constituents. This same debate occurred during development of the TCLP, and it continues today. For example, the Lead Industries Association Inc., commenting on the Phase IV supplemental proposed rule, cited an EPA study that 39 40The chelation property of a reagent (such as acetate and citrate) refers to the ability of the reagent to bind with and 41 solubilize metal contaminants. The low chelation ability of acetate buffer might result in fewer metal constituents being leached into the extract. "Preliminary Proposal to Require the TCLP in Lieu of the Waste Extraction Test,"suprafootnote 37. 42


### Page 3-45 Synthetic Acid Precipitation Leach Test (SPLP) The SPLP is similar to the TCLP, but the initial liquid-solid separation step has been eliminated and the acetate buffer extraction fluid has been replaced by a dilute nitric acid/sulfuric acid mixture. The TCLP addresses co-management of industrial and non-industrial wastes in an organic acid environment, a scenario that does not match the disposal setting of many treated wastes, while the SPLP simulates disposal in an acid rain environment. The SPLP is currently used by several state agencies to evaluate the leaching of TC hazardous constituents from wastes.

California Waste Extraction Test

(Cal WET) Cal WET was developed by the State of California to classify hazardous wastes. This test uses sodium citrate buffer as the leachate, a 10:1 liquid-to-solids ratio, and a testing period of 48 hours. Cal WET applies a soluble threshold limit concentration (STLC) as the regulatory standard. STLC standards for metal concentrations in the leachate are similar to those for the TCLP. Cal WET also develops a Total Threshold Limit Concentration (TTLC), which is equivalent to the Total Waste Analysis (TWA) procedure. Cal WET is a more aggressive test when compared to the TCLP. That is, Cal WET almost always extracts higher levels of contaminants, and the citrate buffer used in this test has greater chelation effect than the acetate buffer used in the TCLP. stated that acetic acid leaching fluid could selectively solubilize toxicants (specifically lead) and incorrectly classify the material as hazardous when, in fact, no mobilization (leaching) would be expected to occur in the landfill environment. Kennecott Corporation and National Mining Association, also in response to the Phase IV supplemental proposed rule, stated similar concerns. The SPLP (see text box at right) is one test that has been considered for addressing this issue. TCLP may underestimate the chelation-facilitated mobility of some waste constituents. A recent analysis of the TCLP and Cal WET (see text box at right) indicates that the low chelation activity of the acetate buffer used in 41 

### the TCLP may underestimate the ability of leachate containing chelating agents to mobilize waste constituents. Cal WET uses a citrate buffer that

42 

### approximates the chelation ability of many other compounds of landfill leachate and, thus, overcomes the constraints of the TCLP test. TCLP does not account for the oxidation/reduction reactions occurring in landfills. A recent study noted that the addition of iron filings to stabilize foundry sandStabilized waste is a concern for the Scoping Study because some non-hazardous industrial waste either is treated (e.g., 43 using stabilization) to reduce the release of hazardous constituents or is derived from characteristically hazardous waste that has been "decharacterized" via treatment. Douglas Kendall, "Impermanence of Iron Treatment of Lead-Contaminated Foundry Sand--NIBCO, Inc. Nacogdoches, Texas," 44 National Enforcement Investigations Center--Project PA9, April 18, 1996. Northwestern University, "Chapter 4 - Evaluation of Procedures for Analysis and Disposal of Lead-Based Paint-Removal 45 Debris,"Issues Impacting Bridge Painting: An Overview, Infrastructure Technology Institute, FHWA/RD/94/098, August 1995. Dusing, D.C., Bishop, P.L., and Keener, T.C.,"Effect of Redox Potential on Leaching from Stabilized/Solidified Waste 46 Materials,"Journal of Air and Waste Management Association, Vol. 42, N1, p. 56(7), January 1992.
See footnote 36. 47U.S. Environmental Protection Agency, Office of Research and Development,Technical Resource Document - 48 Solidification/Stabilization and Its Application to Waste Materials, June 1993. Perry, K.J, Prange, N.E., and Garvey, W.F., "Long-Term Leaching Performance for Commercially Stabilized Waste," 49 Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes, Vol. 2, ASTM STP 1123, T.M. Gilliam and C.C. Wiles, Eds, American Society for Testing and Materials, Philadelphia, pp. 242-251, 1992.


### Page 3-46 wastes seems to mask the potential leachability of lead by interfering with the TCLP. If metallic iron (iron

43 44 

### filings) are added to the waste, the lead concentration in the TCLP extract may be decreased by an oxidation/ reduction reaction to levels below the lead TC level. If, however, the waste is placed in a landfill or surface impoundment, the iron oxidizes over time and loses its ability to further reduce the lead ions. This results in the leaching of lead to the environment. Another recent study reviewed the practice of using iron as an additive in stabilizing paint waste. The 45 

### study notes that the iron reduces the lead ions in paint waste to the less soluble metallic lead, which is subsequently removed by filtration from the leachate being analyzed. This use of iron allows the lead-containing waste to pass the TCLP. The study notes, however, that repeated leaching of the same waste sample increases the leaching rate to a point where lead is sufficiently solubilized to exceed the TC regulatory level. Finally, another study showed that oxidation/reduction potential has a significant effect on leaching of metals from stabilized waste materials. This study showed that the leaching of chromium increases significantly 46 

### under highly oxidizing conditions, and the leaching of arsenic, vanadium, lead, and iron increase significantly under reducing conditions. TCLP may not predict long-term mobility of organic contaminants in some treated wastes. A fairly recent 47 

### Superfund Innovative Technology Evaluation (SITE) field evaluation examined the long-term performance of stabilization treatment of lead and other metals, oil and grease, and mixed volatile and semivolatile organic compounds. Portland cement and a proprietary additive were used as stabilizing agents. Durability was tested

48 

### with weathering tests by wet-dry and freeze-thaw cycling and by sampling stabilized treated waste after 9 and 18 months of burial. The results showed that organic contaminants were not effectively immobilized (although the testing also showed that lead and other metals remained highly immobilized, the physical properties of the stabilized treated waste deteriorated only slightly, and the porosity decreased). Another study conducted on the long-term leaching performance of commercially stabilized waste demonstrated a highly waste-dependent effect of time on the TCLP results. In this study, TCLP extraction was 49Alternate Soil Leaching Procedures, Interoffice Memorandum to the Environmental Response Division Staff from Alan J. 50 Howard, Environmental Response Division, Michigan Department of Natural Resources, January 5, 1995. The TCLP does account for the loss of volatile contaminants that occur during the liquid/solid separation and extraction 51 process; however, this is only for correcting the leachate concentration, not for simulating releases to air.


### Page 3-47 performed on both the raw waste and the treated waste. The treated waste consisted of samples at 28, 90, 200, 470, and 650 days after treatment. The results showed that leachate values for some metallic wastes increased over time. TCLP may not be appropriate for some contaminated soil. The Michigan Department of Natural Resources (MDNR) believes that the TCLP is not appropriate for soils contaminated with cyanides, sulfides, and hexavalent chromium. Furthermore, MDNR reports that the SPLP (see previous text box) more accurately simulates the

50 

### conditions of contaminated soil and therefore is an appropriate alternative test for soil contaminated with cyanides, sulfides, and hexavalent chromium. TCLP does not predict releases to non-groundwater pathways. As discussed in Section 3.4, the TCLP was designed to simulate the leaching of waste constituents to groundwater and not for releases to non-groundwater pathways. The TCLP does not simulate the release of volatile organic contaminants into air either directly or through entrained dust, nor does it simulate releases through surface runoff.51

### Page 3-48

CHAPTER 3. POTENTIAL GAPS ASSOCIATED WITH

HAZARDOUS WASTE CHARACTERISTICS DEFINITIONS

.............. 3-1 3.1 Types of Risks Addressed by RCRA Hazardous Waste Characteristics

............. 3-1 3.1.1 Statutory and Regulatory Framework

.................................. 3-1 3.1.2 Risks Associated with Physical Hazards

............................... 3-3 3.1.3 Acute Toxic Hazards to Humans

..................................... 3-4 3.1.4 Chronic Toxicity Risks to Humans

................................... 3-4 3.1.5 Risks to Non-Human Receptors

...................................... 3-5 3.1.6 Other Risks Associated with Non-Hazardous Industrial Waste Management

. . 3-6 3.2 Ignitability Characteristic

.................................................. 3-8 3.2.1 Definition of Ignitability

............................................ 3-8 3.2.2 Potential Gaps Related to Definition of Ignitability

....................... 3-9 3.2.3 Potential Gaps Related to Ignitability Test Methods

....................... 3-12 3.3 Corrosivity

............................................................ 3-12 3.3.1 Definition of Corrosivity

.......................................... 3-12 3.3.2 Potential Gaps Related to Definition of Corrosivity

..................... 3-13 3.3.3 Potential Gaps Related to Corrosivity Test Methods

..................... 3-16 3.4 Reactivity

............................................................. 3-16 3.4.1 Definition of Reactivity

........................................... 3-16 3.4.2 Potential Gaps Related to Definition of Reactivity

...................... 3-17 3.4.3 Potential Gaps Related to Reactivity Test Methods

...................... 3-19 3.5 Potential Gaps Associated with the Toxicity Characteristic

...................... 3-19 3.5.1 Definition of Toxicity Characteristic

................................. 3-19 3.5.2 Changes in Groundwater Pathway Analysis

........................... 3-21 3.5.3 Potential Inhalation Pathway Risks Associated with TC Analytes

.......... 3-27 3.5.4 Potential Risks from Surface Water Exposures

......................... 3-33 3.5.5 Potential Indirect Pathway Risks from TC Analytes

..................... 3-35 3.5.6 Potential for Acute Adverse Effects of Exposures to TC Analytes

.......... 3-38 3.5.7 Potential Risks to Ecological Receptors from TC Analytes

............... 3-38 3.6 Potential Gaps Associated with TCLP

....................................... 3-39 3.6.1 TCLP Background

............................................... 3-39 3.6.2 Limitations of the TCLP

........................................... 3-42

### Page 3-49

Exhibit 3-1. Risks Potentially Associated with Non-Hazardous Industrial Waste Management

........ 3-7 Exhibit 3-2 Materials Formerly Classified by DOT as Combustible Liquids (which generally are not RCRA ignitable)

...................... 3-11 Exhibit 3-3 Other Definitions of Reactivity

.......................... 3-18 Exhibit 3-4 TC Constituents and Regulatory Levels (mg/l)

................... 3-20 Exhibit 3-5 Comparison of TC Regulatory Concentrations and HWIR-Waste Proposed Exit/Leach Levels

.................... 3-25 Exhibit 3-6 Summary of Inhalation Pathway Screening Methods, Input Data, and Models Used for Bounding Risk Analysis

............... 3-29 Exhibit 3-7 Emission Fraction for Air Releases of Volatile TC Analytes

............... 3-30 Exhibit 3-9 Major Fate and Transport Parameters for TC Analytes

................. 3-36 Exhibit 3-10 Ratios of TC Leachate Regulatory Levels to Ambient Water Quality Criteria for Aquatic Life

................. 3-40Page 4-1



# CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH

NON-TC CHEMICALS

This chapter identifies potential gaps in the hazardous waste characteristics associated with chemicals not on the toxicity characteristic list. Chemicals and chemical classes are identified as potential gaps based on their hazardous properties such as toxicity to humans and ecological receptors, their fate and transportproperties such as persistence and bioconcentration potential, and their potential for occurrence in nonhazardous industrial wastes. This approach to identifying gaps is complemented by the approach discussed in Chapter 5, which identifies gaps in terms of the important environmental risks and their potential association with waste management, rather than focusing on specific chemicals. 4.1 Overview of Methodology EPA identified potential gaps in the characteristics associated with non-TC chemicals through a six-step process, as shown in Exhibit 4-1. Each of these steps is described below. Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents An essential task in this analysis is identifying a universe of chemicals that are either known or likely to be present in non-hazardous industrial wastes, excluding TC analytes (which are addressed in Chapter 3). In the analysis that follows, these two classes of chemicals are referred to asknownnon-hazardous industrial waste constituentsandpossiblenon-hazardous industrial waste constituents, respectively. As described in Section 4.2, the identification of the "known" non-hazardous constituents is relatively straightforward, although reliable data on the composition of non-hazardous industrial waste are limited. The data sources used to identify these constituents are shown in the top panels of Exhibit 4-1. They are the non-hazardous industrial waste release descriptions (discussed in Chapter 2), the Industrial Studies Data Base (ISDB), Effluent Guidelines Development Documents, and Listing Documents from recent rulemakings for dyes and pigments and solvent wastes. As discussed in Section 4.2, the distinguishing characteristic that makes a chemical a “known” non-hazardous industrial waste constituent is that it has been documented through direct chemical analysis to occur either in non-hazardous industrial waste or in environmental media contaminated by releases from non-hazardous industrial waste management units. Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents In addition to the chemicals that are known to be present in non-hazardous industrial wastes, EPA identified other chemicals that have a high likelihood of being present in such wastes and could pose significant risks to human health or the environment. Unlike the known non-hazardous industrial waste constituents, however, the possible waste constituents have not been confirmed as non-hazardous industrial waste constituents through direct chemical analysis in any of the data sources used by the Agency. To identify non-hazardous industrial waste constituents that could pose risks to human health or ecological receptors, the Agency reviewed 36 lists of chemicals created for regulatory and advisory purposes by EPA, other federal agencies, states, other countries, and advisory and scientific bodies. These lists were originally created based on criteria such as toxicity, fate and transport characteristics, production volume, widespread use, and detection in environmental media.Page 4-2



### InsertExhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential Gaps in the TC Characteristics

In graphicsPage 4-3 

### Rather than include all the chemicals on these lists as possible non-hazardous industrial waste constituents, EPA narrowed the list of chemicals to those most likely to pose significant risks to human health and the environment. The screening was performed in two steps, as shown in the upper right-hand panels of Exhibit 4-1. First, chemicals were screened with regard to individual toxicity and fate and transport properties. Then, the resulting high-hazard chemicals were screened against 1994 national Toxic Release Inventory (TRI) release data, serving as a proxy for potential occurrence in waste. Section 4.3 describes the process of compiling and screening possible non-hazardous industrial waste constituents. Step 3: Apply Hazard-Based Screening Criteria In this step, which is described in detail in Section 4.4, EPA compared the lists of known and possible non-hazardous industrial waste constituents and screened them against single and multiple hazard-based screening criteria. In Step 2, individual chemicals that are possible non-hazardous industrial waste constituents were screened on the basis of single indicators of hazard (e.g., a low reference dose or a high bioconcentration factor). This step refines this analysis by examining both the known and possible non-hazardous industrial waste constituents against single and multiple indicators of toxicity, fate, transport, and occurrence in waste, and by reviewing the implications of this screening for classes of chemicals. Step 4: Review Relevant Multipathway Risk Modeling ResultsSection 4.5 reviews the results of the multipathway risk modeling conducted as part of the proposed HWIRWaste (Hazardous Waste Identification Rule for Process Wastes) determination of exit levels, where available for chemicals on the combined list of known or possible non-hazardous industrial waste constituents. The proposed exit levels and risk-driving pathways provide information on the relative risks posed by the various constituents and on the most important exposure pathways. Step 5: Identify Potential Acute HazardsIn the prior steps, the evaluation of potential hazards associated with the possible and known nonhazardous industrial waste constituents has focused on chronic toxic effects. In Section 4.6, the possible and known constituents are compared to acutely hazardous chemical lists developed by EPA and other regulatory agencies. This analysis thus addresses risks from acute exposures and from physical hazards associated with reactivity, flammability, and corrosivity. Step 6: Summarize Findings Chapter 4 concludes by identifying non-TC chemicals and groups of chemicals that constitute potential gaps in the hazardous waste characteristics. Section 4.7 presents a table identifying these potential gaps, the rationale for their identification, and the major issues and data gaps remaining to be resolved to judge the severity of these potential gaps. 4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes Chemicals present in non-hazardous wastes that have been released from non-hazardous industrial waste management units into the environment may constitute potential gaps in the hazardous waste characteristics. This section reviews the available evidence concerning such chemicals. Reliable data concerning the chemical composition of non-hazardous industrial wastes, however, are quite limited for two major reasons. First, such wastes may be generated by virtually any industrial facility or operation and are inherently heterogeneous. Second, state requirements to analyze non-hazardous industrial wastes and to report analytical results are quite limited.Page 4-4 

### In the course of this Scoping Study, the Agency identified four sources of information regarding the composition of non-hazardous industrial wastes:

The descriptions of environmental releases from non-hazardous industrial waste management facilities, compiled as part of this Scoping Study, which were summarized in Chapter 2; The Industrial Studies Data Base (ISDB), which includes information on point of generation constituent concentrations on various industries; Chemicals identified as being present in liquid non-hazardous wastes by EPA Effluent Guideline Development Documents, as summarized in the Capacity Analysis for the Phase III Land Disposal Restrictions (LDR) Rule; and Chemicals identified as being present in non-hazardous industrial waste that were not listed as hazardous wastes in background documents for recent Agency listing/no-listing proposals for pigments and dyes industries and for solvents. The first source provides information on chemicals detected in environmental media (primarily groundwater) that were released from non-hazardous industrial waste management facilities, while the other three sources provide information on the composition of non-hazardous industrial wastes. Although not reflected in this Study, infuture investigations the Agency will consider examining the constituents present in remediation waste from nonhazardous industrial waste management units. The descriptions of environmental releases in Chapter 2 identify the constituents found in environmental media near non-hazardous industrial waste management units, their maximum detected concentrations, the types of units from which the releases occurred, and the industries responsible for the releases. The release descriptions provide direct evidence of potential environmental exposure to non-hazardous industrial waste constituents and damage to human health and the environment. They, however, do not encompass all instances where non-hazardous industrial waste management has resulted in releases to the environment or other potential risks. As noted in Chapter 2, the release descriptions come from only a small proportion of the states. However, they do represent a large proportion of the readily identifiable releases from facilities regulated by state non-hazardous industrial waste programs. In addition, some types of occurrences (e.g., fires and explosions) and units (e.g., waste piles) are generally not regulated by these state programs, and would not show up in the records EPA examined. The quantitative data from these descriptions generally were limited to groundwater monitoring results. Few releases to other media were identified. In addition, the chemicals identified tend to be those whose monitoring is required under existing regulatory programs. The potential for identifying chemicals not already recognized as hazardous is therefore limited. Finally, the data sources evaluated did not provide useful information on various types of uses constituting disposal, such as cement additives, soil amendments, or aggregate. The ISDB was the second source of data used to identify known waste constituents. EPA has maintained this data set since 1982. It contains information on point-of-generation constituent concentrations for 16 industries. The sources of information include RCRA Section 3007 questionnaires, plant visit reports, sampling and analysis reports, and engineering analysis. Its major limitations include data that are sometimes more than 15 years old and the coverage of only selected industries.U.S. Environmental Protection Agency, Office of Solid Waste,Background Document for Capacity Analysis for Land Disposal 1 Restrictions Phase III - Decharacterized Wastewaters, Carbamate Wastes, and Spent Potliners (Final Rule), Volume 1, February 1996. U.S. Environmental Protection Agency, Office of Solid Waste,Assessment of Risks from the Management of Used Solvents 2 (Draft), May 3, 1996. U.S. Environmental Protection Agency, Office of Solid Waste,Listing Background Document: Final Hazardous Waste Listing 3 Determination for the Dyes and Pigments Industries, November 30, 1994, non-confidential business information version.

Page 4-5 

### The third data source was information gathered by EPA's Office of Water in preparing Effluent Guidelines Development Documents. These data are summarized in OSW's Capacity Analysis Background Document for the Phase III LDR. The data describe the composition of non-hazardous industrial wastewaters generated by major industry 1 

### groups. These wastewater data are of varying age, and therefore their continued representativeness is unclear. Also, the number of analytes in the database is quite limited. As seen below, a very high proportion of the waste constituents identified in this source also are identified in one or both of the two data sources described above. Thus, the effluent guidelines data serve mainly to confirm data from the other sources. The Agency also reviewed two recent proposed listing decisions for hazardous wastes, those for solvent wastes and for wastes from the dyes and pigments industries. Several additional chemicals were identified as being constituents of unlisted (non-hazardous) solvent waste streams that were not found in any of the other data sources: 2-methoxyethanol, 2-ethoxyethanol acetate, cyclohexanol, isophorone, and diethylamine. No non- 2 

### hazardous industrial waste constituents from the dyes and pigments industry were identified, because all of the data concerning the compositions and generation rates of these wastes were held as confidential by the industries that submitted data.3 

### Excluding TC analytes, which are addressed in Chapter 3, a total of 146 chemicals were identified in the release descriptions, 183 in the ISDB, and 19 in the effluent guidelines data. An additional five unique constituents were found in the listings background document. Overall, a total of 250 unique chemicals were identified. The chemicals and waste constituents identified in the three data sources are sorted into major chemical classes and shown in Exhibit 4-2. These constituents span a wide range of chemical classes. Even with a number of possibly redundant entries, the most common category of chemicals was metals and inorganics, with 48 chemicals. Other prominent families of chemicals included volatile chlorinated organics (38), other semivolatile organics (46), other volatile organics (45), and pesticides and related compounds (29). Included among the chlorinated organics are several trihalomethanes and two chlorofluorocarbons. The “other semivolatile” category contains a wide range of compounds, many of which are found only in the ISDB data. The pesticides category contains mostly chlorinated organic pesticides and intermediates, but also contains some nonchlorinated compounds.

### Page 4-6 Exhibit 4-2. Known Non-Hazardous Industrial Waste Constituents Found in Case Studies, ISDB, Listings Documents, and Effluent Guidelines by Chemical Class

### Page 4-7 Less prominent categories of chemicals include the PAHs (18 compounds), volatile hydrocarbons (12), phenolic compounds (8), and phthalate esters (6). The PAHs range from low-molecular weight, noncarcinogenic compounds (such as naphthalene) to the higher molecular weight carcinogens and mutagens (such as benzo(a)pyrene). All but one of the volatile hydrocarbons (styrene) are commonly found as constituents in kerosene, gasoline, and related fuels. Styrene is a monomer used in plastics production. The phenolic compounds include creosote components (cresols) and two nitrophenols. Most of the phthalate esters are found in all the first three data sources, including the suspect carcinogen bis-(2-ethylhexyl)-phthalate. Polychlorinated biphenyls (PCBs) and chlorinated dioxins (represented by 2,3,7,8-TCDD) were found in the ISDB. The number of compounds in the various categories does not necessarily reflect the relative potential importance of the chemicals or categories. As noted above, some chemicals occur only in one database, while others occur in two, three, or all four. In addition, some chemicals occur in more than one release description, that is, at more than one facility, or are identified as waste constituents from more than one industry group. Except for the chemicals in the release descriptions, there is no indication of the relative concentrations of the chemicals in wastes. Given the wide range of chemical classes represented in the lists, and the relatively small total number of non-TC chemicals in the four datasets (250), the Agency found no convincing reason to eliminate any candidate chemicals from inclusion in the gaps analysis. Given that toxicological and fate and transport data are available for most of these chemicals, all the chemicals were carried forward for further analysis. 4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern This section describes the approach to identifying additional chemicals that might constitute potential gaps in the hazardous waste characteristics. Unlike the previous analysis, which began with four relatively narrow and specific data sources, this analysis begins with a wide range of data sources, in order to avoid excluding chemicals of potential concern. Subsequently, a substantial proportion of the large universe of chemicals are screened out on the basis of toxicity, fate and transport characteristics, and potential for occurrence in waste. A large portion also could not be evaluated because of a lack of data. The result is a focused list of possible non-hazardous industrial waste constituents that could pose significant risks to human health or the environment. The list of possible non-hazardous industrial waste constituents supplements the list of known non-hazardous industrial waste constituents developed in the previous section. 4.3.1 Approach to Identifying Potentially Hazardous Chemicals Excluding TC analytes, EPA identified over 2,300 distinct chemicals from 36 regulatory and advisory lists originally created by EPA, other federal agencies, state and national regulatory agencies, and special environmental task forces and advisory bodies. Exhibit 4-3 identifies these lists. The RCRA regulatory lists included are the 40 CFR 261 Appendix VII and VIII lists of hazardous waste constituents, the proposed HWIR-Waste Chemicals, and the HWIR-Media “Bright Line” chemicals. Other major federal regulatory lists include the Clean Water Act Section 307 Toxic Pollutants and Section 311(b)(2) Hazardous Substances, the CERCLA list of hazardous substances with reportable quantities, the Emergency Planning and Community Right-to-Know (EPCRA) Toxic Chemicals and Extremely Hazardous Substances lists, the Clean Air Act Amendments Section 112(b) Hazardous Air Pollutants and Section 112(r) Regulated Toxic Substances, and chemicals for which OSHA has published Permissible Exposure Limits (PELs). The U.S. Department of Transportation (DOT)

### Page 4-8

Exhibit 4-3. Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents
RCRA Section 3001 Hazardous Waste, 40 CFR Part 261, Appendix VII RCRA Section 3001 Hazardous Waste, 40 CFR Part 261, Appendix VIII CWA Section 307 Toxic Pollutants CWA Section 311(b)(2)(A) List of Hazardous Substances CERCLA Hazardous Substances Reportable Quantity List CAA Section 112(b) Hazardous Air Pollutants CAA Section 112(r) Regulated Toxic Substances HWIR-Media (Bright-Line) Chemicals HWIR-Waste Chemicals HWIR-Waste Ecotoxicity Chemicals OSHA Permissible Exposure Limits for Chemicals EPCRA Section 302 Extremely Hazardous Substances EPCRA Section 313 Toxic Chemicals List Industrial Studies Data Base Canada's Toxic Substances Management Policy Canadian ARET Toxics Scoring Protocol (A1-A2 LISTS) Canadian ARET Toxics Scoring Protocol (B1 LIST) Canadian ARET Toxics Scoring Protocol (B2 LIST) Canadian ARET Toxics Scoring Protocol (B3 LIST) Chemicals on Five or More Lists for Short-Term Exposure Criteria to Identify Chemicals for Sunsetting in Great Lakes Basin Deferred Toxicity Characteristic Chemicals Effluent Guidelines Chemicals Potential Endocrine Disruptors EPA Hazardous Substance Task Force (Levels 1 and 2) FIFRA Active Ingredients Focus Chemicals for the Great Waters Study (USEPA 1991) Great Lakes Water Quality Agreement Standard Methods Chemicals Highly Flammable Chemicals (Based on Several Lists) Highly Reactive Chemicals (Based on Several Lists) Michigan Critical Materials Register Persistent Bioaccumulative Chemicals Screening Proposed Water Quality Guidance, Great Lake Systems (1994) UN ECE Task Force on Persistent Organic Pollutants (1993) University of Tennessee Chemical Ranking System (1994) DOT Hazardous Materials Transportation Act, Hazardous Materials Regulationsa



### Notes: ched manually. Data base sear aU.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,Report of the EPA Hazardous Substances 4 Task Force, April 1992. U.S. Environmental Protection Agency, Office of Air Quality, Planning and Standards,Deposition of Air Pollutants to the 5 Great Waters, First Report to Congress, Publication EPA-453/R-93-055, May 1994. U.S. Environmental Protection Agency, Office of Solid Waste, November 15, 1996. 6


### Page 4-9 Hazardous Materials Transportation Act (HMTA) Hazardous Materials Registry (HMR) also was used to identify potential gap chemicals, but could not be directly included in the database in time because of format differences in the available machine-readable forms of the list. Some of the advisory lists that were included are the 1992 EPA Hazardous Substance Task Force's Level 1 4 

### and Level 2 hazardous chemicals that were identified as not being controlled under RCRA or DOT regulations, the Focus Chemicals for the Great Waters Study, chemicals identified by Environment Canada under the ARET Toxics 5 

### Scoring Protocols, chemicals identified by the University of Tennessee Chemical Ranking System, and the Michigan Critical Materials Register. Some lists address specific types of hazards, such as potential endocrine disruptors, acutely toxic chemicals, highly flammable chemicals, and highly reactive chemicals. Brief descriptions of the lists and the selection criteria that were applied to derive them are provided in "Background Document: Identification of Chemicals from Regulatory and Advisory Lists Representing Potential Gaps in the Hazardous Waste Characteristics."6 

### Naturally, there is a high degree of overlap among the chemical lists. Some lists are subsets of, combinations of, or otherwise derived from other lists. Nonetheless, the chemicals identified represent a very broad spectrum of potential hazards. High-volume and highly toxic chemicals appear on many lists, as do acutely toxic, flammable, and reactive chemicals. Several lists specifically seek to include carcinogens, mutagens, and teratogens. Some lists are derived based on considerations of ecotoxicity, persistence, and bioaccumulation potential, or based on specific environmental media or geographical concerns. The overall goal in the Scoping Study was to identify the broadest possible set of chemicals of potential concern, and then to screen them down to the chemicals with the highest potential to pose risks to human health or the environment. 4.3.2 Screening Approach EPA performed the hazard-based screening of potentially hazardous constituents in two steps. First, the entire list of chemicals was screened against criteria related to toxicity to humans and aquatic organisms and separately against various fate and transport criteria. Chemicals for which data were not available for at least one of these criteria were not included in further analysis. In the second step, EPA took all of the chemicals identified as either highly toxic, mobile, persistent, or bioaccumulative and first screened them against the proxy for occurrence in waste, namely the TRI release data. Any chemical passing this screen has a high potential for occurrence in waste and was identified as a possible non-hazardous industrial waste constituent. Chemicals were also retained in the analysis if they were not on the TRI list. Only the chemicals confirmed as having low releases through the TRI data were eliminated from being possible constituents. The criteria considered for use in screening (both the possible constituents described in this section and the combined lists discussed in Section 4.4) are summarized in Exhibit 4-4. These criteria were derived using professional judgment to provide a reasonable level of discrimination between

### Page 4-10 Exhibit 4-4 Criteria Considered for Screening Non-Hazardous Industrial Waste Constituentsa

Parameter Cutoff Value Rationale I. Toxicity Values Oral RfD <1.3x10 mg/kg-day 50th percentile -2 Oral CSF Any Value All Suspect Carcinogens >2.9x10 (mg/kg-day) 50th percentile

-1 -1 Inhalation RfC <1x10 ug/m 50th percentile -2 3 Inhalation UR Any Value All Suspect Carcinogens >3.3x10 (ug/m) 50th percentile

-4 3 -1 Primary MCL <5x10 mg/l 50th percentile -2 Acute AWQC <130 mg/l 50th percentile Chronic AWQC <5.2 mg/l 50th percentile II. Fate and Transport Parameters Fish BCF >1,000 l/kg About 85th percentile, lists range from 500-100,000 Fish BAF >1,000 l/kg About 50th percentile, lists range from 500-15,000 Kow >100,000 (unitless) About 75th percentile, lists range from 10,000-1,000,000 Beef Biotransfer >7.8x10 day/kg 75th percentile -3 Vegetable Root CF >15 (ug/gm)/(ug/gm) 75th percentile Forage BCF >3.5 (ug/gm)/(ug/gm) 75th percentile Henry's Law Constant (kH) >1x10 atm-M/mole 50th percentile, moderately volatile -5 3 Vapor Pressure >1.3x10 atm About 70th percentile = 1 mm Hg -2 Air-Leafy Plant Factor >5.3x10 (ug/gm)/(ug/gm) 75th percentile -4 Air Half Life >0.15 years 75th percentile Soil Deg. Constant <0.5 year About 75th percentile, DAF risk reduction = 100x -1 Water Deg. Constant <0.5 year About 75th percentile, DAF risk reduction = 100x -1 III. Indicators of Possible Occurrence in Waste 1994 TRI Release Data >10 lbs. Includes 99 percent of all releases to air, water, and land 6 (including underground injection) 1994 Production Data (TSCA >10 lbs. Indicates potential for widespread use, occurrence in Inventory Update) waste and release potential 6
All of these criteria were considered for use in the screening of both the possible non-hazardous industrial waste a constituents and the combined lists discussed in Section 4.4. As discussed in the text, only a subset of these criteria ultimately were used.Background Document: Identification of Chemicals from Regulatory and Advisory Lists Representing Potential Gaps in the 7 Hazardous Waste Characteristics,suprafootnote 6. U.S. Environmental Protection Agency, Office of Solid Waste,EPACMTP Background Document for Finite Source Methodology for 8 Chemical with Transformation Products, Chapter 6, 1995.


### Page 4-11 chemicals with relatively high-hazard potential and those with lower potential. For most toxicity parameters, which were available only for a relatively small number of more toxic chemicals, the cutoff values were set at the 50th percentile of the entire range of values. For many fate and transport parameters, the criteria were set at or around the 75th percentile (or 25th percentile, if a low value implied high hazard potential) of the entire range of the parameter values for all of the chemicals for which the parameter was available. In some cases, the screening criteria were set at levels generally recognized as indicative of hazard potential. In the course of the Scoping Study, many different criteria for and approaches to the screening process were evaluated; the background document to this Study provides further detail. The criteria and approach 7 

### described in this section is a relatively simple one that evolved from those previous efforts. One of the major lessons learned in that work was that screening is inherently imprecise, and no single screen will catch or exclude all the chemicals desired. Another lesson learned is that screening large lists against complex criteria can quickly become very complicated, and the return on the complexity, in terms of useful information, can be quite low. Therefore, EPA has focused on a relatively small number of criteria that are important in determining risk potential and has critically interpreted the results of the screening. In the case of carcinogens, two sets of criteria were used. The first set indicates whether a cancer slope factor (CSF) had been promulgated for the chemical. The second indicates whether an inhalation unit risk (UR) had been developed. These criteria identified the bulk of human carcinogens. For noncarcinogenic effects, two sets of criteria again were used. The first indicates whether an ingestion reference dose (RfD) had been developed at a sufficiently toxic level for the purposes of this analysis (i.e., below the 50th percentile). The second indicates whether an inhalation Reference Concentration (RfC) had been developed below the 50th percentile. For aquatic effects, the 50th percentile of the Chronic Ambient Water Quality Criteria (AWQC) was used. EPA used several criteria to screen fate and transport properties. The screening criteria for the fish bioconcentration factor (BCF) and bioaccumulation factor (BAF) were both set at 1,000 l/kg, the beef biotransfer factor was set at 7.8x10 day/kg, and the octanol-water partition coefficient (Kow) was set at 10 . These four -3 5 

### values indicate the potential for the chemicals to be taken up and/or accumulated by organisms. The vapor pressure criterion, used as a proxy for volatilization release, was set at 1 mm Hg. A Henry's Law constant (kH) value of 10-5 

### atm-m/mole was also used to identify chemicals with high volatilization potential. The criterion used to

3 

### identify persistent chemicals in soil or water (degradation rate constant less than 0.5/year) was selected based on an analysis of the EPACMTP findings for organic pollutant transport in groundwater, which indicated that, atrate constants above this value, the calculated DAF values begin to differ substantially from those for nondegrading pollutants with similar properties.8 

### As noted in Section 3.5, the screening-level risk analysis also was used to identify screening criteria and their importance. For example, Henry’s Law constants were found not to be a good indicator of the potential for long-term volatilization releases, so that the parameter is not used as a primary screening factor (although it is examined briefly in the next section). Instead, vapor pressure is used to screen chemicals for volatilization release. Even this screen must be interpreted cautiously, however, since chemicals with low vapor pressures can still volatilize from treatment units if no other processes are occurring to limit the releases.Toxicological criteria only have apotentialto screen out chemicals because, as discussed below, chemicals may be 9 considered high hazard (for the purposes of this analysis) because of fate and transport characteristics.


### Page 4-12 The primary data source that is used as a proxy for occurrence of hazardous chemicals in non-hazardous industrial wastes is the release data, reported under the Emergency Planning and Community Right-to-Know Act (EPCRA) Toxic Release Inventory (TRI) requirements. For purposes of the screening conducted for this study, EPA considered those chemicals with releases to air, land, water, and underground injection exceeding one million pounds in 1994. Under EPCRA Section 313, facilities with more than 10 full-time employees that are classified in SIC codes 20 through 39 (i.e., manufacturing) must submit reports if they manufacture or process more than 25,000 pounds of a TRI chemical or otherwise use more than 10,000 pounds of a TRI chemical in a given calendar year. There were a total of 73 unique chemicals and 10 classes of chemicals in this category, out of the 345 individual chemicals for which reports are required. These chemicals account for greater than 99.8 percent of the total TRI releases of all chemicals. As discussed in Section 4.4.2, the combined list of known and possible non-hazardous industrial waste constituents were also screened against non-CBI 1994 production data from the TSCA Inventory. A major limitation of this screening approach is that quantitative toxicity and fate and transport parameter values were available for only a fraction of the over 2,300 non-TC chemicals identified. Human toxicity parameters were available for just over 430 chemicals, ambient water quality data for 105 chemicals, and complete fate and transport data for 194 chemicals. For this reason, the screening approaches were supplemented by searching lists that identify chemicals presenting specific types of hazards, even if no quantitative parameter value was available, and by applying professional judgment to identify where potential risk findings for individual chemicals may be generalized to broader classes of chemicals. The results of this screening are described in a background report (see footnote 6). 4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial Waste Constituents Exhibit 4-5 summarizes the results of the screening for possible non-hazardous industrial waste chemicals against the toxicity criteria. The first two columns indicate the chemicals that are suspect or known human carcinogens having ingestion CSFs or inhalation URs. The last three columns identify the chemicals with oral RfDs, inhalation RfCs, and AWQCs below the 50th percentile of these parameter values (a low value indicates high toxicity) for all chemicals for which these values have been developed. Note that this table does not include TC analytes or chemicals previously identified as known non-hazardous industrial waste constituents. As noted previously, the number of chemicals identified on all 37 lists of chemicals is much greater than the numbers of chemicals for which toxicity parameters have been developed. Furthermore, the list of chemicals, which includes practically all of the known chemicals from Section 4.2 and all of the TC analytes, includes almost all chemicals for which these toxicity values have been derived. Thus, the toxicological screen has the potential9 

### to screen out most of the possible non-hazardous industrial waste constituents simply because most of the constituents do not have toxicity values, and therefore the effectiveness of the individual toxicity screening criterion is substantially

### Page 4-13 Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous

Industrial Waste Constituents

Chemicals with CSFs Chemicals with Unit Risks Chemicals with Low RfDs 2,4,6-Trinitrotoluene 1,3-Butadiene 3,3'-Dichlorobenzidine Aramite 1,1,2 Trichloropropane 4,4'-Methylenebis(N,N-dimethyl)benzenamine Asbestos (friable) 1,2,4 Tribromobenzene Acephate Azobenzene 1,3,5-Trinitrobenzene Aramite Benzidine 1,3 Phenylenediamine Azobenzene Bis(chloromethyl) ether 1,4 Dibromobenzene Benzidine Hexachlorocyclohexane 1,4 Dithiane Bis(2-ethylhexyl) adipate HxCDD 2-Chlorophenol Bis(chloromethyl) ether N-Nitrosodi-n-butylamine 2-Cyclohexyl-4,6-dinitrophenol Cyclotrimethylene trinitramine N-Nitrosodiethylamine 2,3 Dichloropropanol Dichlorvos N-Nitrosopyrrolidine 2,4,5-T acid Folpet Nickel subsulfide 2,4,6-Trinitrotoluene Fomesafen Propylene oxide 2,4-DB Furmecyclox 2,6-Dimethylphenol Hexachlorocyclohexane 3,4 Dimethylphenol Hexachlorodibenzo p dioxin, mixture (HxCDD) Acephate N-Nitrosodi-n-butylamine Acetataldehyde, trichloroN-Nitrosodi-n-propylamine Acifluoren, sodium salt N-Nitrosodiethanolamine Alachlor N-Nitrosodiethylamine Aldicarb sulfone N-Nitrosomethylethylamine Aluminum phosphate N-Nitrosopyrrolidine Ametryn Prochloraz Amitraz Propylene oxide Avermectin B1 Trifluralin Bentazon (50th percentile)

Benzidine Bis(tributyltin) oxide Captafal Carbamothioic acid, dipropyl-S-propyl ester Carbosulfan Chlorpyrifos Cyclotrimethylene trinitramine Cyhalothrin Decabromodiphenyl oxide Demeton Dichlorvos Dicrotophos Dinitrobutyl phenol Diquat Diuron Dodine EPN Ethion Ethylene thiourea Fenamiphos Flometuron Fluvalinate Fonofos Glufosinate ammonium Glycidylaldehyde Haloxyfop methyl

### Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous Industrial Waste Constituents (continued)

Page 4-14 Low RfDs (continued) Low RfCs Low AWQCs (<50th percentile) (50th Percentile) (50th percentile)
Hexabromobenzene 2-Chloroacetophenone Azinphos-methyl Hexachlorophene Antimony trioxide Chlorpyrifos Hydramethylnon Arsine Demeton Imazalil Chlorine dioxide Malathion Lactofen Dichlorvos Mirex Linuron Hexamethylene-1,6-diisocyanate Maneb Methylenebis(phenylisocyanate) Mecoprop Toluenediisocyanate (mixed isomers) Mercuric chloride Triethylamine Merphos Vinyl bromide Methacrylonitrile Methamidophos Methidathion Methoxone Methyl mercury Mirex N,N-Dimethylaniline Naled NuStar Octabromodiphenyl ether Oxydiazon Oxyfluorfen Parquat dichloride Pentabromodiphenyl ether Phenylmercuric acetate Primiphos methyl Prochloraz Prometryn Propachlor Propanil Propargyl alcohol Propiconazole Propoxur Quinalphos Quintozene Quizalofop-ethyl Rotenone, commercial S,S,S-Tributyltrithiophosphate Selenious acid Simazine Sodium azide Sodium fluoroacetate Strychnine Terbacil Terbutryn Tetraethyl lead Thallium chloride TlCl Thallium(I) acetate Thallium(I) carbonate Thallium(I) nitrate Thallium(I) sulfate Thiobencarb Triallate Tribenuron methyl Trifluralin Warfarin Zinc phosphide

### Exhibit 4-5. Toxicity Screening Results for Possible Non-Hazardous Industrial Waste Constituents (continued)

Page 4-15 limited for a large proportion of the chemicals identified on the 37 lists. Nevertheless, because all chemicals with cancer toxicity values are considered high hazard for this portion of the analysis, no chemicals would be screened out on the basis of carcinogenicity. The toxicity screening reduced the number of chemicals dramatically from the original universe of over 2300. As noted above, this reduction is primarily a function of the relatively small number of chemicals (about 400) for which human or ecotoxicity data are available. The screened list contains about one-third (25/74) of the chemicals for which CSFs were available, and about one-quarter (13/52) of those for which inhalation unit risks are available. The chemicals with low (<50th percentile) RfDs comprise by far the largest (107) set of all the chemicals identified by the toxicity screening, representing about one-third of the total number of chemicals for which RfDs have been derived. A large proportion of these chemicals are pesticides. Relatively few chemicals were identified having low inhalation RfCs and AWQCs for aquatic life. Exhibit 4-6 summarizes the results of the screening of chemicals with regard to fate and transport properties. The first two columns address the potential to volatilize for soil and water, as indicated by the vapor pressure and Henry’s Law constant. Since these parameters are directly related, the chemicals in these two columns overlap substantially. The next column lists chemicals with soil or water column degradation constants less than 0.5/year. Since the values for these two media are close for most of the chemicals, separate columns are not provided for each medium. The final three columns identify the chemicals with relatively high aquatic BCFs, beef biotransfer factors, or Kows. Since all three of these values are related to partitioning between lipid and water phases, the chemicals in these three columns also overlap substantially. As was the case for the toxicity screens, consistently-derived fate and transport parameters are not available to screen the majority of the chemicals. Thus, the menu of chemicals that are identified by the screening criteria related to each individual parameter again is determined primarily by the availability of data. In the case of the fate and transport screening, fewer chemicals are identified as being potentially hazardous. In addition, the fate and transport screening identifies a smaller proportion of the chemicals for which data are available. In all cases, the chemicals exceeding the screening criteria represent less than 10 percent of the chemicals for which data are available. 4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste Constituents Chemicals not screened out by the toxicity or fate and transport criteria were screened against the 1994 TRI data (used as a proxy for occurrence in wastes). The results of this final screening are presented in Exhibit 4-7. Of the 151 unique chemicals or classes of chemicals that were identified in the toxicity or fate and transport screening, TRI release data were available for 24 of them. Five of these chemicals (Freon 113, 1,3-butadiene, chlorine dioxide, chloroprene, and propylene dioxide) had TRI releases above one million pounds in 1994. Nineteen of the chemicals had TRI releases less than a million pounds. This latter group of chemicals were eliminated from further analysis. As noted previously, the remaining 132 chemicals for which no TRI data were available were retained in the analysis.

### Page 4-16 Exhibit 4-6. Persistence and Bioconcentration/Bioaccumulation Screening Results

for Possible Non-Hazardous Industrial Waste Constituents

Vapor Pressure> 1.3x10 atm Henry's Law Constant > 10atm-m/mol e years -3 -5 3 Soil/Water Degradatio

n Rate Constant < 0.5

-1 2-Chlorophenol 2-Chlorophenol 3-Methylcholanthrene Chloroprene Bis(2-chloroisopropyl) ether Kepone cis-1,3-Dichloropropene Chloroprene Quintozene Ethyl methacrylate cis-1,3-Dichloropropene Freon 113 Dinitrobutyl phenol Methacrylonitrile Ethyl methacrylate N-Nitrosodi-n-propylamine Freon 113 N-Nitrosodiethylamine Methacrylonitrile N-Nitrosomethylethylamine N-Nitrosodi-n-butylamine N-Nitrosodi-n-propylamine Quintozene Safrole Tris(2,3-dibromopropyl) phosphate

Fish BCF > 1,000 l/kg > 7.8x10 Kow > 10 Beef Biotransfer Factor -4 5 3-Methylcholanthrene 3-Methylcholanthrene 3-Methylcholanthrene Chlorobenzilate Diethylstilbestrol Diethylstilbestrol Diallate Hexachlorophene Hexachlorophene Diethylstilbestrol Kepone Kepone Kepone Quintozene

### Page 4-17 Exhibit 4-7 Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes

### Page 4-18 Exhibit 4-7 (continued) Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes

### Page 4-19 Exhibit 4-7 (continued) Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating Possible Non-Hazardous Industrial Waste Constituents Against TRI Release Volumes

### Page 4-20 4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents Exhibit 4-8 summarizes the results of the TRI screening process. It places the possible non-hazardous waste constituents into the same chemical categories as were used to characterize the known non-hazardous industrial waste constituents in Exhibit 4-2. The largest number of possible waste constituents (74) are pesticides and related compounds. As discussed in Section 4.3.2, these chemicals are identified as being potentially hazardous primarily by virtue of low RfDs, although there are also some potent ecotoxins, as well as persistent and bioaccumulative chemicals, among this group. The next most numerous category among the possible constituents are the other semivolatile organic chemicals. This diverse group includes chemicals recognized both for their toxicity and their fate and transport properties. Twelve metals/inorganic elements or groups are identified including five different thallium salts. Similarly, the other volatile organics group includes 5 nitrosamines among a total of 13 compounds. Also included in this group are two very toxic organometallic compounds, methyl mercury and tetraethyllead. Among the seven chlorinated organics are two of the five chemicals with TRI releases greater than one million pounds (Freon 113 and chloroprene). No other chemical category is represented by more than five chemicals. 4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents In this section, the known (from Section 4.2) and possible (from Section 4.3) non-hazardous industrial waste constituents are combined and screened against toxicity, fate, and transport criteria. Unlike the prior section, screening is oriented more toward groups of chemicals rather than toward individual chemicals, and toward comparing the properties of known versus possible non-hazardous industrial waste constituents. There is, inaddition, another screening step related to potential for occurrence in wastes, namely, comparison to 1994 nonconfidential TSCA production volume data. 4.4.1 Combine the Lists The lists of known and possible non-hazardous industrial waste constituents are shown in Exhibits 4-2 and 4-8. Exhibit 4-9 summarizes the screening of the known non-hazardous industrial waste constituents in the same way that Exhibit 4-7 provides these data for the possible constituents. As seen in these exhibits, thedistribution of chemicals within chemical classes is somewhat different between the known and possible nonhazardous industrial waste constituents. These differences, however, are exaggerated by the removal of the known constituents from consideration as possible constituents. (Logically, a chemical cannot be both a “known” and “possible” waste constituent.) Theknown non-hazardous industrial waste constituents are distinguished by a relatively high proportion of metals and inorganics, chlorinated volatile organics, other volatile organics, and polycyclic aromatic hydrocarbons, compared to thepossiblenon-hazardous waste constituents. In contrast, pesticides and related compounds constitute a much higher proportion of the possible non-hazardous industrial waste constituents than the known constituents. The pattern of differences in chemical category can be partially explained by the differences in the data sources. The relatively high prominence of volatile organics among the possible constituents probably reflects the difficulties in controlling fugitive releases of these high-volume chemicals during storage and processing. Such chemicals are somewhat less likely to turn up in groundwater samples (in the release descriptions or in aqueous effluents) because of their high volatility. The prominence of the less volatile organics in the known non-hazardous industrial waste constituents again reflects the greater stability of these chemicals in solid and liquid wastes.

### Page 4-21 Exhibit 4-8 Possible Non-Hazardous Industrial Waste Constituents by Chemical Class

### Page 4-22 Exhibit 4-9 Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release Volumes

### Page 4-23 Exhibit 4-9 (continued) Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release Volumes

### Page 4-24 Exhibit 4-9 (continued) Screening of Known Non-Hazardous Industrial Waste Constituents

Against TRI Release VolumesThis number includes both unique compounds (e.g., ethylbenzene) and categories of compounds (e.g., antimony compounds). 10The list of endocrine disrupting chemicals was developed based on information from Colborn, T., F.S. Saal, and A.M. Soto, 11 1993, "Developmental Effects of Endocrine-Disrupting Chemicals in Wildlife and Humans,"Environmental Health Perspectives, 101:378-384, October 1993; and Warhurst, M., 1996,Introduction to Hormone Disrupting Chemicals, on the World Wide Web at http://www.ed.ac.uk/~amw/oestrogenic.html.


### Page 4-25 Exhibit 4-9 also shows that the known waste constituents include a much higher number of chemicals with TRI release values greater than one million pounds (45) than is found among the possible constituents (5). This 10 

### is primarily due to the fact that the known waste constituents were identified first. Many of the high TRI release chemicals also would have been identified as possible non-hazardous industrial waste constituents if they had not been identified as known constituents. The implications of these findings for the potential severity of gaps in the hazardous characteristics are discussed in more detail in Chapter 10. In the analysis that follows, the known and possible non-hazardous industrial waste constituent lists are combined, and screened against single and multiple parameters related to toxicity, fate and transport, and release potential. 4.4.2 Screen Combined List Against Single Criteria Quantitative Human Toxicity Indicators. Exhibit 4-10 summarizes the toxicological properties of the combined known and possible non-hazardous industrial waste constituents. The chemicals are screened using the same criteria as described for the possible constituents alone in Section 4.3, with the exception that additional criteria related to carcinogenic potency are added (oral CSF and inhalation UR > 50th percentile). The list of suspect carcinogens (i.e., the first and third columns in Exhibit 4-10) contains a large proportion of all chemicals for which EPA has developed CSFs and URs. The proportion of the chemicals with high CSFs or URs (i.e., the second and fourth columns) is likewise very near to one-half of the total suspect carcinogens. This finding indicates that, as expected, the large universe of chemicals initially screened contains almost all of the chemicals that EPA has evaluated as potential human carcinogens. Many classes of chemicals (inorganics, volatile chlorinated organics, pesticides, other volatile chemicals) are represented among the suspect carcinogens. Ecotoxicity. As shown in the last column of Exhibit 4-10, 18 of the combined known and possible constituents have low AWQCs (below 50th percentile), indicating the potential for adverse effects on aquatic organisms. Many of these chemicals are pesticides, and most of the pesticides are persistent chlorinated pesticides. Although most of these chemicals are no longer produced, their presence among the known non-hazardous industrial waste constituents may give rise for some concern. Also included in this group are selenium, silver, and hydrogen sulfide. Potential Endocrine Disruptors. Because of the rapidly-evolving state of knowledge regarding chemicals that may act as endocrine disruptors, estrogen inhibitors, or have other hormone-like effects, it is difficult to estimate precisely how many of the combined known and possible non-hazardous industrial waste constituents fall into this category. Based on the rather broad list of potential endocrine disruptors, 23 of the combined 11 

### constituents are implicated as being potential endocrine disruptors (Exhibit 4-11). (Nine of the TC analytes are also potential endocrine disruptors.) Because of the lack of knowledge concerning dose-response relationships for exposures to single and multiple

### Page 4-26

Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents

### Page 4-27

Known and Possible Constituents TC Analytes 2,3,7,8-tetrachlorodibenzodioxin (2378-TCDD) cadmium 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) heptachlor and heptachlor expoxide alachlor lead aldicarb lindane b-hexachlorocyclohexane (b-BHC) mercury butylbenzylphthalate (BBP) methoxychlor DDD pentachlorophenol (PCP) DDE toxaphene DDT dibromochloropropane (DBCP) dibutyl phthalate (DBP) dieldrin diethylhexyl phthalate (DEHP) dimethyl phthalate (DMP) dioctyl phthalate (DOP) endosulfan mirex parathion polychlorinated biphenyls (PCBs) polychlorinated dibenzodioxins (PCDDs) styrene Exhibit 4-11 Potential Endocrine Disruptors

endocrine disruptors, it is difficult to predict if these chemicals would present risk to humans and non-human receptors. Nevertheless, the fact that so many of these chemicals are present among the constituents may cause concern.Potential for Frequent Occurrence in Wastes. The combined list of known and possible non-hazardous industrial waste constituents were also searched to identify those chemicals with high potential for occurrence in wastes, as indicated by TRI releases and/or non-confidential TSCA Inventory production data. The results of this analysis are summarized in Exhibit 4-12. Constituents are included in the table only if either TRI release data or non-CBI TSCA inventory data are available for them. Volatility and Persistence. As discussed in Section 3.5, volatility and persistence appear to be key indicators of potential risks for the TC analytes. In the first four columns of Exhibit 4-13, the known and possible non-hazardous industrial waste constituents are screened against these properties. Vapor pressure of 1.3x10 atmosphere (which is approximately equivalent to 1 mm Hg) is used to identify volatile chemicals. This

-3 

### measure approximates the potential to volatilize; many chemicals with lower vapor pressure could volatilize readily under certain waste management conditions. Even so, 70 known or possible non-hazardous industrial waste constituents fall into this category. This

### Page 4-28

Exhibit 4-12 TRI Releases and Non-Confidential TSCA Production Volume Data for the Known and Possible NonHazardous Industrial Waste Constituents

### Page 4-29

Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Summary Potential of Known and Possible Non-Hazardous Industrial Waste

Constituents

### Page 4-30

finding suggests that, as for the volatile TC analytes, volatilization releases and inhalation exposures (and possibly indirect exposures) may be a concern for some of these chemicals. Two chemicals, both chlorinated organics, are identified as having long half-lives (greater than 0.15 year) in air. This finding does not mean that all of the other constituents are too short-lived to be of concern through air exposures. Half-lives on the order of a few hours or days also may be of concern in terms of direct inhalation exposures. This criterion is more indicative of the potential for long-range (e.g., regional or global-scale) transport of these chemicals in the vapor phase. Also, as noted in Section 3.5, the air half-lives of many of the inorganic waste constituents (especially the metals) bound to particulates would also be limited only by how long the particles remained suspended in the atmosphere.
The third column of Exhibit 4-13 identifies the non-hazardous industrial waste constituents that are relatively persistent either in soils or in the water column. The metals all fall into this category, along with the PAHs, many chlorinated pesticides, and 2,3,7,8-TCDD. The only volatile organic chemical in this category is 1,2-dichloropropane. Appearance in this category arouses concern for potential inhalation and indirect pathway exposure risks, as discussed in Section 3.5. A high Kow, as indicated in the fourth column, indicates a high potential to bind to soil organic matter. It is highly correlated with the tendency to bioaccumulate. Thirty-one of the known and possible waste constituents including many persistent pesticides and PAHs, are in this category.
Bioaccumulation Potential. The last three columns of Exhibit 4-13 indicate the potential for bioaccumulation by the known and possible non-hazardous industrial waste constituents in aquatic and terrestrial food chains. The constituents with aquatic BCFs or BAFs greater than 1,000 are limited to the chlorinated pesticides, several phthalate esters, and diethylstilbestial (DES). This finding does not imply that no other constituents present significant risks through indirect pathways; nevertheless, the identified chemicals are all clearly recognized as being problematic from the point of view of bioconcentration. If these chemicals were released in significant amounts from non-hazardous waste industrial management activities, they could present substantial risks through food-chain exposures. The last column of the table lists chemicals that are taken up from feed by beef cattle with above-average (greater than 75th percentile) efficiency. This list includes most chemicals that also are of potential concern for aquatic ecosystems. Also, several additional classes of chemicals are identified, including the metals and PAHs. Although the beef biotransfer factor is only one of many parameters determining the potential for risks to humans from beef consumption, it is a reasonable indicator of potential concern for this pathway and is a useful indicator of exposure potential in other terrestrial food chains.
LNAPL and DNAPL Formation. The potential to form nonaqueous phase liquids (NAPLs) is of great concern from the point of view of waste management risks. Historically, NAPLs have been serious problems in the remediation of hazardous waste, because of their high potential risks and high remediation costs. Any chemical that is relatively insoluble in water and is a liquid at ambient temperature can be the principal component of a NAPL. If the chemical or chemical mixture is denser than water, then a dense nonaqueous phase liquid (DNAPL) is formed. If the liquid is less dense than water, a light nonaqueous phase liquid (LNAPL) may be formed.U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,Evaluation of the Likelihood of DNAPL 12 Presence at NPL Sites, EPA 540-R-93-073, September 1993. BTEX refers to benzene, toluene, ethylbenzene, and xylene, which are common constituents of gasoline. 13


### Page 4-31 DNAPLs are of particular concern because, when they escape to groundwater, they will sink through the unsaturated zone or aquifer until they encounter bedrock or another barrier. They can remain at the bottom of the aquifer (for example, in bedrock fractures) where they are hard, or in some cases nearly impossible, to remediate. Most DNAPLs undergo only limited degradation in the subsurface, and persist for long periods while slowly releasing soluble organic constituents to groundwater. Even with a moderate DNAPL release, dissolution may continue for hundreds of years or longer under natural conditions before all the DNAPLs are dissipated and concentrations of soluble organics in groundwater return to background levels. When released into surface water, DNAPLs tend to sink to the bottom and contaminate sediments. LNAPLs, in contrast, will tend to float on the surface of an aquifer, where they are easier to remedy; yet, they also can contaminate large volumes of groundwater through slow dissolution. Both LNAPLs and DNAPLs also can facilitate the transport of toxic waste constituents by solubilizing chemicals that would otherwise be immobile in waste or soil matrices. It is difficult to predict the circumstances under which LNAPL and DNAPL formation will occur and pose a risk to human health or the environment. Whether significant amounts of NAPLs will form depends on the composition of the wastes and the management practices employed. Reports of nonaqueous phase liquids were not found among the release descriptions for non-hazardous industrial waste management summarized in Chapter 2, possibly due to limitations in monitoring requirements. EPA has recently conducted a study of the potential for DNAPL formation at hazardous waste (NPL) sites, and identified several industries where NAPL formation is particularly likely to occur. These industries include wood treating sites, general manufacturing, organic chemical production, and

12 

### “industrial waste landfills”. A wide variety of chemicals have been found in NAPLs, and it appears that if a chemical is to be the major constituent of a NAPL, the most important requirements are relative insolubility in water and liquidity at ambient temperatures. Exhibit 4-14 identifies a number of the known and possible non-hazardous industrial waste constituents with the requisite physical properties. Since there is no clear dividing line between chemicals likely and not likely to form NAPLs, this list was developed using a combination of professional judgment and information about the physical properties of the waste constituents. All of the chemicals listed are organics, have relatively low water solubilities, and are liquid at room temperature (melting points greater than 7oC, boiling point greater than 30oC). Those indicated as being potential DNAPL formers have bulk liquid densities greater than 1 gm/cc,while those with densities less than water are indicated as potential LNAPL formers. The distinction is not clearcut however, as a mixture of light and heavy constituents at different relative concentrations might have widely varying densities. Exhibit 4-14 identifies more potential DNAPL formers than LNAPL formers found among the known andpossible waste constituents. Based on density considerations, the LNAPL formers tend to be primarily the nonhalogenated hydrocarbons, including “BTEX” and compounds with similar properties, whereas the DNAPL formers tend 13 

### to be primarily chlorinated and brominated chemicals. Not included in the NAPL list are pesticides that also fulfill the physical criteria, but which are no longer produced (see Chapter 9) and thus are less likely to be present in significant amounts in pure form in non-hazardous industrial wastes. These findings suggest that, on physical bases alone, manyU.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response,Evaluation of the Likelihood of DNAPL 14 Presence at NPL Sites, EPA 540-R-93-073.


### Page 4-32 Exhibit 4-14 LNAPL/DNAPL Formation Potential of Known and Possible Non-Hazardous Industrial Waste Constituents
Chemical Name NAPL Type Chemical Name NAPL Type a a 

### 1,1,1,2-Tetrachloroethane D Chloropropene D 1,1,1-Trichloroethane D cis-1,2-Dichloroethylene D 1,1,2-Trichloropropane D cis-1,3-Dichloropropene D 1,1,2,2-Tetrachloroethane D Cumene L 1,1,2-Trichloroethane D Di(2-ethylhexyl) phthalate L 1,2,3-Trichloropropane D Dibutyl phthalate D 1,2-Dibromo-3-chloropropane D Dichlorobromomethane D 1,2-Dibromoethane D Diethyl phthalate D 1,2-Dichlorobenzene D Dimethyl phthalate D 1,2-Dichloroethylene, trans D Ethylbenzene L 1,2-Dichloropropane D Ethylidene Dichloride D 1,3-Dichloropropylene D Freon 113 D 2,3-Dichloropropanol D Hexachlorocyclopentadiene D 2,3,4,6-Tetrachlorophenol D n-Dioctylphthalate L 2,4-Dichlorophenol D N-Nitrosodi-n-propylamine L 2-Chloroacetophenone L p-Chloroaniline D Acetophenone L Propylene oxide L Allyl chloride L Safrole L Benzyl chloride D Styrene L Bromoform D Toluene L Butyl benzyl phthalate D trans-1,3-Dichloropropene D Carbon disulfide D Trichlorofluoromethane D Chlorodibromomethane D Xylene (mixed isomers) L

Notes: re compound > 1.0 gm/cc) D = DNAPL (density of pu a 

### L = LNAPL (density of pure compound < 1.0 gm/cc)

of the known and possible non-hazardous industrial waste constituents could form LNAPLs or DNAPLs. As noted above, however, when this actually occurs depends to a large degree on the specific characteristics of the wastes and waste management practices. EPA's analysis of DNAPL formation at NPL sites found that the contaminants most directly associated with DNAPL presence include creosote compounds, coal tar compounds, polychlorinated biphenyls (PCBs), chlorinated solvents, and mixed solvents.14

### Page 4-33 4.4.3 Screen Combined List Against Multiple Parameters This section discusses the results of one last round of screening conducted on the entire combined list of known and possible non-hazardous industrial waste constituents. This analysis combines toxicity, persistence, volatility, and bioaccumulation screens in various combinations in order to identify the chemicals most likely to pose risks by various exposure pathways. Only constituents in the intersections of the screens remain (e.g., only constituents that are persistentandhighly toxic). For human toxicity, the criteria have been applied in the following order: Persistent and Highly Toxic to Humans. This combination is intended to identify highly

toxic chemicals that could pose risks through any pathways involving long-term release and transport of contaminants, such as groundwater and indirect pathways involving air, surface water, or groundwater releases. Persistent, Highly Toxic to Humans and Bioaccumulative. This screen narrows the above waste constituents to those with potential for adverse effects through indirect food chain exposure. Persistent, Highly Toxic to Humans, Bioaccumulative, and Volatile. This combination further narrows the above chemicals to those with potential to cause indirect pathway risks through air releases. A fourth screen applied persistent, ecotoxic, and bioaccumulative criteria to the combined list of constituents. This combination of screening criteria is intended to identify chemicals for which potential harm to ecological receptors is a potential concern. The individual criteria used in combination are described in Section 4.3. The persistence screen consisted of a determination of whether the chemicals had soil or water column degradation rate constants of less than 0.5/year. “Highly toxic” indicates any chemical having a CSF or Unit Risk above the 50th percentile of all chemicals, or a chronic RfD below the 50th percentile. Volatility was screened against Henry's Law constant of 10-5 

### atm-m/mole, and bioaccumulation potential determined by an aquatic BCF or BAF value of greater than 1,000 L/Kg.

3 

### The results of the combined screening of known and possible non-hazardous industrial waste constituents are summarized in Exhibit 4-15. To a substantial degree, these results parallel the screening-level modeling results for the TC analytes discussed in Section 3.5. Four of the nine persistent and highly toxic chemicals are chlorinated pesticides or degradation products, along with three metals (antimony, beryllium, and molybdenum), benzo(a)pyrene, and 2,3,7,8-TCDD. The appearance of benzo(a)pyrene suggests that other high molecular weight PAHs (some of which are also carcinogens) might also pass this screen if CSF values were available for these compounds. In addition, several other chlorinated pesticides have properties that just miss the toxicity or persistence cutoff values. When bioaccumulation potential is added to the screening conditions (second column of Exhibit 4-15), no chemicals drop out. This finding shows the high correlation between persistence and bioaccumulative potential: if a chemical was not persistent, it would lack the opportunity to accumulate in environmental media or tissue.

### Page 4-34 Exhibit 4-15 Multiple Screening Criteria Applied to Known and Possible Non-Hazardous Industrial Waste Constituents

Persistent and Highly Toxic Bioaccumulative Bioaccumulative Bioaccumulative Persistent, Highly Persistent, Highly Persistent, Toxic, and Toxic, and Ecotoxic, and

Volatile,

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) 2,3,7,8-TCDD Aldrin 2,3,7,8-TCDD Aldrin Aldrin DDE DDT

a 

### Antimony Antimony DDT Dieldrin Benzo[a]pyrene Benzo[a]pyrene Beryllium Beryllium DDE DDE DDT DDT a 

### Dieldrin Dieldrin Molybdenum Molybdenum a

a a

a a



### Notes: elled under FIFRA. Use has been canc a



### When the criterion of volatility is added to the preceding screens, three chemicals, all persistent pesticides remain. This result again parallels the results seen for the TC analytes in Section 3.5. If vapor pressure cutoff (1 mm Hg), rather than Henry’s Law constant (10 atm.-M/mole) is used to characterize the -5 3 

### potential to volatilize, none of the chemicals qualify in this category. The last column of Exhibit 4-15 identifies persistent, bioaccumulative, and ecotoxic chemicals. As might be expected from the previous screening results, these chemicals include chlorinated pesticides and 2,3,7,8-TCDD. Because the AWQC screen is based only on harmful concentrations, it does not include any screening for the concentrations normally encountered in the environment. Thus, if a much less toxic chemical (for example zinc or copper) were released into the environment in much larger amounts than the pesticides, the exposure concentrations might be much greater and adverse effects on ecological receptors might occur. 4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste Constituents EPA has previously evaluated the potential risks associated with the management of many known and possible non-hazardous industrial waste constituents in the context of deriving proposed risk-based exit levels for the proposed HWIR-Waste rulemaking. As discussed in Section 3.5, these proposed exit levels were derived by back-calculating concentrations in wastewaters and nonwastewaters corresponding to acceptable risk levels. The magnitude of the modeled exit levels is inversely proportional to the magnitude of risk posed by the chemical when placed in the specified management units. Proposed exit levels are calculated for groundwater exposures and other pathways. Thus, the proposed exit levels also indicate the relative importance of the exposure pathways for each chemical. Exhibit 4-16 tabulates the exit levels for 128 of the known or possible non-hazardous industrial waste constituents (i.e., the entire combined list prior to any screens that were also addressed in the HWIR-wasteThe Agency is currently revising the proposed HWIR-Waste exit level risk modeling methods in response to comments from the 15 Science Advisory Board and other reviewers. Thus, the proposed exit levels shown in Exhibit 4-15 should be regarded as preliminary. Edelstein, Maravene, "Memorandum to Paul Tobin on the Subject of a Database of Chemicals of Interest for Short Term 16Inhalation Exposure," September 1993. Sources of data for the database include the Emergency Planning and Community Right-toKnow Act (EPCRA) (40 CFR Part 355), Section 112(r) of the Clean Air Act (CAA) (40 CFR Part 68), and the Occupational Safety and Health Administration (OSHA) Process Safety Management (PSM) Standard (29 CFR Part 1910).


### Page 4-35 proposed rulemaking), and the exposure pathways that were risk drivers for setting the exit levels. As in the case of the similar analysis for the TC analytes in Section 3.5, many of the known or possible non-hazardous industrial waste constituents have proposed exit levels that are quite low (68 are below 0.1 mg/l). Therefore, the Agency has determined that the presence of these constituents in wastes at even relatively low concentrations may pose significant risks to human health. Again it should be noted that the target cancer risk level used to derive the exit levels was 10 , rather than the 10 level used in the derivation of TC regulatory levels. Even so, these -6 -5 

### levels indicate potential cause for concern for many of these chemicals at even low concentrations in wastes.15 

### As was also the case for the TC analytes, non-groundwater pathway risks drive the establishment of exit levels for about one-quarter of the known or possible non-hazardous industrial waste constituents. The driving pathways include direct inhalation and vegetable and milk ingestion. Pesticides make up a large proportion of the chemicals for which non-groundwater pathways drive the risks, but many volatile chlorinated and nonchlorinated organics also fall into this category. Ecological, rather than human health risks, drive the setting of proposed exit levels for two chemicals (copper and parathion). These findings confirm the indications from the toxicity and fate and transport screening presented in the previous sections that inhalation and indirect pathways could be of concern for many of the known or possible non-hazardous industrial waste constituents. 4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial Waste ConstituentsTo this point, the evaluation of the potential hazards associated with the possible and known nonhazardous industrial waste constituents has focused on chronic toxic effects. As discussed in Chapter 3, waste constituents may also pose risks from acute exposures, as well as from physical hazards associated with reactivity, flammability, or corrosivity. To investigate the possibility of acute adverse effects, the Agency has compared list of the known and possible waste constituents to lists developed by the EPA and other regulatory agencies that identify such hazardous properties. The results of this comparison are summarized in Exhibit 4-17. As shown in the exhibit, 38 of the known and possible non-hazardous industrial waste constituents have been identified in one or more regulatory contexts as being acutely toxic. Although most of these chemicals are 16 

### volatile organics, several acid gases and other inorganic compounds also are included. Appearance on these lists does not automatically indicate that acute

### Page 4-36 Exhibit 4-16 Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous Industrial Waste Constituents

### Page 4-37 Exhibit 4-16 (continued) Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous Industrial Waste Constituents

### Page 4-38 Exhibit 4-16 (continued) Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous Industrial Waste ConstituentsICF Incorporated,Draft Physical/Chemical Properties Criteria Database, October 1987. Sources of data for the database 17 include the Department of Transportation (DOT) Hazardous Materials Table (49 CFR 172.101) and the National Fire Protection Association (NFPA) publication 325M,Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids

. 

### Page 4-39 Exhibit 4-17 Potential Acute Hazards Associated with Known and Possible Non-Hazardous Industrial Waste Constituents Acutely Toxic Chemicals HighlyFlammable Chemical s Highly Reactive Chemicals 1,1,1-Trichloroethane Furan 1,3-Butadiene 1,3,5-Trinitrobenzene 1,3-Butadiene Hydrazine Acetaldehyde 2,4,6-Trinitrotoluene Acetaldehyde Hydrogen cyanide Chloroethane Acrolein Hydrogen fluoride Chloromethane Acrylonitrile Hydrogen sulfide Dimethylamine Allyl alcohol Methacrylonitrile Ethane, 1,1'-oxybisAllyl chloride Methanol Ethylene oxide Ammonia Methyl iodide Formaldehyde Arsine Methyl isocyanate Furan Bis(chloromethyl) ether Methyl mercaptan Hydrogen cyanide Bromomethane Nickel carbonyl Hydrogen sulfide Carbon disulfide Nitric oxide Methyl mercaptan Chlorine Nitrogen dioxide Phosphine Chlorine dioxide Phosgene Propylene oxide Chloromethane Phosphine Vinylidene chloride Epichlorohydrin Propylene oxide Ethylene oxide Toluene Fluorine Vinyl acetate Formaldehyde Xylene (mixed isomers)

Notes: orization criteria. See text for categ a



### adverse effects will occur, only that such effects could potentially be associated with management of wastes containing these chemicals. Fifteen of the waste constituents are also identified as being highly flammable. These are mostly 17 

### volatile organics, along with a few inorganic gases and liquids. They substantially overlap with the previous list. Only two of the known or possible non-hazardous industrial waste constituents are identified as being highly reactive.

### Page 4-40

4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps The analyses in the previous sections help to clarify the nature of potential gaps in the hazardous waste characteristics associated with specific chemicals and chemical classes related to chronic human health risks and ecological risks. The analyses identified groups of chemicals most likely to be present in non-hazardous industrial waste, and screened them in terms of their toxicity, fate, and transport properties. The results of the proposed HWIR-waste modeling were reviewed, where available, to confirm and expand the findings of the screening results. Finally, the known and possible non-hazardous industrial waste constituents were reviewed with regard to their potential to cause acute adverse effects. As a result of these efforts, a number of potential gaps have been identified, as summarized in Exhibit 4-18. This listing of potential gaps for non-TC analytes should not be taken as being either exhaustive or definitive. These gaps are potential, not actual gaps. They have been identified for purposes of targeting further analysis, not for purposes of choosing what constituent or wastes to regulate. Other potential gaps related to natural resource damages and regional or global environmental problems are discussed in Chapter 5. Also, Chapter 6 describes how several states have expanded the TC, implicitly identifying gaps in the TC. In Chapter 10, some of the unresolved issues identified in Exhibit 4-18 are discussed and the available information about the potential significance of these impacts is reviewed in detail. EPA recognizes the limitations of this analysis. As noted previously, the data concerning the composition of non-hazardous industrial wastes are quite limited and generally quite old. This lack of data in large part explains the need for the elaborate screening procedures employed in this chapter. Few data are available on the current patterns of non-hazardous industrial waste generation, management, and disposal. In addition, the chemical-specific screening is further complicated by the lack of toxicity and fate and transport parameter data for a large proportion of the universe of possible waste constituents, which necessitated extensive use of professional judgment to supplement the screening process.

### Page 4-41 Exhibit 4-18 Potential Gaps in the Hazardous Waste Characteristics Identified Based on the Hazardous Properties of Known and Possible Non-Hazardous

Industrial Waste Constituents

Potential Gap Basis for Identification Gaps ImportantUnresolved Issues, Data Groundwater exposure to toxic Potential variability in groundwater Amounts and concentrations disposed; metals transport; finding of metals in groundwater management practices; leaching above HBLs in release descriptions; proposed characteristics HWIR-waste risk results Groundwater and inhalation Findings above HBLs in release descriptions; Amounts and concentrations disposed; pathway exposures to volatile large number of volatiles among non-hazardous management practices chlorinated organic compounds industrial waste constituents; screeninglevel risk results; proposed HWIR-waste risk results Inhalation pathway exposure to Screening level risk modeling; screening based Whether these pesticides are still persistent organic pesticides on toxicity, fate and transport parameters being managed in substantial amounts as non-hazardous wastes Exposure to persistent organic Screening risk results; screening of waste Whether these pesticides are still pesticides and some metals throughconstituents for persistence, being managed in substantial amounts aquatic indirect pathways bioaccumulation, toxicity, proposed HWIR- as non-hazardous wastes Waste risk results indicating non-groundwater pathways drive risks Risks to aquatic ecosystems from Ecotoxicity, persistence, bioaccumulation Whether these pesticides are still persistent pesticides screening; analogy to screening risk modeling being managed in substantial amounts as non-hazardous wastes Risks to humans, ecological Toxicity, fate and transport screening; Amounts and concentrations managed receptors from chlorinated analogy to screening risk results; proposed (not high-volume chemicals) dioxins, PCBs HWIR-Waste risk results Endocrine disruption (humans and Findings in release descriptions; Dose-responses relationships for ecological receptors) from toxicological properties; fate and transport individual and multiple agents; exposure to chlorinated screening combined exposures are largely pesticides, phthalate esters unknown Adverse effects to humans from Occurrence in release descriptions above HBLs; Amounts and concentrations disposed exposure to “BTEX” hydrocarbonsfate and transport screening a Groundwater exposures to phenolic Occurrence in release descriptions above HBLs Relatively low toxicity compounds; compounds amounts and concentrations in nonhazardous wastes 

### Exhibit 4-18 (continued) Potential Gaps in the Hazardous Waste Characteristics Identified Based on the Hazardous Properties of Known and Possible Non-Hazardous

Industrial Waste Constituents

### Page 4-42 Potential Gap Basis for Identification Gaps ImportantUnresolved Issues, Data

Potential for LNAPL and DNAPL Large number of waste constituents have NAPL formation is highly dependent on formation, primarily for physical properties consistent with NAPL waste characteristics and specific halogenated solvents formation (mostly DNAPLs) management practices; few data are available Exposure to PAHs Occurrence in Subtitle D data; persistence; Amounts and concentrations disposed toxicity screening Acute effects; toxicity and other Many constituents are acutely toxic, highly Acute risks are highly dependent upon injuries flammable, or highly reactive nature and composition of wastes and management practices Notes: Toluene, ethylbenzene, xylenes; these compounds are all commonly found in gasoline, kerosene, and related petroleum a products.

### Page 4-43

CHAPTER 4. POTENTIAL GAPS ASSOCIATED WITH NON-TC CHEMICALS

.............................. 4-1 4.1 Overview of Methodology

................................................. 4-1 Step 1: Identify and Classify Known Non-Hazardous Industrial Waste Constituents

... 4-1 Step 2: Identify and Screen Possible Non-Hazardous Industrial Waste Constituents

... 4-1 Step 3: Apply Hazard-Based Screening Criteria

............................... 4-3 Step 4: Review Relevant Multipathway Risk Modeling Results

................... 4-3 Step 5: Identify Potential Acute Hazards

..................................... 4-3 Step 6: Summarize Findings

............................................... 4-3 4.2 Identify and Classify Known Constituents of Non-Hazardous Industrial Wastes

...... 4-3 4.3 Identify Possible Non-Hazardous Industrial Waste Constituents of Potential Concern

. . 4-7 4.3.1 Approach to Identifying Potentially Hazardous Chemicals

................. 4-7 4.3.2 Screening Approach

............................................... 4-9 4.3.3 Toxicity, Fate, and Transport Screening for Possible Non-Hazardous Industrial Waste Constituents

............................................... 4-12 4.3.4 Release Volume Screening of Possible Non-Hazardous Industrial Waste Constituents

.................................................... 4-15 4.3.5 Summary of Possible Non-Hazardous Industrial Waste Constituents

........ 4-20 4.4 Combine and Screen Known and Possible Non-Hazardous Industrial Waste Constituents 4-20 4.4.1 Combine the Lists

................................................ 4-20 4.4.2 Screen Combined List Against Single Criteria

.......................... 4-26 4.4.3 Screen Combined List Against Multiple Parameters

..................... 4-34 4.5 Driving Risk Pathways for the Known and Possible Non-Hazardous Industrial Waste Constituents

........................................................... 4-35 4.6 Potential Acute Hazards Associated With Known and Possible Non-Hazardous Industrial Waste Constituents

...................................................... 4-36 4.7 Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps

. 4-41

### Page 4-44

Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing Potential

Gaps in the TC Characteristics

............................................. 4-2 Exhibit 4-2 Known Non-Hazardous Industrial Waste Constituents Chemicals Found in Case

Studies, ISDB, Listings Documents, Effluent Guideline Documents by Chemical Class and Listing Documents

............................................... 4-6 Exhibit 4-3 Lists Used to Identify Possible Non-Hazardous Industrial Waste Constituents

........ 4-8 Exhibit 4-4 Criteria Considered for Screening Non-Hazardous Industrial Waste Constituents

.... 4-10 Exhibit 4-5 Toxicity Screening Results for Possible Non-Hazardous Industrial Waste

Constituents

........................................................... 4-13 Exhibit 4-6 Persistence and Bioconcentration/Bioaccumulation Screening Results for

Possible Non-Hazardous Industrial Waste Constituents

......................... 4-16 Exhibit 4-7 Screening of High-Toxicity, Persistent, Bioaccumulative/Bioconcentrating

Possible Non-Hazardous Industrial Waste Chemicals Against TRI Release Volumes

. 4-17 Exhibit 4-8 List of Known and Possible Non-Hazardous Industrial Waste Constituents By

Chemical Class

......................................................... 4-21 Exhibit 4-9 Screening of Known Non-Hazardous Industrial Waste Constituents Against TRI

Release Volumes

....................................................... 4-22 Exhibit 4-10 Toxicity Summary of Known and Possible Non-Hazardous Industrial Waste Constituents 4-27 Exhibit 4-11 Potential Endocrine Disruptors

............................................ 4-28 Exhibit 4-12 TRI Releases and TSCA Production Volume Data for the Known and Possible Non-Hazardous

Industrial Waste Constituents

............................................. 4-29 Exhibit 4-13 Volatility, Persistence, and Bioaccumulation/Bioconcentration Potential of Known and

Possible Non-Hazardous Industrial Waste Constituents

......................... 4-30 Exhibit 4-14 LNAPL/DNAPL Formation Potential of Known and Possible Non-Hazardous Industrial

Waste Constituents

...................................................... 4-33 Exhibit 4-15 Multiple Screening Criteria Applied to Known and Possible Non-Hazardous

Industrial Waste Constituents

............................................. 4-35 Exhibit 4-16 Lowest Proposed HWIR-Waste Exit Levels for Known and Possible Non-Hazardous

Industrial Waste Constituents

............................................. 4-37 Exhibit 4-17 Potential Acute Hazards Associated with Known and Possible Non-Hazardous

Industrial Waste Constituents

............................................. 4-40 Exhibit 4-18 Potential Gaps in the Hazardous Waste Characteristics Identified Based on the

Hazardous Properties of Known and Possible Non-Hazardous Industrial Waste Constituents

........................................................... 4-42Release Descriptions ISDB Data Listing Documents

Effluent Guidelines Development Documents Known NonHazardous Industrial Waste Constituents Exhibits 4-2, 4-9 Regulatory, Advisory Lists Exhibit 4-3

Screen Against Single Toxicity and Fate and Transport Criteria Exhibits 4-4, 4-5, 4-6

Screen Against TRI Release Data Exhibit 4-7

Possible NonHazardous Industrial Waste Constituents Exhibit 4-8

Known and Possible Non-Hazardous Industrial Waste Constituents

Screen Against Single and Multiple Toxicity, Fate and Transport, Persistence, and Bioaccumulation Criteria, TSCA Production Volumes Exhibits 4-10, 4-12, 4-13, 4-15 Identify Potential Endocrine Disrupters Exhibit 4-11 Identify Potential LNAPL, DNAPL Formers Exhibit 4-14

Identify HWIRWaste Risk Driving Exposure Pathways Exhibit 4-16 Identify Acutely Hazardous, Ignitable, Corrosive, and Reactive Constituents Exhibit 4-17

Identify Individual Chemicals and Classes of Chemicals Constituting Potential Gaps Exhibit 4-18 

### Step 5: Acute Hazards

Step 6: Summary Step 4: Multipathway Risk Modeling Step 3: Hazard Based Screening Criteria Step 2: Possible Non-Hazardous Industrial Waste Constituents Step 1: Known Non-Hazardous Industrial Waste Constituents

c6n020-1 

### Exhibit 4-1 Flow Chart of Procedures Used to Identify Non-TC Chemicals Posing

Potential Gaps in the TC Characteristics

Page 4-2EXHIBIT 4-2 KNOWN NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS FOUND IN CASE STUDIES, ISDB, LISTINGS DOCUMENTS, AND EFFLUENT GUIDELINES BY CHEMICAL CLASS
Metals/ Inorganics Volatile Chlorinated Organics Volatile Hydrocarbons Other Volatile Organics Pesticides/ Intermediates/ Degradation Products Phthalate Esters Phenolic Compounds Polycyclic Aromatic Hydrocarbons Other Semivolatile Organics Aluminum (fume or dust) 1,1,1,2-Tetrachloroethane 1,2,4-Trimethylbenzene 1,2-Dibromoethane 2,3,4,6-Tetrachlorophenol Butyl benzyl phthalate 2,4-Dimethylphenol 2-Methylnaphthalene 1,2-Diphenylhydrazine Ammonia 1,1,1-Trichloroethane Cumene 1,4-Dioxane Aldicarb Di(2-ethylhexyl) phthalate 2,4-Dinitrophenol 7,12-Dimethylbenz[a]anthracene 2,3,7,8-TCDD Antimony 1,1,2,2-Tetrachloroethane Ethylbenzene 2-Ethoxyethanol Aldrin Dibutyl Phthalate 2-Nitrophenol Acenaphthene 2,4-Diaminotoluene Beryllium 1,1,2-Trichloroethane m-Xylene 2-Ethoxyethanol acetate alpha-Endosulfan Diethyl Phthalate 4,6-Dinitro-o-cresol Acenaphthylene 2,4-Dichlorophenol Boron and compounds 1,2,3-Trichloropropane n-Butylbenzene 2-Hexanone alpha-Hexachlorocyclohexane Dimethyl Phthalate 4-Nitrophenol Anthracene 2,6-Dinitrotoluene Calcium 1,2,4,5-Tetrachlorobenzene n-Propyl benzene 2-Methoxyethanol Atrazine n-Dioctyl phthalate p-Chloro-m-cresol Benz[a]anthracene 3,3'-Dimethoxybenzidine Calcium Carbonate 1,2,4-Trichlorobenzene o-Xylene 2-Methyllactonitrile beta-BHC Phenol Benzo(a)phenanthrene 4-Aminobiphenyl Carbon dioxide 1,2-Dibromo-3-chloropropane p-Xylene 2-Methylpyridine beta-Endosulfan Phenolics Benzo(a)pyrene 4-Aminopyridine Chloride 1,2-Dichlorobenzene sec-Butylbenzene 2-Nitropropane Carbofuran Benzo(k)fluoranthene 5-Nitro-o-toluidine Chlorine 1,2-Dichloroethylene Styrene Acetaldehyde DDE Benzo[b]fluoranthene Acetophenone Cobalt 1,2-Dichloropropane Toluene Acetone DDT/DDD Benzo[ghi]perylene Acrylamide Copper 1,3-Dichlorobenzene Xylenes Acetonitrile Diazinon Dibenz[a,h]anthracene Acrylic acid Copper cyanide 1,3-Dichloropropylene Acrolein Dieldrin Fluoranthene Adipic acid Cyanides (sol. salts/complexes) Allyl chloride Acrylonitrile Dimethoate Fluorene Aniline Cyanogen chloride Benzoic trichloride Allyl alcohol Disulfoton Indeno(1,2,3-cd)pyrene Benzal chloride Fluoride/fluorine/hydrogen fluoride Bis(2-chloroethyl) ether Benzenethiol Endosulfan Isophorone Benzoic acid

Fluorine Chlorobromomethane Benzyl alcohol Endosulfan sulfate Methapyrilene Benzyl chloride Hydrogen cyanide Chlorodibromomethane Bromoform Endothall Pyrene Biphenyl Hydrogen fluoride Chloroethane Bromomethane Endrin aldehyde Coal tars Hydrogen sulfide Chloromethane Carbon disulfide Endrin ketone Creosote Iron cis-1,2-Dichloroethylene Crotonaldehyde Fampur Dibenzofuran Magnesium Dichloro-2-propanol, 1,3- Cyclohexanol Mesitylene Dichlorobenzene (mixed isomers) Manganese Dichlorobromomethane Cyclohexanone Methyl iodide Diphenyl ether Molybdenum Dichlorodifluoromethane Dimethylamine Methyl parathion Diphenylamine Nickel Dichloroethylene, N.O.S. Dimethyl sulfate Molinate Ethyl dipropylthiocarbamate Nickel carbonyl Dichloromethane Dimethylamine O,O-Diethyl O-pyrazinyl phosphorothioate Formic acid Nitrates/nitrites Dichloropropane Ethane, 1,1'-oxybis- Parathion m-Dinitrobenzene Nitric oxide Epichlorohydrin Ethyl acetate Phorate Maleic anhydride Nitrite Ethyl chloride Ethylene glycol Sulfotep Maleic hydrazide Nitrogen Ethylidene Dichloride Ethylene oxide N-Nitroso-dimethyl amine Nitrogen dioxide Hexachlorocyclopentadiene Formaldehyde N-Nitrosodiphenyl amine Phosgene Pentachloroethane Furan Naphthalene Phosphine Tetrachloroethane, N.O.S. Furfural Nitrosamine, N.O.S. Phosphorus trans-1,2-Dichloroethylene Hydrazine O-Chlorotoluene Potassium trans-1,3-Dichloropropene Isobutyl alcohol Ortho(2-)Nitroaniline Silica Trichloroethane Malononitrile p-Chloroaniline Silicon Trichlorofluoromethane Methanol p-Chlorotoluene Sodium Trichloromethanethiol Methyl isobutyl ketone p-Nitroaniline Sodium cyanide Methyl isocyanate Pentachlorobenzene Strontium Methyl mercaptan Phenanthrene Sulfide Methyl methacrylate Phthalic acid Sulfite Methylene bromide Phthalic anhydride Thallium n-Butyl alcohol Polychlorinated biphenyls Tin (total) Urethane Resorcinol Titanium Vinyl acetate Thioacetamide Vanadium (fume or dust) Thiram Vanadium pentoxide Zinc Total: 48 38 12 45 29 6 8 18 46

4-2.txtEXHIBIT 4-7 SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thAWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3Beef Biotransfer Factor >7_8e-4

0000076-13-1 Freon 113 5,077,542 ✔ ✔ 0000106-99-0 1,3-Butadiene 2,711,287 ✔ 0010049-04-4 Chlorine dioxide 1,501,041 ✔ 0000126-99-8 Chloroprene 1,157,755 ✔ ✔ 0000075-56-9 Propylene oxide 1,076,879 ✔ ✔ 0000101-68-8 Methylenebis(phenylisocyanate) 846,938 ✔ 0000103-23-1 Bis(2-ethylhexyl) adipate 844,594 ✔ 0001163-19-5 Decabromodiphenyl oxide 469,811 ✔ 0001332-21-4 Asbestos (friable) 294,368 ✔ 0000126-98-7 Methacrylonitrile 80,802 ✔ ✔ ✔ 0026471-62-5 Toluenediisocyanate (mixed isomers) 50,695 ✔ 0000092-87-5 Benzidine 31,606 ✔ ✔ ✔ 0000121-69-7 N,N-Dimethylaniline 22,676 ✔ 0001582-09-8 Trifluralin 15,304 ✔ ✔ 0000593-60-2 Vinyl bromide 2,620 ✔ 0000082-68-8 Quintozene 2,558 ✔ ✔ ✔ ✔ ✔ 0000062-73-7 Dichlorvos 1,286 ✔ ✔ ✔ 0002164-17-2 Fluometuron 832 ✔ 0000096-45-7 Ethylene thiourea 529 ✔ 0012427-38-2 Maneb 272 ✔ 0000542-88-1 Bis(chloromethyl) ether 255 ✔ ✔ 0000091-94-1 3,3'-Dichlorobenzidine 10 ✔ 0000114-26-1 Propoxur 4 ✔ 0000070-30-4 Hexachlorophene ✔ ✔ ✔ 0000133-07-3 Folpet ✔ 0000126-72-7 Tris(2,3-dibromopropyl) phosphate ✔ 0000122-34-9 Simazine ✔ 0000121-82-4 Cyclotrimethylene trinitramine ✔ ✔ 0000140-57-8 Aramite ✔ ✔ 0000141-66-2 Dicrotophos ✔ 0000143-50-0 Kepone ✔ ✔ ✔ ✔ ✔ 0000131-89-5 2-Cyclohexyl-4,6-dinitrophenol ✔ 0000576-26-1 2,6-Dimethylphenol ✔ 0000709-98-8 Propanil ✔ 0000621-64-7 N-Nitrosodi-n-propylamine ✔ ✔ ✔ 0000616-23-9 2,3 Dichloropropanol ✔ 0000615-54-3 1,2,4 Tribromobenzene ✔ 0000330-55-2 Linuron ✔ 0000598-77-6 1,1,2 Trichloropropane ✔ 0000150-50-5 Merphos ✔ 0000563-68-8 Thallium(I) acetate ✔ 0000563-12-2 Ethion ✔ 0000532-27-4 2-Chloroacetophenone ✔ 0000510-15-6 Chlorobenzilate ✔ 0000505-29-3 1,4 Dithiane ✔ 0000330-54-1 Diuron ✔ 0000300-76-5 Naled ✔ 0000608-73-1 Hexachlorocyclohexane ✔ ✔ 0000078-00-2 Tetraethyl lead ✔ 0000088-85-7 Dinitrobutyl phenol ✔ ✔

4-7.XLSEXHIBIT 4-7 (CONTINUED) SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thAWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3Beef Biotransfer Factor >7_8e-4

0000108-45-2 1,3-Phenylenediamine ✔ 0000086-50-0 Azinphos-methyl ✔ 0000085-00-7 Diquat ✔ 0000083-79-4 Rotenone, Commercial ✔ 0000121-75-5 Malathion ✔ 0000078-48-8 S,S,S-Tributyltrithiophosphate ✔ 0000093-65-2 Mecoprop ✔ 0000075-87-6 Acetaldehyde, trichloro- ✔ 0000062-74-8 Sodium fluoroacetate ✔ 0000062-38-4 Phenylmercuric acetate ✔ 0000057-24-9 Strychnine ✔ 0000056-53-1 Diethylstilbestrol ✔ ✔ ✔ 0000056-49-5 3-Methylcholanthrene ✔ ✔ ✔ ✔ ✔ 0000056-35-9 Bis(tributyltin) oxide ✔ 0000081-81-2 Warfarin ✔ 0000101-61-1 4,4'-Methylenebis(N,N-dimethyl)benzenamine ✔ 0000121-44-8 Triethylamine ✔ 0000118-96-7 2,4,6-Trinitrotoluene ✔ ✔ 0000765-34-4 Glycidylaldehyde ✔ 0000107-19-7 Propargyl alcohol ✔ 0000924-16-3 N-Nitrosodi-n-butylamine ✔ ✔ ✔ 0000087-82-1 Hexabromobenzene ✔ 0000103-33-3 Azobenzene ✔ ✔ 0000093-76-5 2,4,5-T acid ✔ 0000099-35-4 1,3,5-Trinitrobenzene ✔ 0000097-63-2 Ethyl methacrylate ✔ ✔ 0000095-65-8 3,4 Dimethylphenol ✔ 0000095-57-8 2-Chlorophenol ✔ ✔ ✔ 0000094-82-6 2,4-DB ✔ 0000094-74-6 Methoxone ✔ 0000094-59-7 Safrole ✔ 0000106-37-6 1,4 Dibromobenzene ✔ 0022967-92-6 Methyl mercury ✔ 0033089-61-1 Amitraz ✔ 0000822-06-0 Hexamethylene-1,6-diisocyanate ✔ 0032534-81-9 Pentabromodiphenyl ether ✔ 0030560-19-1 Acephate ✔ ✔ 0029232-93-7 Pirimiphos methyl ✔ 0028249-77-6 Thiobencarb ✔ 0012035-72-2 Nickel subsulfide ✔ 0025057-89-0 Bentazon ✔ 0035554-44-0 Imazalil ✔ 0022224-92-6 Fenamiphos ✔ 0020859-73-8 Aluminum phosphide ✔ 0019666-30-9 Oxydiazon ✔ 0019408-74-3 Hexachlorodibenzo p dioxin, mixture (HxCDD) ✔ ✔ 0015972-60-8 Alachlor ✔ 0013593-03-8 Quinalphos ✔ 0000834-12-8 Ametryn ✔ 0026628-22-8 Sodium azide (Na(N3)) ✔

4-7.XLSEXHIBIT 4-7 (CONTINUED) SCREENING OF HIGH-TOXICITY, PERSISTENT, BIOACCUMULATIVE/BIOCONCENTRATING POSSIBLE NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thAWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3Beef Biotransfer Factor >7_8e-4

0067747-09-5 Prochloraz ✔ ✔ 0085509-19-9 NuStar ✔ 0077501-63-4 Lactofen ✔ 0077182-82-2 Glufosinate ammonium ✔ 0076578-14-8 Quizalofop-ethyl ✔ 0072178-02-0 Fomesafen ✔ 0069806-40-2 Haloxyfop methyl ✔ 0032536-52-0 Octabromodiphenyl ether ✔ 0068085-85-8 Cyhalothrin ✔ 0039638-32-9 Bis(2-chloroisopropyl) ether ✔ 0067485-29-4 Hydramethylnon ✔ 0065195-55-3 Avermectin B1 ✔ 0062476-59-9 Acifluorfen, sodium salt ✔ 0060568-05-0 Furmecyclox ✔ 0060207-90-1 Propiconazole ✔ 0055285-14-8 Carbosulfan ✔ 0042874-03-3 Oxyfluorfen ✔ 0069409-94-5 Fluvalinate ✔ 0001314-84-7 Zinc phosphide ✔ 0002385-85-5 Mirex ✔ ✔ 0002303-16-4 Diallate ✔ 0002104-64-5 EPN ✔ 0001929-77-7 Carbamothioic acid, dipropyl-, S-propyl ester ✔ 0001918-16-7 Propachlor ✔ 0001646-88-4 Aldicarb sulfone ✔ 0002425-06-1 Captafol ✔ 0001309-64-4 Antimony trioxide ✔ 0001116-54-7 N-Nitrosodiethanolamine ✔ 0000950-37-8 Methidathion ✔ 0000944-22-9 Fonofos ✔ 0000930-55-2 N-Nitrosopyrrolidine ✔ ✔ 0101200-48-0 Tribenuron methyl ✔ 0000886-50-0 Terbutryn ✔ 0000055-18-5 N-Nitrosodiethylamine ✔ ✔ ✔ 0001910-42-5 Paraquat dichloride ✔ 0007791-12-0 Thallium chloride TlCl ✔ 0010595-95-6 N-Nitrosomethylethylamine ✔ ✔ 0010265-92-6 Methamidophos ✔ 0010102-45-1 Thallium(I) nitrate ✔ 0002303-17-5 Triallate ✔ 0008065-48-3 Demeton ✔ ✔ 0002439-10-3 Dodine ✔ 0007784-42-1 Arsine ✔ 0007783-00-8 Selenious acid ✔ 0007487-94-7 Mercuric chloride ✔ 0007446-18-6 Thallium(I) sulfate ✔ 0007287-19-6 Prometryn ✔ 0006533-73-9 Thallium(I) carbonate ✔ 0005902-51-2 Terbacil ✔ 0002921-88-2 Chlorpyrifos ✔ ✔ 0010061-01-5 cis-1,3-Dichloropropene ✔ ✔

4-7.XLSEXHIBIT 4-8 POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS BY CHEMICAL CLASS
Metals / Inorganics Volatile Chlorinated Organics Volatile

Hydrocarbons Other Volatile Organics Pesticides/Intermediates/Degradation Products Phenolic Compounds Polycyclic Aromatic Hydrocarbons Other Semivolatile Organics Antimony trioxide 1,1,2 Trichloropropane 1,3-Butadiene 1,4 Dithiane 2,4,5-T acid Imazalil 2,6-Dimethylphenol 3-Methylcholanthrene 1,2,4 Tribromobenzene Arsine 2,3 Dichloropropanol Azobenzene 2,4-DB Kepone 2-Chlorophenol 1,3,5-Trinitrobenzene Chlorine dioxide Acetaldehyde, trichloro- Glycol Ethers Acephate Lactofen 2-Cyclohexyl-4,6-dinitrophenol 1,3-Phenylenediamine Copper Bis(2-chloroisopropyl) ether Methyl mercury Acifluorfen, sodium salt Linuron 3,4 Dimethylphenol 1,4 Dibromobenzene Cyanide Chloroprene N-Nitrosodi-n-butylamine Alachlor Malathion Dinitrobutyl phenol 2,4,6-Trinitrotoluene Manganese cis-1,3-Dichloropropene N-Nitrosodi-n-propylamine Aldicarb sulfone Mecoprop 2-Chloroacetophenone Mercuric chloride Freon 113 N-Nitrosodiethanolamine Aluminum phosphide Merphos 4,4'-Methylenebis(N,N-dimethyl)benzenamine Nickel subsulfide N-Nitrosodiethylamine Ametryn Methamidophos Avermectin B1 Selenious acid N-Nitrosomethylethylamine Amitraz Methidathion Cyclotrimethylene trinitramine Sodium azide (Na(N3)) Propargyl alcohol Aramite Methoxone Diethylstilbestrol Thallium(I) chloride Propylene oxide Azinphos-methyl Mirex Ethyl methacrylate Thallium(I) acetate Tetraethyl lead Bentazon N-Nitrosopyrrolidine Glycidylaldehyde Thallium(I) carbonate Triethylamine Bis(tributyltin) oxide Naled Hexabromobenzene Thallium(I) nitrate Captafol NuStar Hexachlorodibenzo p dioxin, mixture Thallium(I) sulfate Carbamothioic acid, dipropyl-, S-propyl ester Oxydiazon Hexamethylene-1,6-diisocyanate Zinc Carbosulfan Oxyfluorfen Octabromodiphenyl ether Chlorobenzilate Paraquat dichloride Pentabromodiphenyl ether Chlorpyrifos Phenylmercuric acetate Propiconazole Cyhalothrin Pirimiphos methyl Safrole Demeton Prochloraz Tris(2,3-dibromopropyl) phosphate Diallate Prometryn Dicrotophos Propachlor Diquat Propanil Diuron Quinalphos Dodine Quizalofop-ethyl EPN Rotenone, Commercial Ethion S,S,S-Tributyltrithiophosphate Fenamiphos Simazine Fluvalinate Sodium fluoroacetate Folpet Strychnine Fomesafen Terbacil Fonofos Terbutryn Furmecyclox Thiobencarb Glufosinate ammonium Triallate Haloxyfop methyl Tribenuron methyl Hexachlorocyclohexane Warfarin Hexachlorophene Zinc phosphide Hydramethylnon 12 1 7 1 13 75 5 1 20 Notes: 1. All thallium salts are counted as one entry.

4-8.XLSEXHIBIT 4-9 SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thBeef Biotransfer Factor >7_8e-4AWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BAFFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3

0000067-56-1 Methanol 255,766,934 ✔ ✔ 0000108-88-3 Toluene 168,958,681 ✔ ✔ 0001330-20-7 Xylene (mixed isomers) 108,936,037 ✔ ✔ 0000075-15-0 Carbon disulfide 83,384,729 ✔ ✔

---- Zinc compounds 81,764,720 ✔ ✔ 0000075-09-2 Dichloromethane 63,774,566 ✔ ✔ ✔ ✔

---- Glycol Ethers 48,991,927

---- Copper compounds 47,115,338 ✔ ✔ ✔

---- Manganese compounds 41,504,786 ✔ ✔ 0000100-42-5 Styrene 40,156,848 ✔ ✔ 0000071-55-6 1,1,1-Trichloroethane 38,056,891 ✔ ✔ 0000071-36-3 n-Butyl alcohol 30,081,146 ✔ 0000108-10-1 Methyl isobutyl ketone 25,501,571 ✔ ✔ 0000050-00-0 Formaldehyde 19,755,899 ✔ ✔ ✔ 0000075-05-8 Acetonitrile 18,264,054 ✔ ✔ ✔ 0000075-07-0 Acetaldehyde 13,052,168 ✔ ✔ 0000100-41-4 Ethylbenzene 12,802,139 ✔ ✔ 0000064-18-6 Formic acid 11,267,572 ✔ 0007440-66-6 Zinc 10,155,449 ✔ ✔ 0007439-96-5 Manganese 9,354,553 ✔ 0000079-10-7 Acrylic acid 6,915,166 ✔ 0000107-13-1 Acrylonitrile 6,379,861 ✔ ✔ ✔ ✔ ✔ 0000079-06-1 Acrylamide 5,217,625 ✔ ✔ ✔ 0000074-87-3 Chloromethane 5,174,937 ✔ ✔ 0000075-71-8 Dichlorodifluoromethane 4,872,594 ✔ ✔

---- Cyanide compounds 4,382,509 ✔ 0000091-20-3 Naphthalene 3,230,142 ✔ 0000074-90-8 Hydrogen cyanide 3,143,253 ✔ 0000075-69-4 Trichlorofluoromethane 2,994,474 ✔ ✔ 0000074-83-9 Bromomethane 2,669,788 ✔ ✔ ✔ ✔ 0000080-62-6 Methyl methacrylate 2,583,587 ✔ ✔ 0007440-50-8 Copper 2,204,032 ✔ ✔ ✔ 0000098-82-8 Cumene 2,057,269 ✔ ✔ 0000062-53-3 Aniline 1,976,326 ✔ ✔

---- Nickel compounds 1,665,815 ✔ ✔ ✔

---- Antimony compounds 1,445,522 ✔ ✔ ✔ ✔

4-9.XLSEXHIBIT 4-9 (CONTINUED) SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thBeef Biotransfer Factor >7_8e-4AWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BAFFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3

0000107-02-8 Acrolein 170,087 ✔ ✔ ✔ 0007440-36-0 Antimony 128,663 ✔ ✔ ✔ ✔ 0000099-65-0 m-Dinitrobenzene 100,719 ✔ 0000074-95-3 Methylene bromide 77,545 ✔ ✔ 0007723-14-0 Phosphorus 50,768 ✔ 0007440-62-2 Vanadium (fume or dust) 41,023 ✔ ✔ ✔ 0000079-46-9 2-Nitropropane 40,523 ✔ ✔ 0000051-28-5 2,4-Dinitrophenol 39,344 ✔ 0000542-75-6 1,3-Dichloropropylene 24,756 ✔ ✔ ✔ 0007440-41-7 Beryllium 23,795 ✔ ✔ ✔ ✔ ✔ ✔ 0000075-34-3 Ethylidene Dichloride 23,492 ✔ ✔ 0000100-44-7 Benzyl chloride 23,331 ✔ ✔ ✔ 0000106-93-4 1,2-Dibromoethane 18,537 ✔ ✔ ✔ ✔ 0000302-01-2 Hydrazine 16,956 ✔ ✔ 0000120-83-2 2,4-Dichlorophenol 14,760 ✔ 0000079-34-5 1,1,2,2-Tetrachloroethane 14,027 ✔ ✔ ✔ ✔ 0000630-20-6 1,1,1,2-Tetrachloroethane 11,746 ✔ ✔ ✔ ✔ 0000077-47-4 Hexachlorocyclopentadiene 9,174 ✔ ✔ ✔ ✔ ✔ ✔ 0000111-44-4 Bis(2-chloroethyl) ether 3,237 ✔ ✔ ✔ ✔ 0000137-26-8 Thiram 3,184 ✔ 0000098-07-7 Benzoic trichloride 2,868 ✔ 0000056-38-2 Parathion 1,147 ✔ 0007440-28-0 Thallium 1,010 ✔ ✔ ✔ 0000075-27-4 Dichlorobromomethane 0 ✔ ✔ ✔ 0000086-30-6 N-Nitrosodiphenylamine 0 ✔ ✔ 0001336-36-3 Polychlorinated biphenyls 0 ✔ ✔ ✔ ✔ ✔ 0000096-18-4 1,2,3-Trichloropropane ✔ ✔ ✔ 0000095-94-3 1,2,4,5-Tetrachlorobenzene ✔ ✔ ✔ ✔ 0000096-12-8 1,2-Dibromo-3-chloropropane ✔ ✔ 0000156-60-5 1,2-Dichloroethylene, trans ✔ ✔ 0000122-66-7 1,2-Diphenylhydrazine ✔ ✔ 0000058-90-2 2,3,4,6-Tetrachlorophenol ✔ ✔ 0001746-01-6 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) ✔ ✔ ✔ ✔ ✔ ✔ 0000057-97-6 7,12-Dimethylbenz[a]anthracene ✔ ✔ 0000083-32-9 Acenaphthene ✔ 0000067-64-1 Acetone ✔ ✔ 0000116-06-3 Aldicarb ✔ 0000309-00-2 Aldrin ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 0000959-98-8 alpha - Endosulfan ✔ 0000319-84-6 alpha-Hexachlorocyclohexane ✔ ✔ ✔ 0000056-55-3 Benz[a]anthracene ✔ ✔ ✔ ✔ 0000218-01-9 Benzo(a)phenanthrene ✔ ✔ ✔ ✔ 0000050-32-8 Benzo[a]pyrene ✔ ✔ ✔ ✔ ✔ 0000205-99-2 Benzo[b]fluoranthene ✔ ✔ ✔ ✔ ✔ 0033213-65-9 beta - Endosulfan ✔

4-9.XLSEXHIBIT 4-9 (CONTINUED) SCREENING OF KNOWN NON-HAZARDOUS WASTE CONSTITUENTS AGAINST TRI RELEASE VOLUMES

Chemical CAS Chemical Name Release VolumeOral CSFInhalation Unit RiskOral RfD < 50thRfC < 50thBeef Biotransfer Factor >7_8e-4AWQC (Chronic) < 50thDegradation Rate for Water ColumnFish BAFFish BCFHenry's Law ConstantKowSoil Degradation RateVapor Pressure > 1_3e-3

0000319-85-7 beta-BHC ✔ ✔ ✔ 0000075-25-2 Bromoform ✔ ✔ ✔ ✔ 0000085-68-7 Butyl benzyl phthalate ✔ ✔ 0001563-66-2 Carbofuran ✔ 0000124-48-1 Chlorodibromomethane ✔ ✔ ✔ 0018540-29-9 Chromium(VI) ✔ ✔ 0000156-59-2 cis-1,2-Dichloroethylene ✔ ✔ 0008007-45-2 Coal tars ✔ 0000544-92-3 Copper cyanide ✔ 0000057-12-5 Cyanides (soluble salts and complexes) ✔ 0000072-54-8 DDD ✔ ✔ ✔ ✔ ✔ ✔ 0000072-55-9 DDE ✔ ✔ ✔ ✔ ✔ ✔ ✔ 0000050-29-3 DDT ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 0000053-70-3 Dibenz[a,h]anthracene ✔ ✔ ✔ ✔ 0000060-57-1 Dieldrin ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔ 0000060-51-5 Dimethoate ✔ 0000298-04-4 Disulfoton ✔ 0000115-29-7 Endosulfan ✔ ✔ ✔ 0000060-29-7 Ethane, 1,1'-oxybis- ✔ ✔ 0000141-78-6 Ethyl acetate ✔ ✔ 0000206-44-0 Fluoranthene ✔ ✔ 0000086-73-7 Fluorene ✔ 0000110-00-9 Furan ✔ ✔ ✔ 0000098-01-1 Furfural ✔ 0007783-06-4 Hydrogen sulfide ✔ ✔ ✔ 0000193-39-5 Indeno(1,2,3-cd)pyrene ✔ ✔ ✔ ✔ 0000078-83-1 Isobutyl alcohol ✔ ✔ 0000078-59-1 Isophorone ✔ 0000298-00-0 Methyl parathion ✔ 0002212-67-1 Molinate ✔ 0007439-98-7 Molybdenum ✔ ✔ ✔ ✔ 0000117-84-0 n-Dioctylphthalate ✔ ✔ ✔ 0000062-75-9 N-Nitrosodimethylamine ✔ ✔ ✔ 0000106-47-8 p-Chloroaniline ✔ ✔ ✔ 0000608-93-5 Pentachlorobenzene ✔ ✔ ✔ ✔ ✔ 0000298-02-2 Phorate ✔ 0007803-51-2 Phosphine ✔ ✔ 0000129-00-0 Pyrene ✔ ✔ ✔ ✔ 0003689-24-5 Sulfotep ✔ 0010061-02-6 trans-1,3-Dichloropropene ✔ ✔ 0001314-62-1 Vanadium pentoxide ✔

4-9.XLSEXHIBIT 4-10 TOXICITY SUMMARY OF KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Inhalation Unit Risk (All) Inhalation Unit Risk > 50th Percentile Oral CSF (All) Oral CSF > 50th Percentile Oral RfD < 50th Percentile Oral RfD < 50th Percentile (Continued) AWQC (Chronic Freshwater) < 50th Percentile 1,1,1,2-Tetrachloroethane Acrylamide 1,1,1,2-Tetrachloroethane 1,2-Dibromoethane 1,1,2 Trichloropropane Glycidylaldehyde 2,3,7,8-TCDD 1,1,2,2-Tetrachloroethane Aldrin 1,1,2,2-Tetrachloroethane 1,2-Diphenylhydrazine 1,1,2-Trichloroethane Haloxyfop methyl alpha - Endosulfan 1,1,2-Trichloroethane alpha-Hexachlorocyclohexane 1,1,2-Trichloroethane 2,3,7,8-TCDD 1,2,3-Trichloropropane Hexabromobenzene Antimony 1,2-Dibromoethane Benzidine 1,2-Dibromoethane Acrylamide 1,2,4 Tribromobenzene Hexachlorocyclopentadiene Azinphos-methyl 1,2-Diphenylhydrazine Beryllium 1,2-Diphenylhydrazine Acrylonitrile 1,2,4,5-Tetrachlorobenzene Hexachloroethane beta - Endosulfan 1,3-Butadiene beta-BHC 1,4-Dioxane Aldrin 1,2,4-Trichlorobenzene Hydramethylnon Chlorpyrifos Acetaldehyde Bis(2-chloroethyl) ether 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) alpha-Hexachlorocyclohexane 1,3,5-Trinitrobenzene Hydrogen sulfide Copper Acrylamide Coal tars 2,4,6-Trinitrotoluene Benzo[a]pyrene 1,3-Dichloropropylene Imazalil Cyanides (soluble salts and complexes) Acrylonitrile Dieldrin 4,4'-Methylenebis(N,N-dimethyl)benzenamine Benzoic trichloride 1,3-Phenylenediamine Lactofen DDT Aldrin Hexachlorocyclohexane Acephate Beryllium 1,4 Dibromobenzene Linuron Demeton alpha-Hexachlorocyclohexane HxCDD, mixture Acrylamide beta-BHC 1,4 Dithiane m-Dinitrobenzene Dieldrin Aramite Hydrazine Acrylonitrile Bis(2-chloroethyl) ether 2,3 Dichloropropanol Mecoprop Endosulfan Azobenzene N-Nitrosodi-n-butylamine Aldrin DDE 2,4,5-T acid Mercuric chloride Hexachlorocyclopentadiene Beryllium N-Nitrosodiethylamine alpha-Hexachlorocyclohexane DDT 2,4,6-Trinitrotoluene Merphos Hydrogen sulfide beta-BHC N-Nitrosodimethylamine Aniline Dieldrin 2,4-DB Methamidophos Malathion Bis(2-chloroethyl) ether N-Nitrosopyrrolidine Aramite Hexachlorocyclohexane 2,4-Dichlorophenol Methidathion Mirex Bis(chloromethyl) ether Nickel subsulfide Azobenzene HxCDD, mixture 2,4-Dinitrophenol Methoxone Parathion Bromoform Benzo[a]pyrene Hydrazine 2,6-Dimethylphenol Methyl mercury Polychlorinated biphenyls Coal tars Benzoic trichloride N-Nitrosodi-n-butylamine 2-Chlorophenol Methyl parathion DDT Benzyl chloride N-Nitrosodi-n-propylamine 2-Cyclohexyl-4,6-dinitrophenol Mirex Dichloromethane Beryllium N-Nitrosodiethanolamine 3,4 Dimethylphenol Molinate Dieldrin beta-BHC N-Nitrosodiethylamine Acephate Molybdenum Epichlorohydrin Bis(2-chloroethyl) ether N-Nitrosodimethylamine Acetaldehyde, trichloro- Naled Formaldehyde Bromoform N-Nitrosomethylethylamine Acetonitrile NuStar Hexachlorocyclohexane Chlorodibromomethane N-Nitrosopyrrolidine Acifluorfen, sodium salt Octabromodiphenyl ether Hexachlorodibenzo p dioxin, mixture (HxCDD) Cyclotrimethylene trinitramine Polychlorinated biphenyls Acrylamide Oxydiazon Hydrazine DDD Vinylidene chloride Alachlor Oxyfluorfen Nickel compounds DDE Aldicarb p-Chloroaniline N-Nitrosodi-n-butylamine DDT Aldicarb sulfone Paraquat dichloride N-Nitrosodiethylamine Di(2-ethylhexyl) phthalate Aldrin Pentabromodiphenyl ether N-Nitrosodimethylamine Dichlorobromomethane Allyl alcohol Pentachlorobenzene N-Nitrosopyrrolidine Dichloromethane Aluminum phosphide Phenylmercuric acetate Nickel subsulfide Dieldrin Ametryn Phosphine Propylene oxide Epichlorohydrin Amitraz Phosphorus Vinylidene chloride Folpet Antimony Pirimiphos methyl Fomesafen Avermectin B1 Prochloraz Furmecyclox Bentazon Prometryn Hexachlorocyclohexane Beryllium Propachlor Hexachlorodibenzo p dioxin, mixture (HxCDD) Bis(tributyltin) oxide Propanil Hydrazine Bromomethane Propargyl alcohol Isophorone Captafol Propiconazole N-Nitrosodi-n-butylamine Carbamothioic acid, dipropyl-, S-propyl ester Quinalphos N-Nitrosodi-n-propylamine Carbofuran Quizalofop-ethyl N-Nitrosodiethanolamine Carbosulfan Rotenone, Commercial N-Nitrosodiethylamine Chlorpyrifos S,S,S-Tributyltrithiophosphate N-Nitrosodimethylamine Copper cyanide Selenious acid N-Nitrosodiphenylamine Cyclotrimethylene trinitramine Simazine N-Nitrosomethylethylamine Cyhalothrin Sodium azide (Na(N3)) N-Nitrosopyrrolidine DDT Sodium fluoroacetate Polychlorinated biphenyls Demeton Strychnine Prochloraz Dicrotophos Sulfotep Propylene oxide Dieldrin Terbacil Vinylidene chloride Dimethoate Terbutryn Dinitrobutyl phenol Tetraethyl lead Diquat Thallium chloride TlCl Disulfoton Thallium(I) acetate Diuron Thallium(I) carbonate Dodine Thallium(I) nitrate Endosulfan Thallium(I) sulfate EPN Thiobencarb Ethion Thiram Fenamiphos Triallate Fluvalinate Tribenuron methyl Fonofos Vanadium pentoxide Furan Vinylidene chloride Furfural Warfarin Glufosinate ammonium Zinc phosphide

4-10.XLSEXHIBIT 4-12 TRI RELEASES AND NON-CONFIDENTIAL TSCA PRODUCTION VOLUME DATA FOR THE KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Chemical CAS Chemical Name 1994 TRI Release Volume > 1 million lbs. 1994 Non-Confidential TSCA Production Volume > 1 million lbs. Known Chemicals 0000071-55-6 1,1,1-Trichloroethane X 0000079-00-5 1,1,2-Trichloroethane X 0000095-63-6 1,2,4-Trimethylbenzene X 0000107-06-2 1,2-Dichloroethane X 0000542-75-6 1,3-Dichloropropylene X 0000075-07-0 Acetaldehyde X 0000075-05-8 Acetonitrile X X 0000079-06-1 Acrylamide X X 0000079-10-7 Acrylic acid X 0000107-13-1 Acrylonitrile X 0007429-90-5 Aluminum (fume or dust) X 0007664-41-7 Ammonia X 0000062-53-3 Aniline X

---- Antimony compounds X 0000071-43-2 Benzene X 0000074-83-9 Bromomethane X CBI 0000075-15-0 Carbon disulfide X 0000056-23-5 Carbon tetrachloride X 0007782-50-5 Chlorine X 0000108-90-7 Chlorobenzene X 0000075-00-3 Chloroethane X 0000067-66-3 Chloroform X X 0000074-87-3 Chloromethane X 0007440-47-3 Chromium X 0007440-50-8 Copper X 0008001-58-9 Creosote X 0001319-77-3 Cresol (mixed isomers) X 0000098-82-8 Cumene X

---- Cyanide compounds X 0000075-71-8 Dichlorodifluoromethane X 0000075-09-2 Dichloromethane X 0000100-41-4 Ethylbenzene X 0000107-21-1 Ethylene glycol X 0000050-00-0 Formaldehyde X 0000064-18-6 Formic acid X

---- Glycol Ethers X 0000067-72-1 Hexachloroethane X 0000074-90-8 Hydrogen cyanide X 0007664-39-3 Hydrogen fluoride X 0007783-06-4 Hydrogen sulfide X 0007439-96-5 Manganese X 0000067-56-1 Methanol X 0000078-93-3 Methyl ethyl ketone X 0000108-10-1 Methyl isobutyl ketone X 0000080-62-6 Methyl methacrylate X 0000071-36-3 n-Butyl alcohol X 0000091-20-3 Naphthalene X

---- Nickel compounds X 0000095-47-6 o-Xylene X 0000106-42-3 p-Xylene X 0000108-95-2 Phenol X 0000100-42-5 Styrene X 0000127-18-4 Tetrachloroethylene X X 0000108-88-3 Toluene X 0000079-01-6 Trichloroethylene X 0000075-69-4 Trichlorofluoromethane X 0000108-05-4 Vinyl acetate X 0000075-01-4 Vinyl chloride X X 0001330-20-7 Xylene (mixed isomers) X 0007440-66-6 Zinc X Possible Chemicals 0000106-99-0 1,3-Butadiene X 0000576-26-1 2,6-Dimethylphenol X 0001332-21-4 Asbestos (friable) X 0010049-04-4 Chlorine dioxide X 0000126-99-8 Chloroprene X 0000121-82-4 Cyclotrimethylene trinitramine X 0000076-13-1 Freon 113 X 0000121-69-7 N,N-Dimethylaniline X 0000075-56-9 Propylene oxide XEXHIBIT 4-13 VOLATILITY, PERSISTENCE, AND BIOACCUMULATION/BIOCONCENTRATION SUMMARY POTENTIAL OF KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS Vapor Pressure > 1.3e-3 atm. Air Half-Life > 75th Percentile Low Soil/Water Degradation Constant (< 0.5) Kow >105 High Fish BAF (>1000) High Fish BCF (>1000) 1,1,1,2-Tetrachloroethane Dichloromethane 1,2-Dichloropropane 2,3,7,8-TCDD 1,2,4,5-Tetrachlorobenzene 2,3,4,6-Tetrachlorophenol 1,1,1-Trichloroethane Polychlorinated biphenyls 2,3,7,8-TCDD 3-Methylcholanthrene alpha-Hexachlorocyclohexane 3-Methylcholanthrene 1,1,2,2-Tetrachloroethane 3-Methylcholanthrene 7,12-Dimethylbenz[a]anthracene beta-BHC Aldrin 1,1,2-Trichloroethane Aldrin Aldrin DDE Butyl benzyl phthalate 1,2,3-Trichloropropane Antimony Benz[a]anthracene DDT Chlorobenzilate 1,2-Dibromoethane Benz[a]anthracene Benzo(a)phenanthrene DDD 1,2-Dichlorobenzene Benzo(a)phenanthrene Benzo[a]pyrene Diallate 1,2-Dichloroethylene, trans Benzo[a]pyrene Benzo[b]fluoranthene Dibutyl phthalate 1,2-Dichloropropane Benzo[b]fluoranthene DDD Dieldrin 1,3-Dichloropropylene Beryllium DDE Diethylstilbestrol 1,4-Dioxane Copper DDT Hexachlorocyclopentadiene 2-Chlorophenol DDD Di(2-ethylhexyl) phthalate Kepone 2-Ethoxyethanol DDE Dibenz[a,h]anthracene Pentachlorobenzene 2-Nitropropane DDT Dieldrin Acetone Dibenz[a,h]anthracene Diethylstilbestrol Acetonitrile Dieldrin Fluoranthene Acrolein Indeno(1,2,3-cd)pyrene Hexachlorocyclopentadiene Acrylonitrile Kepone Indeno(1,2,3-cd)pyrene Allyl chloride Manganese Kepone Benzyl chloride Molybdenum n-Dioctylphthalate Bis(2-chloroethyl) ether Nickel Pentachlorobenzene Bromoform Pyrene Polychlorinated biphenyls Bromomethane Thallium Pyrene Carbon disulfide Vanadium (fume or dust) Chlorodibromomethane Zinc Chloromethane Chloroprene cis-1,2-Dichloroethylene cis-1,3-Dichloropropene Cumene Dichlorobromomethane Dichlorodifluoromethane Dichloromethane EpichlorohydrinEthane, 1,1'-oxybisEthyl acetate Ethyl methacrylate Ethylbenzene Ethylidene Dichloride Formaldehyde Formic acid Freon 113 Furan Isobutyl alcohol Methanol Methyl isobutyl ketone Methyl methacrylate Methylene bromide n-Butyl alcohol N-Nitrosodi-n-propylamine N-Nitrosodiethylamine N-Nitrosodimethylamine N-Nitrosomethylethylamine p-Chloroaniline Styrene Toluene trans-1,3-Dichloropropene Trichlorofluoromethane Vinylidene chloride Xylene (mixed isomers) 4-13.XLSEXHIBIT 4-13 VOLATILITY, PERSISTENCE, AND BIOACCUMULATION/BIOCONCENTRATION SUMMARY POTENTIAL OF KNOWN AND POSSIBLE NON-HAZARDOUS INDUSTRIAL WASTE CONSTITUENTS

Beef Biotransfer Factor > 7.8e-4 1,2,4,5-Tetrachlorobenzene 2,3,7,8-TCDD 3-Methylcholanthrene 7,12-Dimethylbenz[a]anthracene Aldrin Antimony Benz[a]anthracene Benzo(a)phenanthrene Benzo[a]pyrene Benzo[b]fluoranthene Beryllium Butyl benzyl phthalate Copper DDD DDE DDT Di(2-ethylhexyl) phthalate Dibenz[a,h]anthracene Dibutyl phthalate Dieldrin Diethylstilbestrol Fluoranthene Hexachlorocyclopentadiene Indeno(1,2,3-cd)pyrene Kepone Molybdenum n-Dioctylphthalate Nickel Pentachlorobenzene Polychlorinated biphenyls Pyrene Thallium Vanadium (fume or dust)

4-13.XLSEXHIBIT 4-16 LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent Lowest Exit Level for chemicals from HWIR waste models (mg/L) Model 1,1,1,2-Tetrachloroethane 0.0078 Groundwater 1,1,1-Trichloroethane 0.0539 Groundwater 1,1,2,2-Tetrachloroethane 0.0037 Direct inhalation 1,1,2-Trichloroethane 0.0018 Groundwater 1,2,3-Trichloropropane 0.34 Groundwater 1,2,4,5-Tetrachlorobenzene 0.0317 Groundwater 1,2,4-Trichlorobenzene 0.685 Direct inhalation 1,2-Dibromo-3-chloropropane 0.000114 Groundwater 1,2-Dichlorobenzene 6.1 Groundwater 1,2-Dichloropropane 0.0023 Groundwater 1,3,5-Trinitrobenzene 0.003 Groundwater 1,3-Dichloropropylene (1,3-Dichloropropene) 0.00085 Groundwater 1,3-Phenylenediamine 0.3 Groundwater 1,4-Dioxane 0.0136 Groundwater 2,3,4,6-Tetrachlorophenol 0.58 Groundwater 2,3,7,8-TCDD 1.78E-10 Groundwater 2,4,5-T acid 0.64 Groundwater 2,4-Dichlorophenol 0.18 Groundwater 2,4-Dimethylphenol 1.19 Groundwater 2,4-Dinitrophenol 0.105 Groundwater 2,6-Dinitrotoluene 0.064 Groundwater 2-Chlorophenol 0.32 Groundwater 2-Ethoxyethanol 14.7 Direct inhalation 2-Nitropropane 0.00019 Direct inhalation-worker 3,3'-Dimethoxybenzidine 0.0102 Groundwater 3-Methylcholanthrene 1.41E-06 Groundwater 7,12-Dimethylbenz[a]anthracene 2.76E-06 Groundwater Acenaphthene 4.9 Groundwater Acetone 6 Groundwater Acetonitrile 0.3 Groundwater Acetophenone 6.4 Groundwater Acrolein 0.00248 Direct inhalation-worker Acrylamide 0.000038 Groundwater Acrylonitrile 0.00034 Groundwater Aldrin 5.64E-07 Beef/milk ingestion Allyl chloride 0.0742 Direct inhalation alpha-Hexachlorocyclohexane 0.000142 Vegetable/root ingestion Aniline 0.017 Groundwater Antimony 0.053 Groundwater Benz[a]anthracene 4.30E-06 Groundwater Benzidine 6.80E-07 Groundwater Benzo(a)pyrene 7.04E-06 Groundwater Benzo[b]fluoranthene 0.0000661 Groundwater Benzyl alcohol 15 Groundwater Benzyl chloride 1.13 Vegetable/root ingestion Beryllium 0.00032 Groundwater

4-16.txtEXHIBIT 4-16 (CONTINUED - PAGE 2) LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent Lowest Exit Level for chemicals from HWIR waste models (mg/L) Model beta-BHC 0.00021 Groundwater Bis(2-chloroethyl) ether 0.00036 Groundwater Bis(2-chloroisopropyl) ether 0.0019 Groundwater Bromoform 0.018 Groundwater Bromomethane (Methyl bromide) 0.37 Direct inhalation Butyl benzyl phthalate 64 Groundwater Carbon disulfide 0.738 Direct inhalation Chlorobenzilate 0.0057 Groundwater Chlorodibromomethane 0.0018 Groundwater Chloromethane (Methyl chloride) 0.0959 Direct inhalation Chloroprene (Chloro-1,3-butadiene, 2-) 0.515 Direct inhalation cis-1,2-Dichloroethylene 0.64 Groundwater cis-1,3-Dichloropropene 0.00485 Direct inhalation Copper 5.91 Ecological (aquatic plants) DDD 0.000126 Beef/milk ingestion DDE 9.11E-06 Beef/milk ingestion DDT 0.0000181 Beef/milk ingestion Di(2-ethylhexyl) phthalate (BEHP) 0.00044 Beef/milk ingestion Diallate 0.26 Vegetable/root ingestion Dibenz[a,h]anthracene 6.34E-07 Groundwater Dibutyl Phthalate (Di-n-butyl phthalate) 25.2 Groundwater Dichlorodifluoromethane 11.9 Groundwater Dieldrin 0.000059 Beef/milk ingestion Diethyl Phthalate 54 Groundwater Diethylstilbestrol 2.47E-11 Beef/milk ingestion Dimethoate 0.77 Groundwater Dimethyl Phthalate 3 Multimedia model Diphenylamine 2.6 Groundwater Disulfoton 0.0131 Groundwater Endosulfan 0.94 Groundwater Epichlorohydrin 0.335 Direct inhalation-worker Ethyl acetate 114 Groundwater Ethyl methacrylate 6.6 Groundwater Ethylbenzene 8.1 Groundwater Fluoranthene 1.74 Groundwater Fluorene 3.4 Groundwater Formaldehyde 0.0158 Direct inhalation-worker Formic acid 105 Groundwater Glycidylaldehyde 6.2 Groundwater Hexachlorocyclopentadiene 0.00521 Direct inhalation Hexachlorophene 5.15E-06 Beef/milk ingestion Indeno(1,2,3-cd)pyrene 0.0000241 Groundwater Isobutyl alcohol 15 Groundwater Isophorone 0.162 Groundwater Kepone 0.0000264 Beef/milk ingestion

4-16.txtEXHIBIT 4-16 (CONTINUED - PAGE 3) LOWEST PROPOSED EXIT LEVELS FOR CHEMICALS

Constituent Lowest Exit Level for chemicals from HWIR waste models (mg/L) Model m-Dinitrobenzene (1,3-Dinitrobenzene) 0.0064 Groundwater Methanol 30 Groundwater Methyl isobutyl ketone 3 Groundwater Methyl methacrylate 8.1 Groundwater Methyl parathion 0.662 Vegetable/root ingestion Methylene bromide 0.19 Groundwater Molybdenum 1.83 Groundwater n-Dioctyl phthalate 0.002 Beef/milk ingestion N-Nitroso-dimethyl amine 3.40E-06 Groundwater N-Nitrosodi-n-butylamine 0.000036 Groundwater N-Nitrosodi-n-propylamine 0.000017 Groundwater N-Nitrosodiethylamine 3.18E-06 Groundwater N-Nitrosodiphenyl amine 0.046 Groundwater N-Nitrosomethylethylamine 6.80E-06 Groundwater N-Nitrosopyrrolidine 0.000068 Groundwater Naphthalene 2.7 Groundwater Nickel 4.89 Groundwater p-Chloroaniline 0.16 Groundwater Parathion 0.128 Ecological (fish/aquatic organisms) Pentachlorobenzene 0.0543 Groundwater Phenol 32 Groundwater Phenylmercuric acetate 0.0045 Groundwater Phorate 0.106 Vegetable/root ingestion Polychlorinated biphenyls 4.81E-06 Groundwater Pyrene 1.69 Groundwater Safrole 0.00095 Groundwater Strychnine 0.0041 Vegetable/root ingestion Styrene 15.4 Groundwater Thallium 0.0192 Groundwater Toluene 12.6 Groundwater trans-1,2-Dichloroethylene 1.12 Groundwater trans-1,3-Dichloropropene 0.0049 Direct inhalation Trichlorofluoromethane 16 Groundwater Tris(2,3-dibromopropyl) phosphate 0.000099 Groundwater Vanadium (fume or dust) 3.71 Groundwater Xylenes 22.4 Direct inhalation Zinc 38.4 Groundwater
Notes: Bolded chemicals have the lowest exit level in a non-groundwater pathway

4-16.txtPage 5-1



# CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH NATURAL RESOURCE DAMAGES AND LARGE-SCALE

ENVIRONMENTAL PROBLEMS

This chapter discusses risks associated with non-hazardous industrial waste management that are not addressed in Chapters 3 or 4. Chapter 3 examined potential gaps inherent in the current hazardous waste characteristics, thereby focusing on the adverse effects that the characteristics were meant to address, namely risks arising primarily from acute events such as fires, explosions, and acute exposures of waste management and transportation workers, and health risks caused by local environmental contamination near waste management units. Chapter 4 examined potential gaps associated with adverse human health or localized ecological effects from constituents not included in the toxicity characteristic. This chapter addresses a third set of risks associated with non-hazardous industrial waste management.

Section 5.1 addresses the pollution of groundwater by constituents that diminish the value and usability of the resource without threatening human health; Section 5.2 addresses damage from non-hazardous industrial waste management to air quality through odors that harm the quality of life but may not have severe health effects; and Section 5.3 examines possible contributions to regional and global environmental problems from the management of non-hazardous industrial waste, including: air deposition to the Great Waters, damages from airborne particulates, global climate change, potential damage from endocrine disruptors, red tides, stratospheric ozone depletion, tropospheric ozone and photochemical air pollution, and water pollution. These environmental problems may or may not meet the RCRA statutory or regulatory definitions of the types of risks that the hazardous waste management program is meant to address. 5.1 Damage to Groundwater Resources As noted in Chapter 2, the most common and well-documented impact of releases from non-hazardous industrial waste management is groundwater contamination. If contamination is present at high enough concentrations, the use of the groundwater as a water supply for human consumption or other use may result in adverse effects on health. Human health risks associated with exposure to toxic pollutants are not the only concern associated with groundwater contamination, however. Non-toxic pollutants such as iron, chloride, or total dissolved solids may be present in concentrations that damage the aesthetic qualities and usability of the water without posing outright health hazards. In areas where groundwater is used as a drinking water supply, such water pollution must be remediated, limitations must be placed on its use, and/or alternative sources must be found. These actions may be expensive and strain existing water supplies. Where alternative supplies are not economically available, groundwater resources of marginal quality, which do not exceed health-based levels, may continue to be used. Even where the polluted groundwater is not used for drinking water, the value of the resource may decline because it is no longer available for future use as drinking water without remediation. This non-toxic pollution of groundwater from non-hazardous industrial waste management was found relatively often in the environmental release descriptions summarized in Chapter 2. Seventy-five (84 percent) ofPage 5-2



### the 89 release descriptions with data on regulatory levels had constituents detected at levels exceeding nonhealth-based or non-ecologically-based standards, principally on aesthetic or usability criteria developed under the Safe Drinking Water Act as Secondary Maximum Contaminant Levels (SMCLs). Releases at 70 of these 75 sites also exceeded health and/or ecological-based standards. Of the 177 non-TC constituents identified in the release case studies, 9 constituents (plus pH and total dissolved solids) have SMCLs. (Some of these constituents also have health-based or ecologically-based levels.) Exhibit 5-1 lists all constituents with SMCLs and shows how frequently they were found among the 89 case studies where concentration and regulatory standards data were available. The most commonly detected constituents, iron, chloride, and manganese, all have SMCLs. Also, all SMCLs, except those for foaming agents, color, and corrosivity, were violated by at least several documented releases. (See Exhibit 2-6 for additional data on the concentrations at which these constituents were detected.) Exhibit 5-1 Constituents/Properties with SMCLs Found in Release Descriptions
Constituents/Properties Number of Times Detected Number of Times Detected Above SMCL pH 66 24 Iron 54 49 Chloride 52 32 Sulfate 50 29 Total dissolved solids 48 29 Manganese 39 34 Zinc 33 13 Copper 17 2 Aluminum 12 12 Fluorides 12 4 Color 0 0 Corrosivity 0 0 Odor 0 0 Foaming agents 0 0

5.2 Damage to Local Air Quality from Odors Noxious odors historically have been reported in the vicinity of waste management facilities. Odor problems have caused minor health problems, reduced the quality of life, and reduced property values near such facilities. Information on the extent of such problems from non-hazardous industrial waste management is very limited. Odor problems were reported in several of the release descriptions initially identified by EPA, but these cases were excluded because they did not meet the Agency's strict selection criteria. Only one release description included reports by residents of odor problems. Nevertheless, the case study development methodologyPage 5-3



### may have missed many cases of odor problems from non-hazardous industrial waste management facilities because state regulatory programs largely focus on groundwater concerns. Also, odor problems are often handled at the local level and thus the states may not get involved. The potential for odor problems clearly exists at non-hazardous industrial waste facilities that manage certain types of wastes. For example, food processing facilities (e.g., slaughterhouses that must dispose of offal and alimentary contents from slaughtered animals) may have odor problems if their air releases are not carefully managed. In addition to food wastes, potential odor problems may arise from chemical wastes. Exhibit 5- 2 lists a number of the chemicals identified in the release descriptions (although not necessarily for odor) that have extremely low odor thresholds in either air or water. Ten of these chemicals have threshold odor concentrations in air (the lowest concentrations at which odors can be detected or recognized) of 0.01 mg/mor 3 

### less, and six of them can be detected by odor in water solutions at concentrations of 0.006 mg/l or less.

Exhibit 5-2 Chemicals from Release Descriptions with Low Odor Thresholds

Chemical Name Threshold OdorConcentrations i

n Threshold

OdorConcentrations i

n Air Water (mg/m ) (mg/l)

3 

### 1,2,4-Trichlorobenzene

- 0.005 2,4,6-Trichlorophenol 0.001

- 2,4-Dimethylphenol 0.001

- Acetophenone 0.01

- Benzenethiol 0.0005

- beta-BHC

- 0.0003 Chlordane

- 0.0000025 Cresol (mixed isomers) 0.001

- Diphenyl ether 0.01

- Hexachloro-1,3-butadiene

- 0.006 Hexachlorocyclopentadiene

- 0.0016 Hexachloroethane

- 0.001 Methyl mercaptan 0.0002

- Nitrobenzene 0.01

- o-Cresol 0.0003

- p-Cresol 0.004

-
Source: Verscheuren, Karel,Handbook of Environmental Data on Organic Chemicals, Second Edition, 1983


### Because odor problems typically are handled locally and these problems likely do not meet the RCRA definition of risks meant to be addressed by the hazardous waste management program, EPA does not plan to investigate this area further following the Scoping Study.U.S. Environmental Protection Agency, Office of Air QualityPlanning and Standards,Deposition of Air Pollutants to the Great 1 Waters, First Report to Congress, EPA-453/R-93-055, May 1994.

Page 5-4 Exhibit 5-3. Initial List of

Large-Scale Environmental Problems Air deposition to the Great Waters Damages from airborne particulates Global climate change Potential damages from endocrine disruptors Red tides Stratospheric ozone depletion Tropospheric ozone and photochemical air pollution Water pollution 

### 5.3 Large-Scale Environmental Problems EPA considered whether any major large-scale environmental problems (e.g., global climate change, potential damage from endocrine disruptors) might be caused, at least to some extent, by non-hazardous industrial wastes. Depending on the types of wastes and on the relative contributions of these wastes to the problem areas, changes in the hazardous waste characteristics might be one method to help reduce further damages. EPA began this phase of the Scoping Study by developing an initial list of major large-scale environmental problems (or possible problems) that have potential links to non-hazardous industrial wastes (see Exhibit 5-3). Several of these problems overlap considerably with each other and with exposure and other damage pathways discussed previously. Furthermore, EPA recognizes that other environmental problems have potential links to non-hazardous industrial waste; however, given the limited resources available for this Scoping Study, the Agency chose to limit this analysis to some of the more likely areas of concern. Following the development of this list, EPA conducted preliminary evaluations of the problem areas to try to characterize the contributions to the problems from non-hazardous industrial wastes. Because these problems are typically characterized by highly complex interactions of a large number of factors, determining the exact contribution of non-hazardous industrial wastes to each problem is difficult and beyond the scope of this study. Instead, EPA was able to conduct only initial evaluations to identify areas that may have a significant contribution from non-hazardous industrial wastes and thus may warrant further analysis following the Scoping Study. For environmental problems with a possible link to non-hazardous industrial wastes, EPA identified (where possible) the industries and waste streams that could be contributing to the problems and the relevant statutes and programs that are addressing the areas. The environmental problems evaluated for this Scoping Study are discussed below in the order (alphabetical) listed in Exhibit 5-3. 5.3.1 Air Deposition to the Great Waters Pollutants emitted into the atmosphere are transported various distances and can be deposited to aquatic ecosystems far removed from their original sources. Studies show that significant portions)

### often greater than 50 1 

### percent)

### of pollutant loadings to the Great Waters (i.e., Great Lakes, Lake Champlain, Chesapeake Bay, and coastal waters) are from atmospheric deposition. Thus, this pathway is an important factor in the degradation of water quality and the associated adverse health and ecological effects. Because of the mounting concern that air pollution contributes to water pollution, Congress included Section 112(m), Atmospheric Deposition to Great Lakes and Coastal Waters, in the Clean Air Act Amendments of 1990. Both local and distant air emission sources contribute to a pollutant load at a given location. The sources of concern for the Great Waters primarily include industrial activities and processes involvingPage 5-5



### combustion. At present, however, a complete and comprehensive inventory of the locations of particular sources and the amount of individual toxic pollutants that each source emits to the air is lacking. Nevertheless, EPA has identified several known air pollutants of concern for Great Waters. Exhibit 5-4 lists these pollutants and selected U.S. sources. Most pollutants in this exhibit are TC analytes, while a smaller set are chemicals (or chemical groups) of concern discussed in Chapter 4. Thus, these pollutants are likely candidates for further analysis as potential gaps in the hazardous waste characteristics.

Exhibit 5-4. U.S. Sources of Air Pollutants of Concern for Great Watersa

Pollutant Sources of Air Emissions
Cadmium and Fossil fuel combustion; aluminum production; cadmium, copper, lead, and zinc smelting; iron and steel production; battery compounds manufacturing; hazardous waste and sewage sludge incineration; municipal waste combustion; petroleum refining; lime

manufacturing; cement manufacturing; pulp and paper production; combustion of waste oil; pigment manufacturing; soilderived dust; volcanoes
Chlordane Insecticide application;volatilization from soils, water, and treated building foundations due to past insecticide b application; suspension of eroded soil particles
DDT/DDE Insecticide application;volatilization from soils and water due to past insecticide application b
Dieldrin Insecticide application;volatilization from soils and water due to past insecticide application b
Hexachloro- Manufacturing of chlorine and related compounds; combustion of materials containing chlorine; pesticide manufacturing; benzene municipal waste combustion; fungicide application;volatilization from soils and water due to past fungicide application b
-HCH Insecticide application;volatilization from soils and water due to past insecticide application b
Lindane Insecticide application;volatilization from soils and water due to past insecticide application b
Lead and Fossil fuel combustion; aluminum production; lead smelting; ferroalloys production; iron and steel production; battery compounds manufacturing; hazardous waste and sewage sludge incineration; municipal waste combustion; petroleum refining; lime

manufacturing; cement manufacturing; asphalt and concrete manufacturing; pulp and paper production; combustion of waste oil; paint application;motor vehicles;forest fires; suspension of eroded soil particles; volcanoes b b Mercury and Fossil fuel combustion; copper and lead smelting; hazardous waste; municipal waste, medical waste, and sewage sludge compounds incineration; lime manufacturing; cement manufacturing; chlorine and caustic soda manufacturing; paint application;b

suspension of eroded soil particles; erosion from soils and water; volcanoes
PCBs Incineration and improper disposal of PCB-contaminated waste; disposal of waste oil; malfunction of PCB-containing

transformers and capacitors; electrical equipment manufacturing; pulp and paper production; volatilization from soils and water; municipal solid waste incineration and unregulated combustion Polycyclic Combustion of plant and animal biomass and fossil fuels; municipal waste combustion; petroleum refining; steel production; organic matter coke by-product recovery; aluminum production; plywood and particle board manufacturing; surface coating of auto and light

duty trucks; asphalt processing; dry cleaning (petroleum solvent); fabric printing, coating, and dyeing; forest firesU.S. Environmental ProtectionAgency, Office of Research and Development,Strategic Plan for the Office of Research and 2 Development, ORD, EPA/600/R-96/059, May 1996.
Page 5-6



### Exhibit 5-4. U.S. Sources of Air Pollutants of Concern for Great Watersa 

### (continued)

Pollutant Sources of Air Emissions 2,3,7,8-TCDF Hazardous, industrial, municipal, and medical waste and sewage sludge incineration; combustion of fossil fuels and organic

materials containing chlorine; by-product of various metals recovery processes, such as copper smelting; accidental fires of treated wood products and PCB-containing transformers and capacitors; improper disposal of certain chlorinated wastes; pesticide production, application, and spills; pulp and paper production; volatilization and erosion of dust from landfill sites; forest fires 2,3,7,8-TCDD Hazardous, industrial, and medical waste and sewage sludge incineration; municipal waste combustion; combustion of fossil

fuels and organic materials containing chlorine; by-product of various metals recovery processes, such as copper smelting; accidental fires of treated wood products and PCB-containing transformers and capacitors; improper disposal of certain chlorinated wastes; pesticide production, application, and spills; pulp and paper production; volatilization and erosion of dust from landfill sites; forest fires Toxaphene Insecticide application;volatilization from soils and water due to past insecticide application b Nitrogen Fossil fuel and other types of combustion; motor vehicles; fertilizer application; animal waste compounds

From Table 9 of U.S. EPA,Deposition of Air Pollutants to the Great Waters,suprafootnote 1. aNot currently a significant source in the U.S. due to manufacturing or use restrictions. b



### 5.3.2 Airborne Particulates Airborne particulate matter (PM) is one of the six high-priority research topics identified for the next few years by the EPA Office of Research and Development (ORD). PM includes dust, dirt, soot, smoke, and liquid 2 

### droplets directly emitted into the air by sources such as factories, power plants, transportation sources, construction activity, fires, and windblown dust. Concern regarding PM from non-hazardous industrial waste includes toxic constituents entrained on particulates. PM is also formed in the atmosphere by condensation or transformation of emitted gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds into small droplets. Based on studies of human populations exposed to high concentrations of particles (often in the presence of sulfur dioxide) and on laboratory studies of animals and humans, the major concerns for human health include effects on breathing and respiratory symptoms, aggravation of existing respiratory and cardiovascular disease, alterations in the body's defense systems against foreign materials, damage to lung tissue, carcinogenesis, and premature death. The major subgroups of the populations that appear likely to be most sensitive to the effects of particulate matter include individuals with chronic obstructive pulmonary cardiovascular disease, individuals with influenza, asthmatics, the elderly, and children. Particulate matter may injure crops, trees and shrubs, and may damage metal surfaces, fabrics, and other materials. Fine particulates also impair visibility by scattering light and reducing visibility. The haze caused by fine particles can diminish crop yields by reducing sunlight. PM is increasingly being identified as posing a high potential for health and environmental risk and other potential damages. Nevertheless, EPA does not believe that PM is a significant waste characterization issue but rather a waste management issue. Furthermore, other programs (e.g., CAA National Ambient Air Quality Standards)U.S. Environmental Protection Agency, Office of Policy, Planning, and Evaluation,Environmental Goals for America,with 3 Milestones for 2005 (Draft for Federal Review), June 1996. Intergovernmental Panel on Climate Change (IPCC),Climate Change 1995: The Science of Climate Change, Second Assessment Report, 4 Cambridge University Press, 1996. IPCC, WGI Technical Support Unit,IPCC Guidelines for National Greenhouse Gas Inventories: Reporting Instructions, Bracknell, 5 U.K., 1995.

Page 5-7 

### are designed to address this area. Therefore, airborne particulates are not planned for further study as a potential gap. 5.3.3 Global Climate Change Evidence is mounting that the increasing concentrations of greenhouse gases (GHGs) will ultimately raise (and some believe are currently raising) atmospheric and ocean temperatures significantly, which may in turn alter global weather patterns. Global climate already has changed over the past century, and the balance of evidence 3 

### suggests a discernible human influence. Climate is expected to continue to change in the future. 4 

### EPA conducted a brief review of the major anthropogenic sources of the two predominant GHGs, carbon dioxide (CO ) and methane (CH ), to determine the relative contributions of non-hazardous industrial wastes,

2 4 

### including their co-disposal with municipal solid waste (MSW). Before describing the results of this review, it is essential to understand some of the international conventions used to evaluate GHG emissions, as these conventions have a strong bearing on the results. The United States and all other parties to the Framework Convention on Climate Change agreed to develop inventories of GHGs for purposes of developing mitigation strategies and monitoring the progress of those strategies. The Intergovernmental Panel on Climate Change (IPCC) developed a set of inventory methods to be used as the international standard. The screening methodology used in this section to evaluate emissions and sinks of 5 

### GHGs attempts to be consistent with IPCC's guidance. One of the elements of the IPCC guidance that deserves special mention is the approach used to address CO2 

### emissions from biogenic sources. For many countries, the treatment of COreleases from biogenic sources is most 2 

### important when addressing releases from energy derived from biomass (e.g., burning wood), but this element is also important when evaluating waste management emissions (for example, the decomposition or combustion of grass clippings or paper). The carbon in paper and grass trimmings was originally removed from the atmosphere by photosynthesis, and under natural conditions, it would eventually cycle back to the atmosphere as COdue to 2 

### degradation processes. The quantity of carbon that these natural processes cycle through the earth's atmosphere, waters, soils, and biota is much greater than the quantity added by anthropogenic GHG sources. But the focus of the Framework Convention on Climate Change is on anthropogenic emissions emissions resulting from human activities and subject to human control because these emissions have the potential to alter the climate by disrupting the natural balances in carbon's biogeochemical cycle. Thus, for processes with COemissions, if the emissions are from biogenic materials and the materials are 2 

### grown on a sustainable basis, then those emissions are considered to simply close the loop in the natural carbon cycle; that is, they return COto the atmosphere that was originally removed by photosynthesis. In such cases, the 2 

### CO emissionsare not

counted (and thus most COemissions from landfills are not counted). On the other hand, CO 2 2 2 

### emissions from burning fossil fuelsarecounted because these emissions would not enter the cycle were it not for human activity. Likewise, CHemissions from landfillsarecounted, even though the source of carbon is primarily 4Because CHhas a higher global warming potential than CO , CH 's incremental global warming potential is counted. 6 4 2 4 U.S. Environmental Protection Agency, Office of Policy Planning and Evaluation,Inventory of U.S. Greenhouse Gas Emissions an d 7 Sinks: 1990-1994, EPA 230-R-96-006, November 1995.
Ibid. 8
Ibid. 9
61Federal Register

9905, March 12, 1996. 10

Page 5-8 

### biogenic. CHwould not be emitted but for the human activity of landfilling the waste, which creates anaerobic

4 

### conditions conducive to CHformation. This approach does not distinguish between the timing of COemissions, 4 2

6 

### provided that they occur in a reasonably short time scale relative to the speed of the processes that affect global climate change. That is, as long as the biogenic carbon would eventually be released as CO , it does not matter 2 

### whether it is released virtually instantaneously (e.g., from combustion) or over a period of a few decades (e.g., decomposition on the forest floor).
CO accounts for the largest share of U.S. GHG emissions, comprising 1,408 million metric tons of carbon 2 

### equivalent (MMTCE) out of total 1994 U.S. emissions of 1,666 MMTCE. Combustion of fossil fuels results in the vast 7 

### majority of the COemissions (1,390 MMTCE), with the remainder from industrial processes such as cement 2 

### production, lime production, limestone consumption (e.g., iron and steel production), soda ash production and use, and COmanufacture. COemitted from landfills as a product of both aerobic and anaerobic decomposition of

2 2 

### organic wastes is not counted, as described above. Methane is the second most important GHG; U.S. emissions in 1994 were 166 MMTCE. Of the anthropogenic CH 8 

### sources, the largest is landfills (which contribute 36 percent of the total U.S. methane emissions), agricultural activities (32 percent), coal mining (15 percent), production and processing of natural gas and oil (11 percent), fossil fuel combustion (3 percent), and wastewater treatment (0.6 percent). As explained above, CHfrom 9 4 

### landfillsiscounted as an anthropogenic GHG. The majority of landfill CHemissions result from MSW landfills (90 to 95 percent), with the remaining 4 

### methane emitted from the disposal of industrial wastes. Methane emissions from large MSW landfills, however, are currently regulated under EPA's recent New Source Performance Standards and Emissions Guidelines, which require 10 

### collection and control of landfill gas. Small MSW landfills and industrial waste monofills are not subject to these new regulations and thus may warrant further investigation. This is particularly true for small landfills or monofills managing non-hazardous industrial wastes that have a high biochemical oxygen demand (such as wastes from paper mills and food processing), which have a high potential for generating CH

. 4 

### In conclusion, non-hazardous industrial wastes may contribute to GHG emissions to the extent that they are highly degradable and either are disposed in small landfills (which are not subject to the landfill gas rule) or are released directly to the atmosphere. The emissions attributable to these wastes are small compared to other sources of GHGs. Nevertheless, the same highly putrescible wastes that would be of concern when disposed in a landfill environment are likely to cause taste and odor problems that adversely affect local air and water quality. To a large degree, the climate change risk (and much of the potential groundwater resource damage) could be readily averted for highly putrescible wastes by biological pretreatment prior to land disposal to reduce the potential for (a) methane formation and (b) production of odiferous compounds generated in an anaerobic environment. Further research could be conducted in this area to determine whether the potential contribution ofSeveral other terms are and have been used, such as persistent organic pollutants, which actually are a subset of PBTs. 11 U.S. Environmental Protection Agency, Office of Solid Waste, "The Waste Minimization National Plan," EPA530-R-94-045, 1994

. 12Center for the Study of Environmental Endocrine Effects,Environmental Endocrine Effects:An Overview of the State of 13 Scientific Knowledge and Uncertainties, Discussion Draft (firstreleased for public comment at the Sept. 22, 1995 public meeting of the Science Advisory Board of the U.S.-Canada International Joint Commission),Washington, DC (also available on the World Wide Web at http://www.endocrine.org). Arnold, SF, Klotz, DM, Collins, BM, Vonier, PM, Guillette Jr., LJ, and McLachlan, JA, "Synergistic Activation of Estrogen 14 Receptor with Combinations of Environmental Chemicals,"Science, 272 (5267):1489,June 7, 1996; and Suplee, C, "`Environmenta l Estrogens' May Pose Greater Risk, Study Shows," The Washington Post, p. A4, June 7, 1996. Strategic Plan for the Office of Research and Development,suprafootnote 2. 15

Page 5-9 

### non-hazardous industrial wastes to GHG emissions could be significant. However, given the current coverage of this problem area by other programs besides Subtitle C of RCRA, EPA does not plan to pursue global climate change within the context of the hazardous characteristics at this time. 5.3.4 Potential Damages from Endocrine Disruptors Over the past decade, increased attention has been given to a class of chemicals with high persistence, bioaccummulation potential, and toxicity. These chemicals, often referred to as PBTs, include a wide range of 11 

### substances, generally several metals and a variety of organic compounds. EPA's involvement in PBT research and regulation has encompassed many programs. One of these programs, waste minimization, developed the Waste Minimization National Plan. This plan established a national goal to reduce the most persistent, 12 

### bioaccumulative, and toxic chemicals in hazardous wastes by 25 percent by the year 2000 and by 50 percent by the year 2005. Currently many international organizations, including the North American Commission for Environmental Cooperation and various United Nations groups, are debating PBT public policy and ultimately could generate binding commitments (e.g., treaties) that could affect U.S. national policy on PBTs. For example, an initial list of 12 PBTs is being considered for control under an international protocol. Recently, interest in PBTs has escalated due to the growing attention on a subgroup of these chemicals called "endocrine disruptors" (EDs). EDs are substances that have the potential to interfere with hormonal systems in ecological and human receptors. The results of such interference might include adverse reproductive or developmental effects, certain kinds of cancers, learning and behavioral problems, and immune system deficiencies. Recent concern has focused on the potential synergistic effects of EDs.

13 14 

### Significant scientific debate still exists regarding which chemicals are EDs and the degree to which EDs have caused or have the potential to cause adverse human health and environmental effects. This debate has prompted great interest in researching the scope of ED impacts. For example, the study of EDs is one of the six high-priority research topics identified by EPA's Office of Research and Development (ORD) for the next few years. It has also been made a high priority by the U.S. chemical industry; the Chemical Industry Institute for 15 

### Toxicology (CIIT) has reprogrammed much of its research budget into this area. To the extent that the impact of EDs on the environment are largely unknown, these chemicals may represent a substantial gap in the hazardous waste regulations.Colborn, T., vom Saal, F.S.,and Soto, A.M., "Developmental Effects of Endocrine-Disrupting Chemicals in Wildlife and Humans," 16 Environmental Health Perspectives, 101(5):378-384, 1993; Guillette, L.J., Crain, D.A., Rooney, A.A., and Pickford, D.B., "Organization

Versus Activation: The Role of Endocrine-Disrupting Contaminants (EDCs) During Embryonic Developmentin Wildlife," Environmental Health Perspectives, 103(Supp 7):157-164, 1995. Guillette, L.J., Gross, T.S., Masson, G.R., Matter, J.M., Percival, H.F., and Woodward, A.R, "Developmental Abnormalities of 17 the Gonad and Abnormal Sex Hormone Concentrations in Juvenile Alligators FromContaminated and Control Lakes in Florida," Environmental Health Perspectives, 102(8):680-688, 1994. Fox, G.A., "Epidemiological and Pathobiological Evidence of Contaminant-Induced Alterations inSexual Development in Free

18 Living Wildlife," in Colborn, T., and Clement, C. (eds.),Chemically-Induced Alterations in Sexualand Functional Development: The Wildlife/Human Connection, Princeton Scientific Publishing, Princeton, NJ, pp. 147-158, 1992. Fry, D.M., "Reproductive Effects in Birds Exposed to Pesticides and Industrial Chemicals,"Environmental Health Perspectives, 19 103(Supp 7):165-171, 1995. Sumpter, J.P., and Jobling, S., "Vitellogenesis as a Biomarker For Estrogenic Contamination of the Aquat ic Environment," 20 Environmental Health Perspectives, 103(Supp 7):173-178, 1995.
Ibid

. 21

Page 5-10 

### Notwithstanding the current debate, recent review articles summarize convincing evidence that a variety of chemical pollutants can act as endocrine disruptors in wildlife populations. Some specific examples include 16 

### the following: Reptiles.Researchers found that the reproductive development of alligators from Lake

Apopka, Florida was severely impaired, apparently due to DDE, a metabolite of DDT and dicofol. The lake is located adjacent to an EPA Superfund site where a dicofol spill

17 

### had occurred. The specific adverse effects included decreased testosterone and abnormal testicular cells in males and increased estrogen and altered ovaries (increased polyovular follicles and polynuclear oocytes) in females. Birds.A number of researchers have documented severely impaired reproductive success in herring gulls from the Great Lakes. Some specific observations include large clutch 18 

### sizes (attributed to nest sharing by two females), female-female pair bonds, embryonic and chick mortality, and altered nest defense and incubation behavior. These effects were associated with high levels of organochlorines (e.g., DDT, dioxins, and mirex) in the 1960s and early 1970s. Reproductive success increased as levels of these compounds declined in the late 1970s and 1980s. Organochlorines that have been identified as estrogenic to bird embryos in laboratory studies include DDT and methoxychlor.19 

### In these cases, some of the causative agents appear to be organochlorine pesticides that are no longer produced (e.g., DDT) yet persist in the environment due to the nature of their chemical/physical properties. Although these chemicals are not generally expected to be components of non-hazardous industrial wastes, a number of similar chemicals currently used in industry have demonstrated similar endocrine disrupting properties in laboratory studies. These EDs are often present in treated sewage effluent, and are likely to be components of 20 

### non-hazardous industrial waste. A recent field study found that effluent from sewage treatment works induced vitellogenin synthesis in male fish, indicating that the effluent is estrogenic. The effects were pronounced and occurred at all sites 21Arnold, S.F., et al.,suprafootnote 14. 22 Munkittirck, K.R., Portt, C.B., Van Der Krakk, G.J., Smith, I.R., and Rokosh, D.A., "Impact of Bleached Kraft Mill Effluent on 23 Population Characteristics, Liver MFO Activity, and Serum SteroidLevels of A Lake Superior White Sucker (Catostomus Commersoni ) Population,Can. J. Fish. Aquat. Sci., 48:1371-1380, 1991. Davis, W.P., and Bortone, S.A., "Effects of KraftMill Effluent on the Sexuality of Fishes: An Environmental Early Warning?" 24 in Colborn, T., and Clement, C. (Eds.),Chemically-Induced Alterations in Sexualand Functional Development: The Wildlife/Huma n Connection, Princeton Scientific Publishing, Princeton, N.J., pp. 113-127, 1992.

Page 5-11 

### tested. The identity of the chemical or chemicals in the sewage effluent causing the effects is not known, however. A number of chemicals known to be present in sewage effluent were tested for estrogenic effects in fish. These chemicals included nonylphenol, octylphenol, bisphenol-A, DDT, and PCBs. Furthermore, a mixture of different estrogenic chemicals was found to be considerably more potent than each of the chemicals when tested individually, a finding that recently was replicated.22 

### In addition to the effects described above, other documented endocrine disrupting effects in wildlife populations from industrial effluents have unknown causative agents. For example, kraft mill effluent caused a variety of effects in two fish species: white suckers and mosquitofish. Lake Superior white suckers collected 23 

### from a site receiving primary-treated bleached kraft mill effluent exhibited increased age to maturity, smaller gonads, lower fecundity with age, and an absence of secondary sex characteristics. Masculinization of female mosquitofish was noted downstream from the discharge of kraft mill effluent in Elevenmile Creek in Florida.24 

### Several of the chemicals identified in this section are also identified in Chapter 4 as known or possible non-hazardous industrial waste constituents. Some of the relevant chemical groups are described in more detail below. Alkylphenol Compounds.Alkylphenol-polyethoxylates are non-ionic surfactants commonly

used in industrial and domestic detergents as well as some shampoos and cosmetics.Alkylphenols are used as antioxidants in some clear plastics. Alkylphenolpolyethoxylates are biodegraded to alkylphenols during sewage treatment. These compounds persist in rivers and their sediments and can migrate to groundwater. These compounds also have the ability to bioconcentrate in animals. Bisphenol-A.This compound is used to manufacture polycarbonate, a component in a wide array of plastics and other polymer products. Bisphenol-A also is used to manufacture epoxy resins, which are components of a variety of lacquers and adhesives.
Phthalates.Phthalates are one of the most abundant man-made chemicals in the environment. Phthalate esters are used in the production of various plastics. Butylbenzyl phthalate (BBP) also is used in the production of vinyl floor tiles, adhesives, and synthetic leather. Di-n-butylphthalate (DBP) is a common plasticizer in food-packaging materials and polyvinyl chloride. Thousands of tons of plastics are disposed of annually in landfills, thus possibly enabling phthalate esters to migrate into soil and groundwater. These compounds have the ability to bioconcentrate in animals. As seen in Chapter 4, other categories of chemicals with ED characteristics (e.g., heavy metals) are present in wastes generated by numerous industries.Page 5-12 

### In conclusion, the evidence that alkylphenols, bisphenol-A, and phthalates are endocrine disruptors is based mainly on laboratory studies. The effects of these chemicals on wildlife populations is not known. Based on the endocrine disrupting effects of organochlorines on populations of fish, birds, reptiles, and mammals, however, it is possible that alkylphenols, bisphenol-A, phthalates, and other chemicals also could have endocrine disrupting effects in wildlife. Furthermore, as seen in Chapter 4, it is likely that some of these chemicals (e.g., the phthalates) are also components of several non-hazardous industrial wastes.Broad, W.J., "A Spate ofRed Tides Menaces Coastal Seas," The New York Times, August 27, 1996; and Lewitus, A.J., R.V. Jesien, 25 T.M.Kana, J.M.Burkholder, H.B., Jr., Glasgow, E. May, "Discovery of the Phantom Dinoflagellate in Chesapeake Bay," Estuaries 18(2):373-378, 1995. Ikeda, T., T. Matsumoto, H. Kisa, Y.Ishida, A. Kawai, "Analysis of Growth Limiting Factors Causative of Freshwater Red Tid e 26 by Dinoflagellate Peridinum Bipes F. Occultatum,"Jap.-J.-Limnol.-Rikusuizatsu, 54(3): 179-189,1993; Jiang, G., "The Preliminar y Study on The Eutrophication and theRed Tide in the South Coastal Area of Zhejiang,Donghai-Mar.-Sci.-Donghai-Haiyang, 11(2): 55-6, 1993; Okaichi, T., S. Montani, A. Hasui, "The Role of Iron in the Outbreaks of Chattonella Red Tide," Red Tides: Biology, Environmental

Science, and Toxicology, Proceedings of the First International Symposium on Red Tides, heldin November 10-14, 1987, in Takamatsu, Kagawa-Prefecture, Japan, p. 353-356; and "Thousands of Gulf Fish Die; Red TideIs Probable Cause," The New York Times, September 1996. Skojoldal, H.R., "Eutrophication and Algal Growth in the North Sea,"Mar. Environ. Cent., Mar. Res.,Bergen-Nordnes, Norway, 27 p. 445-478, undated. Wu, R.S.S.,"The Environmental Impact of Marine Fish Culture: Towards a Sustainable Future," International Conference on Marin e 28 Pollution and Ecotoxicology, held in Hong Kong, Jan. 22-26, 1995, Vol. 31, no. 4-12, p. 159-166; and Broad,suprafootnote 25. Personal communications with Tony Amos, University of Texas Marine ScienceInstitute, Port Aransas, Texas, and Daniel Baden, 29 School of Marine and Atmospheric Science, Miami, Florida, on October 22, 1996. Personal communication with Scott Rippey, U.S. Food and Drug Administration, October 21, 1996. 30

Page 5-13 

### 5.3.5 Red Tides Red tides are rapid increases in growth (i.e., blooms) of freshwater and marine plants called dinoflagellates, which typically are microscopic unicellular organisms that photosynthesize but also have tails for movement. A red tide occurs when dinoflagellates multiply rapidly due to optimal growth conditions such as abundant dissolved nutrients and sunlight. They produce toxins to defend themselves from zooplankton and other aquatic grazers. The term red tides includes orange, brown, red, and even green blooms. Shellfish, such as clams, mussels, oysters, or scallops, consume dinoflagellates and can accumulate the toxins in their flesh. Usually, the shellfish are not severely affected, but they can contain enough toxins to sicken and even kill humans. The recently discoveredPfiesteria piscidais one of many species of dinoflagellate that causes red tides. It produces potent toxins that cause bleeding sores in fish and can adversely affect humans via air releases. It recently has caused massive fish kills in the Neuse and Pamlico Rivers in North Carolina.25 

### Several case studies have shown the relationship between the levels of nutrients, such as phosphorus, nitrogen, silicon, and iron, in coastal and fresh waters, and the proliferation of red tides. Studies also have 26 

### shown that the high levels of nutrients and eutrophication of the water (which favors the development of red tides) are often caused by surrounding human development and industrial and domestic wastewaters. Recent development 27 

### of agribusiness and factory farms in coastal areas releases wastes with high levels of nutrients into the water that may favor red tides.28 

### Some researchers believe that the occurrence of red tides has been increasing over the years, although improvements in the monitoring and reporting of red tides could account for this. Even if such an increase were 29 

### occurring, however, a commensurate increase in human poisoning from ingestion of shellfish contaminated with dinoflagellate toxins has not been seen, likely because of the improved monitoring and reporting of red tides.30

### Notwithstanding the potential link between red tides and constituents that are often found in nonhazardous industrial waste, little if any evidence has been found during this review concerning the degree toEnvironmental Goals for America, with Milestones for 2005 (Draft for Federal Review),suprafootnote 3. 31 The majorityof these documents were developed to support the first key substitutes rulemaking (59Federal Register 13044, March 32 18, 1994).

Page 5-14 

### which these wastes may be contributing to the problem. Therefore, for the purposes of this hazardous waste characteristic gaps study, EPA does not plan to conduct further research in this area at this time. 5.3.6 Stratospheric Ozone DepletionThe stratospheric ozone layer protects living organisms from damaging solar ultraviolet radiation (UVB). Depletion of the ozone layer means a greater amount of UV-B radiation is reaching the earth's surface, which increases human skin cancers and cataracts, impairs human immune systems, reduces crop yields, and damages plant and animal life. Several industrial chemicals, including chlorofluorcarbons (CFCs), halons, carbon 31 

### tetrachloride, methyl chloroform, and methyl bromide, are known to be stratospheric ozone-depleting substances (ODSs).For many years, ODSs have been used in a variety of manufacturing and other activities. With the ratification of the Montreal Protocol and its subsequent amendments and adjustments, the United States agreed to eliminate the production of ODSs by January 1, 1996 (with a few exceptions). In addition, the disposal of ODSs is tightly controlled in order to prevent further ozone depletion. Thus, EPA believes that, for purposes of the hazardous waste characteristic gaps analysis, ozone-depleting and non-ozone-depleting risks (e.g., via inhalation during combustion or from groundwater during land disposal of residuals) do not need to be examined further at this time. In a related area (though not necessarily a large-scale environmental problem), the ultimate elimination of ODSs has spurred the development of a large number of alternative chemicals and technologies to replace ODSs. In the United States, the Significant New Alternatives Policy (SNAP) Program was put in place by EPA to ensure that alternatives implemented to replace ODSs are not themselves environmentally harmful or unsafe for workers and others who might be exposed to the new chemicals. As part of this program, EPA has developed a series of SNAP Technical Background Documents to address the ODS substitutes. Before a new alternative is developed and 32 

### introduced into interstate commerce, EPA must review the alternative and categorize it as acceptable, acceptable with limitations, or unacceptable, based on a risk screen of the alternative's characteristics. This risk screen addresses global atmospheric effects of the alternative, as well as worker, consumer, and general population exposure. Thus, groundwater damage and other more local adverse effects of the alternative from solid waste generation and management are included in this screening process. Therefore, EPA does not intend to conduct further investigations into the solid waste and hazardous characteristics implications of the SNAP-approved alternatives at this time.U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards,National Air Quality and Emission Trends 33 Report, 1991, EPA 454/R-95-014, October 1995. U.S. Environmental Protection Agency, Office of Water,National Water Quality Inventory Report to Congress, 1994. 34In excess, nutrients can create a chain of impacts that include algal blooms, fish kills, foul odors, and weed growth. 35

Page 5-15 

### 5.3.7 Tropospheric Ozone and Photochemical Air Pollution Photochemical reactions between organic chemicals, nitrogen oxides, and other oxidizing agents can produce ozone and photochemical oxidant pollution. Such pollution occurs in areas where sunlight is intense, emissions of nitrogen oxides and volatile organic compounds (VOCs) are high, and atmospheric conditions impede regional air circulation. Some chemicals emitted from non-hazardous industrial waste management units could contribute to the total emissions of volatile organics in some locations. As shown in Exhibit 4-2, many potentially reactive VOCs have been found as constituents of non-hazardous industrial wastes. This contribution, however, appears to be quite small. Recent emissions studies have shown that, in most municipal areas where 33 

### photochemical pollution is a problem, mobile and utility sources contribute the largest single portion of these emissions, with emissions from other sources generally contributing a smaller amounts. Thus, the Agency did not pursue this issue further as a potential gap in the hazardous waste characteristics. 5.3.8 Water Pollution Based on information reported to EPA by States, Tribes, and other jurisdictions with water quality responsibilities, about 40 percent of the Nation's surveyed rivers, lakes, and estuaries are not clean enough for basic uses such as fishing or swimming. Polluted runoff from rainstorms and snowmelt is the leading cause of this 34 

### impairment. As seen below, the causes of this damage are highly varied.

Rivers.Runoff from agricultural lands is the largest source of pollution for rivers. Municipal sewage treatment plants, storm sewers/urban runoff, and resource extraction also are among the leading sources. Bacteria, which can cause illnesses in swimmers and others involved in water-contact sports, are the most common pollutants impacting rivers. Siltation, nutrients (such as phosphates and nitrates), oxygen-depleting 35 

### substances, and metals are the other leading causes of river pollution.
Lakes.As with rivers, runoff from agricultural lands is the largest source of pollution. Municipal sewage treatment plants, storm sewers/urban runoff, and unspecified nonpoint sources also lead the list. Leading causes of lake pollution are nutrients, siltation, oxygen-depleting substances, metals, and suspended solids. Estuaries.Storm sewers and urban runoff are the leading sources of pollution in estuaries. Municipal sewage treatment plants, agriculture, industrial point sources, and petroleum activities also lead the list. Nutrients, such as phosphates and nitrates, are the most often reported pollutant in estuaries. Other leading causes of pollution are bacteria, oxygen-depleting substances, and oil and grease. Although non-hazardous industrial wastes contribute to this pollution to some degree (e.g., via sewage treatment and industrial point and non-point sources), it is unclear whether this contribution constitutes an actual gap in the hazardous waste characteristics. For example, significant changes in EPA's definition of solid waste would be needed before the hazardous waste characteristics could be used to prevent some of these wastes from40 CFR 261.4(a)(2). This exemption applies only to the actual point source discharge. It does not exclude industrial wastewate r 36 while they are being collected, stored, or treated before discharge; nor does it exclude sludges generated by industrial wastewat er treatment. 40 CFR 261.4(b). This exemption applies to wastes that are returned to the soil as fertilizers, such as animal manures and the 37 unused portion of crops. Some of these controls currently are being implemented. For example, a recentfinal National Pollutant Discharge Elimination 38 System(NPDES) storm water multi-sector general permit was published for industrial activities (60Federal Register 50803, Septembe

r 29, 1995).
Page 5-16 

### entering surface waters and resulting in risks or damage. Industrial wastewaters that are point source discharges subject to regulation under the Clean Water Act are exempt from the definition of solid waste. Many of the wastes 36 

### from agriculture one of the largest contributers to water pollution from runoff are exempt from the definition of hazardous waste (although they are solid wastes). Alternatively, EPA could increase controls on point and 37 

### non-point sources of water pollution via other programs. Thus, for purposes of the hazardous characteristic 38 

### scoping study, EPA does not plan to research this area further at this time.Page 5-17



### CHAPTER 5. POTENTIAL GAPS ASSOCIATED WITH NATURAL RESOURCE DAMAGES AND LARGE-SCALE

ENVIRONMENTAL PROBLEMS

.......................................... 5-1
5.1 Damage to Groundwater Resources

.......................................... 5-1
5.2 Damage to Local Air Quality from Odors

..................................... 5-2
5.3 Large-Scale Environmental Problems

........................................ 5-4
5.3.1 Air Deposition to the Great Waters

................................... 5-4 5.3.2 Airborne Particulates

.............................................. 5-6 5.3.3 Global Climate Change

............................................. 5-7 5.3.4 Potential Damages from Endocrine Disruptors

.......................... 5-9 5.3.5 Red Tides

...................................................... 5-13 5.3.6 Stratospheric Ozone Depletion

...................................... 5-14 5.3.7 Tropospheric Ozone and Photochemical Air Pollution

................... 5-15 5.3.8 Water Pollution

.................................................. 5-15Page 5-18



### Exhibit 5-1 Constituents/Properties with SMCLs Found in Release Descriptions

............... 5-2
Exhibit 5-2 Chemicals from Release Descriptions with Low Odor Thresholds

.................. 5-3
Exhibit 5-3 Initial List of Large-Scale Environmental Problems

............................. 5-4
Exhibit 5-4 U.S. Sources of Air Pollutants of Concern for Great Waters

...................... 5-5U.S. Environmental Protection Agency, Office of Solid Waste,Identifying Higher-Risk Wastestreams in the Industrial D 1 Universe: The State Experience, draft prepared by Science Applications International Corporation and Kerr & Associates, Inc., July 30, 1993.
Page 6-1 

# CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY

CHARACTERISTIC AND LISTINGS

States may adopt hazardous waste regulations that are broader or more stringent than federal RCRA Subtitle C regulations. A number of states have done so by regulating additional wastes as hazardous. For example, states have:

Expanded the ignitability, corrosivity, or reactivity (ICR) characteristics; Expanded the toxicity characteristic (TC); Listed wastes as hazardous that are not hazardous under the federal rules; and Restricted exemptions from the federal program. These expansions beyond the federal hazardous waste identification rules reflect state judgments about gaps in the federal program and thereby constitute potential gaps that may merit further investigation. EPA has identified examples of such expansions by using readily available information on state hazardous waste identification rules. In 1992, the EPA Office of Solid Waste examined state hazardous and non-hazardous industrial waste programs in 32 states. The study identified "state only" hazardous wastes, as well as high-risk 1 

### designations for non-hazardous wastes. For the purposes of this Scoping Study, EPA used data from this report and briefly reviewed current hazardous waste regulations of eight states: California, Michigan, New Hampshire, Oregon, Rhode Island, Texas, Washington, and New Jersey. The first three sections of this chapter address state expansion of the TC, state only hazardous waste listings, and state restrictions on exemptions from the federal regulations, respectively. (State expansions of the ICR characteristics are addressed in Chapter 3.) In addition, Section 6.4 summarizes the findings of the chapter. 6.1 State Expanded Toxicity Characteristics States have expanded the federal toxicity characteristic by: Adding constituents to the list of TC analytes; Establishing regulatory levels for TC analytes that are more stringent than federal levels; Specifying alternative tests for identifying toxic hazardous waste; and Using alternative approaches (other than listing constituents and regulatory levels) to identify toxic hazardous wastes.New Jersey had also added a TC regulatory level for PCBs, but the State recently adopted the federal regulations by reference 2 and will now use the same characteristics and listings as the federal program. A number of states have added PCB wastes to their hazardous waste listings. Identifying Higher-Risk Wastestreams in the Industrial D Universe: The State Experience,suprafootnote 1 at pages 20A-B. 3
Ibid., pages 8-14. 4

Page 6-2 

### California, Michigan, and Washington have added constituents to the list of TC analytes, as shown in Exhibit 6-1. Both California and Michigan have added zinc, and both California and Washington have added PCBs.2 

### Other additional constituents include certain metals, pesticides, dioxins, and potential carcinogens. An example of a state regulatory level that is lower that the federal TC level is California's regulatory level of 1.7 mg/l for pentachlorophenol (versus 100 mg/l under the federal TC). As discussed in Section 3.6, California requires use of the Wet Extraction Test (WET) in addition to the TCLP. Use of the WET test identifies several metal-containing wastes as hazardous that are generally not identified as hazardous using the TCLP. These wastes include spent catalysts from the petroleum refining and food industries and metal dusts, metal sludges, and baghouse wastes from industries including fabricated metals, leather and apparel, electric and electronic products, primary metals, motor vehicles, transportation equipment, chemicals and allied products, and others.3 

### Both California and Washington have established toxicity criteria for wastes based on acute oral LD50, acute dermal LD50, acute inhalation LC50, and acute aquatic 96-hour LC50 (see Exhibit 6-2). A waste is designated hazardous if a representative sample of the waste meets any of the acute toxicity criteria. For example, Washington specifies rat and fish (for acute aquatic toxicity) bioassay tests in a State test methods manual. Generators must either test a representative sample of the waste or use their knowledge of waste constituents and the literature regarding toxicity of those constituents to determine if the waste meets any of the acute toxicity criteria. Finally, California's regulations state that a waste exhibits the characteristic of toxicity if the waste, based on representative samples, "has shown through experience or testing to pose a hazard to human health or environment because of its carcinogenicity, acute toxicity, chronic toxicity, bioaccumulative properties or persistence in the environment" (22 CCR 66261.24(a)(8)). This broad provision tends to shift the burden of identifying toxic wastes to the generator, because in the absence of specific state criteria (e.g., constituents and regulatory levels) the generator is responsible for being aware of experience or tests that show a waste poses a hazard. 6.2 State Only Listings In addition to expanded characteristics, some states have listed state only hazardous wastes. The most common state-only listed wastes are PCBs and waste oil. At least four states include additional "F" Wastes; three include additional "K" wastes; five include additional "P" wastes; and six include additional "U" wastes. Examples of state listed wastes include but are not limited to the following:4Page 6-3 

### Exhibit 6-1 State Toxicity Characteristics: Additional Constituents and More Stringent Regulatory Levels

CALIFORNIA Constituent Regulatory Level (mg/l in leachate unless otherwise noted) antimony 15 aldrin 0.14 asbestos 1 percent beryllium 0.75 chromium (VI) 5 chromium (III) 560 cobalt 80 copper 25 DDT, DDE, DDD 0.1 2,4-dichlorophenoxyacetic acid 10 dieldrin 0.8 dioxin (2,3,7,8-TCDD) 0.001 fluoride salts 180 kepone 2.1 lead compounds, organic 13 mg/kg mirex 2.1 molybdenum 350 nickel 20 pentachlorophenol 1.7 (lower regulatory level than federal) PCBs 5 thallium 7 2,4,5-trichlorophenoxypropionic acid 1 vanadium 24 zinc 250 Any of the following substances at a single or combined concentration equal to or exceeding 0.001 percent by weight: 2-acetylaminofluorene (2-AAF) 3,3,-dichlorobenzidine and its salts (DCB) acrylonitrile 4-dimethylaminoazobenzene 4-aminodiphenyl ethyleneimine (EL) benzidine and its salts alpha-naphthylamine (1-NA) bis(chloromethyl) ether (BCME) beta-naphthylamine (2-NA) methylchloromethyl ether 4-nitrobiphenyl 1,2-dibromo-3-chloropropane (DBCP) n-nitrosodimethylamine (DMN) beta-propiolactone (BPL) vinyl chloride (VCM)Page 6-4 

### Exhibit 6-1 (continued) State Toxicity Characteristics: Additional Constituents and More Stringent Regulatory Levels

MICHIGAN Constituent Regulatory Level(mg/l) aflatoxin 1 copper 100 dioxin (1,2,3,4,7,8-HxCDD) 1 dioxin (1,2,3,6,7,8-HxCDD) 1 dioxin (1,2,3,7,8,9-HxCDD) 1 dioxin (1,2,3,7,8-PoCDD) 1 dioxin (2,3,7,8-TCDD) 1 furan (2,3,7,8-TCDF) 1 zinc 500 WASHINGTON Constituent Regulatory Level(mg/l) PCBs 2

Exhibit 6-2 State Toxicity Criteria Applied to Whole Waste

(Representative Sample)
CALIFORNIA acute oral LD50 < 5,000 mg/kg acute dermal LD50 < 4,300 mg/kg acute inhalation LC50 < 10,000 ppm acute aquatic 96h LC50 < 500 mg/l WASHINGTON acute oral LD50 < 5,000 mg/kg acute dermal LD50 < 20,000 mg/kg acute inhalation LC50 < 200 mg/l acute aquatic 96h LC50 < 1,000 mg/l RHODE ISLAND acute oral LD50 < 5,000 mg/kg OREGON acute aquatic 96h LC50 < 250 mg/l (only includes certain pesticide residues)Ibid

. 5

Page 6-5



### In California, wastes containing any of almost 800 listed materials are presumed hazardous, unless proven through testing not to exhibit any of California's criteria for identifying hazardous waste. Maine has listed certain wastes from the production of linuron and bromacil, and has listedproposed

additions to the federal list of hazardous wastes. Maryland has listed 9 specific chemical warfare agents. Michigan has added certain chemical production wastes to its "K" or specific source list, and has listed many state-only "U" wastes including organics, inorganics in particle form, pharmaceuticals (e.g., phenobarbital), chemical warfare agents, and herbicides. New Hampshire has added a number of wastes to its "F" or non-specific source list, including certain wastes from industrial painting operations and from metals recovery operations. Oregon has listed certain pesticide residues and certain blister agents and nerve gas. 6.3 State Restrictions on Exemptions Another way that states have expanded the universe of wastes they regulate as hazardous is by choosing not to adopt exemptions in the federal regulations. Examples include but are not limited to the following:5



### Colorado does not recognize exemptions for certain injected groundwater that exhibits the TC and is reinjected pursuant to free phase hydrocarbon recovery operations at petroleum facilities (40 CFR 261.4(b)(11)), certain used chlorofluorocarbon (CFC) refrigerants that are reclaimed for further use (40 CFR 261.4(b)(12)), or non-terne plated used oil filters (40 CFR 261.4(b)(13)). Connecticut, New Hampshire, Oregon, and Washington do not include exemptions for certain chromium-bearing wastes from leather tanning and finishing (40 CFR 261.4(b)(6)(ii)). Maine does not recognize exemptions at 40 CFR 261.4(b)(6) through (13). These include:

-- TC chromium wastes where chromium in the waste is nearly exclusively trivalent chromium;

-- certain chromium-bearing wastes from leather tanning and finishing;

-- specified mining and mineral processing wastes;

-- cement kiln dust;

-- certain arsenical-treated wood wastes;

-- petroleum contaminated media and debris that fail the TC;

-- certain injected groundwater;

-- used CFC refrigerants; and

-- non-terne plated used oil filters.Page 6-6 

### Massachusetts, New York, and North Dakota do not recognize exemptions at 40 CFR 261.4(b)(10) through (13). (These wastes include the last four wastes named directly above.) 6.4 Summary Some states appear to be regulating a significant number of wastes as hazardous that are not covered under federal RCRA regulations. Moreover, a few states have taken different approaches to identifying characteristic hazardous wastes. In particular, California and Washington regulations go beyond constituent-by-constituent definitions and apply acute toxicity criteria to the whole waste. State expansions of hazardous waste identification regulations reflect state judgment about gaps in the federal program. State expansions have filled these gaps, but only in the specific states with such expansions. Such potential gaps apparently arenot being filled in the remaining states that have not expanded the federal hazardous waste definitions.Page 6-7



### CHAPTER 6. STATE EXPANSIONS OF THE TOXICITY CHARACTERISTIC AND LISTINGS

. . 6-1
6.1 State Expanded Toxicity Characteristics

...................................... 6-1 6.2 State Only Listings

....................................................... 6-2 6.3 State Restrictions on Exemptions

........................................... 6-5 6.4 Summary

............................................................... 6-6Page 6-8



### Exhibit 6-1 State Toxicity Characteristics: Additional Constituents and More Stringent

Regulatory Levels

........................................................ 6-3
Exhibit 6-2 State Toxicity Criteria Applied to Whole Waste (Representative Sample)

........... 6-4Page 7-1



# CHAPTER 7. SUMMARY OF POTENTIAL GAPS

This chapter reviews the broad categories of potential gaps identified in the previous three chapters. Different ways of organizing the potential gaps are discussed, and a single comprehensive list of the potential gaps is presented. This review lays the groundwork for evaluating the significance of the potential gaps in the following three chapters. 7.1 Organization of the Analysis of Potential Gaps EPA has identified five categories of potential gaps in the hazardous waste characteristics using different approaches in each area:

ICR Characteristics. EPA identified potential gaps associated with these characteristics by reviewing the original 1980 rulemaking record and comparing the ICR definitions and test methods to approaches taken to controlling similar hazards under other federal and state regulatory schemes.
TC Characteristic. The Agency identified potential gaps associated with this characteristic by examining the properties of the TC analytes to determine how they could pose hazards to human health or the environment.
Non-TC Chemicals. In contrast with the prior step, EPA began with a set of properties (including the potential to appear in non-hazardous industrial wastes) and then identified individual chemicals and groups of chemicals that could constitute potential gaps in the characteristics. Natural Resource Damages and Large-scale Environmental Problems. The Agency examined evidence of possible gaps using a hybrid approach that considered potential gap chemicals on the basis of their hazardous properties (e.g., endocrine disruption, stratospheric ozone depletion) and reviewed other potential gaps starting from possible risks to the environment, which, in turn, implied that certain waste constituents might be of concern. State Expansion of TC and State Listings. EPA reviewed how states have expanded their TC and listed as hazardous certain wastes that are not hazardous under the federal rules. These expansions reflect state judgments about gaps in the federal rules and thereby constitute potential gaps for this Scoping Study. The potential gaps presented in the following section are organized primarily by the major categories identified above. Where appropriate, these categories are subdivided into groups of chemicals posing similar types of hazards, and occasionally are subdivided even further by specific hazardous properties or exposure pathways of concern. Some of the potential gaps overlap. For example, endocrine disruptors appear among the concerns associated with the non-TC analytes as well as in a category by themselves under large-scale environmental risks. Although this overlap is inevitable, the potential gaps have been organized so as to minimize it, without omitting any potentially significant gaps.Page 7-2 

### EPA considered other methods of classifying the potential gaps for purposes of further analysis. Gaps could be identified, for example, in terms of individual chemicals and their specific properties and hazards. Alternatively, the gaps could be organized around groups of chemicals with specific hazardous properties or types of risks. EPA rejected these approaches for purposes of this Scoping Study as impractical because too many individual chemicals or groups of chemicals, risks, and pathways are involved. In addition, defining potential gaps in categories that do not parallel the approaches used to identify such gaps would make it more difficult to appreciate the evidence and uncertainty associated with each potential gap. 7.2 Summary of Potential Gaps Exhibit 7-1 lists the potential gaps in the hazardous waste characteristics identified by EPA in the preceding chapters. The individual gaps are organized according to the section or chapter in which they are discussed, with reference to specific chemical classes, exposure pathways, or types of risks, as appropriate. Potential gaps are evaluated in the following chapters in order to assess their potential significance in terms of potential risks to health and the environment. Because of data limitations, most of this evaluation focuses on potential gaps associated with the TC analytes and other chemicals. Chapter 8 examines the relationship between potential gaps, specific industries, and waste management methods. Chapter 9 discusses the extent to which the various potential gaps may already be addressed to some extent by existing regulatory systems. Finally, Chapter 11 presents a Summary evaluation of the potential gaps against a number of risk and regulatory criteria.

Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics Category of Potential Gap Nature of Potential Gap Potential Gaps in the ICR Ignitability Characteristics Exclusion of DOT combustible liquids (Sections 3.2 to 3.4) Exclusion of aqueous flammable liquids References outdated DOT regulations No test method for non-liquids Corrosivity Exclusion of corrosive non-liquids pH limits are potentially not protective pH test methods are not predictive of risk Corrosion of non-steel materials is not addressed Solubilization of non-metals is not addressed Exclusion of irritants and sensitizers Reactivity Definition is broad, non-specific References outdated DOT regulations No test methods are specified Potential Gaps Associated With Groundwater Pathway Risks the TC Analytes (Sections 3.5 DAF values potentially not protective and 3.6)

### Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics (continued)

Category of Potential Gap Nature of Potential Gap

Page 7-3 

### Potential Gaps Associated With Ecological Risks Not Addressed the TC Analytes (Sections 3.5 Potent ecological toxicants and 3.6) (continued) Persistent/bioaccumulative pesticides Non-Groundwater Pathways Not Addressed Inhalation (volatile organics) Surface water pathway Indirect/food chain (volatile, persistent, and bioaccumulative chemicals)
TCLP Limitations May not accurately predict leachate concentration or risks for certain wastes and units Potential Gaps Associated with Major Constituents/Properties of Non-Hazardous Industrial Wastes Not Known and Possible Constituents Addressed of Non-hazardous Industrial Metals/inorganics Waste other than TC Analytes -- groundwater pathway (Chapter 4) Volatile chlorinated organics

-- groundwater and inhalation pathway exposures Volatile hydrocarbons

-- groundwater and inhalation pathways Other volatile organics

-- groundwater and inhalation pathways Pesticides and related compounds

-- inhalation and indirect food chain pathways Phthalate esters

-- indirect pathways Phenolic compounds

-- groundwater and indirect pathways Polycyclic aromatic hydrocarbons

-- indirect pathway exposures Other semivolatile organic compounds

-- all pathways
Generation of LNAPLs and DNAPLs Facilitated transport of organic chemicals Long-lasting and difficult to remediate

### Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics (continued)

Category of Potential Gap Nature of Potential Gap

Page 7-4 

### Potential Gaps Associated with Natural Resource Damages Natural Resource Damages and Groundwater resource damage without health risks Large-Scale Environmental Odors Problems (Chapter 5) Large-scale Environmental Problems Air deposition to the Great Waters Airborne particulates Global climate change Potential damage from endocrine disruptors Red tides Stratospheric ozone depletion Tropospheric ozone and photochemical pollution Water pollution Potential Gaps Associated with State Expansion of TC State Expansion of TC and Additional TC constituents Listings (Chapter 6) More stringent regulatory levels Alternative test methods Use of acute oral, dermal, inhalation, and aquatic LD50 or LC50 criteria applied to representative samples of waste State Only Listings State Restrictions on Federal ExemptionsPage 7-5



### CHAPTER 7. SUMMARY OF POTENTIAL GAPS

......................................... 7-1
7.1 Organization of the Analysis of Potential Gaps

....................................... 7-1 7.2 Summary of Potential Gaps

....................................................... 7-2Page 7-6



### Exhibit 7-1. Summary of Potential Gaps in the Hazardous Waste Characteristics

................... 7-2Page 8-1



# CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF INDUSTRY AND WASTE MANAGEMENT METHODS

This Chapter evaluates the significance of potential gaps by linking the known and possible non-hazardous industrial waste constituents to specific industries and management practices. It is organized as follows:
Section 8.1 describes the primary data sources used in this chapter and their major

limitations;
Section 8.2 discusses the amount of non-hazardous industrial wastes generated by various

industries and the constituents found in their wastes; and
Section 8.3 reviews the methods of managing non-hazardous industrial wastes and the associated

risks to human health and the environment. 8.1 Data Sources and Major Limitations Over the past 15 years, EPA has made several substantial efforts to gather information on the types and amounts of non-hazardous industrial wastes generated by specific industries and the management methods used for specific wastes. Despite these efforts, significant gaps, inconsistencies, and other limitations remain in the available information. Considerably fewer data are available on non-hazardous industrial wastes than on hazardous wastes, in part, because of the limited federal role in regulating non-hazardous industrial wastes and the lack of widespread reporting requirements. The major sources of data on non-hazardous industrial waste generation and management are as follows: Industrial Studies Database (ISDB). EPA has maintained the ISDB since 1982. The database contains information on waste generation, management, and point-of-generation constituent concentrations for 16 industries. The sources of the information include RCRA Section 3007 questionnaires, plant visit reports, sampling and analysis site visit reports, engineering analysis reports, and data collected for hazardous waste listing decisions. The Industrial Subtitle D Telephone Screening Survey. This survey was conducted between November 1986 and April 1987. Over 18,000 facilities in 17 industry sectors were questioned about the quantities and types of non-hazardous industrial wastes generated and managed on-site in 1985, the number and design of on-site management units, and the amounts of such waste managed in on-site landfills, surface impoundments, waste piles, and land application units. National Survey of Treatment, Storage, Disposal, and Recycling Facilities (TSDR Survey). The TSDR Survey was conducted in 1986 to gather information on waste generation and management practices for 1986 and any projected changes in waste management capacity prior to 1992. The Survey questioned approximately 2,500 facilities that manage hazardous waste on-site, including the 2,400 RCRA-permitted or interim status treatment, disposal, or recycling facilities, and approximately 100 of the 700 storage facilities. The Survey addressed both hazardous and non-hazardous waste management at these hazardous waste management facilities. This data source providedSystems Applications International Corporation, August 8, 1992, draft. 1U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, October 1988. 2

Page 8-2



### information related to non-hazardous industrial waste management practices and waste generation by industry groups. Background documents for recent Agency listings decisions. Reports prepared for the Agency's proposed decision not to list certain dyes and pigments wastestreams as hazardous and the proposed decision not to list certain solvent wastestreams as hazardous. The document identifies the industries responsible for these wastestreams. In addition, this Chapter uses data from the 1992 Toxic Release Inventory (TRI) on the amount of certain toxic substances released to land or injected underground by various industries. This data source is discussed in Section 8.2.4. At the time this Study was prepared, facility-specific data from the 1994 TRI were not available. Therefore, 1992 TRI data were used in this chapter. While the use of 1992 instead of more recent TRI data will not significantly affect the analysis, it will limit the results to a smaller set of chemicals and will not reflect recent pollution prevention progress. The first three data sources have the disadvantage of being relatively old. They reflect non-hazardous industrial waste generation and management practices prevalent a decade or more ago. Since then, patterns of waste generation and management are likely to have changed in some significant ways in response to the implementation of RCRA hazardous waste regulations and other federal and state programs. In addition, the ISDB is rather limited in the number of facilities surveyed in each industry sector, particularly with regard to organic analytes. The ISDB and Telephone Screening Survey also address only certain industries. The data sources are not entirely consistent. For example, the estimates of non-hazardous industrial waste generation for similarly defined industry groups often differ substantially among the sources. These inconsistencies arise, in part, from the use of different data collection and summarization methods. In the analyses discussed below, the Agency has used what it considers to be the most reliable and complete data concerning waste generation and management from these sources. EPA has previously analyzed the data from the first three data sources to investigate various aspects of non-hazardous industrial waste generation and management practices. Most of the data presented below come from two of these studies, the "Industrial D Industry Profiles" and the 1988 "Report to Congress: Solid Waste Disposal 1 

### in the United States." The former document summarizes non-hazardous industrial waste generation and management 2 

### practices in 25 industry sectors, while the latter source focuses on the land disposal of all non-hazardous solid waste covered by the RCRA Subtitle D criteria.Ibid., p.2. Thisvolume may include some special wastes, such as in the primary metals or electrical power generation 3 industries.

Page 8-3 

### 8.2 Potential Gaps as a Function of Industry/Waste Source This section discusses non-hazardous industrial waste generation by various industries as follows:
Section 8.2.1 reviews available data on the volume of such waste generated by specific

industries or industry groups;
Section 8.2.2 compares these data with the industries responsible for the releases documented in

Chapter 2;
Section 8.2.3 identifies the industries responsible for generating non-hazardous industrial wastes

containing constituents with the highest risk of adverse human health effects; and
Section 8.2.4 identifies the industries with facilities reporting TRI releases to land and underground

injection of known or possible non-hazardous industrial waste constituents. 8.2.1 Non-Hazardous Industrial Waste Generation by Industry In 1988, the Agency estimated that approximately 7.6 billion tons of non-hazardous industrial waste was generated and managed on-site annually in the United States. Approximately 68 percent of this waste came from 3 

### four major industry groups:

Paper and allied products (SIC 26): 2.25 billion tons (29.6 percent); Chemicals and allied products (SICs 2812-2819, 2821, 2824, 2851, 2891, 2865, 2869, and 287): 1.39 billion tons (18.2 percent); Primary metals industries (SICs 3312-3321 and 3331-3399): 1.37 billion tons (18.0 percent); and Petroleum refining and related industries (SIC 29): 168 million tons (2.2 percent). On the basis of the amounts of waste generated and risk-based screening of waste constituents, the Office of Solid Waste identified these four industry groups as "priority industries" for possible further regulation. Other industries that generate more non-hazardous industrial wastes than petroleum refining were not identified as priority industries on the basis of risk-based screening of waste constituents. Exhibit 8-1 summarizes the estimates of non-hazardous industrial waste generation for the four priority industries and corresponding industry sectors and for other relatively high volume industries and sectors.Page 8-4 

### Exhibit 8-1 Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group

Industry Group SIC (thousand tons/yr.) Total On-site Generation Paper and Allied Products 26 2,251,700 Primary Metals Industry 33 1,367,611 a 

### Primary Iron and Steel 332 1,300,541 Primary Non-ferrous Metals 333 67,070 Chemicals and Allied Products 28 1,324,722 b 

### Industrial Inorganic Chemicals 281 919,725 Fertilizer and Agricultural Chemicals 287 165,623 Plastics and Resins Manufacturing 282 180,510 Industrial Organic Chemicals 286 58,864 Electric, Gas, and Sanitary Services 49 1,151,123 c 

### Electric Power Generation 4911 1,092,277 Water Treatment 4941 58,846 Stone, Clay, Glass, and Concrete 32 621,974 Food and Kindred Products 20 373,517 Textile Manufacturing 22 253,780 Petroleum Refining 29 168,632 Rubber and Miscellaneous Products 30 24,198 Transportation Equipment 37 12,669 Leather and Leather Products 31 3,234

Source: U.S. Environmental Protection Agency, "Report to Congress: Solid Waste Disposal in the United States,"

Volume II, Table 3-5, October 1988. The Primary Metals Industry includes only SICs 332 (Primary Iron and Steel) and 333 (Primary Non-ferrous a Metals). Chemicals and Allied Product Industry includes only SICs 281 (Industrial Inorganic Chemicals), 282 (Plastics b and Resins Manufacturing), 286 (Industrial Organic Chemicals), and 287 (Fertilizer and Agricultural Chemicals). Electric, Gas, and Sanitary Services Industry includes only SICs 4911 (Electric Power Generation) and 4941 c (Water Treatment).Health-based or ecologically-based standards included Primary MCLs, MCLGs, and state standards established to protect healt h 4 or the environment. Non-health-based or non-ecologically-based standards are those set to preserve groundwater usability or aesthetics, such as Secondary MCLs or standards for which any health or ecological bases were not explained. EPA lacks information on the regulatory standards that were exceeded for all releases fromCalifornia and for two releases from 5 other states. All releases described in this Study, however, were documented to have exceeded one ormore applicable federal, state, or local regulatory standards.

Page 8-5 

### The listing documents for solvent wastes and wastes from the dye and pigment industries are another source of information on non-hazardous industrial waste. All of the information related to waste volumes and constituents concentrations for the dye and pigment industries, however, was claimed proprietary by the submitters and, therefore, could not be included in this Study. EPA recently identified non-hazardous industrial solvents in developing a recent proposed rulemaking. The amounts of solvent wastes have not been broken down by industry and, therefore, could not be included in Exhibit 8-1. 8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste Releases The environmental release descriptions discussed in Chapter 2 provide additional evidence about the industries (and waste management practices) associated with potential gaps in the characteristics. Exhibit 8-2 tabulates, by industry, the frequency of documented releases and their exceedence of health-based or ecologically-based regulatory standards. As shown in this exhibit, some of the industries that show up frequently in the release descriptions are among the high-volume industries identified above. The most frequently occurring industry group in the release descriptions is electric, gas, and sanitary services (SIC 49) with all of those release descriptions originating in the refuse systems sector (SIC 4953). This industry sector includes commercial waste management facilities. As noted in Chapter 2, most of these commercial non-hazardous industrial waste management units are located in California, where considerable monitoring data were available. From these data, EPA could not determine the industries that generate the wastes managed by these commercial facilities. The next three industry groups with the most documented releases are the paper and allied products (27 releases), chemicals and allied products (11 releases), and food and kindred products (10 releases). These industry groups also are among the largest generators of non-hazardous industrial waste. The primary metals industry, another high-volume group, also has a moderate number of documented releases; they account for 6 of the 112 total releases documented in Chapter 2.
Exhibit 8-2 also shows the numbers of documented releases at which the maximum detected concentrations of constituents exceeded health-based or ecologically-based standards. All but six of the 101 releases with data on 4 

### the standards exceeded had exceedences of health- or ecologically-based standards. These six releases exceeded 5 

### secondary maximum contaminant levels (SMCLs) only. Sixty-five of these releases also violated other standards. Exhibit 8-3 shows the total numbers of times particular chemicals were found in the release descriptions for various industry sectors. (The totals are the sums of the number of individual chemicals detected at each site, counting all chemicals for each site, even if a chemical is detected at more than one site. For example, the total detections at two sites having 10 chemicals each, 3 of which are the same, is 20, not 17.) In addition, the exhibit shows the numbers of times suchPage 8-6 

### Exhibit 8-2 Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels in the Release Descriptions for Non-Hazardous Waste Management

Industry Group (SIC) Total Exceedences Exceedences Exceedences Number of Release Descriptions

a 

### With Both Health

/ Ecological and With Only With Only NonNon-Health/Non
- Health/ Health/NonEcological Ecological Ecological Electric, Gas, and Sanitary Services (49) 35 11 11 4 Paper and Allied Products (26) 27 22 4 1 Chemicals and Allied Products (28) 11 8 3 0 Food and Kindred Products (20) 10 6 3 0 Primary Metal Industries (33) 6 2 4 0 Nonmetallic Minerals, Except Fuels (14) 4 4 0 0 Petroleum Refining (29) 4 3 1 0 Fabricated Metal Products (34) 3 0 2 1 Transportation Equipment (37) 3 3 0 0 Agricultural Production--Livestock (02) 2 2 0 0 Electronic and Other Electronic Equipment (36) 2 1 0 0 Stone, Clay, and Glass Products (32) 2 2 0 0 Apparel and Other Textile Products (23) 1 1 0 0 Industrial Machinery and Equipment (35) 1 0 1 0 Instruments and Related Products (38) 1 0 1 0 Total 112 65 30 6
The total number of release descriptions in column 2 may not equal the sum of the release descriptions in columns 3, 4, and a 5. Column 2 includes all release descriptions for chemicals that were documented to have exceeded at least one applicable federal, state, or local regulatory standard. Columns 3, 4, and 5 include only those release descriptions in Column 2 for which supporting data indicate which regulatory standards were exceeded. Information was not available on the regulatory standards that were exceeded for all releases from California and for two releases from other states.

### Page 8-7 Exhibit 8-3 Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in Release Descriptions

Industry Group (SIC) Descriptions Total Mean Per Releas e Total Release Total Release Number of Release Mean Per Mean Per

Chemical Detections Regulatory Exceedences Based ExceedencesHealth- or EcologicallyElectric, Gas, and Sanitary Services (49) 35 350 10 91 3 58 2 Paper and Allied Products (26) 27 340 13 148 5 85 3 Chemicals and Allied Products (28) 11 250 23 97 9 73 7 Food and Kindred Products (20) 10 72 7 22 2 13 1 Primary Metal Industries (33) 6 58 10 27 5 24 4 Nonmetallic Minerals, Except Fuels (14) 4 91 23 49 12 34 9 Petroleum Refining (29) 4 40 10 16 4 8 2 Fabricated Metal Products (34) 3 12 4 7 2 5 2 Transportation Equipment (37) 3 48 16 19 6 14 5 Agricultural Production--Livestock (02) 2 18 9 8 4 5 3 Electronic and Other Electronic Equipment (36) 2 16 8 4 2 1 0 Stone, Clay, and Glass Products (32) 2 33 17 14 7 10 5 Apparel and Other Textile Products (23) 1 3 3 3 3 2 2 Industrial Machinery and Equipment (35) 1 7 7 3 3 3 3 Instruments and Related Products (38) 1 2 2 1 1 1 1 Total 112 1,340

--- 509

--- 336

---These are chemicals that were identified as having Cancer Slope Factors or Unit Risks in IRIS or HEAST. 6


### Page 8-8 chemicals were detected above regulatory levels, and the proportions of chemicals found above health-based or ecologically-based standards. The 3 industries with the most releases, electric, gas, and sanitary services (35 releases), paper and allied products (27 releases), and chemicals and allied products (11 releases), also had the highest numbers of chemical detections (350, 340, and 250, respectively). The average number of chemicals detected per facility varies substantially across industries. For example, the 3 industries noted above had means of 10, 13, and 23 chemicals detected per release, respectively. The average number of regulatory and health- or ecologically-based exceedences per release also varies greatly across industries. For example, the electric, gas, and sanitary services industry averages only 3 regulatory and 2 health- or ecologically-based exceedences for every 10 chemical detections. In contrast, the chemical industry averages 9 regulatory and 7 health- or ecologically-based exceedences for every 23 chemical detections. 8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry Another indicator of the potential severity of hazards associated with releases from non-hazardous industrial waste management in various industries is the frequency of occurrence of waste constituents with the highest risk to humans. Exhibit 8-4 identifies the chemicals that appeared most frequently in the release descriptions, the number of total appearances, and the number of times the chemical was present in groundwater above regulatory or other health-based levels based on 10 cancer risks or a hazard quotient greater than 1.0. As -5

### noted in Section 5.1, many of the most frequently occurring chemicals do not have health-based or ecologicallybased standards, but may have SMCLs or other regulatory levels. Among these are the three most common constituents found in the release descriptions: iron, chloride, and sodium, as well as manganese, zinc, calcium, magnesium, potassium, copper, aluminum, and silver. A substantial number of potentially toxic chemicals were detected in the release descriptions. For example, 11 of the 52 most frequently detected chemicals are known or suspect carcinogens by ingestion or inhalation. Only one of the most frequently detected chemicals (phosphorous) is identified as having a low RfD,

6 

### although several other chemicals on the list are generally considered toxic, including lead, mercury, cadmium, arsenic, and chromium. Seven of the most frequently detected chemicals are chlorinated volatile organics, with trichlorethylene, occurring most often (17 times). While all of the inorganic analytes appearing on the list are persistent, none of the most frequently occurring organic chemicals were identified as persistent in Chapter 4. In fact, none of the persistent bioaccumulative chlorinated pesticides identified as posing potentially high risks are seen in the release descriptions more than three times and most were seen in only one release description.Exhibit 8-5 shows the number of occurrences and the number of regulatory, health-based, or ecologicallybased exceedences for the constituents detected most frequently in the release descriptions for each industry group. For each group, the 15 most frequently detected chemicals or all detected chemicals are shown, whichever is smaller. In almost all industry groups, inorganic chemicals are found more often than organics. This finding may be due, in part, to a lack of analytical data for organic chemicals in some industries. Volatile organic chemicals are rarely found among the most frequently detected chemicals, with a few exceptions. Iron, manganese, and sulfate were among the most frequently found chemicals in the electric, gas, and sanitary services release descriptions, and volatile organics represent the bulk of the most frequently detected chemicals for the electronic and other electronic equipment industry and the petroleum refining industry. The relative scarcity of

### Page 8-9 Exhibit 8-4 Most Frequently Occurring Constituents in the Release Descriptions

Constituent Descriptions Regulatory Levels or HBLs Number ofOccurrences in Release Number of Occurrences Above
a 

### TC Constituents Lead 37 22 Chromium 36 21 Arsenic 29 24 Barium 28 28 Cadmium 28 28 Benzene 23 16 Mercury 19 6 Selenium 18 18 Trichloroethylene 17 8 Vinyl chloride 13 6 Silver 12 12 Chlorobenzene 9 9 Tetrachloroethylene 9 9 Chloroform 8 8 1,4-Dichlorobenzene 5 0 SMCL Constituents Iron 54 49 Chloride 52 32 Manganese 39 39 Zinc 33 33 Copper 17 17 Aluminum (fume or dust) 12 12 Fluorides 12 4 Other Constituents Sodium 40 8 Nitrates 33 30 Magnesium 32 3 Calcium 30 0 Potassium 21 0 Other Constituents (continued)

### Exhibit 8-4 (continued) Most Frequently Occurring Constituents in the Release Descriptions

Constituent Descriptions Regulatory Levels or HBLs Number ofOccurrences in Release Number of Occurrences Above
a



### Page 8-10 Toluene 20 20 Phenol 18 18 Ammonia 16 11 Calcium carbonate 15 0 Nickel 14 4 Dichloromethane 12 12 Nitrite 11 9 Ethylidene dichloride 10 10 Xylene (mixed isomers) 10 10 Acetone 9 9 Nitrogen 8 0 Beryllium 7 7 cis-1,2-Dichloroethylene 7 7 Ethylbenzene 7 7 Vanadium (fume or dust) 7 6 1,2-Dichloroethylene 6 6 Boron and compounds 6 3 Chloromethane 6 0 Cyanides 6 6 Phosphorus 6 1 1,2-Dichlorobenzene 5 5 Antimony 5 5 Carbon disulfide 5 5 Cobalt 5 0 Naphthalene 5 3
Regulatory levels include MCLs, SMCLs, AWQCs, or other state health- or ecologically-based standards. HBLs are drinking a water concentrations corresponding cancer risk of 10 or Hazard Quotient of 1.0 for an adult, using IRIS or HEAST toxicity -5 criteria.

### Page 8-11 Exhibit 8-5 Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e

Paper and Allied Products (26) pH 22 12 * Chloride 21 13

* Iron 21 21 * Sulfate 20 12

* Sodium 15 2 Calcium carbonate 12 0 Calcium 11 0 Magnesium 11 2 Zinc 11 11 * TDS 10 7 * Chromium 9 5 Manganese 9 9

* Arsenic 8 7 Barium 7 7 Cadmium 7 7 Refuse Services (495) pH 19 3 * Iron 14 10 * Manganese 13 13

* Sulfate 13 4

* Lead 12 4 Chloride 11 7

* Magnesium 10 1 Nitrate 10 7 TDS 10 1 * Trichloroethylene 10 3 Benzene 9 3 Calcium 9 0 Chromium 9 4 Sodium 9 1 Vinyl Chloride 9 3 Chemicals and Allied Products (28) Benzene 7 6

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-12 Chromium 7 4 Iron 7 6 * Lead 6 4 Manganese 6 6

* Sulfate 6 4

* TDS 6 4 * Zinc 6 6 * Arsenic 5 5 Chloride 5 1

* Fluoride 5 1

* Total Organic Carbon 5 1 Acetone 4 4 Barium 4 4 Cadmium 4 4 Nonmetallic Minerals, Except Fuels (14) Arsenic 4 2 Iron 4 4 * Lead 4 4 Manganese 4 4

* pH 4 2 * Cadmium 3 3 Chloride 3 3

* Copper 3 3

* Nickel 3 1 Potassium 3 0 Sodium 3 0 Sulfate 3 3

* Zinc 3 3 * Aluminum 2 2 Barium 2 2 Food and Kindred Products (20) Nitrite 6 4 Nitrate 5 5

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-13 Nitrogen 5 0 pH 4 0 * TDS 4 3 * Total filterable residue 4 0 Calcium 3 0 Chloride 3 2

* Magnesium 3 0 Sodium 3 2 Sulfate 3 2

* Ammonia 2 1 Bicarbonate 2 0 Conductivity 2 0 Copper 2 2

* Primary Metal Industries (33) Lead 4 4 Chromium 3 3 Aluminum 2 2

* Arsenic 2 2 Barium 2 2 Cadmium 2 2 Chloride 2 2

* Conductivity 2 0 Mercury 2 0 Nickel 2 2 Zinc 2 2 * 2,4,6-Trichlorophenol 1 0 2,4-Dichlorophenol 1 1 2,4-Dimethylphenol 1 1 2,4-Dinitrophenol 1 1 Petroleum Refining (29) Chloride 3 2 * Conductivity 2 1 Di-n-butylphthalate 2 1

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-14 Naphthalene 2 1 pH 2 1 * Sulfate 2 2

* TDS 2 2 * 1,2-Dichloroethane 1 1 2-Methylnaphthalene 1 0 Acenaphthene 1 1 Acetone 1 1 Barium 1 1 Benzene 1 1 Carbon disulfide 1 1 Chlorobenzene 1 1 Agricultural Production--Livestock (02) Ammonia 2 0 Nitrate 2 2 TDS 2 2 * Bicarbonate 1 0 Calcium 1 0 Chemical Oxygen Demand 1 0 Chlorine 1 1

* Iron 1 1 * Magnesium 1 0 Nitrite 1 1 Nitrogen 1 0 pH 1 0 * Phosphorus 1 0 Sodium 1 1 Toluene 1 1 Transportation Equipment (37) Phenol 3 3 Barium 2 2 Chromium 2 1 Total Organic Carbon 2 1

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-15 1,1-Dichloroethane 1 1 2,4-Dimethylphenol 1 0 Aluminum 1 1

* Ammonia 1 1 Antimony 1 1 Arsenic 1 1 BEHP 1 1 Benzene 1 1 Beryllium 1 1 Cadmium 1 1 Calcium 1 0 Electronic and Other Electronic Equipment (36) 1,1-Dichloroethane 1 1 Carbon tetrachloride 1 1 Chloride 1 1

* Chloroform 1 1 Iron 1 1 * Manganese 1 1

* Methylene chloride 1 1 pH 1 0 * Phenolics 1 0 Sodium 1 0 Sulfate 1 1

* Tetrachloroethylene 1 1 Toluene 1 1 Total Organic Carbon 1 0 Total Organic Halogens 1 0 Stone, Clay, and Glass Products (32) Ammonia 1 1 Arsenic 1 1 Barium 1 1 Benzene 1 1 Beryllium 1 1

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-16 Cadmium 1 1 Calcium 1 0 Carbon disulfide 1 1 Chemical Oxygen Demand 1 0 Chloride 1 0

* Chromium 1 1 Cobalt 1 0 Conductivity 1 0 Copper 1 1

* Cyanide 1 1 Fabricated Metal Products (34) Chemical Oxygen Demand 1 0 Chloride 1 1

* Chromium 1 1 cis-1,2-Dichloroethylene 1 1 Lead 1 0 Manganese 1 1

* Nitrate 1 1 pH 1 1 * Phenol 1 1 Total Dissolved Solids 1 0 * Trichloroethylene 1 1 Zinc 1 1 *

### Exhibit 8-5 (continued) Occurrence of Waste Constituents by Industry Group

Industry Group (SIC) Constituent Descriptions based Levels Number of Regulatory, Occurrences in Health- or Release EcologicallyNumber of Occurrences

Abov e



### Page 8-17 Industrial Machinery and Equipment (35) Arsenic 1 0 Cadmium 1 1 Chromium 1 0 Lead 1 1 pH 1 0 * Phenol 1 1 Zinc 1 1 * Apparel and Other Textile Products (23) Cadmium 1 1 Nitrate 1 1 Total Organic Carbon 1 1 Instruments and Related Products (38) Grease and Oil 1 0 Phenol 1 1

Constituents with Secondary Maximum Contaminant Levels. *



### organics for some of the industries could be slightly misleading. For example, a large number of volatile organic chemicals were detected in the release descriptions from the chemicals and allied products industry and petroleum refining, but each chemical was detected infrequently, so they do not appear in Exhibit 8-5. The persistent chlorinated pesticides were not among the most frequently detected chemicals, except in two industries. Pentachlorophenol was detected in a single release description from the primary metals industry. Semivolatile organics are likewise not among the most frequently detected analytes in the release descriptions, but this may be a function of the poor mobility of many of these chemicals in groundwater, rather than their lack of presence in the wastes. As was the case for the volatile organics, a large number of pesticides and semivolatile organics were detected in the release descriptions from the chemicals and allied products sector and each such chemical was found only one or a few times. The pattern of chemical detections and health-based or ecologically-based exceedences varied widely among the industry groups, as discussed in Section 8.1.2. As noted previously, the frequency of non-health-based and non-ecologically-based exceedences is relatively high among some industry groups with the highest number of total chemicals detected. For example, SMCLs, which are based on aesthetic considerations (e.g., water taste and odor), exist for 6 of the 15 most commonly detected analytes for the refuse systems sector (SIC 4953) and the paper and allied products industry (SIC 26), and 7 of the 15 analytes from the chemicals and allied products industry (SIC 28). Again, this finding may be somewhat misleading because many of the less frequently detected analytesDetailed 1994 TRI facility-specific data werenot available when this Study was prepared, therefore, 1992 TRI data were used

. 7


### Page 8-18 from these sectors do have health-based or ecologically-based standards. Furthermore, some constituents with SMCLs may also pose health and ecological risks. The same pattern applies to stone, clay, and gas products (SIC 32), and food and kindred products (SIC 20). In the food and kindred products industry, the only health-based exceedences were for nitrates, nitrites, or both. All of the other most frequent exceedences for this industry group were non-health-based and non-ecologically-based. 8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible Non-Hazardous Industrial Waste Constituents Another indication of the potential importance of the various industries with regard to non-hazardous industrial waste management is provided by data concerning the amounts of chemicals these industries release to the environment, as reported under the EPCRA TRI requirements. Exhibit 8-6 identifies, by industry, volumes of TC analytes or known or possible non-hazardous industrial waste constituents that in 1992 were reported released to land or underground injection in an amount exceeding 1 million pounds. Volumes of waste released to land or 7 

### underground injection are presented in this Study because they are thought to be the most indicative of the volume of non-hazardous waste at the facilities. The listed volumes are the mass of individual constituents in waste streams or other emissions rather than total waste volumes as presented in other exhibits in this chapter. The volumes may include hazardous, special, and municipal solid waste as well as non-hazardous industrial waste. The largest volume of constituents reported released via underground injection in 1992 were from the chemicals and allied products industry, which contributed 99.3 percent of total volume from underground injection. A significant portion of these constituents may be in hazardous wastewaters. The second and third largest volumes of TRI constituents come from the petroleum refining and primary metals industries, which contributed 0.57 and 0.04 percent of total volume from underground injection, respectively. The two constituents released in the largest volumes to underground injection from the chemicals and allied products industry were methanol and acetonitrile, with 38 and 29 percent of total volume for that industry, respectively. Methanol was also released in the highest volume from the petroleum refining industry, comprising 57 percent of the total constituent volume reported for that industry. The largest volume of constituents released to land originates from the primary metals industry, which contributes 74.2 percent of the total volume. Most of that volume (99 percent) is comprised of constituents, such as zinc, copper, and chromium, that may be present in large volume special wastes. (Further investigation is needed to determine whether any of these releases involve special or hazardous wastes.) The two chemicals comprising almost equal proportions released by this industry are zinc and copper, with about 48 percent each. The second and third largest volumes of constituents were from the petroleum refining and paper and allied products industries, respectively. Petroleum refining contributed 10.1 percent of total volume and paper and allied products contributed 8.4 percent of total volume released to land. Naphthalene and xylene, with 43 and 32 percent of total volume reported released to land, constituted the largest proportion of the constituents from the

### Page 8-19

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry

### Page 8-20

Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry (continued)

### Page 8-21

petroleum refining industry. Almost 99 percent of the volume of constituents released to land by the paper and allied products industry was methanol. 8.3 Potential Gaps as a Function of Management Practices This section of the Scoping Study reviews the available information related to management practices:
Section 8.3.1 examines the prevalent management practices among the major non-hazardous

industrial waste generating industries;
Section 8.3.2 reviews the evidence regarding environmental releases as a function of

management type for major management technologies;
Section 8.3.3 describes limited data available on the potential hazards associated with use

constituting disposal; and
Section 8.3.4 briefly discusses the potential nature of the hazards associated with less wellcharacterized management practices. 8.3.1 Waste Management Practices by Waste Type and Industry As noted previously, the data related to non-hazardous industrial waste management practices are quite limited and may be somewhat outdated. Inconsistencies frequently were found between data from the different sources. Exhibit 8-7 summarizes the information for the relatively high volume generation industries. Based on the available information, the vast majority of non-hazardous industrial waste is aqueous and is managed in surface impoundments before treatment and ultimate discharge under NPDES. The proportion of these wastes going to surface impoundments in 1985 ranged from 78.6 percent in the food and kindred products industry to 99.7 percent in the textile manufacturing industry, with a total of 96.5 percent of all wastes managed in this fashion in the 15 industries included in the exhibit. The second most widely used land-based management technology was land application. Only about 1.3 percent of the waste volume from the 15 industries was managed in this fashion in 1985, with substantially larger proportions going this route in the organic chemicals industry (3.1 percent), the food and kindred products industry (20 percent), and water treatment industry (15 percent). Landfills and waste piles each accounted for about one percent of the total waste managed in the 15 industries. Exhibit 8-8 estimates the number of active landfills, surface impoundments, land application units, and waste piles used to manage non-hazardous waste in various industry groups in 1985. At that time, 55 percent of these land-based units were surface impoundments. This finding indicates that, on average, surface impoundments handled larger volumes of waste than other management units since they managed a substantially greater percentage (96 percent) of total on-site non-hazardous industrial waste. In all industries except primary iron and steel and transportation equipment, surface impoundments were the most common type of management units. Waste piles constituted 19 percent of the total units. They were the most common type of unit in the primary iron and steel and transportation equipment industries, were the second most common type in eight industries, and tied for second in another. Land application units represented 16 percent of all units. Over 70 percent of these units, however, were in the food and kindred products industry. Landfills represented only 10 percent of all units.

### Page 8-22 Exhibit 8-7 Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in 1985

Major Industry Group (SIC) Treatment or DisposalMethod (percentages) Total a

Landfill Impoundment Application Piles (1000 tons/yr.)

Surface Land Waste Tons Managed Paper and Allied Products (26) 0.30% 99.30% 0.40% 0.07% 2,251,700 Primary Metals Industry (33) 0.39 98.5 0.04 1.1 1,367,611 b Primary Iron and Steel (332) 0.3 99.2 <0.01 0.5 1,300,541 Primary Non-ferrous Metals (333) 2.1 84.3 0.6 13 67,070 Chemicals and Allied Products (28) 0.74 95.3 0.21 3.7 1,324,722 c Industrial Inorganic Chemicals (281) 0.4 95.1 0.01 4.5 919,725 Plastics and Resins Manufacturing (282) 0.05 98.2 0.02 1.7 180,510 Fertilizer and Agricultural Chemicals (287) 3.5 93.1 0.5 2.9 165,623 Industrial Organic Chemicals (286) 0.4 96.3 3.1 0.08 58,864 Electric, Gas, and Sanitary Services (49) 4.7 94.5 0.78 0.08 1,151,123 d Electric Power Generation (4911) 4.9 95 0.03 0.08 1,092,277 Water Treatment (4941) 0.3 84.5 15 0.1 58,846 Stone, Clay, Glass, and Concrete (32) 1.2 97.3 <0.01 1.5 621,974 Food and Kindred Products (20) 1 78.6 20 0.1 373,517 Textile Manufacturing (22) 0.03 99.7 0.3 <0.01 253,780 Petroleum Refining (29) 0.2 99.6 0.2 0.05 168,632 Rubber and Misc. Products (30) 2.2 97.4 0.2 0.2 24,198 Transportation Equipment (37) 1.4 93.1 <0.01 4.6 12,669 Leather and Leather Products (31) 0.3 99.4 0 0.3 3,234

Total 1.10% 96.50% 1.30% 1% 7,621,147

Source: U.S. Environmental Protection Agency, "Report to Congress: Solid Waste Disposal in the United States," Volume

II, Table 3-5, October 1988. The entries in each column may not add to their respective totals because of rounding. aThe Primary Metals Industry includes only SICs 332 (Primary Iron and Steel) and 333 (Primary Non-ferrous Metals). b Chemicals and Allied Products includes only SICs 281 (Industrial Inorganic Chemicals), 282 (Plastics and Resins c Manufacturing), 286 (Industrial Organic Chemicals), and 287 (Fertilizer and Agricultural Chemicals). Electric, Gas, and Sanitary Services includes only 4911 (Electric Power Generation) and 4941 (Water Treatment). d

### Page 8-23 Exhibit 8-8 Active Non-Hazardous Industrial Waste Management Units in 1985 by Major Industry Group

Major Industry Group (SIC) Landfill Impoundment Application Piles Total Number of Treatment or Disposal Units Surface Land Waste Food and Kindred Products (20) 194 4,166 3,128 540 8,028 Stone, Clay, Glass, and Concrete Products 1,257 3,152 309 2,528 7,246 (32) Paper and Allied Products (26) 259 918 139 232 1,548 Electric Power Generation (4911) 155 1,220 43 110 1,528 Industrial Inorganic Chemicals 120 1,039 24 98 1,281 (2812-2819) Petroleum Refining (29) 61 915 114 158 1,248 Primary Iron and Steel (3312-3321) 201 383 76 464 1,124 Water Treatment (4941) 121 659 147 48 975 Textile Manufacturing (22) 28 741 72 103 944 Primary Non-ferrous Metals (3330-3399) 111 448 9 312 880 Transportation Equipment (37) 63 287 11 362 723 Fertilizer and Agricultural Chemicals 31 274 160 50 515 (2873-2879) Rubber and Miscellaneous Products (30) 77 176 16 123 392 Industrial Organic Chemicals (286) 17 262 27 79 385 Plastics and Resins Manufacturing (2821) 32 292 17 32 373 Selected Chemicals and Allied Products 21 219 17 41 298 (28, except sectors otherwise noted) Leather and Leather Products (31) 9 102 0 54 165

Total 2,757 15,253 4,308 5,335 27,653 a

Source: Report to Congress, "Solid Waste Disposal in the United States," Volume II, EPA, Office of Solid Waste and Emergency Response, October 1988. The entries in each column may not add to their respective totals because of rounding. a

### Page 8-24 Surface impoundments, land application, landfills, and waste piles are clearly not the only management technologies that can be used for non-hazardous industrial wastes. The totals in Exhibit 8-7 do not reflect all of the possible options for waste management. Exhibit 8-9 provides data from theIndustrial D Industry Profiles discussed in Section 8.1 relating to non-hazardous industrial waste management practices in some industries occurring most frequently in the release descriptions. Most of these data are from the 1987 TSDR, and some are from the ISDB. Waste management practices summarized in this source are substantially different from those shown previously. The data are more detailed, and information is given for additional management methods, including container/tank storage, wastewater treatment systems, underground injection, recycle/reuse, and incineration.
The TSDR/ISDB data identify wastewater treatment systems (WWT and tank systems) as the dominant management methods for most industries, instead of surface impoundments. This difference may be partially due to the characterization of management units in the two surveys. Many of the units identified as “impoundments” in the TSS may have been identified as “WWT units” in the TSDR or ISDB. Also, the populations of facilities and wastes covered in the two surveys are different. For example, the TSDR Survey covered facilities in a wide range of industries, but only if they managed hazardous waste. The ISDB, on the other hand, covered a broader range of facilities, but only if they were in certain industry groups. In any event, the two sources generally agree that land-based treatment for aqueous wastes is the dominant management method for non-hazardous industrial wastes. Land application, landfills, and waste piles show up as relatively minor management technologies, by volume, in the TSDR/ISDB data, consistent with the TSS data. Underground injection is also a minor but not insignificant management technology, accounting for up to approximately three percent of total waste management in the industries where it is most widely used. Some non-hazardous industrial wastes from all of the industries evaluated are recycled or reused (up to about 1.5 percent). Incineration also accounted for less than one percent of all non-hazardous industrial wastes managed in the various industries. The only waste management technology identified as being important for any industry other than those mentioned is “other processes/methods,” which accounted for almost 50 percent of the wastes managed from the stone, clay, glass, and concrete industry. The process used to manage these wastes was not indicated, but it may include use in roadbed or fill. 8.3.2 Management Practices Seen in the Release Descriptions The release descriptions for non-hazardous industrial waste management contain information about the types of management units at which releases to the environment have occurred. This source provides some direct evidence as to which types of management practices have the greatest potential for causing releases to the environment. Its major limitations, however, are that it covers only facilities for which data were readily available, namely regulated units, and that some of releases are relatively old.

### Page 8-25 Exhibit 8-9 Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons) Major Waste (thousand

a,b 

### TotalAmoun t

Chemicals and Allied Aqueous Liquid WWT & Tank Systems 79,669 Products (280, 282 (except Organic Liquid 2821), 285, 288, 289 (except 2891, 2892, 2893)) c 

### Surface Impoundments 2,029 c 

### Underground Injection 236 c 

### Incineration 43

c 

### Landfill 14

c 

### Other Processes/Methods 8 c 

### Recycle/Reuse 4

c 

### Land Application <1 b 

### Industrial Inorganic Aqueous Liquid WWT & Tank Systems 25,421 Chemicals (281) Solid Residue Gas Sludge/Slurry c



### Underground Injection 958 c 

### Recycle/Reuse 752

b 

### Other Processes/Methods 395 b 

### Waste Pile Storage 356 b 

### Surface Impoundments 263 b 

### Landfill 43

b 

### Incineration 2

c 

### Plastics and Resins (2821) Aqueous Liquid WWT & Tank Systems 68,414 c 

### Surface Impoundments 45,842 c 

### Underground Injection 421 b 

### Landfill 132

b 

### Recycle/Reuse 73

b 

### Land Application 41 b 

### Incineration 25

b 

### Waste Pile Storage 5 b 

### Other Processes/Methods 3 b 

### Container/Tank Storage <1 b

### Exhibit 8-9 (continued) Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons) Major Waste (thousand

a,b 

### TotalAmoun t

Page 8-26 Drug and Medical Products Aqueous Liquid WWT & Tank Systems 197,143 (283) c 

### Recycle/Reuse 1,818

c 

### Surface Impoundments 193 c 

### Underground Injection 126 c 

### Incineration 18

c 

### Landfill <1

c 

### Industrial Organic Chemicals Aqueous Liquid WWT & Tank Systems 182,642 (268) Gas Organic Liquid c



### Surface Impoundments 78,193 c 

### Recycle/Reuse 3,867

b 

### Other Processes/Methods 3,705 b 

### Underground Injection 3,296 b 

### Incineration 1,667

b 

### Landfill 1,406

b 

### Land Application 225 b 

### Other Processes/Methods 33 c 

### Container/Tank Storage 7 b 

### Waste Pile Storage 3 c 

### Agricultural Chemicals (287) Aqueous Liquid WWT & Tank Systems 110,869 c 

### Surface Impoundments 664 c 

### Underground Injection 462 b 

### Other Processes/Methods 122 c 

### Incineration 52

b 

### Landfill 37

b 

### Land Application 29 b 

### Container/Tank Storage 20 b 

### Recycle/Reuse 13

b 

### Waste Pile Storage 2 b

### Exhibit 8-9 (continued) Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons) Major Waste (thousand

a,b 

### TotalAmoun t

Page 8-27 Products of Petroleum and Aqueous Liquid WWT & Tank Systems 137,446 Coal (29) Sludge/Slurry c 

### Land Application 2,323 b 

### Recycle/Reuse 2,189

b 

### Underground Injection 1,946 b 

### Surface Impoundments 1,237 c 

### Other Processes/Methods 513 b 

### Container/Tank Storage 107 b 

### Landfill 64

b 

### Incineration 6

c 

### Waste Pile Storage 5 c 

### Stone, Clay, Glass, and NA Concrete (32) WWT & Tank Systems 2,210 c 

### Other Processes/Methods 2,174 c 

### Surface Impoundments 180 c 

### Recycle/Reuse 38

c, d 

### Steel Works, Blasting (331) Aqueous Liquid WWT & Tank Systems 428,486 c 

### Recycle/Reuse 2,216

b 

### Surface Impoundments 390 c 

### Underground Injection 332 b 

### Other Processes/Methods 258 b 

### Landfill 47

b 

### Incineration 19

b 

### Container/Tank Storage <1 b 

### Waste Pile Storage <1 c 

### Iron and Steel Foundries NA Surface Impoundments 1,335 (332) c 

### Waste Pile Storage 39 c 

### Other Processes/Methods 39 c

### Exhibit 8-9 (continued) Non-Hazardous Industrial Waste Management by Industry

and Waste Type from TSDR and ISDB

Industry Group (SIC) Type(s) Management Type(s) metric tons) Major Waste (thousand

a,b 

### TotalAmoun t

Page 8-28 Nonferrous Metals Primary NA WWT & Tank Systems 6,656 Smelting (333) c 

### Landfill 24

c 

### Recycle/Reuse <1

c 

### Fabricated Metal Products Aqueous Liquid WWT & Tank Systems 11349 (34) Sludge/Slurry c 

### Surface Impoundments 668 c 

### Other Processes/Methods 15 c 

### Incineration 4

c 

### Landfill 2

b 

### Recycle/Reuse <1

b 

### Container/Tank Storage <1 b 

### Electronics & Other NA WWT & Tank Systems 21,463 Electronic Equipment (36) c 

### Surface Impoundments 1,447 c 

### Recycle/Reuse 10

c 

### Incineration 5

c

NA - No data available Includes waste types greater than 1% of total aISDB b TSDR; total does not include gases cReuse of fuel only d

### Page 8-29 Exhibit 8-10 tabulates by industry the number of waste management units of different types found in the release descriptions. Of the 120 waste management units identified in the release descriptions, 73 (61 percent) are landfills, while 28 (23 percent) are surface impoundments. Twelve land application units (10 percent) and 4 waste piles were also identified, along with one trench, 1 evaporation pond, and 1 stormwater retention pond. These data provide a somewhat different picture than would be expected, merely based on the number of management units in the various industries and the volumes of wastes managed in different types of units. Despite the preponderance of landfills in the release descriptions, the vast majority of the non-hazardous industrial wastes are being managed (or were being managed at the time of the TSS) in surface impoundments. As shown in Exhibit 8-8, for the industries presented, there are 15,253 surface impoundments versus only 2,757 landfills. Several possible explanations for this apparent discrepancy can be advanced. First, better groundwater monitoring data may be available for landfills than for surface impoundments. Second, management methods may have changed substantially in the last 11 years. This explanation seems unlikely; surface impoundments or related treatment systems probably will remain a management method of choice as long as aqueous wastes are the dominant waste form. Some movement to tanks or other treatment systems may have occurred, and process changes may also have reduced the volume of liquid wastes, but EPA has no information as to how extensive these changes may have been. In any event, a large-scale shift away from surface impoundments to landfills seems unlikely, simply based on cost considerations, even if it was technically feasible for some wastes. Another possible explanation is that the initial concentrations of potentially toxic constituents may be lower, on average, for surface impoundments than for landfills, and the highly concentrated solid residues from the impoundments may themselves end up in landfills, or the surface impoundments may be closed as landfills. Finally, design features of non-hazardous industrial waste landfills may make them more prone to releases, although the other factors just discussed are likely to be more important. 8.3.3 Potential Hazards Associated with Use Constituting Disposal Few data are available on use that constitutes disposal (UCD) of solid wastes, which is regulated at the state level. Some data, however, are available for one category of these wastes: certain delisted wastes that are now being used in a manner constituting disposal. In the first case discussed below, a full risk assessment of UCD was not done at the time the waste was delisted. In the second case, pending proposals at the federal level would authorize UCD of delisted wastes; some states, however, may already be permitting some UCD practices for these wastes under other regulatory provisions. Delisted K088 (spent potliners from primary aluminum reduction) that has been treated with lime and heated in a rotary kiln by a specific petitioner and subsequently disposed of primarily in a monofill has caused high leaching rates of cyanides, fluoride, and arsenic. While the treatment residue passes the TCLP test, the leachate from the monofill exceeds the TC level for arsenic and the delisting requirements for cyanides and fluoride. The treatment residual also has a pH of approximately 12.9 and is hazardous and not covered by the petitioner's exclusion. This K088 treatment residual also has been used for on-site road construction, under a state RCRA Subtitle D management permit. A recent site inspection found, after rainfall, large puddles of dark colored water, the same color as the treatment residue used to build the road. Samples of the runoff water are currently being analyzed.

### Page 8-30 Exhibit 8-10 Waste Management Unit Types in the Release Descriptionsa

Industry Group Evaporation Lagoon/ Surfac e Land Retention Waste Pond Impoundment Application Landfill Pond Trench Pile Total Stormwater
Agricultural Production-Livestock (02) 1 1 2 Apparel and Other Textile Products (23) 1 1 Chemicals and Allied Products (28) 6 5 11 Electric, Gas, Sanitary Services (49) 2 33 35 Electronic and Other Electronic Equipment (36) 1 1 2 Fabricated Metal Products (34) 1 2 1 4 Food and Kindred Products (20) 6 7 13 Industrial Machinery and Equipment (35) 1 1 Instruments and Related Products (38) 1 1 Nonmetallic Minerals, Except Fuels (14) 1 3 4 Paper and Allied Products (26) 5 1 23 29 Petroleum Refining (29) 1 2 1 4 Primary Metal Industries (33) 1 2 1 3 7 Stone, Clay, and Glass Products (32) 1 1 2 Transportation Equipment (37) 1 1 2 4 Total Units 1 28 12 73 1 1 4 120 A facility may have more than one waste management unit. a59Federal Register 67256, December 29, 1994. 8


### Page 8-31 This case raises two issues: The appropriateness of the TCLP test for evaluating the leaching potential of this waste treatment residual. The potential unevaluated risks from runoff from this material when used in a manner constituting disposal. The first issue is discussed in Section 3.6. With respect to the second issue, EPA will evaluate the runoff risks from this site and potentially risks from other instances where states have permitted uses constituting disposal for non-hazardous industrial waste. Risks from some UCD practices for some delisted wastes may not be fully understood. Comments on UCD proposals to allow several uses of high temperature metals recovery (HTMR) slags derived from K061, K062, and F006 listed wastes expressed concern about the completeness of risk evaluation. The proposed rulewould allow the de- 8 

### listed HTMR slags to be used in road building as top grade material, as aggregate in cement, and as anti-skid material. EPA evaluated the risk from these materials using the TCLP test to estimate potential for leaching to groundwater. Commentors, however, expressed concerns about risks from surface runoff and wind-blown dust pathways and risks to workers. At the time of the proposal in December 1994, models to evaluate non-groundwater pathway risks were not adequately developed. Since then, such models have been developed and were used in a major rulemaking proposal, the December 1995 HWIR-Waste proposal. These models are undergoing revision in response to comments by the public and the Science Advisory Board (SAB). The modeling developed to support HWIR-Waste could be used to evaluate UCD of de-listed HTMR slags or other stabilized waste once the models are refined. 8.3.4 Potential Hazards Associated with Other Management Practices As noted in Section 8.3.1, it is clear that some non-hazardous industrial wastes are being managed in ways that do not involve treatment or final disposal in land-based units such as surface impoundments or landfills. These other management approaches may also pose potential risks to human health and the environment. In the courseof the Scoping Study, the Agency has found little recent, reliable information as to the types and volumes of nonhazardous industrial wastes being managed using other technologies. A major complication in this regard is that, unlike the situation for hazardous wastes, generators are not required by federal regulations to identify or report non-hazardous industrial wastes, process residuals, or byproducts. Thus, any residual or byproduct material that has potential economic value does not need to be identified as a waste, and instead may simply be used or sold without restriction. In such cases, the distinction between what constitutes the simple commercial sale of a material that happens to be a byproduct of an industrial process, recycling, or use constituting disposal of a non-hazardous industrial waste may not be clear. Putting this problem aside, it is certain that some non-hazardous wastes are being managed using techniques other than land storage, treatment, or disposal. Some of these technologies, such as incineration, unambiguously involve releases to the environment. Others such as recycling and reuse may involve releases, depending upon the nature of the use of the materials. In EPA’s search for release descriptions, no instances were found where any of these alternative management methods had resulted in documented environmental releases meeting the stringent release selection criteria. In addition, as noted previously, the state non-hazardous industrial waste programs that constitute the major source of the release descriptions may not regulate some of these alternative waste management technologies. Thus, the available data do not allow a conclusion to be drawn about

### Page 8-32

whether and to what extent such management methods may pose significant risks to human health or the environment. This data gap is discussed in more detail in Chapter 10.

### Page 8-33

CHAPTER 8. POTENTIAL GAPS AS FUNCTION OF INDUSTRY AND WASTE MANAGEMENT METHODS 8-1
8.1 Data Sources and Major Limitations

.................................. 8-1
8.2 Potential Gaps as a Function of Industry/Waste Source

................... 8-2
8.2.1 Non-Hazardous Industrial Waste Generation by Industry

........... 8-3 8.2.2 Industries Responsible for Documented Non-Hazardous Industrial Waste Releases

.................................................. 8-5 8.2.3 Occurrence of High-Hazard Industrial Waste Constituents by Industry 8-8 8.2.4 Industries Reporting Releases of TC Analytes or Known or Possible NonHazardous Industrial Waste Constituents

....................... 8-18 8.3 Potential Gaps as a Function of Management Practices

.................. 8-21
8.3.1 Waste Management Practices by Waste Type and Industry

......... 8-21 8.3.2 Management Practices Seen in the Release Descriptions

........... 8-28 8.3.3 Potential Hazards Associated with Use Constituting Disposal

...... 8-30 8.3.4 Potential Hazards Associated with Other Management Practices

.... 8-31

### Page 8-34

Exhibit 8-1 Estimated Generation of Non-Hazardous Industrial Waste by Major Industry Group

... 8-4
Exhibit 8-2 Chemicals Exceeding Health-Based and Non-Health-Based Regulatory Levels in the

Release Descriptions for Non-Hazardous Waste Management

..................... 8-6
Exhibit 8-3 Numbers of Chemical Detections and Frequencies of Regulatory Exceedences in

Release Descriptions

..................................................... 8-7
Exhibit 8-4 Most Frequently Occurring Constituents in the Release Descriptions

............... 8-9
Exhibit 8-5 Occurrence of Waste Constituents by Industry Group

.......................... 8-11
Exhibit 8-6 Non-Hazardous Industrial Waste Constituents Reported Released by Industry

....... 8-19
Exhibit 8-7 Volume of Non-Hazardous Industrial Waste Managed in Land-Based Facilities in

1985

................................................................. 8-22
Exhibit 8-8 Active Non-Hazardous Industrial Waste Management Units in 1985 by Major

Industry Group

......................................................... 8-23 Exhibit 8-9 Non-Hazardous Industrial Waste Management by Industry and Waste Type from TSDR

and ISDB

............................................................. 8-24
Exhibit 8-10 Waste Management Unit Types in the Release Descriptions

..................... 8-29EXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY Type of SIC 20 SIC 21 SIC 22 SIC 24 SIC 25 SIC 26 SIC 27 SIC 28 SIC 29 SIC 30 SIC 31 Chemical Namea Chemical UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L 1,1,1-TRICHLOROETHANE VCO 5 25 0 0 0 0 0 0 0 5,800 0 0 0 975 553 1,826 0 288 0 17,403 0 0 1,2-DICHLOROETHANE VCO 0 1,000 0 0 0 0 0 0 0 0 0 0 0 0 6,927 858 0 0 0 0 0 0 1,3-BUTADIENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 0 0 0 0 0 0 ACETALDEHYDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 0 0 0 0 0 0 ACETONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 0 0 0 0 0 0 ACRYLAMIDE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 0 0 0 0 0 0 ACRYLONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 30 0 0 3,795,670 387 0 0 0 7,654 0 0 ANILINE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 0 0 0 0 0 0 BENZENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 268,921 225,952 78,162 114,164 0 0 0 0 BROMOMETHANE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 0 0 0 0 0 0 CARBON DISULFIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 5 0 16 0 0 0 0 CHLOROBENZENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 0 0 0 0 0 0 CHLOROFORM VCO 0 0 0 0 0 0 0 0 0 0 0 11,582 0 0 50,240 17,000 0 0 0 0 0 0 CHLOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 0 0 0 0 0 0 CHLOROPRENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 0 0 0 0 1,811 0 0 CHROMIUM IO 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4,550 0 2,226 0 2 0 7,707 COPPER M/I 0 0 0 0 0 0 5 250 0 0 0 0 0 0 16,460 14,810 0 0 0 0 0 0 CUMENE VH 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11,000 315 4,100 468 0 0 0 0 DICHLORODIFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 0 0 0 0 0 0 DICHLOROMETHANE VCO 0 2,100 0 0 0 0 0 0 0 0 0 251 0 0 1,183,867 377 0 10 0 46,620 0 0 ETHYLBENZENE VH 0 0 0 0 0 0 0 0 0 250 0 0 0 0 190,648 5,735 3,234 271,175 0 0 0 0 FORMALDEHYDE OVO 0 200 0 0 0 0 0 10,139 0 0 0 4,336 0 0 4,916,248 16,314 0 0 0 0 0 0 FREON 113 CFC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17 6 0 0 0 0 0 0 METHANOL OVO 0 20,250 0 0 0 12,482 0 17,495 0 80,327 0 2,957,167 0 3,000 26,852,673 220,185 230,590 1,582 0 0 0 0 METHYL ETHYL KETONE OVO 0 0 0 0 0 0 0 250 0 27,931 0 6,873 0 0 325,390 26,226 40,000 748 0 10,770 0 0 METHYL ISOBUTYL KETONE OVO 0 0 0 0 0 0 0 0 0 139,400 0 0 0 0 129,100 1,823 0 35 0 0 0 0 METHYL METHACRYLATE OVO 0 0 0 0 0 0 0 0 0 0 0 11 0 0 220,000 1,742 0 0 0 2,250 0 0 N-BUTYL ALCOHOL OVO 0 0 0 0 0 0 0 0 0 8,856 0 0 0 0 2,324,731 519 0 0 0 0 0 0 NAPHTHALENE OSO 0 0 0 5 0 0 0 1 0 0 0 8,445 0 0 60,654 23,191 573 1,539,299 0 0 0 0 PROPYLENE OXIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 0 0 0 0 0 0 STYRENE VH 0 0 0 0 0 0 0 0 0 0 0 5 0 0 83,170 60,330 0 0 0 141,153 0 0 TETRACHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12,780 4,264 0 0 0 1,495 0 0 TOLUENE VH 0 0 0 0 0 0 0 434 0 65,114 0 798 0 4,300 1,547,118 26,211 26,778 546,483 0 5 0 0 TRICHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 466 1 0 0 0 0 0 0 TRICHLOROFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 18,912 0 0 0 0 0 0 VINYL CHLORIDE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 0 0 3,100 XYLENE (MIXED ISOMERS) VH 0 0 0 0 0 0 1 0 0 44,914 0 250 0 40 200,309 3,129 18,835 1,142,430 5 0 0 0 ZINC (FUME OR DUST) M/I 0 250 0 0 0 5 0 5 0 0 0 1,100 0 0 120,000 28,710 0 0 0 250 0 0 Total 5 23,825 0 5 0 12,487 11 28,574 0 372,592 0 2,990,848 0 8,315 69,938,141 709,301 402,272 3,618,924 5 229,413 0 10,807 Source: 1992 TRI data. UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6a.txtEXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY (continued) Type of SIC 20 SIC 21 SIC 22 SIC 24 SIC 25 SIC 26 SIC 27 SIC 28 SIC 29 SIC 30 SIC 31 Chemical Namea Chemical UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L UI L 1,1,1-TRICHLOROETHANE VCO 5 25 0 0 0 0 0 0 0 5,800 0 0 0 975 553 1,826 0 288 0 17,403 0 0 1,2-DICHLOROETHANE VCO 0 1,000 0 0 0 0 0 0 0 0 0 0 0 0 6,927 858 0 0 0 0 0 0 1,3-BUTADIENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 0 0 0 0 0 0 ACETALDEHYDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 0 0 0 0 0 0 ACETONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 0 0 0 0 0 0 ACRYLAMIDE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 0 0 0 0 0 0 ACRYLONITRILE OVO 0 0 0 0 0 0 0 0 0 0 0 30 0 0 3,795,670 387 0 0 0 7,654 0 0 ANILINE OSO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 0 0 0 0 0 0 BENZENE VO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 268,921 225,952 78,162 114,164 0 0 0 0 BROMOMETHANE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 0 0 0 0 0 0 CARBON DISULFIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 5 0 16 0 0 0 0 CHLOROBENZENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 0 0 0 0 0 0 CHLOROFORM VCO 0 0 0 0 0 0 0 0 0 0 0 11,582 0 0 50,240 17,000 0 0 0 0 0 0 CHLOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 0 0 0 0 0 0 CHLOROPRENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 0 0 0 0 1,811 0 0 CHROMIUM IO 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 4,550 0 2,226 0 2 0 7,707 COPPER M/I 0 0 0 0 0 0 5 250 0 0 0 0 0 0 16,460 14,810 0 0 0 0 0 0 CUMENE VH 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11,000 315 4,100 468 0 0 0 0 DICHLORODIFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 0 0 0 0 0 0 DICHLOROMETHANE VCO 0 2,100 0 0 0 0 0 0 0 0 0 251 0 0 1,183,867 377 0 10 0 46,620 0 0 ETHYLBENZENE VH 0 0 0 0 0 0 0 0 0 250 0 0 0 0 190,648 5,735 3,234 271,175 0 0 0 0 FORMALDEHYDE OVO 0 200 0 0 0 0 0 10,139 0 0 0 4,336 0 0 4,916,248 16,314 0 0 0 0 0 0 FREON 113 CFC 0 0 0 0 0 0 0 0 0 0 0 0 0 0 17 6 0 0 0 0 0 0 METHANOL OVO 0 20,250 0 0 0 12,482 0 17,495 0 80,327 0 2,957,167 0 3,000 26,852,673 220,185 230,590 1,582 0 0 0 0 METHYL ETHYL KETONE OVO 0 0 0 0 0 0 0 250 0 27,931 0 6,873 0 0 325,390 26,226 40,000 748 0 10,770 0 0 METHYL ISOBUTYL KETONE OVO 0 0 0 0 0 0 0 0 0 139,400 0 0 0 0 129,100 1,823 0 35 0 0 0 0 METHYL METHACRYLATE OVO 0 0 0 0 0 0 0 0 0 0 0 11 0 0 220,000 1,742 0 0 0 2,250 0 0 N-BUTYL ALCOHOL OVO 0 0 0 0 0 0 0 0 0 8,856 0 0 0 0 2,324,731 519 0 0 0 0 0 0 NAPHTHALENE OSO 0 0 0 5 0 0 0 1 0 0 0 8,445 0 0 60,654 23,191 573 1,539,299 0 0 0 0 PROPYLENE OXIDE OVO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 0 0 0 0 0 0 STYRENE VH 0 0 0 0 0 0 0 0 0 0 0 5 0 0 83,170 60,330 0 0 0 141,153 0 0 TETRACHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12,780 4,264 0 0 0 1,495 0 0 TOLUENE VH 0 0 0 0 0 0 0 434 0 65,114 0 798 0 4,300 1,547,118 26,211 26,778 546,483 0 5 0 0 TRICHLOROETHYLENE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 466 1 0 0 0 0 0 0 TRICHLOROFLUOROMETHANE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 18,912 0 0 0 0 0 0 VINYL CHLORIDE VCO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 6 0 0 0 0 0 3,100 XYLENE (MIXED ISOMERS) VH 0 0 0 0 0 0 1 0 0 44,914 0 250 0 40 200,309 3,129 18,835 1,142,430 5 0 0 0 ZINC (FUME OR DUST) M/I 0 250 0 0 0 5 0 5 0 0 0 1,100 0 0 120,000 28,710 0 0 0 250 0 0 Total 5 23,825 0 5 0 12,487 11 28,574 0 372,592 0 2,990,848 0 8,315 69,938,141 709,301 402,272 3,618,924 5 229,413 0 10,807 Source: 1992 TRI data. UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6b.txtEXHIBIT 8-6 TRI REPORTED RELEASES TO LAND OR UNDERGROUND INJECTION BY CONSTITUENT AND INDUSTRY (continued) Type of Chemical Namea Chemical 1,1,1-TRICHLOROETHANE VCO 1,2-DICHLOROETHANE VCO 1,3-BUTADIENE VO ACETALDEHYDE OVO ACETONITRILE OVO ACRYLAMIDE OSO ACRYLONITRILE OVO ANILINE OSO BENZENE VO BROMOMETHANE OVO CARBON DISULFIDE OVO CHLOROBENZENE VCO CHLOROFORM VCO CHLOROMETHANE VCO CHLOROPRENE VCO CHROMIUM IO COPPER M/I CUMENE VH DICHLORODIFLUOROMETHANE VCO DICHLOROMETHANE VCO ETHYLBENZENE VH FORMALDEHYDE OVO FREON 113 CFC METHANOL OVO METHYL ETHYL KETONE OVO METHYL ISOBUTYL KETONE OVO METHYL METHACRYLATE OVO N-BUTYL ALCOHOL OVO NAPHTHALENE OSO PROPYLENE OXIDE OVO STYRENE VH TETRACHLOROETHYLENE VCO TOLUENE VH TRICHLOROETHYLENE VCO TRICHLOROFLUOROMETHANE VCO VINYL CHLORIDE VCO XYLENE (MIXED ISOMERS) VH ZINC (FUME OR DUST) M/I Total SIC 32 SIC 33 SIC 34 SIC 35 SIC 36 SIC 37 SIC 38 SIC 39 Invalid Total UI L UI L UI L UI L UI L UI L UI L UI L UI L Total UI Total Land Combined 0 0 0 2,916 0 39,778 0 6,805 3 10 0 200 0 350 0 0 0 0 561 76,381 76,942 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6,927 1,858 8,785 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 372 1,372 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,905,859 289 1,906,148 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20,111,640 29 20,111,669 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,188,680 963 4,189,643 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 65,880 0 3,861,550 8,071 3,869,621 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,195,676 1,173 1,196,849 0 0 8,600 500 0 0 0 0 0 0 0 20 0 0 0 0 0 0 355,683 340,636 696,319 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,000 0 1,000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2,704 21 2,725 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,000 817 72,817 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 50,240 28,582 78,822 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 86,709 0 86,709 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 54,000 1,811 55,811 0 10,526 8 842,104 70 75,306 0 13,226 0 500 250 455 0 510 0 0 0 0 333 957,112 957,445 0 767 271 12,579,039 0 18,368 0 2,620 0 25,709 0 5,130 0 0 0 645 0 0 16,736 12,647,338 12,664,074 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 15,100 783 15,883 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1,722 23 1,745 0 77 0 12,705 0 0 0 17,101 0 12 0 0 0 60 0 0 0 0 1,183,867 79,313 1,263,180 0 0 0 0 0 11,510 0 48 0 0 0 0 0 0 0 0 0 390 193,882 289,108 482,990 0 105,331 0 38,109 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4,916,248 174,429 5,090,677 0 0 0 0 0 0 0 0 197 850 0 250 0 7,922 0 0 0 0 214 9,028 9,242 0 0 0 411 0 4,296 0 2,305 169 0 0 9,041 0 0 0 0 750 0 27,084,182 3,328,541 30,412,723 0 0 0 0 0 95,930 0 62,575 5 0 0 8,291 0 1,500 0 0 0 700 365,395 241,794 607,189 0 0 0 750 0 23,381 0 21,235 0 0 0 8,291 0 0 0 0 0 71 129,100 194,986 324,086 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 220,000 4,003 224,003 0 0 0 0 0 46,865 0 190 0 0 0 0 0 0 0 0 0 790 2,324,731 57,220 2,381,951 0 0 17,000 96,200 0 0 0 0 0 0 0 0 0 0 0 0 0 0 78,227 1,667,141 1,745,368 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200 2,251 2,451 0 97,000 0 5 0 0 0 0 0 0 0 5,686 0 0 0 0 0 0 83,170 304,179 387,349 0 5 0 0 0 3,585 0 5 0 0 0 0 0 0 0 0 0 0 12,780 9,354 22,134 0 4,926 0 750 0 41,652 0 4,196 5 5 0 8,944 0 0 0 250 0 4,210 1,573,901 708,278 2,282,179 0 0 0 10,050 0 2,250 0 0 0 0 0 8,420 0 5 0 0 0 0 466 20,726 21,192 0 0 0 0 0 250 0 599 0 0 0 0 0 0 0 0 0 0 8 19,761 19,769 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 3,106 3,107 0 5 0 102,068 0 104,695 0 1,337 120 4,350 0 10,961 0 0 0 250 0 10,600 219,270 1,434,429 1,653,699 0 0 0 12,785,679 0 122,303 0 0 0 0 0 102,816 0 0 0 0 0 5 120,000 13,041,123 13,161,123 0 218,637 25,879 26,471,286 70 590,169 0 132,242 499 31,436 250 168,505 0 10,347 0 1,145 66,630 16,766 70,433,762 35,655,029 106,088,791 Source: 1992 TRI data. UI = Underground Injection Industry Groups (SIC) 30 = Rubber and Miscellaneous Plastics Products L = Land 20 = Food and Kindred Products 31 = Leather and Leather Products VCO = Volatile Chlorinated Organics 21 = Tobacco Products 32 = Stone, Clay and Glass Products OVO = Other Volatile Organics 22 = Textile Mill Products 33 = Primary Metal Industries OSO = Other Semivolatile Organics 24 = Lumber and Wood Products 34 = Fabricated Metal Products M/I = Metals/Inorganics 25 = Furniture and Fixtures 35 = Industrial Machinery and Equipment VH = Volatile Hydrocarbons 26 = Paper and Allied Products 36 = Electronic and Other Electronic Equipment IO = Inorganics 27 = Printing and Publishing 37 = Transportation Equipment VO = Volatile Organics 28 = Chemicals and Allied Products 38 = Instruments and Related Products CFC = Chlorofluorocarbons 29 = Petroleum Refining 39 = Miscellaneous Manufacturing Products

8-6b.txtConstituents are included in Appendix VIII if a reputable scientific study has found that the constituent has toxic, 1 carcinogenic, mutagenic, or teratogenic effects on humans or other forms of life.

Page 9-1 

# CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED

BY EXISTING REGULATIONS

The potential gaps described in Chapters 3 and 4 of this Scoping Study were identified solely in terms of their relationship to non-hazardous industrial waste management, and not with regard to whether they might be controlled under RCRA or other regulatory programs. This chapter examines the extent to which existing regulatory programs may already address these potential gaps and thereby helps to evaluate the extent of the potential gaps. The programs reviewed are as follows:

RCRA, Clean Water Act (CWA), Safe Drinking Water Act (SDWA), Clean Air Act (CAA), Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), Toxic Substances Control Act (TSCA), Pollution prevention initiatives, Occupational Safety and Health Act (OSHA), and Hazardous Materials Transportation Act (HMTA). The regulatory control provided by these programs is reviewed in general terms, rather than in detail. Further analysis would be necessary to determine the precise degree of protection that these programs provide against particular risks. 9.1 RCRA Programs Where there are gaps in the hazardous waste characteristics, the RCRA hazardous waste listings and Subtitle D program may reduce any resulting human health and environmental risks. These two programs are discussed below, including both the direct federal regulatory authorities and state-delegated authorities. 9.1.1 Hazardous Waste Programs As described in RCRA Section 3001(a)-(b), EPA is required to develop regulations that both specify criteria for listing hazardous waste and to list particular hazardous wastes. In 40 CFR 261.11, EPA has specified three criteria for listing solid wastes as hazardous:

The waste exhibits a hazardous characteristic; The waste is acutely hazardous because is has been found to be fatal to humans in low doses, or is otherwise capable of causing or significantly contributing to an increase in serious irreversible, or incapacitating reversible, illness; or The waste contains a toxic constituent listed in 40 CFR Part 261, Appendix VIIIand, 1 

### after considering several risk-based and non risk-based factors, is capable of posing aPage 9-2 

### substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.
EPA has established four hazardous waste lists:

Hazardous waste from non-specific sources, or F wastes; Hazardous wastes from specific sources, or K wastes; Discarded commercial chemicals that are toxic, or P wastes; and Discarded commercial chemicals that are acutely hazardous, or U wastes. Because the F and K listings focus on waste streams, rather than on particular constituents, identification of a chemical as a constituent in a listed F or K waste does not automatically imply that all or most industrial wastes containing that constituent are regulated by the hazardous waste listings. For example, the F003 listing regulates benzene when it is a spent solvent, but does not regulate other benzene-containing wastes such as petroleum refining wastes. Similarly, for a chemical to be controlled by a P or U listing, it must be a discarded commercial product. If the source of the chemical is different (e.g., from a waste mixture that is not covered by an F or K listing), it is not regulated as a listed waste. For example, 2,4-dimethylphenol, which is a listed Uwaste (U101) when it is a discarded commercial chemical, was found among the environmental releases from nonhazardous industrial waste management documented in Chapter 2. This chemical also was found in the other two sources of data on non-hazardous industrial waste constituents, the Industrial Studies Database (ISDB) and the Effluent Guidelines Development Documents. 40 CFR Part 261, Appendix VII contains the majority of the "known" non-hazardous industrial waste constituents, including:

40 of the 41 known non-hazardous industrial waste constituents found in all three major data sources: the release descriptions, ISDB,andthe effluent guideline development documents data; and
134 of all 248 known constituents.Although Appendix VII constituents are the basis for individual hazardous waste listings, they also appear in nonhazardous industrial wastes. The listings, therefore, do not regulate all wastes containing these constituents. Most states have developed their own hazardous waste programs and have received EPA approval to implement their regulations in lieu of the federal program. These state hazardous waste regulations may be broader or more stringent than federal RCRA Subtitle C regulations. A number of states have done so by regulating additional wastes as hazardous. For example, states have:

Expanded the ignitability, corrosivity, or reactivity (ICR) characteristics; Expanded the toxicity characteristic (TC); Listed wastes as hazardous that are not hazardous under the federal rules; and Restricted exemptions from the federal program. These expansions beyond the federal hazardous waste identification rules, which are discussed in Chapter 6, reflect state judgments about gaps in the federal program and thereby fill these potential gaps in particular states. Conversely, these expansions constitute potential gaps in other states. 9.1.2 Subtitle DPage 9-3 

### States have primary responsibility for managing non-hazardous industrial wastes. Under RCRA Subtitle D, the Federal Government only establishes minimum criteria that prescribe the best practicable controls and monitoring requirements for non-hazardous waste disposal facilities. EPA has developed separate criteria formunicipal solid waste landfills (MSWLFs), which must comply with the requirements of 40 CFR Part 258, and for nonhazardous industrial (Industrial D) land application units, which must comply with the requirements of 40 CFR Part 257. 40 CFR Part 258 specifies six categories of MSWLF criteria: location, operation, design, ground-water monitoring and corrective action, closure and post-closure care, and financial assurance. Most relevant to addressing potential gaps in the characteristics, any leachate from new MSWLFs (which began accepting waste after October 9, 1993) must not cause contaminant levels in the uppermost aquifer to exceed maximum contaminant levels (MCLs) specified under the Safe Drinking Water Act. In addition, all MSWLFs must be operated in a way that ensures that they do not release pollutants that violate the Clean Water Act. Beyond meeting the minimum federal criteria, approved States are permitted to develop their own standards for MSWLFs. The operating and design requirements for MSWLFs under Part 258 are designed to allow protective disposalof conditionally exempt small quantity generator hazardous waste (CESQG). As a result, MSWLFs can accept nonhazardous and CESQG waste from both municipal and industrial sources. Industrial D landfills can accept conditionally exempt small quantity generator (CESQG) waste (e.g., construction and demolition waste) only if they meet the location, groundwater monitoring and corrective action requirements specified in 40 CFR Part 257. Industrial D landfills that do not meet these requirements are not permitted to accept CESQG waste. To a limited extent, state non-hazardous industrial waste management programs address potential gaps in the hazardous waste characteristics. These state programs, however, vary considerably in the types of requirements imposed, the stringency of such requirements, and even the types of waste management units regulated. They do not provide uniform national coverage of non-hazardous industrial waste management. For example, despite the state requirements placed on these landfills, about 50 chemicals were found in the release descriptions at concentrations above MCLs, including a number of metals (e.g., zinc, nickel, mercury, and lead) and volatile chlorinated organics (e.g., vinyl chloride, carbon tetrachloride, chlorobenzene, and chloroform). Similarly, about 90 percent of all releases were found to be associated with unlined management units; not all states currently require Industrial D units to be lined. 9.2 Medium-Specific Regulations Medium-specific regulations such as the Clean Water Act, the Safe Drinking Water Act, and the Clean Air Act can both directly and indirectly address potential gaps in the hazardous waste characteristics. These programs regulate exposure via specific pathways of potential concern for non-hazardous industrial wastes, as discussed in Chapters 3 and 4. Medium-specific regulations also could indirectly address potential gaps by discouraging or preventing the occurrence of the specific constituents in non-hazardous industrial waste. For example, CWA regulations may cause a manufacturer to alter a production process so that a particular chemical that requires control is not used in the production process, thereby eliminating that constituent from its solid wastestream. Where substitutions or alterations in the production process are not feasible, however, the mediumspecific regulations could result in cross medium transfers, increasing the use of solid waste disposal as the preferred management method of the regulated constituents. The net effect of these two incentives on solid waste disposal practices is uncertain. 9.2.1 Clean Water Act The CWA is designed to restore and protect the physical, chemical, and biological quality of the nation's surface waters. To achieve this goal, all discharges to navigable waters must be permitted. To help permitPage 9-4



### writers, EPA has established effluent limitations for 127 toxic pollutants on direct discharges to waters by 34 industrial source categories and publicly-owned treatment works (POTWs). Permit writers use these guidelines to establish discharge limits and other permit conditions. Where effluent guidelines do not exist for an industry, permit writers use best engineering judgment to determine appropriate permit conditions. CWA regulations and permits directly limit exposures through surface water pathways. The CWA also indirectly addresses exposures to CWA regulated chemicals though other pathways by providing incentives for reducing or eliminating the use of such chemicals or for cross-media transfer of such chemicals. Chapter 3 identified three potential gaps in the current toxicity characteristic that may be addressed to some extent by the Clean Water Act:

Potential risks from direct surface water exposures; Potential indirect pathway risks involving surface waters; and Potential risks to ecological receptors involving surface waters. As discussed in Chapter 3, surface water exposure pathways may be significant for some TC analytes disposed as non-hazardous industrial waste. Because run-off waters from landfills must be managed according to the requirements of the CWA, risks to human health from surface water exposures are addressed if these TC analytes have effluent limits established under the CWA. These effluent limits may also address risks to ecological receptors from exposure surface water, principally at water bodies near waste management units contaminated from surface water run-off. In addition, persistent and bioaccumulative chemicals discharged to surface waters may contaminate fish and shellfish that, when consumed, cause indirect exposure risk to human health. CWA effluent limits can address indirect exposure risks from those TC analytes for which effluent limits are established. As Exhibit 9-1 demonstrates, CWA effluent limits are established for 28 of the TC constituents, including all of the TC metals except barium. Many of these TC constituents are commonly found in the release descriptions. For example, 7 of the top 20 frequently occurring constituents in the release descriptions are TC metals. Other TC constituents occurring five or more times in the release descriptions that have CWA effluent limits include benzene, vinyl chloride, chloroform, chlorobenzene, and tetrachloroethylene. Among these constituents, chlorobenzene, mercury, and lead can pose risks to ecological receptors.Page 9-5 

### Exhibit 9-1 TC Constituents with Effluent Limits Established under CWA

TC Analyte Limit TC Analyte Limit TC Analyte Limit CWA CWA CWA Effluent Effluent Effluent 1,1-Dichloroethylene

-- Chloroform Methyl ethyl ketone

-- 1,2-Dichloroethane Chromium Nitrobenzene 1,4-Dichlorobenzene Cresol (mixed isomers)

-- o-Cresol

-- 2,4,5-Trichlorophenol

-- Endrin p-Cresol

-- 2,4,6-Trichlorophenol Heptachlor Pentachlorophenol 2,4-D, salts and esters

-- Heptachlor epoxide Pyridine

-- 2,4-Dinitrotoluene Hexachlorobenzene Selenium Arsenic Hexachloro-1,3-butadiene

-- Silver Barium

-- Hexachloroethane Silvex (2,4,5-TP)

-- Benzene Lead Tetrachloroethylene Cadmium Lindane Toxaphene Carbon tetrachloride m-Cresol

-- Trichloroethylene Chlordane Mercury Vinyl chloride Chlorobenzene Methoxychlor

--


### The CWA effluent limitations may also address some of the potential gaps identified in Chapter 4 that are associated with non-TC constituents, including indirect pathway exposures to phenolic compounds, DNAPL formation by chlorinated organics, indirect pathway exposure to PAHs, and indirect pathway exposure to phthalate esters. For the CWA to address indirect pathway exposures to these chemicals, releases to surface water from regulated facilities must be involved. Exhibit 9-2 lists chemicals representative of these potential gaps and indicates which chemicals are subject to CWA effluent limitations. Effluent limitations are specified for 7 of the 8 and for 15 of the 18 phenols and PAHs, respectively, on the list of known non-hazardous industrial waste constituents. CWA effluent limitations also control surface water releases of the chemicals that are likely to form DNAPLs, including halogenated chemicals. Exhibit 9-2 lists 35 known non-hazardous volatile chlorinated organics. Of these chemicals, 18 are subject to effluent guideline limits. CWA effluent limitations are specified for all six of the phthalate esters on the list of known non-hazardous industrial waste constituents. Phthalate esters are one class of chemical that bioaccumulate in the environment and may be endocrine disruptors.Page 9-6 

### Exhibit 9-2 CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial Waste Constituents

Phenols Limit DNAPL formers) Limit PAHs Limit CWA CWA CWA Effluent Volatile Chlorinated Organics (Potential Effluent Effluent 2,4-Dimethylphenol 1,1,1,2-Tetrachloroethane

-- 2-Methylnaphthalene

-- 2,4-Dinitrophenol 1,1,1-Trichloroethane 7,12-Dimethylbenz[a]anthracene

-- 2-Nitrophenol 1,1,2,2-Tetrachloroethane Acenaphthene 4,6-Dinitro-o-cresol 1,1,2-Trichloroethane Acenaphthylene 4-Nitrophenol 1,2,3-Trichloropropane

-- Anthracene p-Chloro-m-cresol 1,2,4,5-Tetrachlorobenzene

-- Benz[a]anthracene Phenol 1,2,4-Trichlorobenzene Benzo(a)phenanthrene Phenolics

-- 1,2-Dibromo-3-chloropropane

-- Benzo(k)fluoranthene 1,2-Dichlorobenzene Benzo[a]pyrene 1,2-Dichloroethylene

-- Benzo[b]fluoranthene 1,2-Dichloroethylene, trans Benzo[ghi]perylene 1,2-Dichloropropane Dibenz[a,h]anthracene 1,3-Dichlorobenzene Fluoranthene 1,3-Dichloropropylene Fluorene Allyl chloride

-- Indeno(1,2,3-cd)pyrene Benzoic trichloride

-- Isophorone Bis(2-chloroethyl) ether Methapyrilene

-- Chlorobromomethane

-- Pyrene Chlorodibromomethane Chloroethane Chloromethane cis-1,2-Dichloroethylene

-- Dichloro-2-propanol, 1,3-

-- Dichlorobromomethane Dichlorodifluoromethane

-- Dichloromethane Dichloropropane

-- Epichlorohydrin

-- Ethylidene Dichloride Hexachlorocyclopentadiene Pentachloroethane

-- Tetrachloroethane, N.O.S.

-- trans-1,3-Dichloropropene Trichlorofluoromethane

-- Trichloromethanethiol

--



### As shown in Exhibit 9-3, considerable overlap exists between the industries with established effluent limits under the CWA and those industries responsible for the releases described in Chapter 2 (see Exhibit 2-3). For example, EPA has established CWA effluent limitations for the paper, chemical manufacturing, and primary metals industries, but not for electric, gas, and sanitary services; the food industry; and the non-metallic minerals industry. Further analysis is necessary to determine whether the chemicals covered by the effluent guidelines for these industries appear in their documented releases.Page 9-7 

### Exhibit 9-3 CWA Coverage of Industries Represented in Release Descriptions

Industry Group SIC Code Releases CWA Effluent Limitations Tot al Number of Electric, Gas, and Sanitary 49 35 no Services (refuse only) Paper and Allied Products 26 27 yes Chemicals and Allied Products 28 11 yes; separates organic and inorganic manufacturing Food and Kindred Products 20 10 no Primary Metals 33 6 yes; separates nonferrous and iron/steel manufacturing Non-Metallic Minerals 14 4 no


### 9.2.2 Safe Drinking Water Act Under the Safe Drinking Water Act, EPA has identified contaminants in drinking water that may adversely affect human health. For each contaminant, EPA has established a maximum contaminant level (MCL) that must not beexceeded in drinking water. MCLs are based on maximum contaminant level goals (MCLGs), which are the nonenforceable health-based levels at which no known or anticipated adverse effects on the health of people occur and which allow an adequate margin of safety. MCLGs are adjusted to MCLs based on considerations of feasibility, including technical implementation and economic considerations. As discussed in Section 5.1, EPA also has established non-health based or non-ecological based drinking water standards, based principally on aesthetic or usability criteria, which are called Secondary MCLs (SMCLs). The MCL standards apply to public water systems that regularly supply water to 15 or more connections or to 25 or more individuals at least 60 days per year in the case of residential populations or at least 6 months per year in the case of non-residential populations. The SDWA also regulates, through EPA or approved state programs, the underground injection of wastes to protect aquifers that are or may reasonably be expected to be sources of drinking water. These aquifers must be protected from contamination that violates an MCL or otherwise adversely affect human health. The SDWA has become important beyond the regulation of public water systems and underground injection of waste because the MCLs have been used in other regulatory contexts. For example, RCRA Subtitle D regulations for municipal solid waste landfills specify that MCLs must not be exceeded in the uppermost aquifer underlying a landfill. Because the regulatory levels established under the SDWA apply only to public water systems, its ability to address potential gaps resulting from non-hazardous industrial waste management is limited. The 1996 Safe Drinking Water Act (SDWA) Amendments, however, establish a new emphasis on preventing contamination problems through source water protection. Within 18 months after EPA publishes guidance, states must submit a program for delineating source water areas of public water systems and for assessing the susceptibility of such source waters to contamination. Because SDWA MCLs have been established for a number for TC and non-TC constituents that are related to potential gaps, the SDWA could be used under such source water protection programs to regulate contaminants prior to their entry into public water systems, such as at non-hazardous industrial waste managementPage 9-8



### units. The constituents and possible gaps that the SDWA could address under source water protection programs are discussed below. At this point in time, however, no such source protection programs have been developed. In Chapter 3, groundwater risks associated with TC analytes were identified as a potential gap in the hazardous characteristics. As Exhibit 9-4 shows, MCLs are established for 27 of the TC constituents, including all TC metals with the exception of silver. The seven TC metals with established MCLs are among the top 20 frequently occurring constituents in the release descriptions. MCLs are also established for other constituents frequently occurring in the release descriptions including chlorobenzene, chloroform, tetrachloroethylene, trichloroethylene, and vinyl chloride. The MCLs for chlorobenzene, lead, and mercury may address the ecological risks posed by these constituents, even though EPA did not specifically evaluate ecological risks when setting the MCLs. Exhibit 9-4 TC Constituents with SDWA MCL Levels TC Analyte SDWA MC L TC Analyte SDWA MC L TC Analyte SDWA MC L 1,1-Dichloroethylene

-- Chloroform Methyl ethyl ketone

-- 1,2-Dichloroethane Chromium Nitrobenzene

-- 1,4-Dichlorobenzene Cresol (mixed isomers)

-- o-Cresol

-- 2,4,5-Trichlorophenol

-- Endrin p-Cresol

-- 2,4,6-Trichlorophenol

-- Heptachlor Pentachlorophenol 2,4-D, salts and esters Heptachlor epoxide Pyridine

-- 2,4-Dinitrotoluene

-- Hexachlorobenzene Selenium Arsenic Hexachloro-1,3-butadiene

-- Silver

-- Barium Hexachloroethane

-- Silvex (2,4,5-TP) Benzene Lead Tetrachloroethylene Cadmium Lindane Toxaphene Carbon Tetrachloride m-Cresol

-- Trichloroethylene Chlordane Mercury Vinyl chloride Chlorobenzene Methoxychlor



### Chapter 4 identified two groups of known non-hazardous industrial waste constituents that may present hazards through the groundwater pathway: toxic metals and volatile chlorinated organic compounds. Exhibit 9-5 lists chemicals representative of these gaps and indicates whether they have MCLs and were detected above MCL levels in the release descriptions presented in Chapter 2. In the release descriptions, most of these constituents were detected in groundwater at levels above their MCLs.Page 9-9 

### Exhibit 9-5 MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern in Groundwater Pathways

Metals MCL MCL Volatile Chlorinated Organics MCL MCL Detected abov e Detected abov e
Aluminum (fume or dust)

-- -- 1,1,1,2-Tetrachloroethane

-- -- Antimony 1,1,1-Trichloroethane

-- Beryllium 1,1,2,2-Tetrachloroethane

-- -- Chromium(VI)

-- -- 1,1,2-Trichloroethane Cobalt

-- -- 1,2,3-Trichloropropane

-- -- Copper

-- -- 1,2,4,5-Tetrachlorobenzene

-- -- Iron

-- -- 1,2,4-Trichlorobenzene

-- Magnesium

-- -- 1,2-Dibromo-3-chloropropane

-- Manganese

-- -- 1,2-Dichlorobenzene

-- Molybdenum

-- -- 1,2-Dichloroethylene

-- -- Nickel 1,2-Dichloroethylene, trans Strontium

-- -- 1,2-Dichloropropane

-- Thallium 1,3-Dichlorobenzene

-- -- Tin

-- -- 1,3-Dichloropropylene

-- -- Titanium

-- -- Allyl chloride

-- -- Vanadium

-- -- Benzoic trichloride

-- -- Zinc

-- -- Bis(2-chloroethyl) ether

-- -- Chlorobromomethane

-- -- Chlorodibromomethane

-- Chloroethane

-- -- Chloromethane

-- -- cis-1,2-Dichloroethylene Dichloro-2-propanol 1,3-

-- -- Dichlorobromomethane

-- Dichlorodifluoromethane

-- -- Dichloromethane Dichloropropane

-- -- Epichlorohydrin

-- Ethylidene Dichloride

-- -- Hexachlorocyclopentadiene

-- Pentachloroethane

-- -- Tetrachloroethane, N.O.S.

-- -- trans-1,3-Dichloropropene

-- -- Trichlorofluoromethane

-- -- Trichloromethanethiol

-- --Page 9-10 

### 9.2.3 Clean Air Act Amendments Section 112 of the Clean Air Act Amendments (CAAA) regulates emissions of 189 toxic constituents, or hazardous air pollutants (HAPs). EPA has defined source categories that emit these HAPs and specified the maximum available control technology (MACT) that must be used by these sources to reduce HAP releases. EPA has promulgated air toxics regulations for three source categories that handle solid waste: RCRA Subtitle C facilities, off-site waste operations, and municipal waste combustors. Of these three categories, only off-site waste operations handle non-hazardous industrial waste. Off-site waste operations are defined to include hazardous waste treatment, storage, and disposalfacilities, industrial wastewater treatment facilities, industrial waste landfills that receive waste from offsite, and other facilities that provide waste management support services or recover and/or recycle spent materials. Municipal waste landfills, POTWs, incinerator units, and site remediation activities are not regulated by this rule. Off-site operations must control emissions from tanks and containers that manage material with an average volatile organic compound (VOC) concentration equal to or greater than 100 parts per million by weight. Land disposal of such wastes is prohibited. In addition, a leak detection and repair program must be implemented for all equipment containing material with total VOC concentration of 10 percent or more. Thus, the CAA regulations for these sources could address potential gaps in the hazardous waste characteristics in two ways:

Exposures to waste constituents through inhalation are addressed for non-hazardous industrial wastes with average VOC content greater than 100 ppm, if managed in certain facilities; and Exposure to VOCs at off-site operations through direct contact with solid waste or from groundwater leachate may be reduced or controlled by the prohibition of land disposal of wastes that contain material with an average VOC concentration equal to or greater than 100 parts per million by weight. The CAA has the potential to address inhalation exposures from the TC constituents. As Exhibit 9-6 demonstrates, all but seven TC constituents (counting heptachlor expoxide) are designated as HAPs under the CAA. Inhalation pathway exposure to non-TC volatile chlorinated organic compounds and to persistent organic pesticides were identified in Chapter 4 as a potential gap in the hazardous waste characteristics. As Exhibit 9-7 demonstrates, the CAA regulates emissions of 16 of the 35 known non-hazardous volatile chlorinated organics. EPA also has designated as HAPs two of the six persistent pesticides identified in the second column of Exhibit 4-11. Like the CWA, the CAA specifies emission limits for selected industries. Thus, for a potential gap to be addressed by the CAA, the gap constituents must be generated by one of the industrial categories regulated by the CAA. Exhibit 9-8 demonstrates that little overlap exists between the industries subject to CAA air toxics emission limits and those industries represented in the release descriptions. Among the industries represented in the release descriptions, the CAA specifies emission limits for segments of the chemicals production industry and off-site waste management operations.Page 9-11 

### Exhibit 9-6 TC Constituents Designated as HAPs under CAA

TC Analyte CAA HA P TC Analyte CAA HA P TC Analyte HAP CAA
1,1-Dichloroethylene

-- Chloroform Methyl ethyl ketone 1,2-Dichloroethane Chromium Nitrobenzene 1,4-Dichlorobenzene Cresol (mixed isomers) o-Cresol 2,4,5-Trichlorophenol Endrin

-- p-Cresol 2,4,6-Trichlorophenol Heptachlor Pentachlorophenol 2,4-D, salts and esters Heptachlor epoxide

-- Pyridine

-- 2,4-Dinitrotoluene Hexachlorobenzene Selenium
Arsenic Hexachloro-1,3-butadiene Silver

-- Barium

-- Hexachloroethane Silvex (2,4,5-TP)

-- Benzene Lead Tetrachloroethylene
Cadmium Lindane Toxaphene
Carbon tetrachloride m-Cresol Trichloroethylene
Chlordane Mercury Vinyl chloride
Chlorobenzene MethoxychlorPage 9-12 

### Exhibit 9-7 CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents
Volatile Chlorinated Organics CAA HAP Persistent Organic Pesticides CAA HAP 1,1,1,2-Tetrachloroethane

-- Aldrin

-- 1,1,1-Trichloroethane DDD

-- 1,1,2,2-Tetrachloroethane DDE 1,1,2-Trichloroethane DDT

-- 1,2,3-Trichloropropane

-- Dieldrin

-- 1,2,4,5-Tetrachlorobenzene

-- Hexachlorobenzene 1,2,4-Trichlorobenzene 1,2-Dibromo-3-chloropropane 1,2-Dichlorobenzene

-- 1,2-Dichloroethylene

-- 1,2-Dichloroethylene, trans

-- 1,2-Dichloropropane 1,3-Dichlorobenzene

-- 1,3-Dichloropropylene Allyl chloride Benzoic trichloride Bis(2-chloroethyl) ether Chlorobromomethane

-- Chlorodibromomethane

-- Chloroethane Chloromethane cis-1,2-Dichloroethylene

-- Dichloro-2-propanol, 1,3-

-- Dichlorobromomethane

-- Dichlorodifluoromethane

-- Dichloromethane Dichloropropane

-- Epichlorohydrin Ethylidene Dichloride Hexachlorocyclopentadiene Pentachloroethane

-- Tetrachloroethane, N.O.S.

-- trans-1,3-Dichloropropene

-- Trichlorofluoromethane

-- Trichloromethanethiol

--



### Emissions standards have not yet been established for the paper, food, primary metals, or non-metallic minerals industries. As presented in Exhibit 9-8, however, the most important industry in terms of the potential gaps that the CAA may address is the organic chemicals manufacturing industry. Emissions standards have been established for segments of this industry.Page 9-13 

### Exhibit 9-8 CAA Coverage of Industries Represented in Release Descriptions

Industry Group SIC Code Releases CAA Air Emission Limits Number of Documented
Electric, Gas, and Sanitary 49 35 Off-site waste operations, hazardous waste TSDFs Services (refuse only) Paper and Allied Products 26 27 no Chemicals and Allied Products 28 11 Emissions from synthetic organic chemical industry, elastomer production, epichlorohydrin

production Food and Kindred Products 20 10 no Primary Metals 33 6 no Non-Metallic Minerals 14 4 no



### 9.3 Federal Insecticide, Fungicide, and Rodenticide Act FIFRA controls chemical pesticides through a process whereby the manufacturer registers the composition of the pesticide and certifies to EPA that the pesticide will perform its intended function without unreasonable adverse impacts in the environment under commonly recognized practices for use. EPA can place a registered substance under special review if the substance is suspected of causing unreasonable adverse effects on the environment. Under this process, EPA can prohibit the distribution, sale, and/or use of a pesticide through a cancellation or suspension of its registration. Four TC constituents found in the release descriptions are FIFRA active ingredients: 2,4-D, heptachlor,methoxychlor, and pentachlorophenol. Because FIFRA only places conditions on use, and does not set concentrationbased regulatory levels or regulate pesticide waste disposal, the regulation of these constituents by FIFRA does not automatically imply that releases will not exceed a certain level. FIFRA could only prevent releases of these constituents if EPA were to cancel or suspend the respective registrations. Exhibit 9-9 lists the pesticides, intermediates, and degradation products that are TC analytes or known non-hazardous industrial waste constituents and the current status of the pesticide. Of the 41 pesticides and associated products that are known non-hazardous industrial waste constituents, 25 are currently in use and 16 are cancelled or are not currently used. Several of these pesticides passed the multiple toxicity, persistence, volatility, and bioaccumulation screening criteria presented in Exhibit 4-13, including aldrin, DDT, DDD, DDE, dieldrin, heptachlor epoxide, and hexachlorobenzene. With the exception of heptachlor epoxide, these pesticides have been canceled by EPA. The presense of many of these canceled pesticides as known non-hazardous industrial waste may largely be the result of old data. For example, the release descriptions, which were used to identify known constituents, cover waste management units that may have received wastes more than a decade ago.Page 9-14 

### Exhibit 9-9 Status of Pesticides That are TC Analytes or Known Non-Hazardous Industrial Waste Constituents
Pesticides/Intermediate/Degradation Product Status Aldicarb Active; restricted use Atrazine Active; restricted use Carbofuran Active; restricted use 2,4-D, salts and esters Active Diazinon Active Dimethoate Active Disulfoton Active; restricted use Endosulfan (pesticide is a mixture of alpha and beta isomers) Active Endosulfan, alpha- Active Endosulfan, beta- Active Endosulfan sulfate Metabolic product of endosulfan Endothall Active Heptachlor Active; restricted use Heptachlor epoxide Degradation product of heptachlor Lindane (gamma-HCH) Active; restricted use Molinate Active Mesitylene Active use (registration not required) Methyl iodide Active use (registration not required) Methoxychlor Active Methyl parathion Active; restricted use O,O-Diethyl O-pyrazinyl phosphorothioate (Thionazin) Active Parathion Active; restricted use Pentachlorophenol Active; restricted use Phorate Active; restricted use Sulfotepp Active 2,3,4,6-Tetrachlorophenol Canceled 2,4,5-Trichlorophenol Canceled 2,4,6-Trichlorophenol Canceled Aldrin Canceled alpha-HCH Canceled beta-HCH Canceled; no longer produced in U.S. DDE Degradation product of canceled ingredient DDT/DDD Canceled Dieldrin Canceled Endrin Canceled Endrin aldehyde Byproduct/degradation product of endrin Endrin ketone Byproduct/degradation product of endrin Famphur Most uses canceled; no currently active products Hexachlorobenzene Canceled Silvex (2,4,5-TP) Canceled Toxaphene Most uses canceled; no currently active products
Sources: Farm Chemicals Handbook '94, Meister Publishing Company; U.S. EPA/OPP Database of Pesticide Products, October 8, 1996,

http://www.cdpr.ca.gov/docs/epa/epamenu.htm;Status of Pesticides in Reregistration and Special Review (Rainbow Report), Office of Pesticides and Prevention, U.S. EPA, June 1994;Merck Index, 12th edition, 1996.Page 9-15



### 9.4 Toxic Substance Control Act TSCA was enacted to fill gaps in the Federal Government's authority to regulate problem chemicals. Most EPA regulations, such as the Clean Air Act and the Clean Water Act, regulate chemicals only after they are produced and used. However, there are many opportunities for a chemical to cause harm to human health or the environment prior to it becoming a waste, such as during production or use. Under Section 6 of TSCA, EPA has the authority to regulate the production, use, distribution, and disposal of chemicals that are identified as potentially hazardous. EPA has exercised the authority under Section 6 to regulate the production, distribution, and disposal of PCBs from electrical equipment and as byproducts of chemical manufacturing processes. The presence of PCBs in the release descriptions probably results from the past disposal of old products containing PCBs. Because TSCA bans the production of PCBs, however, their presence in waste should diminish over time. Actions under TSCA do not significantly address any other potential gaps. 9.5 Pollution Prevention EPA has developed a number of pollution prevention initiatives that could address potential gaps in the characteristics by limiting the production of harmful chemicals. These initiatives include:

Source Reduction Review Project (SRRP). EPA has an on-going effort to introduce sourcereduction concepts into individual rules. As part of the SRRP, EPA conducted an indepth analysis of source reduction measures and cross-media issues in the development of 24 rule makings for air toxics (Maximum Achievable Control Technology or MACT standards), water pollution (effluent guidelines) and hazardous wastes (listing determinations) that were pending in 1993 and 1994. The project's goal is to foster the use of source reduction measures as the preferred approach for achieving environmental protection, followed in descending order by recycling, treatment, and as a last resort, disposal. For the long term, EPA hopes that SRRP will provide a model for the regulatory development efforts in all of its programs. Environmental Technical Initiative (ETI). EPA has promoted pollution prevention efforts for selected industries through technology development. For example, the Agency has supported research on recycling plastics, replacing current solvents with less harmful alternatives, and developing cleaner processes in plating and metal finishing. Waste Exchanges. Waste exchanges provide a mechanism for recycling and reusing industrial waste. In general, waste exchanges try to match generators of waste with companies interested in recycling or reusing these materials. The goals of waste exchanges are to reduce disposal costs, reduce disposal quantities, reduce demand for natural resources, and potentially increase the value of wastes. EPA has supported the non-federal waste exchanges through (1) funding a national computerized listing system, the National Materials Exchange Network (NMEN), and (2) issuing grants to develop support for individual waste exchanges or specific waste exchange activities. Toxics Release Inventory (TRI). The TRI can have an instrumental role in pollution prevention by providing communities with the information that can be used to persuade industries to reduce emissions, and by establishing a benchmark to measure progress. For example, EPA established the 33/50 Program whereby companies voluntarily pledged to reduce releases of 17 priority pollutants reported in TRI in 1988 by 33 percent in 1992 and by 50 percent in 1995.A PEL is the average maximum concentration of a chemical in air that is allowable for a worker to be exposed to in the course of 2 an 8-hour working day.
Page 9-16 

### Further research is needed to determine the impact of these initiatives on potential gaps in the characteristics. 9.6 Occupational Safety and Health Act Workplace safety is largely regulated by the Occupational Safety and Health Act (OSHA). The program that most directly relates to chemical hazards encountered in the workplace is the permissible exposure limits (PELs)2 

### established for selected workplace chemicals. Subpart Z of 29 CFR 1910.1000 specifies PELs for toxic and hazardous substances in the workplace. These PELs are based on threshold limits values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH) and on the Recommended Exposure Limits (RELs) developed by the National Institute for Occupation Safety and Health (NIOSH). OSHA has adjusted some of these values when developing PELs. The PELs are intended to reduce diseases such as liver and kidney pains, neuropathy and cardiovascular effects, respiratory effects, deterioration of lung function, narcosis, biochemical and metabolic changes, and other health impairments caused by workplace exposure to chemicals. As discussed above, OSHA regulates workplace inhalation exposure to designated constituents by establishing PELs. As shown in Exhibit 9-10, 33, or over 75 percent, of the TC constituents have PELs established under OSHA. The majority of potential gaps associated with non-TC analytes identified in Chapter 4 are related to exposures to contaminated media, rather than workplace exposures. OSHA PELs, however, could address workplace exposures to a few of the major chemicals classes that comprise several of the potential gaps, including volatile chlorinated organics, other volatile and semivolatile organics, and pesticides. Exhibit 9-11 demonstrates that 21 of the 35 known non-hazardous volatile chlorinated organics in Exhibit 4-2 have OSHA PELs. Similarly, 33 of the 41 and 20 of the 45 other volatile and semivolatile organics, respectively, have OSHA PELs. 9.7 Hazardous Materials Transportation Act HMTA gives the Department of Transportation (DOT) the authority to regulate the transportation of hazardous materials in interstate commerce. The HMTA regulates materials not covered by the hazardous waste characteristic, and therefore addresses hazards from these potential gaps, but only in the context of risks in transportation and to transportation workers. These materials include the following:Page 9-17 

### Exhibit 9-10 TC Constituents with Established OSHA PELs
TC Analyte OSHA PE L TC Analyte OSHA PE L TC Analyte OSHA PE L 1,1-Dichloroethylene

-- Chloroform Methyl ethyl ketone 1,2-Dichloroethane Chromium Nitrobenzene 1,4-Dichlorobenzene Cresol (mixed isomers) o-Cresol

-- 2,4,5-Trichlorophenol

-- Endrin p-Cresol 2,4,6-Trichlorophenol

-- Heptachlor Pentachlorophenol 2,4-D, salts and esters Heptachlor Epoxide

-- Pyridine 2,4-Dinitrotoluene Hexachlorobenzene

-- Selenium Arsenic Hexachloro-1,3- Silver butadiene Barium Hexachloroethane Silvex (2,4,5-TP)

-- Benzene Lead Tetrachloroethylene Cadmium Lindane Toxaphene Carbon Tetrachloride m-Cresol

-- Trichloroethylene Chlordane Mercury Vinyl Chloride Chlorobenzene MethoxychlorPage 9-18 

### Exhibit 9-11 OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents
Volatile Chlorinated Organics PEL Other Volatile Organics PEL Other Semivolatile Organics PEL 1,1,1,2-Tetrachloroethane

-- 1,2-Dibromoethane 1,2-Diphenylhydrazine

-- 1,1,1-Trichloroethane 1,4-Dioxane 2,3,7,8-TCDD

-- 1,1,2,2-Tetrachloroethane 2-Ethoxyethanol 2,4-Diaminotoluene

-- 1,1,2-Trichloroethane 2-Hexanone 2,4-Dichlorophenol

-- 1,2,3-Trichloropropane 2-Methyllactonitrile

-- 2,6-Dinitrotoluene

-- 1,2,4,5-Tetrachlorobenzene

-- 2-Methylpyridine

-- 3,3'-Dimethoxybenzidine

-- 1,2,4-Trichlorobenzene 2-Nitropropane 4-Aminobiphenyl 1,2-Dibromo-3-chloropropane Acetaldehyde 4-Aminopyridine

-- 1,2-Dichlorobenzene Acetone 5-Nitro-o-toluidine

-- 1,2-Dichloroethylene Acetonitrile Acetophenone

-- 1,2-Dichloroethylene, trans

-- Acrolein Acrylamide 1,2-Dichloropropane Acrylonitrile Acrylic acid 1,3-Dichlorobenzene

-- Allyl alcohol Adipic acid

-- 1,3-Dichloropropylene Benzenethiol Aniline Allyl chloride Benzyl alcohol

-- Benzal chloride

-- Benzoic trichloride

-- Bromoform Benzoic acid

-- Bis(2-chloroethyl) ether Bromomethane Benzyl chloride Chlorobromomethane Carbon disulfide Biphenyl Chlorodibromomethane

-- Crotonaldehyde

-- Coal tars Chloroethane Cyclohexanone Creosote

-- Chloromethane Dimethyl sulfate Dibenzofuran

-- cis-1,2-Dichloroethylene

-- Dimethylamine Diphenyl ether Dichloro-2-propanol, 1,3-

-- Ethane, 1,1'-oxybis- Diphenylamine Dichlorobromomethane

-- Ethyl acetate Ethyl dipropylthiocarbamate

-- Dichlorodifluoromethane Ethylene glycol Formic acid Dichloromethane Ethylene oxide m-Dinitrobenzene Dichloropropane

-- Formaldehyde Maleic anhydride Epichlorohydrin Furan

-- Maleic hydrazide

-- Ethylidene Dichloride Furfural N-Nitrosodimethylamine Hexachlorocyclopentadiene Hydrazine N-Nitrosodiphenylamine

-- Pentachloroethane

-- Isobutyl alcohol Naphthalene Tetrachloroethane, N.O.S.

-- Malononitrile

-- Nitrosamine, N.O.S.

-- trans-1,3-Dichloropropene

-- Methanol O-Chlorotoluene Trichlorofluoromethane Methyl isobutyl ketone Ortho(2-)Nitroaniline

-- Trichloromethanethiol

-- Methyl isocyanate p-Chloroaniline

-- Methyl mercaptan p-Chlorotoluene

-- Methyl methacrylate p-Nitroaniline Methylene bromide

-- Pentachlorobenzene

-- n-Butyl alcohol Phenanthrene

-- Urethane

-- Phthalic acid

-- Vinyl acetate Phthalic anhydride Polychlorinated biphenyls Resorcinol Thioacetamide

-- ThiramPage 9-19 

### Combustible liquids defined under HMTA as liquids with a flash point above 141 F and below 200 F. Examples include benzonitrile, camphor oil, chlordane, coal tar distillate, di-isobutyl ketone, ethylene glycol ethers, and fuel oil distillate; Corrosive solids and liquids; aqueous flammable liquids (alcohol solutions < 24 percent); Non-flammable compressed gases and cryogenic liquids; and Certain materials specifically forbidden under HMTA, including materials likely to polymerize at a temperature of 130 F or less, or decompose at 122 F or less, with an evolution of a dangerous amount of heat or gas. 9.8 Summary Most of the potential gaps identified in Chapters 3 and 4 are media-specific. As a result, media-specific regulations provide some control over chemical and chemical classes that comprise the potential gaps. In addition, non-media-specific regulations such as FIFRA and TSCA could address potential gaps associated with particular chemical classes, such as pesticides and PCBs. Exhibit 9-12 presents a summary of the non-RCRA statutes and regulatory programs that could address to varying degrees the potential gaps. Exhibit 9-12 Potential Gaps and Potential Non-RCRA Regulatory Control Statute or Regulatory Program Potential Gap Possibly Addressed Clean Water Act Direct surface water exposure to TC analytes Indirect pathway exposures to TC analytes involving surface waters Risks to ecological receptors involving discharges to surface waters Indirect pathway exposures to phenolic compounds involving surface waters DNAPL formulation by chlorinated organics Indirect pathway exposures to PAHs involving surface waters Safe Drinking Water Act Implementation of 1996 Amendments to CWA has potential to address potential gaps through groundwater exposures to TC constituents, non-TC metals, and non-TC volatile chlorinated organics Clean Air Act Inhalation pathway exposures to volatile chlorinated organics Inhalation pathway exposures to persistent organic pesticides FIFRA Endocrine disruption from chlorinated pesticides, phthalate esters TSCA Risks to humans, ecological receptors from PCBs OSHA Inhalation exposures to TC analytes in workplace HMTA Risks posed by gaps in the ICR characteristicsPage 9-20 

### For a potential gap to be addressed by the CWA or CAA, the gap constituents must both have regulatory levels established by the programs and be generated by one of the regulated industrial categories. The CWA and CAA establish limits for about the same number of volatile chlorinated organics. The industrial categories regulated by the CWA, however, overlap more extensively than those regulated by the CAA with the industries represented in the release descriptions. Therefore the CWA effluent limitations will be more effective in addressing potential gaps. Each of the regulations discussed in this chapter do not address all of the known and possible non-hazardous industrial waste chemicals, and therefore none of the potential gaps are completely addressed by non-RCRA regulations.Page 9-21



### CHAPTER 9. POTENTIAL FOR GAPS TO BE ADDRESSED BY EXISTING REGULATIONS

. . 9-1
9.1 RCRA Programs

......................................................... 9-1 9.1.1 Hazardous Waste Programs

........................................... 9-1 9.1.2 Subtitle D

......................................................... 9-3
9.2 Medium-Specific Regulations

.............................................. 9-3 9.2.1 Clean Water Act

.................................................... 9-4 9.2.2 Safe Drinking Water Act

............................................. 9-7 9.2.3 Clean Air Act Amendments

.......................................... 9-10
9.3 Federal Insecticide, Fungicide, and Rodenticide Act

............................ 9-13
9.4 Toxic Substance Control Act

.............................................. 9-15
9.5 Pollution Prevention

..................................................... 9-15
9.6 Occupational Safety and Health Act

........................................ 9-16
9.7 Hazardous Materials Transportation Act

..................................... 9-16
9.8 Summary

.............................................................. 9-19Page 9-22



### Exhibit 9-1 TC Constituents with Effluent Limits Established under CWA

.................... 9-5 Exhibit 9-2 CWA Effluent Limitations Relevant to Certain Known Non-Hazardous Industrial

Waste Constituents

....................................................... 9-6 Exhibit 9-3 CWA Coverage of Industries Represented in Release Descriptions

................. 9-7 Exhibit 9-4 TC Constituents with SDWA MCL Levels

.................................... 9-8 Exhibit 9-5 MCLs for Known Non-Hazardous Industrial Waste Constituents of Concern in

Groundwater Pathways

.................................................... 9-9 Exhibit 9-6 TC Constituents Designated as HAPs under CAA

............................. 9-11 Exhibit 9-7 CAA Hazardous Air Pollutants (HAPs) Specified for Potential Gap Constituents

.... 9-12 Exhibit 9-8 CAA Coverage of Industries Represented in Release Descriptions

................ 9-13 Exhibit 9-9 Status of Pesticides That are TC Analytes or Known Non-Hazardous Industrial

Waste Constituents

...................................................... 9-14 Exhibit 9-10 TC Constituents with Established OSHA PELs

............................... 9-17 Exhibit 9-11 OSHA PELs Specified for Known Non-Hazardous Industrial Waste Constituents

.... 9-18 Exhibit 9-12 Potential Gaps and Potential Non-RCRA Regulatory Control

.................... 9-19Page 10-1



# CHAPTER 10. SUMMARY EVALUATION OF NATURE AND

EXTENT OF POTENTIAL GAPS

This chapter evaluates potential gaps in terms of their significance to human health and the environment. It synthesizes and summarizes information presented in previous chapters.
Section 10.1 discusses the objectives of the gaps analysis and the specific criteria used to evaluate

potential gaps.
Section 10.2 presents the findings of the evaluation and discusses major data gaps and unresolved

issues.
Section 10.3 describes a possible framework for determining an appropriate course of action based on the

results of this Scoping Study. 10.1 Overview of the Evaluation of Potential Gaps 10.1.1 Objectives of the Gaps Analysis Since this Study is a scoping exercise, the human health and environmental impacts of potential gaps have not been definitively analyzed, and potential gaps are not numerically ranked with regard to their impacts. Instead, the Study's objective is to summarize available information in a manner that will be useful in guiding further, more detailed assessment of the most important potential gaps and their possible solutions. The categories of gaps are evaluated qualitatively against criteria that address the potential for adverse human health and environmental impacts. Many of these criteria have been used in previous chapters to identify and analyze potential gaps. The analysis presented below, however, differs from previous analyses in two ways. First, while the same data sources are used, more detailed analyses are presented for key constituents, pathways, and risks. Second, instead of focusing on individual chemicals, the chapter analyzes groups of chemicals and specific environmental problems. This approach helps to generalize the analysis to include chemicals for which limited data are available regarding appearance in wastes, toxicity, or environmental fate and transport characteristics. 10.1.2 Criteria Used for Evaluating Gaps Section 10.2 presents a series of exhibits (Exhibits 10-1 through 10-4) comparing the various categories of potential gaps identified and reviewed in previous chapters. Potential gaps are compared using criteria that relate to various dimensions of risks to human health and the environment. These criteria, which correspond to columns in the exhibits, are described below. (Because of data gaps or the inapplicability of some criteria to certain potential gaps, some exhibits do not include all of these criteria.)
Nature of Risks. This criterion qualitatively characterizes the nature of the risks posed by potential gaps, including the types of possible injuries or adverse effects, important toxicological effects (e.g., carcinogenicity, reproductive effects, or mutagenicity), and fate and transport properties. These factors are important in evaluating risk potential.Page 10-2 

### Presence in Non-Hazardous Industrial Waste. This entry indicates the number of the TC analytes and known or possible non-hazardous industrial waste constituents identified in Chapter 4 that fall into the potential gap and summarizes other available data on presence in waste. The number of chemicals in a given class indicates, to some extent, the potential frequency of their appearance in non-hazardous industrial wastes or use in different industries. Frequently Detected Constituents in Release Descriptions. This column indicates how frequently the class of chemicals was detected in the documented releases from non-hazardous industrial waste management facilities. These data provide a second indicator of the frequency of the class of chemicals in wastes released to the environment. In some tables, this column also addresses the extent to which the releases had constituent concentrations detected in excess of health- or ecologically-based regulatory standards or other health-based levels. These data address the severity and type of the risk presented by the releases.
TRI Chemicals with Releases > One Million Pounds. This column identifies any constituents falling into the identified potential gaps that have 1994 TRI releases to air, land, water, and underground injection combined greater than one million pounds. Eighty-three of the 250 individual or classes of TRI chemicals for which data were available had reported releases exceeding one million pounds. These data served as a proxy for widespread use and appearance in wastes.
Affected Industries. This column presents two types of data. First, it identifies the industries most often associated with documented releases of a particular class of chemicals in the release descriptions. These data indicate, at least for the population of facilities evaluated, which industries seem to have the highest frequency of releases to the environment of each class of compounds. As noted previously, however, this indicator is imperfect, in part because the available data focus on releases to groundwater and some families of constituents may present risks primarily through other pathways. The column also uses information presented inChapter 8 to identify the industries with particular classes of chemicals frequently occurring in their nonhazardous industrial wastes. Affected Management Methods. This column identifies the types of management units at which the various classes of chemicals are detected most frequently in the release descriptions or other data sources. This criterion has the same limitation as the release description information identified above, namely, it focuses on groundwater contamination and thereby may miss chemicals that pose risks through other pathways. However, since presence in groundwater indicates presence in wastes, this column also provides information about the types of management units or practices that have releases to groundwater and are likely to have releases to other media (e.g., volatilization), as discussed in the screening-level risk results from Section 3.5. Potential Coverage by Other Regulations. This column summarizes information presented in Chapter 5 (for large-scale environmental problems) and Chapter 9 (for TC and non-TC chemicals). It briefly describes the potential extent of coverage of potential gaps by existing regulatory programs. In some cases, despite the appearance that a particular gap is covered by a regulatory program, information from the release descriptions or elsewhere may indicate that such coverage is not preventing releases to the environment. Comments/Data Gaps. The final column of each table identifies the major analytical uncertainties and limitations in the characterization of potential hazardous waste characteristics gaps. As noted above, a major obstacle to identifying gaps accurately and reliably is the shortage of information regarding the generation, composition, and management of non-hazardous industrial wastes and any human health or environmental damages resulting from the management of such wastes. Data may be available to fill some of the identified gaps, but, due to time constraints, these data were not used in preparing this Scoping Study.Page 10-3



### 10.2 Findings of the Evaluation This section summarizes the evaluations of the five different types of potential gaps identified in the previous chapters, namely potential gaps associated with:

The existing ignitability, corrosivity, and reactivity characteristics; The existing toxicity characteristic; Chemicals not included in the toxicity characteristic; Natural resource damages and large-scale environmental problems; and State expansion of the TC and listings. The last part of this section reviews the major data gaps and uncertainties. 10.2.1 Potential Gaps Associated with the ICR Characteristics Ignitability Exhibit 10-1 summarizes the analysis of the potential gaps in the ICR characteristics. (This exhibit does not include a column on the constituents that were frequently detected in the release descriptions because of the difficulty of judging waste ICR properties based on the environmental monitoring data (e.g., groundwater sampling from the release descriptions). The first page of the exhibit addresses the limitations in the ignitability characteristic. The first potential gap in this characteristic relates to the lack of coverage of combustible liquids, that is, liquids with flash points above 140 F and below 200F. The Agency has not found any data on how o o 

### often non-hazardous industrial wastes exhibit this property. While many non-hazardous industrial waste constituents are flammable, the flash point and fire hazard from a given waste depends on its composition and management practices. Thus, the high frequency of appearance of flammable liquids among the waste constituents or groundwater contaminants does not necessarily reflect a high hazard potential. The release descriptions did not allow EPA to evaluate the frequency of fires and explosions at non-hazardous industrial waste management facilities, let alone to determine whether any fires had resulted from combustible liquids. Dilute aqueous solutions of alcohol also are identified as a potential gap in the ignitability characteristic. These solutions might flash, even if they are not capable of sustaining combustion. Ethanol, however, is not a known or possible non-hazardous industrial waste constituent or a TC analyte, suggesting that this gap may not be significant. Nevertheless, the narrow definition of this characteristic excludes other organic liquids that can form potentially flammable mixtures with water. The possible limitations of this narrow definition are illustrated by the presence among waste constituents of water-miscible alcohols, such as methanol (with the highest release volume on the TRI list), n-butanol, and isobutanol, as well as other potentially flammable water-miscible solvents, such as acetone, methylethyl ketone, and acetonitrile. EPA found no data on the extent of potential hazards from ignitable solids. Thus, the consequences of not having a test method for these materials are difficult to characterize. The release

### Page 10-4 Exhibit 10-1 Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries Affected Management Method

s Regulations Comments/Major Data Gap s Presence in Non-Hazardou

s Reported

Releases> One Potential Coverageby Othe

r TRIChemicals with 1994

IGNITABILITY Fires under plausible Some proportion of N-butyl alcohol, MIBK, Wide range of indus- Hazards may be most Variety of local, state, Flash point of waste Exclusion of DOT Combustible Liquids (flash point between 140 F and 200F) o o mismanagement scenarioswastestreams are likely to acetonitrile, ethylene tries produce relevant for waste handling and federal laws address depends on various factors be combustible, but are not glycol, acetaldehyde combustible materials activities such as ignitable hazards, includ- including concentrations of readily identifiable with including chemicals, generation, storage, and ing constituents. existing data. petroleum refining, transportation. -- DOT transportation Difficult to identify Combustible materials asphalt materials and Landfills more likely to rules; potentially affected include certain alcohols, paving be of potential concern than -- Fire codes; wastestreams in the absence low molecular weight ethers, Industries using surface impoundments -- Emergency prevention of flash point data for kerosene, jet fuels, paints, adhesives, inks, because surface and preparedness under specific wastestreams petroleum byproducts, tints and fuels impoundments dilute wastes EPCRA, OSHA, and CAA No data available on and paints, and others. and thereby reduce §112(r); and fires from combustible ignitability; flammable -- State Industrial D rules liquids organic liquids are not limiting landfilling of likely to be managed in liquids. impoundments. Exclusion of These liquids could Many constituents could Methanol, n-butanol, Chemicals, refuse DOT has a similar Aqueous Flammable flash, even if combustion form flammable mixtures with iso-butanol, ethylene services exclusion. Liquids (alcohol is not sustained. water. glycol, acetonitrile, No data available on solutions < 24 MIBK, acetaldehyde fires from these liquids percent) References Outdated Confusion regarding Not applicable Not applicable Not applicable No data available on DOT Regulations definition and test fires due to improper

methods due to incorrect testing or failures to test DOT citation No Ignitability More difficult to Could include soils and Not addressed Not addressed Potential gap is diffiTest Method for Non- interpret, comply with, sorbents contaminated with cult to characterize. liquids and enforce regulations. ignitable materials DOT and NFPA have defined test methods for flammable solids.

### Exhibit 10-1 (continued) Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries Affected Management Method

s Regulations Comments/Major Data Gap s Presence in Non-Hazardou

s Reported

Releases> One Potential Coverageby Othe

r TRIChemicals with 1994



### Page 10-5 CORROSIVITY Skin, eye injuries and Not addressed Not addressed Not addressed Not addressed Several states regulate Lack of data on specific Exclusion of Corrosive Non-liquids ecological risks, corrosive solids as substances, wastes, and/or

facilitated transport of hazardous waste. damage cases that fall pollutants within potential gaps. pH Limits Poten- pH test may not Not addressed Not addressed Not addressed DOT and OSHA rules use a tially Not Protective, identify some corrosive dermal corrosion test (not pH Test Methods Not materials pH); they cover worker and Predictive of Risk transportation risks. Corrosion of Non- Corrosion of plastic, Many NAPL-formers; Toluene, xylene, carbon Waste management methodsCAA limits disposal of Steel Materials Not clay, other liner alcohols, ketones disulfide, styrene, that involve materials such solvents in certain units. Addressed materials and non-steel ethylbeneze, as plastic, clay, and other

containers or tanks trichlorofluoromethane, materials besides steel phenols (as group), various alcohols Solubilization of Organic solvents may Many potential LNAPL or Toluene, xylene, carbon Waste management methodsCAA limits disposal of Non-Metals Not solubilize organic DNAPL forming constituentsdisulfide, styrene, with potential for discharge solvents in certain units. Addressed constituents could solubilize other ethylbeneze, to water bodies or other organics. trichlorofluoromethane, habitats phenols (as group) Exclusion of Allergic reaction in Numerous chemicals Ammonia, formaldehyde, Waste handling situations OSHA hazard communication Irritants and waste management and including ammonia, copper, (of those listed in where spills could occur standard covers irritants Sensitizers transportation workers beryllium, cobalt, copper, prior column) and sensitizers, which Unclear whether this nickel, carbonyl, affords protection to hazard meets RCRA formaldehyde, isobutyl employees at wide range of Subtitle C statutory alcohol, n-Dioctyl facilities (e.g., level of concern phthalate, benzoic acid, and generating facilities, coal tars waste management facilities)

### Exhibit 10-1 (continued) Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics

Potential Gap Nature of Risk Industrial Waste Million lbs. Affected Industries Affected Management Method

s Regulations Comments/Major Data Gap s Presence in Non-Hazardou

s Reported

Releases> One Potential Coverageby Othe

r TRIChemicals with 1994



### Page 10-6 REACTIVITY Ambiguity may allow Many constituents are Ammonia, hydrochloric Not addressed Not addressed Explosions and other Potential gap is diffi- Broad, Non-Specific Definition substances posing risks DOT-reactive, none are acid, phosphoric acid, related hazards covered by cult to characterize

of gas generation or identified as "highly nitric acid, sulfuric programs including fire and because reactive wastes are violent reaction to be reactive". acid, hydrogen fluoride, building codes, DOT already regulated as managed improperly. hydrogen cyanide, chlorine regulations (for hazardous dioxide transportation only), OSHA regulations, and accident prevention and preparedness regulations under EPCRA and CAA §112(r) References Outdated Confusion about DOT Regulations relevant standards may

reduce compliance and increase risks of violent reactions. No Test Methods More difficult to Specified interpret, comply with,

and enforce regulations"Fluorides/fluorine/hydrogen" (the slashes indicate that the exact chemical species is not identified) are among the freq uently 1 detected constituents, but these detections most probably refer to fluoride ion, rather than to the acid.


### Page 10-7 descriptions do not, as noted above, identify any fires related to flammable solids. Also, as noted in Chapter 3, various data searches failed to identify any incidents that could be unambiguously related to flammable solids in non-hazardous industrial waste management units. At least one potential variety of flammable solids, soils contaminated with petroleum byproducts, are explicitly excluded by statute from RCRA Subtitle C jurisdiction. Finally, the test methods referenced in the ignitability characteristic are outdated and need to be revised. The U.S. Department of Transportation has promulgated new methods in different sections of theCode of Federal Regulations. EPA, however, is not aware of any fires or other adverse events arising from confusion over the proper test methods. Corrosivity The second panel in Exhibit 10-1 addresses potential gaps in the corrosivity characteristic. Severalpotentially corrosive substances, primarily strong acids, are identified among the known and possible nonhazardous industrial waste constituents. These compounds are not among the most frequently detected groundwater contaminants in the release descriptions, however. No information is available concerning corrosive non-liquids 1 

### in the release descriptions. A potential gap associated with the pH range of the corrosivity characteristic also was identified. The release descriptions identify decreased or elevated pH levels in groundwater near management units for a number of the industries. While the reported pH levels are not associated with skin or eye injury or injury to biota, the appearance of elevated or depressed pH in groundwater after dilution indicates that high- and low-pH wastes are frequently encountered among the non-hazardous industrial wastes. The extent to which the pH of these wastes falls into the potential gap between the existing pH limits in the corrosivity characteristic and possible more stringent limits is not known, however. The corrosivity characteristic also does not address corrosion of materials other than steel. Specifically, the Agency has identified potential corrosion of plastics and clay (common materials used in liners of non-hazardous industrial waste management units) as a potential gap. For example, the plastic liners may be corroded by nonaqueous phase liquids (NAPLs) if present in significant amounts; as is discussed in more detail in Section 4.2.3, a number of TC analytes and known and possible waste non-hazardous industrial constituents could form NAPLs. In addition, certain ketones and alcohols could dehydrate or otherwise adversely affect the physical integrity of clay liners. Finally, the corrosivity characteristic excludes irritants and sensitizers. The Agency has found a number of allergic sensitizers to be constituents of non-hazardous industrial wastes, including ammonia, beryllium, cobalt, copper, nickel, nickel carbonyl, formaldehyde, isobutyl alcohol, n-dioctyl phthalate, benzoic acid, and coal tars. Further analysis may identify other substances. While the release descriptions do not reportany incidents of allergic sensitization, dermatitis is one of the most common occupational illnesses, and nonhazardous industrial waste could contribute to these potential risks to waste management and transportation workers. Occupational Safety and Health Act regulations prescribe measures to limit dermal exposures to hazardous substances in the workplace, however. Thus, this problem is at least partially addressed by non-RCRA regulations. Reactivity

### Page 10-8 The final panel of Exhibit 10-1 summarizes the information related to the potential gaps in the reactivity characteristic. A major question for this potential gap is whether the over-broadness of the definition has increased the occurrence of human health or environmental damages or risks due to reactive materials. The release descriptions do not contain information related to violent chemical reactions. Also, while some DOT-classified reactive chemicals are among the non-hazardous industrial waste constituents, there is no evidence that would indicate whether these chemicals are present in forms or concentrations that are reactive. The need to specify test methods is likewise linked both to the severity of reactivity as a problem for non-hazardous industrial waste management operations, and to the extent to which such issues are not already addressed by the DOT regulations, OSHA regulations, or process safety management practices. 10.2.2 Potential Gaps Associated with TC Analytes Exhibit 10-2 summarizes the analysis of five types of potential gaps associated with the toxicity characteristic: TC regulatory levels for the groundwater pathway;

Risks through non-groundwater pathways, including inhalation, surface water, and indirect pathways; Acute human health risks; Risks to ecological receptors; and
Limitations in the TCLP. Each of these gaps is discussed below, following a brief review of data applicable to all four potential gaps. One indication of the significance of these potential gaps is that 25 of the 40 TC analytes were detected in at least one of the descriptions of releases from non-hazardous industrial waste management units described in Chapter 2. Many are detected frequently above regulatory levels. Six TC metals and arsenic are among the most commonly detected analytes in the release descriptions. All TC analytes are regulated under federal and state regulatory schemes in addition to the RCRA hazardous waste characteristics. The TC analytes are included in 40 CFR Part 261, Appendix VIII, and therefore many wastes have been listed based on the presence of TC chemicals. Media-specific regulatory programs also control individual analytes. MCLs or MCLGs have been promulgated to limit exposures to about half the TC analytes in community drinking water systems. Most volatile TC analytes are Hazardous Air Pollutants under the CAA, and most TC analytes have OSHA Permissible Exposure Limits (PELs), which limit occupational exposures. CWA Ambient Water Quality Criteria trigger regulatory control of most of the TC analytes through NPDES permits and state surface water quality standards, although, as noted in Chapter 3, the TC regulatory levels may not be adequately protective against surface water risks for some analytes.

### Page 10-9 Exhibit 10-2 Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

Potential Gap Nature of Risk Descriptions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gap s Detection in Release Reported Releases > Mil
- Affected Managemen

t Coverage by Other TRI Chemicalswith 199

4

Groundwater pathway risks Wastes with TC constituents below 7 TC metals (lead, Methyl ethyl ketone, Industries with Landfills, surface RCRA listings, state Variability and from wastes below TC regulatory levels may pose chronic chromium, arsenic, cadmium,trichloroethylene, frequent detections of impoundments, land Industrial D, SDWA uncertainty in calculated regulatory levels health cancer risk >10 , noncancer barium, mercury, selenium) chromium compounds, metals in release application units, DAF values, depending on Uniform DAF value hazard quotient > 1 in nearby populations are among top 20 frequently lead compounds, chloro- descriptions include waste piles, poten- modeling assumptions potentially not exposed through groundwater ingestion. detected constituents. form, tetrachloro- chemicals, paper, tially others Limited non-hazardous protective for some TC Other TC constituents ethylene, benzene, 1,2- refuse systems, industrial wastestream data constituents. occurring > 5 times are ben- dichloroethane, industrial sand, -5

zene, trichloroethylene, chromium, arsenic and primary metals, and

vinyl chloride, silver, compounds, others. chlorobenzene, chloroform, chlorobenzene, vinyl and tetrachloroethylene. chloride Inhalation risks were not For 16 TC organics with inhalation cancerVinyl chloride, Methyl ethyl ketone, Chemicals, refuse Surface impound- RCRA listings, state Most organic analytes considered in derivation risk data, risk > 10 was found for: chloroform, chlorobenzene, chloroform, 1,2- systems, and others ments, land applica- Industrial D, CWA that exceed inhalation risk of TC levels. Volatile 0 and 12 analytes in central tendency 1,4-dichlorobenzene and dichloroethane, vinyl tion units, landfills, NPDES, CAA, OSHA PELs thresholds are not very organics pose such risks. and high-end surface impoundments carbon tetrachloride are chloride and possibly waste persistent in either soil or -5
respectively; and among most frequently handling water. 0 and 4 in central tendency and high- detected analytes. Release descriptions did end LAUs respectively. not identify inhalation For 4 TC organics with inhalation non- problems. cancer risk data, HQ > 1 was found for: Limited wastestream data 3 or 4 of central tendency or high-end respectively of both surface impoundments and LAUs. Surface water risks to Potential chronic health cancer risks Toxic, bioaccumulative Specific constituents Not addressed Surface impound- Intentional Risks may be significant human health were not >10 , noncancer risks HQ > 1 in nearby constituents of potential of potential concern ments, landfills, land discharges limited by only in narrow range of considered in the deriva- populations exposed to surface water by concern were not identified were not identified. application units, NPDES; state CWA conditions. tion of TC levels. consumptive use or recreational use frequently in the release waste piles Industrial D design Limited wastestream data -5
descriptions. requirements limit Release descriptions unintentional include few surface water releases releases. Indirect/food chain Potential human health risks from Lead, mercury, arsenic, Lead compounds, Industries with Surface impound- RCRA listings, state Limited data on pathway risks to human consumption of fish, crops, beef/dairy chloroform were frequently chloroform, arsenic frequent detection of ments, land applica- Industrial D, CWA wastestreams, releases to health were not products detected. compounds metals include tion units, and NPDES, CAA, FIFRA various media, and resulting considered in derivation Persistent bioaccumulative TC Persistent pesticides chemical, paper, and landfills damages of TC levels. Persistent analytes are chlorinated pesticides, were not frequently sanitary services. and bioaccumulative chloroform, hexachloro-1,3-butadiene, detected. chemicals pose such mercury, arsenic, and lead. risks.

### Exhibit 10-2 (continued) Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

Potential Gap Nature of Risk Descriptions lion lbs. Affected Industries Methods Regulations Comments/Major Data Gap s Detection in Release Reported Releases > Mil
- Affected Managemen

t Coverage by Other TRI Chemicalswith 199

4



### Page 10-10 Acute adverse health Screening analysis showed that short- Specific constituents of Specific constituents Not addressed Not addressed. OSHA PELs, CAA Acute hazards are effects were not term concentrations of all volatile TC potential concern were not of potential concern addressed by ICR considered in derivation organics calculated at fenceline were identified. were not identified. characteristics of TC levels. far below applicable short-term (occupational) exposure standards Unusual release events (e.g., fires orexplosions) could result in higher exposures Ecological risks were not Potential damage to nearby aquatic Lead, mercury, silver, and Chlorobenzene Chemicals, refuse Waste piles, land State Industrial D, Uncertainty in estimating considered in derivation ecosystems from releases to surface chlorobenzene each were systems, paper, application units, CWA effluent limits, degradation and dilution of TC levels. TC water and through aquatic and possibly detected at more than 5 of primary metals, and surface impoundments, FIFRA Limited data on constituents include terrestrial food chain exposures from 112 releases. others landfills wastestreams and releases to potent ecotoxins, runoff various pathways persistent and TC analytes with a ratio of TC leachate bioaccumulative concentration to AWQC > 10,000 include pesticides. chlorinated pesticides, chlorobenzene, lead, mercury, pentachlorophenol, silver, toxaphene, and 2,4,5-trichlorophenol. Ratio is > 100,000 for mercury, methoxychlor, silver, and toxaphene. TCLP may not accurately Release concentrations may be higher Lead, cadmium, chromium, Chromium compounds, Not addressed All types RCRA listings, state Limited data on predict leachate concen- or lower than predicted, implying higher arsenic, barium, benzene, lead compounds, arsenic Industrial D; states wastestreams and management tration or risks for or lower exposure concentrations and selenium, lindane, and vinyl compounds, and vinyl have developed alter- unit environments certain wastes and units. risks. chloride were detected in chloride (of those native leaching proce- Waste heterogeneity, Main concerns are for oily wastes; groundwater at levels listed in prior column) dures, e.g., Cal WET sampling procedures, sample highly alkaline wastes; wastes with exceeding their TC levels, preparation, leaching multiple constituents; wastes disposed indicating that TCLP may procedure contribute to in certain types of landfills; some types have underestimated the uncertainty in test results. of treated wastes; some types of con- long-term releases of some taminated soil; and non-groundwater wastes. pathways.

### Page 10-11 TC Regulatory Levels for Groundwater The first of the potential TC gaps concerns whether the existing leachate concentrations remain demonstrably protective of human health through the groundwater pathway, given advances in toxicological, fate, and transport data and modeling since the TC was promulgated. As noted in Section 3.5.2, the only changes in toxicological values that have occurred since the TC was promulgated are the reduction of the RfD for pentachlorophenol, promulgation of a cancer slope factor for this compound, the reduction in the RfD for p-cresol, the replacement of the MCL for lead with a lower action level, and replacement of the MCL for silver with an SMCL. Of these changes, only the classification of pentachlorophenol as a carcinogen significantly changes the risk implicit in the TC regulatory levels. EPA also has refined its approach for modeling the fate and transport of both organic and inorganic constituents in groundwater. Most recently, groundwater risks were modeled for the TC analytes in the HWIR-Waste proposed rulemaking. This modeling, which is still undergoing revisions, was performed using some assumptions that differ significantly from those made in the derivation of the TC regulatory levels. Nevertheless, the results, which are proposed health-protective exit levels for releases to groundwater, can be interpreted to imply that some TC regulatory levels may not protect human health to the extent originally intended. Without more detailed modeling that duplicates, where appropriate, the TC input assumptions, no firm conclusions can be drawn about which TC regulatory levels do or do not meet the original risk objectives, however. Risks Through Non-Groundwater Pathways Another major potential TC gap relates to exposures associated with inhalation, surface water, and indirect exposure pathways. These pathways were not considered when the TC was promulgated. The results of the proposed HWIR-Waste modeling also provide evidence that non-groundwater pathway risks may be important for several TC analytes. For nine of these substances, non-groundwater indirect exposures resulted in the highest risks and thereby determined the HWIR-Waste proposed exit concentrations. These pathways included both air and surface water. In most cases, the proposed exit concentrations for the indirect pathways are considerably lower than those based only on the groundwater pathway. These modeling results provide further evidence that the TC levels may not be sufficiently protective for some highly toxic, volatile, persistent, and/or bioaccumulative chemicals when pathways other than groundwater are considered. The screening-level modeling in Section 3.5.3 identified various TC constituents that may present inhalation risks when present in wastes at TC regulatory levels. For example, estimated lifetime cancer risks exceeded 10-5 for 12 of the 16 TC analytes for which EPA has promulgated inhalation Unit Risk values, assuming management in “high-end” surface impoundments. Cancer risks exceeded 10-5 for 4 of these 16 analytes when management in a high-end land application unit (LAU) was assumed. None of the analytes posed cancer risks above this level when managed in “central tendency” units. The Agency has promulgated inhalation pathway Reference Concentrations for only four TC analytes (chlorobenzene, methyl ketone, nitrobenzene, and 1,4-dichlorobenzene). When releases were modeled from high-end impoundments or LAUs, all four analytes had inhalation pathway hazard quotients above 1.0. When the central tendency impoundments are modeled, three of the four analytes (all but 1,4-dichlorobenzene) still have HQ values above 1.0. All the analytes with screening-level risk estimates above levels of potential concern were found in the release descriptions; several of them occur frequently in the release descriptions. Four of these constituents are among the chemicals with total TRI release volumes greater than one million pounds, as noted in Exhibit 10-2. EPA did not perform quantitative risk modeling of surface water and indirect pathways. Instead, the Agency reviewed the toxicity and fate and transport parameter values for the TC analytes to develop a qualitative

### Page 10-12

indication of the potential risks to human health that they might present when managed in Subtitle D units, as discussed in Section 3.5.4. A substantial proportion of the analytes have properties, such as volatility, persistence in air, soil, and water, and high bioaccumulation potential, that suggest potential exposure through surface water or indirect pathways might result in significant risks. The proposed HWIR-Waste modeling results for indirect pathways discussed above suggest the need for more detailed modeling, using assumptions consistent with those used to derive the TC regulatory levels, to better determine which indirect pathways are the most important for which TC analytes. Acute Adverse Effects The TC was originally established based on the need to protect individuals from adverse health effects due to chronic exposures to the TC constituents consumed in groundwater. This approach to protecting against groundwater exposure risks is conservative because the relatively long time scale generally involved ingroundwater transport to receptors means that limiting concentrations in any time period to the low chronic riskbased levels also will protect against short-term adverse effects. This relationship may not apply to exposure through pathways not involving slow releases to groundwater. For example, the rapid evaporation of volatile chemicals from a ruptured container, the catastrophic release due to overtopping of a surface impoundment, or runoff erosion from an extreme storm event has the potential to result in short-term (acute) exposures to humans and environmental receptors. Thus, EPA evaluated the potential for acute adverse effects associated with rapid volatilization of chemicals from land management units. This screening-level analysis indicated that the short-term concentrations of all volatile TC analytes calculated at the fenceline were far below applicable short-term exposure standards (in this case, occupational exposure standards). This simple modeling does not unconditionally eliminate the possibility of adverse effects from acute exposures to the TC analytes. Unusual release events, such as fires or explosions, could result in higher exposures than calculated assuming simple volatilization. In addition, high winds or other events could result in high concentrations of particle-bound metals and other nonvolatile analytes. The potential for these kinds of release events strongly depends on specific waste characteristics, site conditions, and management practices. Risks to Ecological Receptors The next potential gap in the TC is its lack of specific consideration of potential adverse effects on ecological receptors. Section 3.5.7 found that several TC analytes are highly toxic to aquatic biota, which suggests that this potential gap may be significant. Some of these constituents occur frequently in the release descriptions. One potent ecological toxicant (chlorobenzene) is among chemicals with TRI releases greater than one million pounds. Several TC analytes, including the chlorinated pesticides, chlorobenzene, mercury, and silver have TC levels greater than 1,000 times their respective AWQC, which indicates a risk to aquatic biota value if dilution after release is less than 1,000-fold. Mercury, methoxychor, silver, and 2,4,5-trichlorophenol have TC levels more than 10,000 times their AWQCs. In addition, as discussed in more detail in Section 10.2.4, several TC analytes (cadmium, heptachlor, heptachlor oxide, lead, mercury, methoxychlor, and toxaphene) have been identified as suspect endocrine disruptors for wildlife, as well as humans. All these lines of evidence support the importance of this potential gap. Some ameliorating considerations, however, include the relative lack of evidence for environmental damage in the release descriptions summarized in Chapter 2, and the existing bans and/or use restrictions on many of the TC pesticides, which comprise most of the potent ecological toxicants.

### Page 10-13 TCLP Limitations The final potential gap in the TC characteristic is the limitations in the ability of the TCLP to accurately predict releases of hazardous constituents from wastes. The Agency has received numerous comments and data on the utility of the TCLP in general and for specific wastes and environments. Potential limitations of the method include difficulties in performing the analysis on oily, hydrophobic wastes and in simulating leachate characteristics for highly alkaline wastes, certain types of landfill environments, long-term mobility of organics in some treated (non-hazardous) wastes, and some contaminated soils. Furthermore, the TCLP was not designed to simulate releases into non-groundwater pathways (e.g., air). In the context of this Scoping Study, EPA has not identified any significant new information bearing on the magnitude of this potential gap. The Agency has reviewed other possible leaching methods (such as the SPLP and Cal WET methods), but has not found compelling evidence that they are more appropriate for general use than the TCLP. The high frequency of occurrence of TC analytes in groundwater above MCLs or HBLs near non-hazardous industrial waste facilities, as shown in the release descriptions, suggests that the TCLP may not adequately detect situations that could result in harm to human health or the environment. The blame cannot unambiguously be placed on the TCLP, however. Even if the TCLP accurately predicts TC leachate levels, site-specific fate and transport processes (e.g., dilution by a factor of less than 100) and waste management practices could result in the exceedances of MCLs and other regulatory levels. 10.2.3 Potential Gaps Associated with Non-TC Waste Constituents Exhibit 10-3 summarizes the evaluation of potential gaps associated with non-TC chemicals that are known or possible non-hazardous industrial waste constituents. Separate evaluations are presented for each of the 10 categories of chemicals identified in Chapter 4, which are associated with the groundwater, inhalation, or indirect pathways:

Metals and other inorganics; Volatile chlorinated organics; Volatile hydrocarbons; Other volatile organics; Pesticides and related compounds; Phthalate esters; Phenolic compounds; Polycyclic aromatic hydrocarbons; Other semivolatile organic compounds; and LNAPLs and DNAPLs.
Nature of Risk. A number of chemicals in some of the groups listed above are suspect carcinogens. Other chemicals have the potential to cause reproductive and/or developmental effects in

### Page 10-14 Exhibit 10-3 Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemica l Type Nature of Risk trial Waste tions lion lbs. AffectedIndustries Methods Regulations Comments/Major Data Gap s Presence in Non- Constituents in 1994 Reported Hazardous

Indus- Release Descrip- Releases> One Mil
- Affected Managemen

t Potential

Coverageby Other
a Frequently

Detecte d TRIChemicals wit

h

GROUNDWATER PATHWAYS Metals/Inorga- Potential cancer risks > 61 elements, com- Beryllium, man- Copper, zinc, Chemicals, refuse 78 percent of State Industrial D; Cali- Exposure at individual nics 10 and noncancer risks of pounds, or families ganese, zinc, cop- manganese, cyanides, systems, paper have detections from fornia TC includes 10 addi- residential wells not -5 HQ>1 of compounds; most per, nickel, nickel, antimony about 66 percent of landfills; 15 per- tional metals; Michigan TC known important are prob- cyanides detections in cent from surface includes copper and zinc; many ably the metals, release descrip- impoundments; 5 have MCLs or SMCLs beryllium, copper, tions; 10 other percent from land manganese, nickel, industries have application units. zinc, cyanides frequent detections Volatile Potential cancer risks > 45 compounds Methylene chlo- Methylene Refuse systems, 79 percent of State Industrial D; most in Limited data on Chlorinated 10 and noncancer risks of ride, ethylidene chloride, trichloro- paper, and chemicals detections from Appendix VIII; RCRA listings; wastestream and waste Organics HQ>1 dichloride ethene, 1,1,1-tri- have about 85 percent landfills; 13 per- California TC includes 1,2- management practices -5 Many of these chemicals chloroethane, of detections cent from surface dibromo-3-chloropropane; manycontributing to are suspect carcinogens. chloromethane, Freon impoundments. have MCLs, MCLGs groundwater releases 113 Volatile Potential cancer risks > 13 compounds Toluene, xylenes Toluene, xylenes, Chemicals, refuse 68 percent of State Industrial D; RCRA Petroleum hydrocarbons Hydrocarbons 10 and noncancer risks of styrene, ethylbenz- systems, and paper detections from listings; all in Appendix exempt from RCRA -5 HQ>1. ene, cumene have 80 percent of landfills; 27 per- VIII; most have MCLs and/or Limited data on detections cent from surface AWQCs wastestreams and manimpoundments. agement practices contributing most to groundwater releases Other Volatile Potential cancer risks > 58 compounds Acetone Methanol, methyl Chemicals, refuse 75 percent of State Industrial D; most in Wide range of toxicOrganics 10 and noncancer risks of ethyl ketone, systems, and paper detections from Appendix VIII; RCRA listings; ological, fate and trans- -5 HQ>1 methyl-isobutyl industries have 88 landfills and the California TC includes port properties Highly variable toxicity ketone, n-butanol, percent of detec- remainder from acrylonitrile; few have MCLs, Limited data on and fate and transport formaldehyde, aceto- tions surface impound- MCLGs wastestreams and manproperties nitrile, acetalde- ments. agement practices conhyde, acrylonitrile, tributing to groundwater vinyl acetate, releases propylene oxide Phenolic Com- Potential noncancer 13 compounds Phenol Phenol; combined 10 industries with 56 percent of State Industrial D; all in Most compounds are of pounds risks of HQ>1 cresols release detections; among detections at land- Appendix VIII relatively low toxicity, exceeds one million the most widespread fills; 36 percent at biodegradable at low pounds of constituent surface impound- concentrations

classes, despite low ments; and 8 percent Limited data on number of detections at land application wastestreams

units.

### Exhibit 10-3 (continued) Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemica l Type Nature of Risk trial Waste tions lion lbs. AffectedIndustries Methods Regulations Comments/Major Data Gap s Presence in Non- Constituents in 1994 Reported Hazardous

Indus- Release Descrip- Releases> One Mil
- Affected Managemen

t Potential

Coverageby Other
a Frequently

Detecte d TRIChemicals wit

h



### Page 10-15 LNAPLs and Facilitated transport of 33 potential Potential 8 compounds plus LNAPLs/DNAPLs notNo data. State Industrial D; RCRA Frequency of NAPL DNAPLs organic chemicals from DNAPL formers, 13 LNAPL/DNAPL formers the phthalate esters reported in release Management prior- listings; some chemicals have problems in non-hazcontainment potential LNAPL were found in many (combined) descriptions ities are key to MCLs ardous waste appears to Long-lasting, difficult formers release descrip- DNAPL generation. be infrequent, espeto remediate reservoir of tions cially in recent years groundwater contamination LNAPLs/ DNAPLs Limited wastestream (DNAPL) were not reported and waste management data as problem in any release descriptions, possibly because of limited reporting requirements Other Semi- Potential cancer risks > 67 compounds None Formic acid, acry- Chemicals industry Approximately State Industrial D; many in Highly variable toxivolatile Organic 10 and noncancer risks of lic acid, naph- has 45 percent of equal frequency in Appendix VIII; RCRA listings; cological, fate, and Compounds HQ>1 thalene detections, landfills and sur- a few have MCLs; PCBs covered transport properties -5 Some are persistent remainder in five face impoundment by TSCA and some state Limited data on and/or bioaccumulative. other industries releases hazardous waste regulations wastestreams and man- Highly variable fate and agement practices contransport properties tributing to groundwater releases INHALATION PATHWAYS Volatile Chlo- Potential cancer risks > 45 compounds Methylene Methylene chlo- Refuse systems, 79 percent of State Industrial D; most in Limited data on rinated Organics 10 and noncancer risks of chloride, ride, trichloroeth- paper, and chemi- detections from Appendix VIII; RCRA listings; wastestream and waste -5 HQ>1 ethylidene ene, 1,1,1-trichlo- cals, have about 85 landfills; 13 per- California TC includes 1,2- management practices Many of these chemicals dichloride roethane, chloro- percent of detec- cent from surface dibromo-3-chloropropane; contributing to air are suspect carcinogens methane, Freon 113 tions impoundments majority are CAA HAPs; vinyl releases chloride has NESHAP; many have OSHA PELs Volatile Potential noncancer 13 compounds Toluene, xylenes Toluene, xylenes, Chemicals, refuse 68 percent of State Industrial D; all in Petroleum hydrocarbons Hydrocarbons risks of HQ>1 styrene, ethylbenz- systems, and paper detections from Appendix VIII RCRA listings; exempt from RCRA

Benzene is the only ene, cumene have 80 percent of landfills; 27 per- all are CAA HAPs Limited data on carcinogen detections cent from surface wastestreams and impoundments management practices contributing most to air releases

### Exhibit 10-3 (continued) Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemica l Type Nature of Risk trial Waste tions lion lbs. AffectedIndustries Methods Regulations Comments/Major Data Gap s Presence in Non- Constituents in 1994 Reported Hazardous

Indus- Release Descrip- Releases> One Mil
- Affected Managemen

t Potential

Coverageby Other
a Frequently

Detecte d TRIChemicals wit

h



### Page 10-16 Other Volatile Potential cancer risks > 58 compounds Acetone Methanol, Chemicals refuse 75 percent of State Industrial D; most in Wide range of toxi- <Organics 10 and noncancer risks of methylisobutyl systems, and paper detections from Appendix VIII; RCRA listings; cological, fate and -5 HQ>1 ketone, n-butanol, industries have 88 landfills and re- California TC includes transport properties Highly variable toxicity formaldehyde, percent of detec- mainder from surface acrylonitrile; most are CAA Limited data on and fate and transport acetinitrile, tions impoundments. HAPs; most have OSHA PELs wastestreams and properties acetaldehyde, management practices acrylonitrile, vinyl contributing to air acetate, propylene releases oxide Pesticides and Potential cancer risks > 103 compounds None None Chemicals industry 87 percent of State Industrial D; RCRA Future generation is Related Com- 10 and noncancer risks of has 80 percent of detections at sur- listings; most in Appendix unclear because of pounds HQ>1 detections; refuse face impoundments; VIII; several are CAA HAPs; production and use -5 Some suspect endocrine systems have 10 remainder at land- FIFRA banned production or restrictions; potential disruptors percent fills restricted use of many presence in remediation Possible reproductive waste may merit examining toxicity and human devel- Limited data on opment effects management practices Many are persistent and contributing to air bioaccumulative. releases Polycyclic Potential cancer risks > 19 compounds None (but PAHs None Relatively equally Relatively equally State Industrial D; many Highly variable Aromatic 10

. are not mobile in frequent in frequent at have CAA HAPs; many have OSHA toxicological, fate, and Hydrocarbons Some are persistent and groundwater) detections from landfills and sur- PELs transport properties -5
bioaccumulative. petroleum refining face impoundments Limited data on and chemicals wastestreams and industries; low management practices frequency overall contributing to nongroundwater releases Other Potential cancer risks > 67 compounds None Formic acid, Chemicals industry Approximately State Industrial D; many in Highly variable Semivolatile 10 and noncancer risks of acrylic acid, has 45 percent of equal frequency in Appendix VIII; RCRA listings; toxicological, fate, and Organic Com- HQ>1 naphthalene detections, remain- landfills and sur- many have OSHA PELs; some are transport properties pounds Some are persistent der in five other face impoundment CAA HAPs Limited data on -5

and/or bioaccumulative. industries detections wastestreams and Highly variable fate and management practices transport properties contributing to nongroundwater releases

### Exhibit 10-3 (continued) Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemica l Type Nature of Risk trial Waste tions lion lbs. AffectedIndustries Methods Regulations Comments/Major Data Gap s Presence in Non- Constituents in 1994 Reported Hazardous

Indus- Release Descrip- Releases> One Mil
- Affected Managemen

t Potential

Coverageby Other
a Frequently

Detecte d TRIChemicals wit

h



### Page 10-17 INDIRECT/FOOD-CHAIN PATHWAYS Pesticides and Potential cancer risks > 103 compounds None None Chemicals industry 87 percent of State Industrial D; RCRA Future generation is Related Com- 10 and noncancer risks of has 80 percent of detections at sur- listings; most in Appendix unclear because of pounds HQ>1 detections; refuse face impoundments; VIII; several have AWQCs; production and use -5 Some suspect endocrine systems have 10 remainder at land- FIFRA banned production or restrictions; potential disruptors. percent fills restricted use of many presence in remediation Possible reproductive waste may merit toxicity and human devel- examining. opment effects Limited data on Many are persistent and management practices bioaccumulative. contributing to releases Phthalate Esters Potential cancer risks > 6 compounds None None; combined Chemicals industry 54 percent of State Industrial D; di(2- High-volume chemicals

10 (one compound) phthalate ester has 70 percent of detections at sur- ethylhexyl)phthalate has MCL with high exposure -5 Suspect endocrine releases exceed one detection; petroleum face impoundments and AWQC potential, but often low disruptors million pounds, industry has 15 and 38 percent at toxicity Possible reproductive however percent landfills Limited understanding toxicity, human develop- of dose-response ment effects relationships, Several are persistent especially for endocrine and bioaccumulative. disruption Unclear significance ofexposures from nonhazardous waste relative to other sources Phenolic Com- Potential noncancer 13 compounds Phenol Phenol; combined 10 industries with 56 percent of State Industrial D; all in Most compounds are of pounds risks of HQ>1 cresols release detections; among detections at land- Appendix VIII; several have relatively low toxicity, exceeds one million the most widespread fills; 36 percent at AWQC biodegradable at low pounds of constituent surface impound- concentrations

classes, despite low ments; 8 percent at Limited data on number of detections land application wastestreams

units Polycyclic Potential cancer risks > 19 compounds None (but PAHs None Relatively equally Relatively equally State Industrial D; most Highly variable Aromatic 10 are not mobile in frequent in frequent at have CWA effluent limits; a toxicological, fate, and Hydrocarbons Some are persistent, groundwater) detections from landfills and sur- few have AWQC; many are CAA transport properties -5
bioaccumulative. petroleum refining face impoundments HAPs Limited data on and chemical wastestreams and industries; low management practices frequency overall contributing to nongroundwater releases

### Exhibit 10-3 (continued) Evaluation of Potential Gaps Associated with Non-TC Chemicals

Chemica l Type Nature of Risk trial Waste tions lion lbs. AffectedIndustries Methods Regulations Comments/Major Data Gap s Presence in Non- Constituents in 1994 Reported Hazardous

Indus- Release Descrip- Releases> One Mil
- Affected Managemen

t Potential

Coverageby Other
a Frequently

Detecte d TRIChemicals wit

h



### Page 10-18 Other Potential cancer risks > 67 compounds None Formic acid, Chemicals and Approximately State Industrial D; many in Highly variable Semivolatile 10 and noncancer risks of acrylic acid, naph- allied products have equal frequency in Appendix VIII; RCRA listings; toxicological, fate, and Organic Com- HQ>1 thalene 45 percent of landfills and sur- a few have AWQC transport properties pounds Some are persistent and detections, face impoundment Limited data on -5

bioaccumulative. remainder in five detections wastestreams and Highly variable fate and other industries management practices transport properties contributing to nongroundwater releases
Source: Exhibits 4-2 and 4-8. aEach chemical detected at a release site constit utes one detection. Thus, each release may have multiple detections (i.e., 2 multiple constituents) and each chemical may have multiple detections (i.e., be found at multiple releases).


### Page 10-19 humans and ecological receptors. These and other indicators of hazard, combined with indicators of exposure potential, demonstrate the potential for risks to human health or the environment.
Presence in Non-Hazardous Industrial Waste. The numbers of chemicals in the various classes that are known or possible non-hazardous industrial waste constituents varies widely:

103 pesticides and related compounds, 67 other semi-volatile organic compounds, 61 metals or other inorganics, 58 other volatile organics, 45 volatile chlorinated organics; 46 NAPL formers (30 DNAPL formers and 9 NAPL formers), 19 polycyclic aromatic hydrocarbons, 13 volatile hydrocarbons, 13 phenolic compounds, and 6 phthalate esters. Frequently Detected Constituents in Release Descriptions. Six non-TC metals are among the most frequently occurring analytes in the release descriptions, along with three volatile chlorinated organics, one other volatile organics, and one phenolic compound. The other classes of chemicals were not detected frequently in the release descriptions, which predominately included groundwater contamination. The constituents found in the release descriptions, however, frequently violated MCLs and other health-based levels. TRI Chemicals with 1994 Reported Releases Exceeding One Million Pounds. These broad categories of potential gaps include many chemicals with high TRI release volumes. In the case of the non-TC metals and other inorganics, copper, zinc, manganese, and cyanides (as CNH) fell into this category. As was the case for the frequency of occurrence in the release descriptions, several volatile organic waste constituents (chlorinated and nonchlorinated) that have high TRI release volumes are TC analytes. None of the pesticides, phthalate esters, or PAHs were among the chemicals with TRI releases greater than one million pounds. Two phenolic compounds and three semivolatile organics were among the waste constituents with the highest TRI releases. Many of the potential NAPL forming compounds also are high-release compounds.
Affected Industries. A relatively small number of industries tend to account for the bulk of the occurrences of most categories of wastes with chemicals of concern. For almost all chemical classes, most detections of chemicals constituents identified in the release descriptions were associated with three industry 2 

### groups: chemicals and allied products, refuse systems, and paper and allied products. Phenolic compounds diverge from this pattern. The three industries identified above account for only about 35 percent of the releases of such compounds, and 8 other industries had detections of phenolic constituents. Affected Management Methods. As noted in Chapter 8, about 65 percent of the release descriptions were associated with landfills, 28 percent with surface impoundments, and 11 percent from land application units, 4 percent from waste piles, with the other management units accounting for less than 1 percent each. (Several release descriptions involved more than one facility.) This pattern generally applies to the individual classes of chemicals, with a few significant exceptions. Since metals and inorganics were detected much more often than other constituents, data on these detections dominate the overall pattern. The other classes of chemicals with relatively high numbers of detections (volatile hydrocarbons, other volatile organics, phenolic compounds, and

### Page 10-20

chlorinated volatile organics) were most commonly found in landfill releases, like the metals. For some chemical classes with relatively low numbers of detections, such as other semivolatile organics, phthalate esters, and PAHs, the proportions of detections from landfills and surface impoundments is almost equal, with few releases are reported from other management units. Potential Coverage by Other Regulations. As noted in Chapter 10, the chemicals associated with potential gaps are subject to regulatory requirements that have some potential for controlling risks to human health and the environment associated with nonhazardous industrial waste management. Since the bulk of these chemicals are included in 40 CFR Part 261, Appendix VII, some wastes containing these chemicals are RCRA listed hazardous wastes. Of course, other wastes with these constituents are not listed. The design and operation of non-hazardous industrial waste management facilities managing all of the various classes of waste constituents is largely under the control or potential control of state Industrial D programs. All of these programs include a federally-mandated minimum set of design and monitoring requirements for landfills. In some states, as discussed in Chapter 10, these minimum requirements have been expanded for certain types of waste management units, wastes, and/or constituents. These requirements, however, vary considerably from state to state. The appearance of various chemicals in groundwater at levels exceeding regulatory standards suggests that the control of these chemicals under state Subtitle D programs may not afford the intended level of protection nationwide. The various chemical classes also are subject to medium-specific regulations under Safe Drinking Water Act, Clean Air Act, and Clean Water Act. Most of the metals and commonly occurring inorganic and organic analytes have MCLs established to protect drinking water quality. Many of the volatile chemicals are CAA Hazardous Air Pollutants (HAPs). The effectiveness of this designation in protecting against exposures from waste management is unclear, however, because the regulatory requirements apply only to facilities emitting more than 10 tons of HAPs per year. Vinyl chloride is also controlled by a National Emission Standard for Hazardous Air Pollutants, which is risk-based and protective to roughly the same risk level as the TC. Some of the pesticides, identified as being among the most potentially hazardous waste constituents in Chapter 4, are already banned or strictly limited in their use by FIFRA. 10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental Problems Chapter 5 briefly evaluated the following potential gaps in the hazardous waste characteristics related to the following natural resource damages and large-scale environmental problems: Natural Resource Damages Groundwater pollution that may not present a health risk; Odor problems; Large-Scale Environmental Problems Air deposition to the Great Waters; Damages from airborne particulates; Global climate change; Potential damages from endocrine disruptors; Red tides; Stratospheric ozone depletion; Tropospheric ozone and photochemical air pollution; and

### Page 10-21 Water pollution. At this time, the Agency does not plan to further consider any of these potential gaps, except possibly air deposition and endocrine disruptions. These two potential gaps are discussed below and summarized in Exhibit 10- 4. Air Deposition to the Great Waters Few data are available on the contribution of non-hazardous industrial waste management to the deposition of toxic particulates (including toxic metals and persistent chlorinated organic chemicals) in the Great Waters ecosystems. While non-hazardous industrial waste constituents include toxic metals such as cadmium, lead, and mercury, the extent of their long-range transport is unknown. Persistent chlorinated organic chemicals also are among non-hazardous industrial waste constituents. Many of them have been banned from manufacture or further use and therefore are unlikely to be managed in significant quantities as non-hazardous industrial wastes. They may, however, continue to be found in remediation wastes. Potential Damages from Endocrine Disruptors The next potential gap is exposure to suspect endocrine disruptors. Depending upon what criteria are used to identify these constituents, 28 suspect endocrine disruptors have been found among the TC analytes and known or possible non-hazardous industrial waste constituents. Only the metals are encountered frequently in the release descriptions, however. These metals are most commonly present in releases detected from facilities in the chemicals and allied products, refuse systems, paper and allied products, industrial sand, and primary metals industries. These releases are most often seen from landfills, followed by surface impoundments, based on the release descriptions summarized in Chapter 2. One suspect endocrine disruptor, styrene, is high on the TRI list, having total releases of 40 million pounds in 1994. Almost all of the styrene releases are to air, with well under one million pounds being released to land. Releases of the phthalate esters as a class also exceed one million pounds, although the releases of these compounds individually are all less than one million pounds. The use of many suspect endocrine disrupting pesticides has been banned or strictly limited. A significant portion of the endocrine disruptors are TC analytes or otherwise listed in 40 CFR Part 261, Appendix VIII. The greatest uncertainty concerning this potential gap is a lack of knowledge about dose-response relationships for single and multiple agents, and the relative contribution of non-hazardous industrial waste management to the total exposure of human and environmental receptors.

### Page 10-22 Exhibit 10-4 Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems

Potential Gap Nature of Risk Waste ReleaseDescriptions lbs. Affected Industries Methods Other Regulations Gaps Presence in Non- FrequentlyDetected 1994 Reported Hazardous Industrial Constituents in Releases > Million Affected Management Potentia l Coverage by Comments/Major Dat a TRI Chemicals

with

Air Deposition to the Adverse ecological Many constituents, Lead, cadmium, Lead compounds Chlorinated organics Metals releases CAA Section 112(m) and Limited data on air Great Waters effects on Great Lakes, such as pesticides, mercury are found in release predominantly from National Emissions deposition Chesapeake Bay, Lake PCBs, dioxins, Pesticides were not descriptions from only a landfills and surface Standards for Hazardous contributions from Champlain, and coastal cadmium, lead, and frequently detected. few industries and found impoundments Air Pollutants non-hazardous water ecosystems mercury seldom therein Pesticide releases industrial waste Metals are found predominantly from management frequently in release surface impoundments Uncertainty about descriptions from many regional transport industries patterns Potential Damage from Impaired 30 suspect endocrine Cadmium, lead, and Styrene, lead Most major generating 68 percent of RCRA listings, FIFRA, Limited waste stream Endocrine Disruptors reproduction and disruptors mercury compounds industries detections in release SDWA, CWA and release data developmental Releases descriptions descriptions were from Dose-response data disorders among humans found them in 12 landfills and 24 percent for exposure to single and wildlife industries, with 70 from surface or multiple agents is percent of the detections impoundments. lacking in the chemicals, paper, and sanitary services industries.

### Page 10-23 10.2.5 Gaps Associated with State TC Expansions and Listings A number of states have expanded their hazardous waste program to regulate additional waste as hazardous. These state expansions include:

Adding constituents to the list of TC analytes. These additional constituents include zinc, other metals, PCBs, pesticides, dioxins, and potential carcinogens. Lowering existing TC regulatory levels. For example, California lowered the TC regulatory level for pentachlorophenol from 100 mg/l to 1.7 mg/l. Specifying alternative testing methods for identifying toxic hazardous waste. For example, California requires use of the Wet Extraction Test (WET) in addition to the TCLP. This test identifies several metal-containing wastes as hazardous that are generally not identified as hazardous using the TCLP. Using alternative approaches (other than listing constituents and regulatory levels) to identify toxic hazardous wastes. For example, both California and Washington have established toxicity criteria for wastes based on acute oral LD50, acute dermal LD50, acute inhalation LC50, and acute aquatic 96-hour LC50 of the wastestreams taken as a whole. A waste is designated hazardous if a representative sample of the waste meets any of the acute toxicity criteria. In addition, California's regulations state that a waste exhibits the characteristic of toxicity if the waste, based on representative samples, "has shown through experience or testing to pose a hazard to human health or environment because of its carcinogenicity, acute toxicity, chronic toxicity, bioaccumulative properties or persistence in the environment." Listing additional wastes as hazardous. The most common state-only listed wastes are PCBs and waste oil. At least four states include additional "F" Wastes; three include additional "K" wastes; five include additional "P" wastes; and six include additional "U" wastes. Restricting exemptions from the federal rules. Examples include chromium-bearingwastes from leather tanning and finishing, various special wastes, certain arsenicaltreated wood wastes, petroleum contaminated media and debris that fail the TC, certain injected groundwater, used CFC refrigerants that are reclaimed, and non-terne plated used oil filters. Thus, several states appear to be regulating a significant number of wastes as hazardous that are not covered under federal RCRA regulations. These expansions reflect state judgments about gaps in the federal program and thereby constitute potential gaps that may merit further investigation. State expansions have filled these gaps, but only in the specific states with such expansions. Such potential gaps are possiblynot being filled in the remaining states that have not expanded the federal hazardous waste definitions. 10.2.6 Major Data Gaps and Uncertainties The significance of potential gaps in the hazardous waste characteristics directly depends on the magnitude of risks that are not addressed by the current characteristics or other programs. Thus, data gaps in the Agency's ability to assess these risks are critical.

### Page 10-24 A key step in any risk analysis is characterizing the sources of releases of toxic or otherwise hazardous materials to the environment. Thus, possibly the most important data gap is the lack of current data on the generation, composition, and management of non-hazardous industrial wastes. EPA's most recent comprehensive dataon these topics are approximately a decade old. Many of the data are even older. While the basic nature of nonhazardous industrial wastes and waste management practices are not likely to have changed dramatically, nonetheless, some important changes are likely to have occurred because of regulatory, economic, and technical developments since the data were gathered. Additional data gaps relate to exposure potential. Because of the lack of site-specific data, the Agency had to rely primarily on proxies for exposure and risk potential. Environmental fate, transport, and toxicological parameters have been used as a primary screening criteria to identify and evaluate hazards. As noted in Chapter 5, consistent and reliable data related to these properties are available for only a relatively limited portion of the universe of chemicals under consideration.Likewise, the Agency has no direct data on the amounts of certain constituents released from nonhazardous industrial waste management units. Instead, 1994 TRI release data were used as proxies for such data.Another data source the Agency employed to assess exposure potential was the release descriptions from nonhazardous industrial waste management facilities. While these data provide direct evidence of environmental contamination, it is often not clear whether the management practices that resulted in releases are still in use. Some data gaps in this analysis are common to all risk analyses. For example, the need to conduct analysis on a national scale and to consider a wide range of site conditions, facility characteristics, and geographic settings dictates the use of generic, rather than site-specific modeling to estimate exposures through the various pathways. Thus, the analysis of groundwater exposures relies on probabilistically-defined dilution and attenuation values and the screening-level risk modeling uses highly generic release, transport, and exposure models. This approach only roughly approximates potential risks to humans and ecological receptors. Moreover, extensive professional judgment was required to generalize from generic modeling for specific chemicals to broad classes of waste constituents.Another major source of uncertainty is associated with toxicity of the waste constituents. The doseresponse models and data used are the most current available to the Agency. Nevertheless, substantial uncertainty exists regarding the probability and severity of adverse effects as a function of dose for many chemicals. The use of a generically defined "chronic" exposure period may mask important relationships between exposure periods and effects. Also, the Agency was not able to derive any specific dose-response relationships for endocrine disruptors or for any non-additive combinations of pollutant exposures. These uncertainties, unlike some of the others just discussed, are not likely to be resolved in the near future. 10.3 Framework for Determining an Appropriate Course of Action The U.S. Environmental Protection Agency will consider the appropriate course of action to address significant gaps or potential gaps in the hazardous waste characteristics identified by the Study. This section describes the framework that EPA plans to use in considering what course of action is appropriate. As part of this process, the Agency will consider comments on the Study from interested parties. EPA's approach for considering a course of action will include two main steps: Step 1: Identify the critical research needs and associated next steps necessary to analyze key issues and fill major data deficiencies identified in the Scoping Study; and

### Page 10-25 Step 2: Identify and evaluate options to address the environmental management concerns resulting from any gaps in the characteristics that were clearly identified in the Scoping Study. Both of these steps are described in more detail below. 10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze Key Issues and Fill Major Data Deficiencies The results of the Scoping Study vary greatly in terms of the certainty that can be attributed to gaps in the hazardous waste characteristics. Some of the potential gaps, most notably certain limitations in the ICR characteristics, are clearly identifiable problems. Most potential gaps, however, are associated with considerable uncertainty that limits the degree to which conclusions can be made about either the precise nature and extent of the gap or how, if at all, it should be addressed. Thus, a critical activity in the near-term will be to assess what additional data and analysis are needed to reduce uncertainty and better determine the significance of the most important potential gaps in the characteristics identified by the Scoping Study. 10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps Some of the gaps identified in the Scoping Study are sufficiently defined that the Agency can consider options for addressing the problem. Modifying an existing characteristic or developing a new characteristic may be an appropriate method of filling some of these gaps. Other gaps may be better addressed through other regulatory programs or in coordination with such programs. Thus, the list of options that the Agency may consider include: Specifying additional or revised test methods;

Expanding the definitions of existing characteristics; Modifying the characteristics to reflect new risk data and modeling techniques; Creating new characteristics, including contingent characteristics based on management method or the type of generator or waste; Identifying new hazardous waste listings or modifying existing listings; Modifying other regulatory programs (e.g., Subtitle D); Developing a non-regulatory approach (e.g., recycling, waste minimization); and Promoting voluntary industry programs. In evaluating a range of feasible options for particular gaps, the Agency will consider a variety of factors including, but not necessarily limited to the following:

Affected industries, wastes, and management practices; Human health and environmental benefits, such as reduced hazards and loadings of hazardous constituents;

### Page 10-26 Compliance costs and difficulties; and Implementation and administration costs and difficulties. Evaluating options can be a highly complex and data-intensive activity. Thus, the Agency may be unable to determine quickly that a particular approach is appropriate. Nevertheless, analyzing options can help to narrow the range of feasible and appropriate actions and help to identify the critical issues that need to be resolved in selecting an approach.

### Page 10-27

CHAPTER 10. SUMMARY EVALUATION OF NATURE AND EXTENT OF POTENTIAL GAPS

........................ 10-1 10.1 Overview of the Evaluation of Potential Gaps

................................. 10-1 10.1.1 Objectives of the Gaps Analysis

.................................... 10-1 10.1.2 Criteria Used for Evaluating Gaps

................................... 10-1 10.2 Findings of the Evaluation

................................................ 10-3 10.2.1 Potential Gaps Associated with the ICR Characteristics

.................. 10-3 10.2.2 Potential Gaps Associated with TC Analytes

.......................... 10-8 10.2.3 Potential Gaps Associated with Non-TC Waste Constituents

............. 10-14 10.2.4 Potential Gaps Associated With Resource Damage and Large-Scale Environmental Problems

...................................................... 10-22 10.2.5 Gaps Associated with State TC Expansions and Listings

................ 10-25 10.2.6 Major Data Gaps and Uncertainties

................................. 10-26 10.3 Framework for Determining an Appropriate Course of Action

................... 10-27 10.3.1 Step 1: Identify Critical Research Needs and Next Steps Necessary to Analyze Key Issues and Fill Major Data Deficiencies

.......................................... 10-27 10.3.2 Step 2: Identify and Evaluate Options to Address Any Clearly Identified Gaps10-27

### Page 10-28

Exhibit 10-1 Evaluation of Potential Gaps Associated With the Ignitability, Corrosivity, and Reactivity (ICR) Characteristics 10-4 Exhibit 10-2 Evaluation of Potential Gaps Associated with Toxicity Characteristic Analytes and TCLP

........... 10-9 Exhibit 10-3 Evaluation of Potential Gaps Associated with Non-TC Chemicals

............................. 10-15 Exhibit 10-4 Evaluation of Potential Gaps Associated With Certain Large-Scale Environmental Problems

........ 10-24