Technical Guidance

for Hazards Analysis

Emergency Planning for 

Extremely Hazardous Substances 

U.S. Environmental Protection Agency 

Federal Emergency Management Agency 

U.S. Department of Transportation 

December 1987 
Preface

This guide was developed by the U.S. Environmental Protection Agency in conjunction with the 

Federal Emergency Management Agency 

(FEMA) and the Department of Transportation 

(DOT) . 

In November 1985, as part of its National Strategy for Toxic Air Pollutants, EPA published the 

Chemical Emergency Preparedness Program 

(CEPP) Interim Guidance and invited public review and comment. The Interim Guidance contained information on how to organize planning 

committees, write a plan, and conduct a hazards analysis on a site-specific basis. In April 

1986, EPA began collaborating with FEMA and 

other Federal agency members of the National 

Response Team (NRT) in the revision of FEMA’s 

widely-distributed Planning Guide and Checklist 

for Hazardous Materials Contingency Plans 

(popularly known as “FEMA-10”). In October 

1986, during the time that a revised FEMA-10 

was being prepared, the Superfund Amendments and Reauthorization Act of 1986 (SARA) 

was enacted. Title Ill of SARA is also known as 

the Emergency Planning and Community Rightto-Know Act. Section 303 of SARA required the 

NRT to publish guidance to assist local emergency planning committees (LEPCs) with the development and implementation of comprehensive hazardous materials emergency response 

plans. The Federal agencies revising FEMA-10 

prepared a document that included guidance for 

meeting the SARA Title Ill planning requirements. 

The NRT published this document as the Hazardous Materials Emergency Planning Guide 

(NRT-1) on March 17, 1987. 

This current guide supplements NRT-1 by providing technical assistance to LEPCs to assess 

the lethal hazards related to potential airborne 

releases of extremely hazardous substances 

(EHSs) as designated under Section 302 of Title 

Ill of SARA. Future revisions of this guidance 

(scheduled for publication in 1988) will consider 

flammables, corrosives, explosives, and other 

hazards. Anyone using this guide also needs to 

acquire and use NRT-1. 

12/87 i 

There are many definitions of “hazards analysis. ” In an effort to develop and maintain consistency among Federal guidance documents, 

this guide adopts the approach to community 

level hazards analysis adopted by 14 Federal 

agencies in NRT-1. NRT-1 defines “hazards 

analysis” as a three step process: hazards identification, vulnerability analysis, and risk analysis, and provides general descriptions and specific procedures for each. This guide provides a 

technical discussion of, and specific procedures 

for, a method that can be employed in conducting a hazards analysis that will allow planners to 

consider the potential risks in their local communities. 

Although the use of this guide is not mandatory, 

it does have many advantages, some of which 

are the following: 

� It enables local planners to conduct a hazards analysis, which is an essential step in 

the planning process, and thereby assists local planners in meeting planning requirements of SARA Title Ill; 

� It will facilitate community awareness of the 

potential risks of chemical releases while 

helping the community to plan for, respond 

to, and reduce those risks. 

� It is consistent with NRT-1 mandated under 

SARA and approved by 14 Federal agencies: 

� It is consistent with training programs (e.g. 

contingency planning) that are being conducted by the Emergency Management Institute in Emmitsburg, Maryland: 

� It can be used by software developers who 

want their products to be consistent with the 

planning requirements of Title Ill of SARA: 

and

 It will promote consistency among local 

emergency plans. 

Techniques presented in this guide and NRT-1 

will also be helpful to LEPCs during the annual 

review and updating of their plans, as required 

by SARA Title Ill. 
Table of Contents

PAGE

PREFACE ............................................................ i

1. INTRODUCTION AND OVERVIEW ...................................... 1-1

1 .1 Purpose of this Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2 Emergency Planning: the National Response Team Planning Guide . . . . . . . . 1-1

1.3 Beginning to Plan ............................................ 1-3

1.4 Hazards Analysis ................................................. 1-3

A. Hazards identification . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

B. Vulnerability analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

C. Risk analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

1.5 Background ...................................................... 1l- 5

1.5.1 EPA’s Chemical Emergency Preparedness Program ................. 1-5

1.5.2 Other Public and Private Sector Programs ......................... 1l-5

1.5.3 Emergency Planning and Community Right-to-Know Act of 1986

(Title Ill of SARA) ............................................. 1l-6

A. Identifying the Extremely Hazardous Substances that Trigger

the Planning Process ........................................... 1- 6

B. Planning Structure and Process .................................. 1-6

C. Other Title Ill Information for Planners ............................. 1-8

1.6 Contents of this Guide .............................................. 1-8

2. HAZARDS ANALYSIS: AN OVERVIEW .................................. 2-1

2.1 Hazards Identification .............................................. 2-1

2.1 ............................ .1 Identification of Hazardous Chemicals 2-2

2.1.2 Procedures for Hazards Identification ............................. 2-2

2.1.3 Summary of Useful Information Resulting from Hazards Identification ... 2-6
Table of Contents (Continued) 

PAGE 

2.2 Vulnerability Analysis for Airborne Extremely Hazardous Substances . . . . . . . . 2-7

2.2.1 General Description of Estimation of Vulnerable Zones .............. 2-7

2.2.2 Variables in Estimating Size of Vulnerable Zones ................... 2-9

A. Quantity and Rate of Release to Air ............................... 2-9

B. Meteorological Conditions ....................................... 2-9

C. Surrounding Topography ........................................ 2-13

D. Levels of Concern ............................................. 2-13

2.2.3 The Relationship of Estimated Vulnerable Zones to Actual Releases . . . 2-13

2.2.4 Application of Estimated Vulnerable Zones to Hazards Analysis for

Extremely Hazardous Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17

2.2.5 Evacuation Considerations for Airborne Releases of Extremely

Hazardous Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18

2.3 Risk Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

2.3.1 Overall Approach to Risk Analysis: Ranking of Hazards . . . . . . . . . . . . . . 2-21

2.3.2 Types of Information Required for Risk Analysis . . . . . . . . . . . 2-22

2.3.3 Limiting the Collection of Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25

2.3.4 Assembly of the Information Obtained from the Hazards Analysis . . . . . 2-25

2.3.5 Relative Ranking of Risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28

3. STEP-BY-STEP PROCEDURES FOR CONDUCTING A HAZARDS ANALYSIS OF

EXTREMELY HAZARDOUS SUBSTANCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

3.1 Initial Screening to Set Priorities Among Sites . . , . . . . . . . . . . . . . . . . . . . . . . 3-1

3.1.1 Hazards Identification .......................................... 3-1

3.1.2 Estimate Vulnerable Zones for Screening Purposes ................. 3-2

A. Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

B. Liquids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

C. Solids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Worked Examples for Initial Screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

3.1.3 Risk Analysis for Initial Screening of Reporting Facilities . . . . . . . . . . . . . . 3-7
Table of Contents (Continued) 

PAGE 

3.2 Reevaluation: Planning for Facilities by Priority . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

3.2.1 Hazards Identification .......................................... 3-7

3.2.2 Reevaluation of the Vulnerable Zones ............................ 3-7

A. Gases ........................................................ 3-8

B. Liquids ........................................................ 3-8

C. Solids ........................................................ 3-8

3.2.3 Risk Analysis ................................................. 3-10

4. USING THE RESULTS OF A HAZARDS ANALYSIS ........................ 4-l

4.1 What the Plan Must Contain ........................................ 4-l

4.2 Planning Information Provided by the Hazards Analysis .................. 4-2

4.3 Case Studies from Hazards Analysis ................................. 4-3

4.4 Plan Reviews in the Context of Local Resource Needs .................. 4-7

4.5 Use of Computerized Systems in Planning ........................ 4-8

APPENDICES

APPENDIX B: THE CRITERIA USED TO IDENTIFY EXTREMELY

APPENDIX G: EQUATIONS USED FOR THE ESTIMATION OF VULNERABLE

APPENDIX A: ACRONYMS AND GLOSSARY OF TERMS . . . . . . . . . . . . . . . . . . . . . . A-1

ACRONYMS ...............................,...................... A-1

GLOSSARY OF TERMS. . . . ........... ......................... A-4

HAZARDOUS SUBSTANCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

APPENDIX C: THE LIST OF EXTREMELY HAZARDOUS SUBSTANCES . . . . . . . . . . C-1

APPENDIX D: ADDITIONAL INFORMATION ON LEVELS OF CONCERN . . . . . . . . . . D-1

APPENDIX E: SAMPLE PROFILE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1

APPENDIX F: FIRE AND REACTIVITY HAZARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . F-1

ZONES ....................................................... ........................ G-1
List of Exhibits

PAGE 

EXHIBITS 

1-1 Overview of Planning Process ..................................... 1-2

1-2 Title Ill Information from Facilities Provided in Support

of Plan Development ............................................ 1-7

1-3 Title Ill Planning Steps ............................................ 1-9

2-1 Types of Facilities Where Certain Extremely Hazardous Substances

Might Be Found in Quantities Greater than Their TPQs ................. 2-5

2-2 Information from Hazards Identification ............................. 2-8

2-3 The Movement Downwind of a Plume of Airborne Extremely Hazardous

Substances Following an Accidental Release ......................... 2-10

2-4 Vulnerability Zones for a Hypothetical Community Resulting from

Airborne Releases of Chemicals A and B .......................... 2-11

2-5 Vulnerable Zones along a Transportation Route When Airborne Releases

of Chemicals A and B Occur ...................................... 2-12

2-6 The Effect of Different Assumptions on the Calculation of the Size

of the Estimated Vulnerable Zone .................................. 2-14

2-7 Vulnerable Zones for Five Facilities in a Hypothetical Community ........ 2-15

2-8 Plume Development and Movement During a Hypothetical Accidental

Release ....................................................... 2-16

2-9 Factors Affecting Vulnerable Zone Estimations ....................... 2-19

2-10 Summaries of Some Accidents that Occurred in 1980-81 .............. 2-24

2-11 Steps in Hazards Analysis ........................................ 2-26

2-12 Example Hazards Analysis Matrix for a Hypothetical Community ......... 2-29

2-13 Example Qualitative Definitions of Probability of Occurrence ............ 2-31

Example Definitions of Severity of Consequences to People ............ 2-31

2-14 Risk Analysis Matrix .............................................. 2-32

3-1 Vulnerable Zone Distances for Quantity of Release and Level of Concern.

Rural, F Air Stability, Low Wind Speed. For Quantities of Release Up to

500 Pounds/Minute .............................................. 3-11
List of Exhibits

PAGE 

3-2 Vulnerable Zone Distances for Quantities of Release and Level of 

Concern. Urban, F Air Stability, Low Wind Speed. For Quantities of 

Release Up to 500 Pounds/Minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13 

3-3 Vulnerable Zone Distances for Quantity of Release and Level of 

Concern. Rural, D Air Stability, 12 Miles Per Hour Wind Speed. For 

Quantities of Release Up to 500 Pound/Minute . . . . . . . . . . . . . . . . . . . . . . . 3-15 

3-4 Vulnerable Zone Distances for Quantity of Release and Level of 

Concern. Urban, D Air Stability, 12 Miles Per Hour Wind Speed. For 

Quantities of Release Up to 500 Pounds/Minute . . . . . . . . . . . . . . . . . . . . . . 3-17 

4-1 Example Hazards Matrix for Planning Community . . . . . . . . . . . . . . . . . . . . 4-4 

B-1 Criteria to Identify Extremely Hazardous Substances that May 

Present Severe Health Hazards to Humans Exposed During 

a Chemical Accident or Other Emergency . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3 

B-2 Criteria to Identify Other Hazardous Substances Produced in 

Large Quantities that May Present Severe Health Hazards to 

Humans Exposed During a Chemical Accident or Other Emergency . . . . . B-5 

B-3 Other Extremely Hazardous Substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-6 

C-1 List of Extremely Hazardous Substances and Data for Hazards 

Analysis (Alphabetical Order) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2 

C-2 List of Extremely Hazardous Substances and Data for Hazards 

Analysis (CAS # Order) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-11 

D-1 Emergency Response Planning Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . D-7 

D-2 (Alphabetical) Published Toxicity Guidelines for Extremely Hazardous 

Substances that could be used for the Level of Concern . . . . . . . . . . . . . . D-9 

D-3 (CAS #) Published Toxicity Guidelines for Extremely Hazardous 

Substances that could be used for the Level of Concern . . . . . . . . . . . . . . D-18 

G-1 Formulas Recommended by Briggs (1973) .......................... G-6 

J-1 Sample Event Tree Analysis ...................................... J-5 

J-2 Example Fault Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J-7 
1. Introduction and Overview

1.1 Purpose of This Guide 

The purpose of this guide is to help local emergency planning committees (LEPCs) conduct 

site-specific hazards analyses for airborne releases of extremely hazardous substances 

(EHSs) as required by Title Ill of the Superfund 

Amendments and Reauthorization Act of 1986 

(SARA), also known as the Emergency Planning 

and Community Right-to-Know Act (EPCRA) . 

Although these substances may also threaten 

property and the environment, this guide is primarily concerned with lethal effects of airborne 

substances on humans. An expanded version of 

this document which will also address hazards 

such as flammability, explosivity, corrosivity, 

and reactivity, is planned. The hazards analysis 

guidance in this present document will help to 

identify potential problems and serve as the 

foundation for planning and prevention efforts 

with emphasis on EHSs. (See Section 1.3 for a 

definition and brief description of “hazards 

analysis. ” See Section 1.5.3 for a description of 

“extremely hazardous substance. “) 

This document represents a joint effort by the 

Environmental Protection Agency (EPA), the 

Federal Emergency Management Agency 

(FEMA), and the Department of Transportation 

(DOT) to provide coordinated and coherent 

technical guidance. Although this guide can be 

useful to all community and industry planners, it 

is intended especially for LEPCs established under the provisions of SARA. The three steps of 

hazards analysis--hazards identification, vulnerability analysis, and risk analysis--provide a decision-making process for the LEPCs to follow 

as they undertake the development of comprehensive emergency plans mandated by SARA Title Ill. This chapter includes a description of: 

the relationship of this guide to general planning 

guidance, a general description of hazards 

analysis, the legislative and programmatic background for this technical guidance, and an overview of the remaining chapters. 

1.2 Emergency Planning;

the National Response Team Planning Guide 

Title Ill of SARA requires each LEPC to prepare a Hazardous Materials Emergency 

comprehensive emergency plan by October 17, Planning Guide 

1988. For general assistance in preparing a WH-562A 

comprehensive emergency plan, planners 401 M Street, S.W. 

should consult the Hazardous Materials Emer- Washington, DC 20460 

gencv Planning Guide (NRT-1) prepared by the LEPCs should obtain, read, and understand 

National Response Team (NRT). NRT-1 is a NRT-1 before using this technical guide. statutory requirement under SARA and was published on March 17, 1987. It is available free of Exhibit l-l illustrates the various activities that 

charge from: are part of the emergency planning process. 

1-1
Exhibit l-l 

Overview of Planning Process* 

12/87 1-2
NRT-1 offers general guidance on how to accomplish all of these planning activities. This 

present document offers specific technical guidante for conducting a hazards analysis for the 

airborne release of EHSs, as well as a general 

consideration of other hazardous substances. 

The shaded box in Exhibit l-l indicates where 

the material in this technical guide fits into the 

overall planning process described in NRT-1, 

1.3 Beginning to Plan

Before actually developing a plan, the LEPC 

should: review existing plans, review existing response capabilities, and conduct a hazards 

analysis. 

Information from existing plans will prove helpful 

in the development of an emergency plan under 

Title Ill. Existing plans may have been prepared 

by individual facilities, by communities, by the 

State, or by the Regional Response Team (RRT) 

of the Federal government. The plans can be 

reevaluated and information in them can be tailored to present needs. 

NRT-1 and Appendix I of this guide include lists 

of questions that LEPCs can use to identify what 

prevention and response capabilities are present 

at facilities, among transporters, and within local 

communities. 

LEPCs should conduct a hazards analysis of all 

facilities reporting that they have EHSs in quantities greater than the threshold planning quantity 

(TPQ). This hazards analysis should help planners identify what additional response capabilities are needed. This analysis serves as the basis for development or revision of the emergency response plans that are mandatory under 

Title Ill of SARA. 

1.4 Hazards Analysis

Hazards Identification 

Chemical Identity

Location

Quantity

Nature of

the Hazard

Vulnerability Analysis 

Vulnerable Zone

Human Populations

Critical Facilities

Environment

Risk Analysis 

Likelihood of a

Release Occurring

Severity of the

Consequences

A hazards analysis’ is a necessary step in com- community. This guide follows the definition of 

prehensive emergency planning for a commu- “hazards analysis” used in NRT-1 and focuses 

nity. Comprehensive planning depends upon a principally on hazards analysis for airborne reclear understanding of what hazards exist and leases of EHSs. 

what risk they pose for various members of the 

Hazards analysis as presented in this guidance is intended for use in emergency response planning for EHSs. Its 

purpose and the meaning of its terminology are different from the purpose and terms used in “risk assessment” as 

defined by NAS. Because local communities will be conducting hazards analyses (as described in this guide) and 

risk assessments under different sections of SARA, a discussion of risk assessment can be found in NAS Press, 

1983, Risk Assessment in the Federal Government: Managing the Process. Washington D.C. 191 pp. 

12/87 1-3 

1
The hazards analysis described in this guide is a 

3-step decision-making process to identify the 

potential hazards facing a community with respect to accidental releases of EHSs. All three 

steps should be followed even though the level 

of detail will vary from site to site. The hazards 

analysis is designed to consider all potential 

acute health hazards within the planning district 

and to identify which hazards are of high priority 

and should be addressed in the emergency response planning process. The Title Ill emergency response plan must address all EHSs that 

are reported to the State Emergency Response 

Commission (SERC), but other substances including EHSs below their TPQs may also be included. Depending upon the size and nature of 

a planning district, the hazards analysis may be 

complex or relatively easy. LEPCs that have access to the necessary experts might want to 

conduct a detailed quantitative hazards analysis. 

Such a complete analysis of all hazards may not 

always be feasible or practical, however, given 

resource and time constraints in individual planning districts. 

General information and an approach to understanding the three components of hazards 

analysis as it is applied to the EHSs are discussed in Chapter 2. A brief overview is presented below. 

A. Hazards identification typically provides specific information on situations that have the potential for causing injury to life or damage to 

property and the environment due to a hazardous materials spill or release. A hazards identification includes information about: 

Chemical identities: 

The location of facilities that use, produce, process, or store hazardous 

materials: 

The type and design of chemical container or vessel: 

The quantity of material that could be 

involved in an airborne release: and 

The nature of the hazard (e.g., airborne toxic vapors or mists which are 

the primary focus of this guide; also 

other hazards such as fire, explosion, 

large quantities stored or processed, 

handling conditions) most likely to accompany hazardous materials spills or 

releases. 

B. Vulnerability analysis identifies areas in the 

community that may be affected or exposed, individuals in the community who may be subject 

to injury or death from certain specific hazardous materials, and what facilities, property, or 

environment may be susceptible to damage 

should a hazardous materials release occur. A 

comprehensive vulnerability analysis provides information on: 

The extent of the vulnerable zones 

(i.e., an estimation of the area that 

may be affected in a significant way as 

a result of a spill or release of a known 

quantity of a specific chemical under 

defined conditions) ; 

The population, in terms of numbers, 

density, and types of individuals (e.g., 

facility employees: neighborhood residents: people in hospitals, schools, 

nursing homes, prisons, day care centers) that could be within a vulnerable 

zone: 

The private and public property (e.g., 

critical facilities, homes, schools, hospitals, businesses, offices) that may 

be damaged, including essential support systems (e.g., water, food, 

power, communication, medical) and 

transportation facilities and corridors; 

and 

The environment that may be affected, 

and the impact of a release on sensitive natural areas and endangered species. 

Chapter 2 discusses vulnerability analysis with a 

special emphasis on human populations. 

C. Risk analysis is an assessment by the community of the likelihood (probability) of an accidental release of a hazardous material and the 

actual consequences that might occur, based 

on the estimated vulnerable zones. The risk 

analysis is a judgement of probability and severity of consequences based on the history of previous incidents, local experience, and the best 

12187 1-4 
available current technological information. It 

provides an estimation of: 

The likelihood (probability) of an accidental release based on the history of 

current conditions and controls at the 

facility, consideration of any unusual 

environmental conditions (e.g., areas 

in flood plains), or the possibility of simultaneous emergency incidents 

(e.g., flooding or fire hazards resulting 

in the release of hazardous materials); 

Severity of consequences of human injury that may occur (acute, delayed, 

and/or chronic health effects), the 

number of possible injuries and 

deaths, and the associated high-risk 

groups: 

This section briefly describes EPA’s original 

Chemical Emergency Preparedness Program 

(CEPP), other recent public and private sector 

programs, and EPCRA. 

1.5.1 EPA’s Chemical Emergency Preparedness Program 

For the past several years, EPA has pursued an 

active voluntary program to enhance preparedness and response capabilities for incidents involving the airborne release of EHSs. In June 

1985, EPA announced a two-part National Strategy for Toxic Air Pollutants. The first part, established under Section 112 of the Clean Air Act, 

deals with routine releases of hazardous air pollutants. The second part was the development 

of the CEPP, designed to address, on a voluntary basis, accidental airborne releases of 

acutely toxic chemicals. Since its inception, 

CEPP has had two goals: to increase community awareness of chemical hazards and to enhance State and local emergency planning for 

dealing with chemical accidents. These goals 

and initial activities influenced the legislative action that led to the enactment of Title Ill of SARA, 

where many CEPP objectives are addressed 

(see Section 1.5.3). 

Severity of consequences on critical 

facilities (e.g., hospitals, fire stations, 

police departments, communication 

centers); 

Severity of consequences of damage 

to property (temporary, repairable, 

permanent); and 

Severity of consequences of damage 

to the environment (recoverable, permanent) . 

To have an accurate view of the potential problems in a district, the LEPC would need to address all of the steps in hazards analysis outlined 

above. Each of the three steps should be followed even if extensive information is not available for each site. The process anticipates that 

local judgement will be necessary. 

1.5.2 Other Public and Private Sector Programs 

Awareness of the 1984 Bhopal, India tragedy 

and less catastrophic incidents in the United 

States has led many State and local governments to improve their preparedness and response capabilities for chemical emergencies. 

They developed emergency plans for chemical 

accidents, enacted right-to-know legislation to 

provide citizens access to information about 

chemicals in their community, and organized 

hazardous materials planning councils and response teams. 

In the private sector, the Chemical Manufacturers Association (CMA) has developed and implemented the Community Awareness and 

Emergency Response (CAER) program. The 

CAER program encourages chemical plant managers to contact community leaders and assist 

them in preparing for possible incidents involving 

hazardous materials, including those involving 

airborne toxics. CAER industry participants can 

provide information about chemicals and chemical processes that exist within the community 

(an important source for the "hazards identification” phase of a hazards analysis); professional 

1.5 Background 

12/87 l-5 
expertise to help communities develop emergency plans; equipment and personnel to assist 

local officials during emergency notification and 

response operations: and specific assistance in 

training responders and exercising emergency 

plans. 

1.5.3 Emergency Planning and Community 

Right-to-Know Act of 1986 (Title Ill of 

SARA) 

On October 17, 1986, SARA became law. Title 

Ill of SARA contains numerous requirements for 

Federal, State, and local governments as well as 

private industry in the areas of emergency planning, community right-to-know, hazardous 

emissions reporting, and emergency notification. These requirements build upon the original 

CEPP (elements of which are now mandatory), 

numerous existing State and local programs 

aimed at community right-to-know and preparedness, and the CMA CAER program. 

The objectives of Title Ill are to improve local 

chemical emergency response capabilities (primarily through improved emergency planning 

and notification) and to provide citizens and local governments access to information about 

chemicals in their localities. 

Title Ill addresses planning by: (1) identifying 

the EHSs that trigger the planning process: (2) 

requiring facilities to identify themselves if they 

have quantities of EHSs exceeding the TPQs; (3) 

requiring the establishment of a State and local 

planning structure and process (including specifics on committee membership); (4) requiring facilities to make information available to local 

planners: and (5) specifying the minimum contents of local emergency plans. This guidance 

includes information about all of these topics. 

(See NRT-1 for an additional discussion of plan 

contents and guidance for planning). Exhibit 1-2 

summarizes the types of information that will be 

available as a result of compliance with Title Ill, 

and indicates how local planners can use the information. Planners should not only be aware of 

Federal, but also of State and local requirements that apply to emergency planning. 

A. Identifying the Extremely Hazardous 

Substances that Trigger the Planning 

Process. 

Title Ill required EPA to publish a list of EHSs and 

TPQs for each of those substances. EPA fulfilled 

this requirement in a rule published on April 22, 

1987 (Federal Register, Vol. 52, No. 77, pp. 

13378-13410). The list of EHSs included the 

402 chemicals found in the CEPP Interim Guidance List of Acutely Toxic Chemicals2

 and four 

additional chemicals added as a result of new 

information. Four chemicals have been removed from the list and 36 others are proposed 

for delisting as they do not meet the acute lethality criteria. (See Appendix C for the list of 

EHSs and Appendix B for an explanation of the 

criteria used in identifying these chemicals.) 

B. Planning Structure and Process. 

Sections 301-303 of Title Ill include the following 

required steps: 

State Governors appointed SERCs by 

April 17, 1987. SERCs identified local 

emergency planning districts (LEPDs) 

by July 17, 1987 and appointed members of the LEPC by August 17, 1987. 

SERCs are to coordinate and supervise 

the work of the LEPCs, and review all 

emergency plans to ensure that all the 

local plans for any one State are coordinated. 

Facilities had to notify SERCs by May 

17, 1987 if they have any listed EHS(s) 

that exceed the designated TPQ. The 

TPQ is a specific quantity assigned to 

each of the EHSs. If a facility has present at any time an EHS in an amount 

greater than the TPQ, the facility must 

identify itself to the SERC. The SERC 

notifies the LEPC to include the facility, 

if appropriate, in its comprehensive 

emergency plan. SERCs can specify 

other facilities to be included in the 

emergency plan. 

2 Title II1 of SARA replaces the term “acutely toxic chemical” with “extremely hazardous substance”. 

12/87 1-6 
-Exhibit 1-2 

TITLE III INFORMATION FROM FACILITIES PROVIDED

IN SUPPORT OF PLAN DEVELOPMENT

Information Generated by How LEPC Can Use

Title Ill Compliance Title Ill Authority the Information

Facilities subject to Title Ill planning requirements 

(including those designated by the Governor or SERC) 

Additional facilities near subject facilities (such as hospitals, 

natural gas facilities, etc.) 

Transportation routes 

Major chemical hazards (chemical name, properties, 

location, and quantity) 

Facility and community response methods, procedures, 

and personnel 

Facility and community emergency coordinators 

Release detection and notification procedures 

Methods for determining release occurence and 

population affected 

Facility equipment and emergency facilities; persons 

responsible for such equipment and facilities 

Evacuation plans 

Training programs 

Exercise methods and schedules 

Section 302;

Notice from Governor/SERC

Sections 302 (b) (2) ; 303 (c) (1)

Sections 303(c) (1) ; 303(d) (3)

Section 303 (d) (3) for extremely

hazardous substances used,

produced, stored

Section 311 MSDSs for chemicals

manufactured or imported

Section 312 inventories for

chemicals manufactured or imported

Sections 303(c) (2); 303(d) (3)

Sections 303 (c) (3) ; 303 (d) (1)

Sections 303(c) (4) ; 303 (d) (3)

Sections 303 (c) (5) ; 303 (d) (3)

Sections 303 (c) (6) ; 303 (d) (3)

Sections 303(c) (7) ; 303(d) (3)

Sections 303 (c) (8) ; 303(d) (3)

Sections 303(c) (9); 303(d) (3)

Hazards analysis -- Hazards 

identification 

Hazards analysis -- Vulnerability 

analysis 

Hazards analysis -- Hazards 

identification 

Hazards analysis -- Hazards 

identification 

Response functions (see pp. 49ff 

of NRT Planning Guide) 

Assistance in preparing and 

implementing the plan (see p. 11 

of NRT Planning Guide) 

Initial notification; Warning systems 

(see pp. 50, 53 respectively of 

NRT Planning Guide) 

Hazards analysis -- Vulnerability 

analysis and risk analysis 

Resource management 

Evacuation planning 

Resource management 

Testing and updating 
iii. Facilities must provide the following information to the LEPC: the name of a 

facility representative (by September 

17, 1987) to serve as facility emergency coordinator and assist the LEPC 

in the planning process; information requested by the LEPC that is necessary 

for developing and implementing the 

emergency plan (see Section 

303(d) (3) of Title Ill of SARA); and any 

changes at the facility that could affect 

emergency planning. (Facility compliance with this SARA requirement will 

make available much information that 

should prove helpful for hazards analysis and annual plan revisions.) 

iv. LEPCs must prepare comprehensive 

emergency plans for all facilities subject to the regulations by October 17, 

1988. 

V. Transporters of EHSs do not have to 

notify SERCs under Section 302. Section 327 of Title Ill of SARA states that 

Title Ill does not apply to any substance 

or chemical being transported, includThe components of a hazards analysis are discussed in more detail in the next chapter of this 

guide. The discussion in Chapter 2 is as simplified and direct as possible, given the complexity 

of hazards analysis. Additional technical material 

is in the appendices. Chapter 3 provides a detailed step-by-step procedure for hazards 

analysis of the EHSs at the local level. Guidance 

for incorporating results of a hazards analysis 

into the overall planning process is found in 

Chapter 4. 

Several appendices have been included in this 

guide. Appendix A contains a list of abbreviations and acronyms and a glossary of technical 

terms. (Users of this guide should regularly consult Appendix A for help in understanding the 

terms used). Appendix B describes EPA’s criteria for identifying EHSs. Appendix C contains the 

list of EHSs designated by Title Ill of SARA both 

alphabetically and by Chemical Abstract Service 

ing transportation by pipeline, except 

as provided in Section 304. Section 

304 requires notification of releases of 

EHSs and Comprehensive Environmental Response, Compensation and 

Liability Act of 1980 (CERCLA) hazardous substances from facilities, pipelines, motor vehicles, rolling stock and 

aircraft. Barges and other vessels are 

exempted from Section 304 reporting. 

The Title III planning structure for receiving information and formulating plans is displayed in Exhibit 1-3. 

C. Other Title III Information for Planners. 

This guide does not include a detailed description of Sections 304, 311, 312, and 313 of Title 

Ill. Details of these sections may be found in 

Appendix A of NRT-1. What is important for users of this guide to know is that facilities complying with these sections of Title Ill will provide information to LEPCs that may prove useful for 

hazards analysis and emergency plan development and revision. 

(CAS) number. This appendix also provides information on important physical properties of 

each substance and the levels of concern (LOC) 

which are required to estimate vulnerable zones. 

Appendix D provides information and calculations concerning exposure levels of EHSs and 

the basis for the LOC. Appendix E is a sample 

chemical profile of one of the EHSs (acrolein). 

Appendix F contains descriptions of fire and reactivity hazards. Appendix G contains more 

technical information for estimating and 

reevaluating vulnerable zones. As a warning to 

planners to avoid automatically establishing 

evacuation distances from the estimated vulnerable zones, Appendix H includes a discussion of 

issues to be considered for evacuation. Appendix I supplements Chapters 3 and 4 with a procedure for gathering important information to 

evaluate sites for contingency planning. Appendix J details other methods for evaluating 

hazards and supplements Chapters 2 and 3. 

1.6 Contents of this Guide 

12/87 l-8 
Exhibit l-3 

Title III Planning Steps

l-9 
Appendix K provides an evaluation guide for the 

use of computerized systems that could be of 

assistance in emergency response planning. 

Appendix L is an annotated bibliography of pertinent references. Appendix M lists the EPA Regional preparedness contacts and coordinators 

as well as FEMA Regional contacts. 

12/87 I-10 
2. Hazards Analysis: An Overview

This chapter provides an overview of hazards 

analysis as it relates to emergency planning for 

extremely hazardous substances (EHSs) under 

Title III of the Superfund Amendments and 

Reauthorization Act of 1986 (SARA). The approch to hazards analysis presented here is not 

mandatory but it will assist localities in meeting 

the planning requirements of SARA Title Ill. As in 

Chapter 1 this chapter follows the same general 

format and supports the principles presented in 

NRT-1. It represents a relatively simple yet effective means of evaluating potential hazards resulting from the accidental release of an EHS. 

The three basic components in the hazards 

analysis discussed here are (1) hazards identification, (2) vulnerability analysis, and (3) risk 

analysis. 

The step-by-step process planners should follow in conducting a hazards analysis is outlined 

in Exhibit 2-1 1 (pp. 2-26 and 2-27) and described in detail in Chapter 3. The overview in 

this chapter should be carefully read and understood before attempting an actual hazards 

analysis as outlined in Chapter 3. The information in Appendices I and J should also be reviewed. 

2.1 Hazards Identification 

Risk Analysis 

Likelihood of a 

Release Occurring 

Severity of the 

Consequences 

Hazards identification, the first step in hazards This information can be used by emergency 

analysis, is the process of collecting information planners, as well as by fire/rescue services, poon: lice departments, and environmental protection 

� The types and quantities of hazardous departments as they prepare for, respond to, 

materials in a community; and recover from emergencies involving hazardous materials. Section 2.1 .1 discusses the 

� The location of facilities that use, pro- types of hazards that chemicals may pose to the duce, process, or store hazardous mate- community. Section 2.1.2 discusses sources of rials; data for hazards identification and procedures 

� Conditions of manufacture, storage, proc- that planners may use in gathering data. Infor­ essing, and use: mation derived from hazards identification will 

� Transportation routes used for transport- subsequently be used in vulnerability analysis 

ing hazardous materials: and (described in Section 2.2) and risk analysis (de­

� Potential hazards associated with spills or scribed in Section 2.3).

releases.

2-l 
2.1.1 Identification of Hazardous Chemicals 

Hazards are situations that have the potential for 

causing injury to life and/or damage to property 

and the environment. Chemicals may be potentially hazardous because of their toxicity or 

physical/chemical properties such as flammability and reactivity. Comprehensive planning for 

hazardous materials emergencies should encompass all hazards capable of causing loss of 

life, injury or damage to health, or damage to 

property or the environment. The guidance in 

this document focuses on the single hazard of 

acute toxicity, specifically acute lethality to individuals as a result of airborne releases of EHSs. 

Extremely Hazardous Substances 

Chemicals with high acute lethality have the potential for causing death in unprotected populations after relatively short exposure periods at 

low doses. On the basis of toxicity criteria (discussed in Appendix B), EPA identified a list of 

chemicals with high acute toxicity (listed in Appendix C) from the more than 60,000 chemicals 

in commerce. This is the list of EHSs required 

by Title Ill of SARA. Because airborne releases 

of acutely lethal substances, while infrequent, 

can be catastrophic, Title Ill requires consideration of these EHSs in emergency plans. 

Although all of the listed substances are extremely toxic, the hazards presented by a spill 

will also vary depending on the physical and 

chemical properties of the substance spilled and 

the conditions under which the substance is handled (e.g., elevated temperatures and pressures) . Some substances are highly volatile and 

thus likely to become airborne, while others are 

non-powdered solids that are unlikely to become airborne. The potential to become airborne was considered in the determination of 

the threshold planning quantity (TPQ) for ‘EHSs. 

A summary of publicly available information on 

the listed substances is presented in the EPA 

Chemical Profiles issued in December 1985 as 

part of the Chemical Emergency Preparedness 

Program (CEPP) Interim Guidance. The profile 

for each chemical includes synonyms as well as 

information on recommended exposure limits, 

physical/chemical characteristics, fire and explosion hazards and fire fighting procedures, reactivity, health hazards, use, and precautions. 

Profiles for each EHS are available. The profiles 

are currently being updated and supplemented 

with additional information, including emergency 

medical treatment guidance and information 

about personal protective equipment which 

should be used by emergency response teams. 

The revised profiles should be available by 

spring 1988. See Appendix E for a revised sample chemical profile. 

Other Hazards 

In addition to acute lethality, substances may 

cause other types of toxic effects in people exposed to them (e.g., long-term or short-term 

illness, damage to skin or eyes). Criteria for the 

identification of chemicals (other than those that 

are acutely lethal) that cause serious health effects from short-term exposures are being developed on a priority basis. When such criteria 

are established, they will be used in expanding 

the list of EHSs. At that time, guidance will be 

provided to address planning for chemicals that 

cause these other toxic effects. It should be 

noted that even substances that are relatively 

less toxic may pose a hazard if they become airborne in large quantities. 

Hazards other than toxicity (e.g., fire, explosion, 

and reactivity) that may be associated with both 

EHSs and other substances should be considered in emergency preparedness and response 

planning and are discussed briefly in Appendix F. 

In many cases, emergency response agencies 

such as fire departments may have already addressed these types of hazards. Hazards other 

than toxicity will be considered in future revisions 

to the list of EHSs. 

2.1.2 Procedures for Hazards Identification 

Hazards identification begins with the identification of the facilities that have EHSs in the community. Mandatory reporting by facilities, under 

Title Ill, will now identify those facilities that possess one or more of the EHSs in excess of its 

TPQ . In addition, because considerable information on the properties, amounts, and conditions of use of EHSs is needed to prepare reliable emergency plans, Title Ill specifically 

states: “the owner or operator of the facility 

shall promptly provide information to such committees necessary for developing and implementing the emergency plan” (Section 

303 (d) (3) ). Supplemental information on the 

quantity and location of hazardous chemicals will 

2-2 12/87 
become available in March of 1988, fulfilling requirements under Sections 311 and 312, Title Ill 

of SARA. Facility inspections will remain important information-gathering activities for local 

planners, as well as for safety and emergency 

response personnel who must establish accident 

prevention programs and pre-emergency plans. 

Other information available from the site may include facility hazard assessments, facility safety 

audits, spill prevention and control countermeasures (SPCC), and probability-based risk assessments (PRAs) . Although hazards identification should also include identification of transportation routes through the community for 

EHSs, this information will not be reported under 

Title Ill of SARA. 

This section will discuss how to obtain information on EHSs and the types of facilities that are 

engaged in manufacturing , processing, storing, 

handling, selling, and transporting EHSs. This 

section also briefly discusses sources of information on other hazardous substances. 

Extremely Hazardous Substances 

EHSs present in quantities above their TPQ will 

be identified for the Local Emergency Planning 

Committee (LEPC) by the reporting facilities. 

However, EHSs in quantities below the TPQ 

could also present a hazard to the community 

under certain circumstances and the LEPCs may 

wish to include them in their hazards analysis. 

As noted in Section 1.5.3, Title Ill of SARA includes the following provisions concerning EHSs: 

If a facility has one or more chemicals 

from the current list of EHSs in quantities 

exceeding its TPQ, it must report this fact 

to the State emergency response commission (SERC). 

The committee can obtain from the facility 

information on what chemicals are present and in what amounts. The facility 

emergency coordinator will be the primary 

source of information. The specific 

chemical identity of an EHS may sometimes be withheld as a trade secret. Even 

when the chemical identity is held confidential, however, certain information on 

the specific chemical is important for subsequent steps in hazards analysis and will 

be provided by the facility. 

The following points should be discussed with facility representatives to obtain information for 

hazards identification: 

Chemical identity, including chemical 

name and Chemical Abstract Service 

(CAS) number for substances not claimed 

as trade secret; 

Quantities of EHSs normally present, including: 

(1) Total quantity of each EHS at the facility. The quantity of chemical can 

vary from day to day depending on 

operations. Planners should determine the amount that is typically on 

hand on any given day. This information is necessary to assess the potential impact should an accident involving this quantity occur. 

(2) Maximum quantity that could be present in each storage or processing 

location. Facilities may use the same 

chemical in many different locations 

and have the capacity to store more 

than what is typically on hand. Planners need to determine the maximum 

quantity, even though the facility may 

rarely have this much on-site. Hazards associated with the maximum 

quantity may be much different than 

the hazards associated with the typical quantity. These differences need 

to be addressed by planners. 

(3) Configuration of storage, including 

the maximum potential quantity in a 

single storage or processing vessel. 

Some facilities handle. quantities of 

chemicals in isolated storage vessels 

while others may have two or more 

interconnected vessels to allow 

greater flexibility in the use of storage 

capacity. It is possible that an accident involving one vessel will involve 

the inventory in another if they are interconnected. The maximum potential quantity in a single vessel or 

group of interconnected vessels must 

be known to estimate the impact of 

an accidental release (see “vulnerability analysis” in Section 2.2). 

2-3 
• If the chemical identity is held confidential, 

information about certain properties of the 

substance will be provided by the facility 

to allow a hazards analysis to proceed, including: 

(1) Physical state. At ambient conditions 

(room temperature and atmospheric 

pressure) is the chemical a gas, liquid, or solid? If solid, is it powdered 

(with less than 100 micron particle 

size), in solution, or molten? 

(2) Approximate vapor pressure (in millimeters of mercury or atmospheres), 

if the substance is a liquid or is a 

solid handled in molten form. For the 

liquid, the vapor pressure at handling 

temperature should be obtained, 

while the vapor pressure at the melting point should be obtained for the 

molten solid. 

(3) Approximate level of concern (LOC) 

(the concentration of EHS in air 

above which there may be serious irreversible health effects or death as 

a result of a single exposure for a 

relatively short period of time). The 

approximate concentration in air that 

equals the LOC in grams per cubic 

meter is needed in the vulnerable 

zone analysis (see Appendices C and 

D) . 

The approximate values provided should 

be sufficiently close so as not to significantly alter the size of the estimated 

zones (see Section 2.2). 

Conditions under which the chemicals are 

processed, handled, or stored, including: 

(1) Temperature. Facilities may keep 

certain substances at temperatures 

other than ambient depending on 

their use. 

(2) Pressure. Some substances must be 

stored under pressure (e.g., liquefied gases). 

(3) Other unique features of the handling 

systems employed to manufacture, 

process, store, use or otherwise handle the substance at the facility. This 

information is useful for the risk 

analysis portion of the hazards analysis. See Appendix J for more information. Note that some of this information might be held as trade secret 

by the facility. Planners should work 

closely with facility representatives to 

obtain information necessary for 

emergency plan development. 

Exhibit 2-1 presents several chemicals from the 

list of EHSs and some types of facilities other 

than chemical plants where these chemicals 

might be present in quantities exceeding the 

TPQ. Some of the EHSs in the exhibit might be 

found in other types of facilities in smaller quantities (e.g., chemicals in laboratories). 

Hazardous materials, including EHSs, are also 

transported through, by, or over communities by 

highway vehicles, rail cars, watercraft, and aircraft virtually 24 hours a day. Shipments may 

range from less than a pound to thousands of 

pounds of material. Because transporters are 

not required to report under SARA Sections 302 

and 303, identification of routes through a community over which EHSs are transported will be 

more difficult than the identification of fixed facilities. Nevertheless, transportation routes and 

transported chemicals should be identified if 

possible. 

The experience gained through Department of 

Transportation (DOT) pilot planning projects 

demonstrates that identification of transportation 

hazards for emergency planning can be done by 

gathering information directly at the community 

level (see Hazardous Materials Transoortation: A 

Svnthesis of Lessons Learned from the DOT 

Demonstration Project) . Usefull information may 

be collected with assistance from representatives of trucking. rail, air freight, and shipping 

industries. Facility representatives may be able 

to provide data on the shipping and transfer of 

EHSs, although this approach will identify only 

those transported materials destined for local facilities. The following points could be discussed 

with facility representatives: 

� Frequency of shipments (daily, weekly, irregular schedule) ; 

� Form of shipment (tank truck, tank car, 

drums, boxes, carboys in trucks or vans, 

pipelines, barges) ; 

12/87 2-4 
Exhibit 2-l 

Types of Faclities where Certian Extremely Hazardous Substances Might be 

Found in Quantities Greater than their TPQs 

Etremely Hazardous Substance (TPQs in parentheses) 

Ammonia Chlorine Sulfuric Acid Phosgene Aldicarb 

Type of Facility (100 Ibs) (100 Ibs) (500 Ibs) (10 Ibs) (100 lbs/ 

10,000 Ibs) 

Blueprinting Facilities X X

Frozen Food Processing

Processing Plants/

Plumbing, Heating, and Air

Bulk Storage Facilities X X

Farms X X

Facilities X

Pesticide Distributors X

Formulators X X X X

Conditioning Companies X

Pulp and Paper Plants X X

Retail Stores X

Swimming Pools X

Warehouses X X X

Water Treatment Facilities X X

*TPQ for Aldicarb is 100 pounds for fine powders or solutions, 10.000 pounds otherwise. 

12187 2-5
Quantity of shipments (tons; gallons; 

number of drums, tanks, vats or carboys); and 

Transportation routes through the community (highways, railroads, pipelines). 

The Hazardous Materials Transportation Act 

(HMTA) establishes DOT as the responsible 

agency for guidance on routing controls. Proposed Changes in routes should be made in accordance with the Guidelines for Applving Criteria to Designate Routes for Transporting Harzardous Materials, DOT FHWA 1980. 

Other Hazardous Materials 

Planners can apply the toxicity criteria used by 

EPA for the list of EHSs (see Appendix B) to determine whether other chemicals at facilities in 

the area qualify as EHSs even though they are 

not listed as such under the Federal regulations. 

Planners may also want to obtain information on 

transportation of other hazardous materials, as 

described above for EHSs. The discussion points 

listed in the previous section on EHSs could also 

be raised with facility representatives and transportation industry representatives with reference 

to other hazardous substances. 

Hazardous materials can be found throughout 

most communities in several types of sites and 

facilities. Besides obvious sites and facilities 

(e.g., flammable liquid storage tanks, gasoline 

stations, chemical supply companies), hazardous materials are likely to be found at other 

places, see Exhibit 2-1 (e.g., dry cleaners, auto 

body shops, hospitals, and construction sites). 

Information on hazards other than toxicity associated with the chemicals on the list of EHSs 

may be obtained from the EPA Chemical Profiles. Flammability and reactivity data on many 

other chemicals are available in the Fire Proteqtion Guide on Hazardous Materials developed by 

the National Fire Protection Association (NFPA) . 

The Hazardous Materials Table (49 CFR 172), 

developed by DOT, classifies hazardous materials in transportation by the type of hazards they 

present. (See also the DOT Hazardous Materials 

Table in the Proposed Rule of November 6, 

1987, Federal Register, Vol. 52, No. 215, pp. 

42787-42931.) Planners might Want to use 

those chemicals listed by the NFPA with the 

highest flammability and reactivity ratings, and 

those listed by DOT in certain hazard classes, as 

a starting point for identification of these types 

of hazards in the community. The United Nations 

publication, Recommendations on the Transport 

of Dangerous Goods, is also a useful source of 

information. Another source of information on 

many chemicals is the Coast Guard’s Chemical 

Hazards Response Information System (CHRIS) 

hazardous chemical data base. 

2.1.3 Summary of Useful Information Resulting from Hazards Identification 

At the conclusion of the hazards identification 

step of hazards analysis, planners should have 

the following information: 

A list of EHSs present at facilities in the 

district in quantities exceeding the TPQ; 

the properties of these EHSs: and where, 

in what quantity, and under what conditions they are used, produced, processed, or stored. Mixtures of chemicals 

will be reported if the portion of EHSs in the 

mixture is equal to or greater than one 

percent and more than the TPQ. 

Information on chemicals claimed as trade 

secret, including physical state, approximate vapor pressure of liquids and molten 

solids, and approximate LOC as defined in 

this guidance. 

Routes used for transportation of EHSs 

through the planning district. 

In addition, although it is not presently required 

to meet the statutory requirements for emergency plan development under Title Ill of SARA, 

planners may obtain the following information 

during hazards identification if necessary for developing and implementing an emergency plan: 

� A list of EHSs present in quantities less 

than the TPQ and where, in what quantity, 

and under what conditions they are used, 

produced, processed, or stored. 

� Hazards besides airborne toxicity posed 

by the EHSs in the community. 

� Chemicals other than those listed that 

meet the acute lethality criteria. 

12/87 2-6 
� A list of other hazardous chemicals and 

where, in what quantity, and under what 

conditions they are used, produced, processed, or stored; and the type of hazard 

they pose. 

� Routes used for transportation of other 

hazardous materials through the community. 

Exhibit 2-2 summarizes the types and sources 

of information obtained during hazards identification. 

2.2 Vulnerability Analysis for Airborne Hazardous Substances 

Vulnerability analysis is the second part of the 

three-part hazards analysis. This section outlines a process that can be used in performing a 

vulnerability analysis for facilities that have 

chemicals on the Section 302 list of extremely 

hazardous substances (EHSs) and transportation routes used for transporting these substances to and from the fixed facilities or 

through the communities. (The facilities and 

transportation routes should be identified as described in Section 2.1). 

The vulnerability analysis will provide information 

that will be helpful in fulfilling planning requirements under Title Ill of SARA. This information 

includes:

 An estimation of the vulnerable zone for 

each EHS reported and the conditions and 

assumptions that were used to estimate 

each vulnerable zone: 

� The population, in terms of numbers and 

types (e.g., neighborhood residents: high 

density transient populations such as 

workers and spectators in auditoriums or 

stadiums; sensitive populations in hospitals, schools, nursing homes, and day 

care centers) that could be expected to 

be within the vulnerable zones: and 

� Essential service facilities such as hospitals, police and fire stations, emergency 

response centers, and communication facilities, 

Although this guide is primarily concerned with 

the impact of EHSs on the surrounding human 

population, planners may also choose to consider as part of their vulnerability analysis the private and public property (e.g., homes, schools, 

hospitals, businesses, offices) that may be affected, including essential support systems 

(e.g. water, food, power, medical), as well as 

sensitive environments (e.g., drinking water 

supplies, food crops, or animal habitats). Consideration of property and sensitive environments may be particularly important for chemical releases that pose hazards other than those 

associated with acute toxicity. Planners can refer to community emergency services (e.g., fire 

departments, police departments, hospitals) for 

assistance in obtaining information about the 

population and essential services within the vulnerable zone. 

2.2.1 General Description of Estimation of 

Vulnerable Zones 

For purposes of this guidance, a vulnerable zone 

is an estimated geographical area that may be 

subject to concentrations of an airborne EHS at 

12/87 2-7 
Exhibit 2-2 

INFORMATION FROM HAZARDS IDENTIFICATION 

Essential Information 

Facilities in community with 

EHSs in quantities exceeding 

the TPQ 

identity of EHSs in community 

Quantity of EHSs present 

Transportation routes for EHSs 

Other Useful information 

identity and location of other 

acutely toxic chemicals 

� Information on hazards other than 

toxicity of EHSs 

� Information on other hazardous 

substances, including:

Identity

Location

Quantity

Hazards 

Transportation routes 

Source of Information 

Facilities must report to SERC 

information will be made available 

to LEPC’s 

Facility emergency coordinator 

Facility emergency coordinator 

Facility emergency coordinator, 

representative of transportation 

industries 

Information to be provided now under 

Section 303 (d) (3) and in the 

future under Sections 311, 312, 

and 313 of SARA: facility 

emergency coordinators 

EPA Chemical Profiles; facility 

emergency coordinators 

Information to be provided now under 

Section 303 (d) (3) and in the 

future under Sections 311, 312, and 313 

of SARA: community sources 

Representatives of transportation 

industries and facilities receiving shipments of chemicals 

12/87 2-8 
levels that could cause irreversible acute health 

effects or death to human populations within the 

area following an accidental release. Vulnerable 

zones are based on estimates of the quantity of 

an EHS released to air, the rate of release to air, 

airborne dispersion, and the airborne concentration that could cause irreversible health effects 

or death. Release and dispersion methodologies are not precise and provide only estimates 

of the actual distances and areas that may be 

affected by an accidental release. Many methods are available to evaluate both releases and 

airborne dispersion. They vary in their assumptions and therefore the results obtained may 

differ. The dispersion models selected for this 

guidance are described in Appendix G. 

At the time of an accidental release, with the 

wind generally moving in one direction, the area 

affected by a release is the area downwind only. 

Because the wind direction at the time of an actual accidental release cannot be predicted, 

planners must consider all possible wind directions and subsequent plume paths. (A plume is 

the cloud formation of airborne chemical that results from a release (Exhibit 2-3).) Consequently, the estimated vulnerable zones are circles with the potential release site located at the 

center (Exhibit 2-4). Because it is not possible 

to predict the exact location of a transportation 

accident, the estimated vulnerable zone for potential releases associated with transportation of 

an EHS is a “moving circle” or corridor (Exhibit 

2-5). 

The size of an estimated vulnerable zone depends upon the distance the airborne chemical 

travels before it disperses and is diluted in the 

air to a concentration below a “level of concern” 

(see subsection D below) for acute health effects or death. This distance depends on several variable factors. 

2.2.2 Variables in Estimating Size of Vulnerable Zones 

Many of the variables are very complex and it is 

beyond the scope of this document to discuss 

them all in detail. In addition many do not have 

a significant impact on the size of estimated vulnerable zones given the imprecise nature of 

these assumptions. The major factors affecting 

the size of a vulnerable zone for emergency 

planning are described below. 

A. Quantity and Rate of Release to Air 

Not all of a released chemical will necessarily 

become airborne. The quantity that actually becomes airborne and the rate at which it becomes airborne depend upon: 

� Total quantity released or spilled: 

� Physical state (solid, liquid, gas); and 

� Conditions (e.g., temperature, pressure) 

under which the chemical is stored or handled. 

Gases typically become airborne more readily 

than liquids. Liquids or molten solids generally 

become airborne by evaporation. The rate at 

which they become airborne (rate of volatilization) depends on their vapor pressure, molecular weight, handling temperature, the surface 

area of the spill (pool size), and the wind speed 

at the time of the spill. A spilled liquid with a 

higher vapor pressure will become airborne 

(through evaporation) more rapidly than a 

spilled liquid with a low vapor pressure at the 

same temperature. Also, a liquid will evaporate 

faster if the surface area or pool size of the spill 

is increased, if the liquid has a higher than ambient temperature, and if it is exposed to greater 

wind speeds. Molten solids will volatilize much 

faster than those in solid state. Solids as powders are likely to become airborne only if propelled into the air by force (e.g., by an explosion 

or the loss of air filtration in a pneumatic conveying system). Solids that are not powdered are 

less likely to become airborne. 

The size of an estimated vulnerable zone is proportional to the quantity and rate of release. 

Smaller release volumes based on similar assumptions will yield lower release rates which will 

reduce the size of the estimated vulnerable 

zone. 

The application of these variables in the vulnerable zone estimate will be discussed later in this 

chapter and also in Chapter 3. For more information on the calculations and derivations related to these variables, see Appendix G. 

B. Meteorological Conditions 

Among the many meteorological factors, wind 

speed and atmospheric stability have the greatest effect on the size of estimated vulnerable 

zones.. Increased wind speed and the 

12/87 2-9 
Exhibit 2-3 

The Movement Downwind of a Plume of an Airborne

Extremely Hazardous Substance Following

an Accidental Release.

12/87 2-10 
Exhibit 2-4 

Vulnerable Zones for Community Planning

Resulting from Airborne Releases of Chemicals A and B

12/87 2-11 
Exhibit 2-5 

Vulnerable Zones along a Transportation Route

When Airborne Releases of Chemicals C and D Occur

12/87 2-12 
accompanying decreased atmospheric stability 

will result in greater airborne dispersion (and dilution) of a chemical, and a resultant decrease 

in the size of the estimated vulnerable zone. 

Additional information on these meteorological 

variables is presented in Appendix G. 

C. Surrounding Topography 

The topography of the area surrounding a potential release site will affect the size of the estimated vulnerable zones. 

The principal topographical factors are natural 

obstructions such as hills and mountains, and 

man-made structures such as high-rise buildings. Natural formations and surface conditions 

are always site-specific and therefore beyond 

the scope of this guidance. If significant natural 

barriers exist within estimated vulnerable zones, 

appropriate technical support should be solicited 

from local, State, or EPA Regional meteorologists or experts in the private sector including 

the facility. On the other hand, general methodologies do exist for describing the dispersion of 

chemical substances in urban areas containing 

high buildings and in flat, rural areas. The methodology for estimating vulnerable zones in urban 

and rural areas is discussed later in this chapter 

and is presented in Chapter 3. 

D. Levels of Concern 

A level of concern (LOC), for purposes of this 

document, is defined as the concentration of an 

EHS in air above which there may be serious irreversible health effects or death as a result of a 

single exposure for a relatively short period of 

time. 

There is at present no precise measure of an 

LOC for the chemicals listed as EHSs. Various 

organizations over the past several years have 

been developing acute exposure guidelines for a 

limited number of hazardous chemicals; the 

methodology, however, is still under development. The preliminary guidelines and the progress to date are described in detail in Appendix 

D. Until more precise measures are developed, 

surrogate or estimated measures of the LOC 

have been identified for the listed EHSs. Local 

officials may choose values for the LOC different 

from those estimated in this guidance, depending upon their requirements, the specific characteristics of the planning district or site, and the 

level of protection deemed appropriate. Extreme caution and prudence should be exercised when choosing an LOC. 

For the purposes of this guidance, an LOC has 

been estimated by using one-tenth of the "Immediately Dangerous to Life and Health” (IDLH) 

level published by the National Institute for Occupational Safety and Health (NIOSH) or one-tenth 

of an approximation of the IDLH from animal toxicity data. Other exposure guidelines that may 

be used to estimate LOC include the “Threshold 

Limit Value” (TLV) published by the American 

Conference of Governmental Industrial Hygienists (ACGIH), guidelines developed by the National Research Council (NRC) of the National 

Academy of Sciences (NAS), and Emergency 

Response Planning Guidelines (ERPGs) under 

development by a consortium of chemical companies. These values are discussed and listed 

in Appendix D. The use of LOC in the vulnerable 

zone estimate is discussed later in this chapter 

and in Chapter 3. 

2.2.3 The Relationship of Estimated Vulnerable Zones to Actual Releases 

The estimated vulnerable zones are shown as 

circles with different radii in Exhibits 2-6 and 2-7 

to illustrate how changing conditions or assumptions can influence the vulnerable zone estimate. At the time of an accidental release, only 

some portion of the estimated vulnerable zone 

will actually be involved. The specific area covered by the plume will be determined principally 

by wind direction and the degree of dispersion of 

the plume. The area through which the plume 

moves is generally referred to as a plume “footprint.” Exhibit 2-8 shows the plume footprint for 

the release of a sample chemical substance. 

Note that the actual concentration of the airborne chemical tends to decrease as it moves 

further downwind from the release site because 

of continual mixing and dilution (dispersion) of 

the chemical with air. Note also that the plume 

movement is affected by the speed of the wind. 

Although a footprint represents the area enveloped by a plume, it is not possible to predict 

with any high degree of accuracy the wind direction and wind speed. Therefore the direction and 

shape which the plume may take at the time of 

an accidental release is not known in advance. 

2-13 12/87 
Exhibit 2-6 

The Effect of Different Assumptions on the Calculation 

of the Radius of Estimated Vulnerable Zones 

12/87 2-14 
Exhibit 2-7 

12/87 2-15
Exhibit 2-8 

Plume Development and Movement during 

a Hypothetical Accidental Release 
Further, both wind speed and direction may 

change during the course of the release. Because of this, it is suggested that planners use a 

circle for fixed sites or a corridor for transportation routes when estimating vulnerable zones. 

2.2.4 Application of Estimated Vulnerable 

Zones to Hazards Analysis for Extremely Hazardous Substances 

This section provides an overview of how vulnerable zones can be estimated as part of a hazards analysis. To estimate the zone, specific 

values must be assigned to each of the variables 

discussed in the previous sections. Values may 

be obtained from the reporting facilities, from 

techniques contained in this document, or other 

sources recommended in this guide. In several 

instances, this guide provides liquid factors 

which replace a series of calculations. These 

factors are intended to make the process of estimating the vulnerable zones much easier for 

local emergency planning committees (LEPCs) . 

The step-by-step hazards analysis described in 

Chapter 3 of this guidance is divided into two 

major phases. The first phase involves a 

screening of all reporting facilities to set priorities among facilities so that more detailed hazards analysis can be conducted for those facilities that pose the greatest risk should a release 

occur. The first phase employs assumptions for 

a credible worst case scenario. The second 

phase involves the reevaluation of the facilities 

by priority. During this phase the LEPCs have 

the opportunity to reevaluate the assumptions 

used in the screening phase on a case by case 

basis using data that may be unique to a particular site. 

Estimating Vulnerable Zones for Initial 

Screening 

Because of time and resource limitations, local 

planners may not be able to evaluate all reporting facilities at the same time or to the same 

extent. Thus planners should set an order of priority among potential hazards for all facilities 

that have reported the presence of one or more 

EHSs in excess of the TPQ. One way to do this 

is to estimate a vulnerable zone radius using assumptions for a credible worst case scenario. 

Values that reflect these assumptions are assigned to all the variables discussed in Section 

2.2.2. In this way, all facilities and substances 

are similarly evaluated to establish a relative 

measure of potential hazard for purposes of 

prioritization. 

The initial estimated screening zones are based 

on the following credible worst case assumptions. 

Quantity released: maximum quantity that 

could be released from largest vessel or 

interconnected vessels. 

Rate of release to air: total quantity of 

gas, solid as a powder, or solid in solution 

is assumed to be released in 10 minutes; 

for liquids and molten solids, the rate is 

based on the rate of evaporation (rate of 

voltization). As explained in Appendix G 

this guidance simplifies the calculation of 

the rate of evaporation with a liquid factor 

which approximates. a series of calculations. This number is called liquid factor 

ambient (LFA), liquid factor boiling (LFB), 

or liquid factor molten (LFM) depending 

on the handling conditions of the EHS. 

Temperature: not applicable to gases or 

solids as powders or in solution; for liquids, dependent on whether they are used 

at ambient temperature or near their boiling points: for molten solids, at their melting point. 

Meteorological conditions: wind speed of 

1.5 meters per second (3.4 miles per 

hour) ; F atmospheric stability. 

Topographic conditions: flat, level, unobstructed terrain: use of the dispersion 

model for rural areas. 

LOC: one-tenth of the (NIOSH) published 

(IDLH) value or one-tenth of its approximation. * (See Appendix D for a discussion of LOC.) 

* Provided it is not exceeded by the ACGIH TLV. In this case, the TLV is used. 

2-17 12/87 
As a result, the only information necessary to utmost care and prudence. Although some 

estimate the vulnerable zone for initial screening changes in estimated or assumed values may is: increase the size of the estimated vulnerable 

Chemical identity:

Maximum potential quantity in a single

vessel or interconnected vessels (obtained from the facility);

Location of vessel and facility (obtained

from the facility);

LOC (found in Appendix C); and

In instances of confidentiality claims, the

approximate LOC as defined in this guidance, physical state, and approximate vapor pressure of a liquid or molten solid

(obtained from the facility).

Planners can use the estimated zone, together 

with an initial consideration of population and essential service facilities within this zone and any 

readily available information on the likelihood of 

a release to establish an order of priority among 

the facilities. The considerations of population 

and critical services are discussed in Section 2.3 

of this chapter. 

Reevaluation of the Estimated Zones 

Once the prioritization of facilities is completed, 

the LEPCs should begin a systematic reevaluation of those facilities which initially appear to 

represent the greatest potential hazards. This 

will require careful review of the considerations 

presented in Chapters 2 and 3 and Appendices 

G and I in this document, consultation with facility officials, and perhaps the aid of experts in the 

appropriate technical areas. After careful evaluation of new data, planners may wish to alter 

certain values and assumptions such as: 

Quantity likely to be released (use information from facility);

Likely rate of release to air (obtain information from facility or other sources);

Meteorological conditions (obtain information from facility, local, State, or regional

experts, or other sources);

Topographical considerations (e.g., urban

versus rural landscape); and

Values used for the LOC.

zone, in many instances the zone will be reduced by such changes. Exhibit 2-9 provides a 

summary table of how the principal variables affect the estimated zone. For example, discussions with a facility representative may indicate 

that in one particular operation, vessels are 

rarely filled to maximum capacity or that equipment is engineered or designed to minimize or 

contain accidental releases. Chemicals may be 

subjected to higher temperatures or pressures 

than was originally assumed. Meteorological 

data may show that the worst-case conditions 

prevail for only a small percentage of the time or 

that they prevail for a large percentage of the 

time. The use of one-tenth of the IDLH or an 

approximation of this value as the LOC may or 

may not be considered overly protective for local circumstances. Local planners may favor 

the use of another value as an appropriate 

guideline for an LOC. 

Decisions to alter the values or assumptions that 

affect the size of the estimated vulnerable zone 

involve a consideration of acceptable risk and 

are a matter of judgement at the local level. 

There is no guidance available that can provide 

values that would ensure no risk or that can provide an acceptable balance between risk and the 

appropriate level of planning for each district. 

This decision rests with local officials. 

It is possible that reevaluation of the screening 

zones may lead to the estimation of several vulnerable zones as shown in Exhibit 2-7. Planners 

must then carefully consider the populations and 

essential services at risk, both within and outside 

these zones and reach conclusions on the level 

and type of planning they believe is necessary. 

Section 2.3 provides information on analyzing 

the risk associated with releases of EHSs to 

populations and essential services facilities 

within the planning district. 

2.2.5 Evacuation Considerations for Airborne 

Releases of Extremely Hazardous Substances 

Decisions about whether or not to evacuate as 

well as about evacuation distances are incident- Reevaluation of the screening zones based on specific and must be made at the time of an ac­ “credible worst case” assumptions used for 

screening purposes should be performed with 

12/87 2-18 
EXHIBIT 2-9 

FACTORS AFFECTING VULNERABLE ZONE ESTIMATIONS 

IF IT WILL CAUSE RESULTING IN 

the quantity on site 

that might be involved in 

an accident is reduced 

the time period of 

release of a given 

quantity increases 

the release source point 

is above ground level 

the terrain considered 

is rough (uneven and 

mountainous) instead of 

flat 

the area is urban, 

containing high buildings 

and other man-made 

structures 

a higher value 

for LOC is chosen 

a lower value for 

LOC is chosen 

a reduction in the smaller estimated zones 

total airborne quantity 

and the quantity released 

per minute 

a reduction in the smaller estimated zones 

airborne quantity 

released per minute 

an increase in dispersion smaller estimated zones 

(mixing and diluting of the (possibly) 

chemical in air) 

an increase in dispersion smaller estimated zones 

(mixing and diluting of 

the chemical in the air) 

an increase in dispersion smaller estimated zones 

(mixing and diluting of 

the chemical in the air) 

a reduction in the geographical smaller estimated zones 

area with airborne concentrations 

above the LOC 

an increase in the geographical larger estimated zones 

area with airborne concentrations 

above the LOC 

2-19 
tual release. An estimated vulnerable zone 

should not automaticallv be used as the basis for 

evacuation during an incident response, For example, the following variable factors are always 

part of an evacuation decision: wind speed and 

direction, temperature, humidity, air dispersion 

conditions, and time of day. In addition, the vulnerable zone is described as a circle or a corridor surrounding the possible incident site and 

provides no information on the breadth of a potential plume. An evacuation zone is typically a 

pathway through which a plume might move 

from the point of release. The vulnerable zone 

is helpful because it identifies an area about 

which evacuation decisions might need to be 

made, but the evacuation zone will always depend on other factors. 

Evacuation during incidents involving the airborne release of acutely toxic chemicals is 

sometimes , but by no means always , 

necessary. Release of airborne toxics can occur 

and move downwind so rapidly that there would 

be no time to evacuate residents. For shortterm releases, the most prudent course of action for the protection of the nearby residents 

would often be to remain indoors with the doors 

and windows closed and the heating and air conditioning systems shut off. An airborne cloud will 

frequently move quickly past. Vulnerable populations, such as the elderly and sick, may suffer 

more injury by being evacuated than by staying 

inside and putting simple countermeasures into 

effect. If the releases occur over an hour or 

more, or if there is a fire that cannot be readily 

controlled within a short time, then evacuation 

may be a sensible alternative. 

The disadvantages of evacuation in incidents involving airborne releases of EHSs are numerous. 

Two have already been alluded to, namely that 

events occur so rapidly that there may be no 

time to evacuate and that vulnerable populations 

would sustain fewer adverse effects by remaining inside until the toxic cloud has passed. 

Slight changes in wind velocity and direction 

could be very important if evacuation were begun during a release of airborne toxic chemicals: 

differences in temperature between air layers 

could also cause the toxic cloud to disperse in 

ways that would be hard to predict. It would be 

difficult to estimate how long a community would 

be exposed to a toxic cloud. 

The estimated vulnerable zone for a potential 

airborne release of a specific quantity of EHS 

represents the area surrounding the potential release site within which vulnerable populations 

and facilities might be affected. It does not reflect the time frame of the impact of an accident. It also does not mean that just beyond the 

zone boundary residents are safe. The many 

assumptions made in the calculations for the 

vulnerable zones and the fact that no safe levels 

for any of the chemicals on the list of EHSs have 

been established for the general population, 

make it inappropriate to base evacuation solely 

on these estimates. If the estimated vulnerable 

zone is greater than planners can cope with, the 

community should work closely with the facility 

to discuss the possibility of reducing the risk of 

exposure. This could be achieved by reducing 

inventories, establishing controls or alarms to 

make sure no release occurs, and by installing 

early warning systems. A more detailed discussion of evacuation is given in Appendix H. 

12/87 2-20 
2.3 Risk Analysis

Risk analysis is the third part of the hazards 

analysis process. Risk analysis can provide a 

relative measure of the likelihood and severity of 

various possible hazardous events and enable 

the emergency plan to focus on the greatest potential risks. Risk analysis requires certain information collected during the first two steps of the 

hazards analysis (hazards identification and vulnerability analysis), as well as other information 

specific to the facility or the local area. The appropriate level of detail and scope of the risk 

analysis must be determined based on the local 

situation and the resources available. This guide 

is meant primarily to assist local emergency 

planning committees (LEPCs) in carrying out a 

relatively quick and inexpensive risk analysis. 

LEPCs with access to the necessary resources 

may wish to conduct a detailed quantitative risk 

analysis. However, a risk analysis of this type is 

beyond the scope of the guidance presented 

here and it is recommended that committees 

seek other guidance and expert advice for conducting quantitative risk assessments. A quantitative risk assessment is not deemed essential 

to performing a hazards analysis suitable for 

emergency response planning in most cases. 

The real value of risk analysis derives from the 

fact that it gives planners an ability to put each 

potential situation into perspective (in terms of 

the probability that it will occur and the resulting 

effects it will have) and results in emergency 

plans that will address the most likely and most 

severe potential hazards. 

2.3.1 Overall Approach to Risk Analysis: 

Ranking of Hazards 

Because available safeguards such as containment, controlled flow, and proper venting may 

greatly reduce the opportunity for, or extent of, 

exposure, the mere presence of a hazardous 

chemical is insufficient to identify the level of risk 

involved. Whenever a hazard exists, however, 

there is always some risk, however small it 

might be. 

Risk analysis includes an estimate of the probability or likelihood that an event will occur. Risk 

can be characterized in qualitative terms as 

high, medium, or low, or in quantitative terms 

using numerical estimates and statistical calculations. For practical purposes, a risk analysis 

may be based on a subjective, common-sense 

evaluation. Few people live in daily fear of being 

struck by a meteorite. They know that, although 

the risk exists, it is very small because the probability is low. A busy street corner, known to be 

the site of frequent auto accidents, could be 

considered to present a high risk of accidents. 

Citizens know that the likelihood of being struck 

by an automobile is much greater and requires 

safeguards (e.g., looking both ways before 

crossing a street). In both of these situations, 

the evaluation of the probability of a future incident is based on knowledge of the frequency 

with which that incident has occurred in the 

past. Historical records of past events can, 

therefore, be put into practical use in risk analysis. 

12/87 2-21 
Both probability and consequences are extremely important in evaluating risk. A high risk 

situation can be the result of a high probability 

with severe consequences (e.g., irreversible 

health effects or death due to an airborne toxic 

chemical, a fire or explosion with injuries or fatalities) , whereas moderate risk situations can 

be a result of either high probability with mild 

consequences or low probability with more severe consequences. Diminishing the likelihood 

of an accident or minimizing the consequences 

will reduce risk overall. 

A relative ranking of hazards for the purposes of 

community emergency planning does not require extensive mathematical evaluations, application of statistics, or extensive support from 

experts. Application of readily available information and common sense, when combined with 

site-specific evaluations such as the vulnerability analysis, will complete much of the risk analysis process. Because it is based on the knowledge, experience, local considerations, and the 

priorities of the people in the planning district or 

community involved, there is no universal right 

answer in risk analysis. 

2.3.2 Types of Information Required for Risk 

Analysis 

Much of the information concerning sources of 

hazard, populations, and essential services subject to damage should have been assembled 

during the screening portion of the hazards identification and vulnerability analysis. Risk analysis 

will also require information on facility and community plans and safeguards, existing local response capabilities in place, and an historical record of past incidents and their outcomes. 

Planners who have used the screening methodology to estimate vulnerable zones as described 

in Section 2.2 of this chapter and in Chapter 3 

will then need additional information about priority facilities for which they will develop plans first. 

The process described in this section is iterative: (1) Planners gather additional information 

about high priority facilities first; (2) Planners 

then reevaluate and rank the risks associated 

with highest priority sites (and make emergency 

plans accordingly); (3) Planners then return to 

the original list of facilities that were assigned a 

lower priority during the screening and repeat 

the process until all reporting facilities have been 

reevaluated. Following the reevaluation of all facilities, appropriate emergency plans should be 

developed. 

Facility Information 

Facilities are an important source of information 

about risk. They are required under Title Ill of 

SARA to provide both chemical inventory and release information to LEPCs. Information required 

under Section 304 about spills or releases that 

have occurred will be useful for this phase of 

hazards analysis. Certain State and local governments have additional community-right-toknow regulations and spill reporting requirements with which facilities must also comply. 

Thus industries can and should be approached 

with questions regarding the hazards and safeguards present at their facilities. Interaction with 

facilities should be based on cooperation, respect for trade secrets and other confidential 

business information, and recognition of the industry as a member of the community. Facilities should be aware of the importance of certain information (e.g., the results of a facility risk 

assessment) and should cooperate in providing 

as much pertinent information as possible. Specific types of information concerning extremely 

hazardous substances (EHSs) that LEPCs may 

want to request from facilities include: 

Anticipated adverse health effects of a 

substance and their degree of severity: 

Safeguards in place on-site: 

Recommendations made by facilities for 

community safeguards: 

Prevention approaches used for past 

events in which adverse health effects 

were prevented, and details of the events: 

Lessons learned from past events in which 

adverse health effects occurred, and details of the events: 

Hazards evaluations conducted by the facility (e.g., HAZOP; see Appendix J). 

In addition to the information and recommendations which they will provide, facilities may be 

willing to contribute resources to assist in emergency response management including: 

� Assistance in planning and response by 

facility technical experts: 

12/87 2-22 
Copies of facility emergency response 

plans and spill prevention control and 

countermeasures (SPCC) plans (see Appendix I); 

Assistance in cleanup and recycling of 

spilled materials: and 

Training and safe handling instructions. 

Community Plan and Safeguard Information 

Many communities will already have in place one 

or more emergency response plans developed 

to address a variety of hazards. Such plans may 

require revision to include recent new regulations and perhaps may be incomplete in addressing acutely toxic airborne releases, but will 

provide a valuable starting point for additional 

planning. Specific types of plans which may already exist include: 

Local multi-hazard emergency operations 

plans (EOPs) (developed under Federal 

Emergency Management Agency (FEMA) 

guidance); 

Emergency plans for transportation-related hazards (developed under Department of Transportation (DOT) guidance); 

Community Awareness and Emergency 

Response (CAER) plans (developed by 

the Chemical Manufacturers Association 

(CMA) ); and 

The SPCC plans of individual facilities. 

Historical Accident Records 

There are two benefits to the review of historical 

records of hazardous materials incidents in risk 

analysis. First, an analysis of the sites and materials involved in prior accidents will indicate 

hazards that may represent significant risks. Although no two accidents will be identical, certain 

situations, if unaltered, can precipitate other 

more severe incidents. A second benefit is the 

development of an ability to recognize and assess potential risks which would not be apparent 

to an untrained evaluator. The development of 

an appreciation for what could happen can be 

achieved through a review of what has happened in the past. To assist in increasing the 

overall awareness of the nature and complexity 

of hazardous incidents, Exhibit 2-10 includes 

brief summaries of some accidents that occurred during 1980 and 1981 throughout the 

world. The Acute Hazardous Events Data Base 

prepared for the EPA Office of Toxic Substances 

(December 1985) has information on the chemicals involved in accidents that posed high risks 

to human health. The historical record of local 

hazardous incidents may be more valuable in 

identifying possible hazards in each district. Facility compliance with Section 304 of Title Ill of 

SARA will provide this type of information in the 

future. 

An historical record of local hazardous materials 

incidents should include information from the following organizations: 

� Fire department and rescue squad: 

� Police department: 

� Public health department: 

� Local hospitals and physicians: 

� Local chemical cleanup and spill response 

companies; 

� Universities (chemistry, chemical engineering, and science laboratory safety 

personnel); 

� Local industry: and

 News media (print and broadcast). 

When accumulating records of past incidents, 

information concerning the responsible parties 

will not be essential to the risk analysis process. 

Many of the information sources listed above 

may be more willing to provide the needed data 

(e.g., date, time, location, material, extent of 

incident, injuries sustained, remedial actions 

taken, safeguards implemented) if they are assured that blame will not be assigned in the 

process. 

Changing Factors Affecting Future Incidents 

The historical record of incidents will contain 

valuable information. However, to properly apply such data to the risk analysis process requires that any changes which have occurred be 

taken into account. For example, the assembled historical record may contain several accidents involving the release of hazardous materials at a particular site. If the engineering controls, containment facilities or processes used 

are altered over time, the results of the risk 

analysis may be substantially different from what 

the historical record might predict. Any evaluation of past accidents must take into account 

any changes in the following: 

12/87 2-23 
Exhibit 2-10 

SUMMARIES OF SOME ACCIDENTS THAT OCCURRED IN 1980-81 
Surrounding populations and critical facilities;

Transportation routes: and

Engineering control methods.

2.3.3 Limiting the Collection of Information 

The preceding section contains some general 

guidance concerning the types of information required for a risk analysis and where to obtain 

such data. Appendix I contains suggestions for 

more detailed questions and concerns which 

may be raised during discussions to collect the 

needed information. These are all tools for use 

in determining what information to collect: none 

of them, however, will be wholly adequate for 

emergency planning needs. Community-specific checklists will have to be developed for use 

in collecting information since each locality and 

community has different needs, requirements, 

and points of emphasis. 

The suggested approach for using the tools in 

this guide to aid in the development of such a 

community-specific checklist is to: 

1) Review Appendix I for the types of information that appear to be needed. 

2) Highlight and amend the suggestions in 

Appendix I to reflect the specific needs of 

your local.community or planning district. 

3) Develop a detailed checklist of information 

needed based on the amended (tailored) 

version of Appendix I and the types of information outlined in the prior section of 

this guidance. 

4) Set a priority for each item of information 

based on perceived need, effort involved, 

and available resources. 

5) Request the needed information and assemble it. (This process will be described 

in the next section.) 

It is very important to recognize when enough 

information has been collected. A cursory review of Appendix I, which is by no means a complete set of discussion points, will demonstrate 

the volume of information that can be collected 

for the risk analysis. Collection of data on all 

possible interactions of elements would be extremely time consuming. The complexity of the 

analysis and the effort required to perform it will 

depend directly on the volume of data collected. 

The focus of the information collection should be 

on developing a relative measure of the likelihood and severity of possible hazardous events. 

This goal does not demand an exhaustive collection of data. Reviewing data as they are collected will greatly assist in identifying information 

that is essential as opposed to that which is peripheral to the risk analysis process. If in doubt, 

base decisions on whether the information: 

� Has the potential for altering the relative 

ranking of the hazard to the community: 

and 

� Directly involves identification of a hazard, 

determination of likelihood of an incident, 

assessment of outcome of an accident, or 

identification of the safeguards needed or 

available to reduce the magnitude of the 

damage. 

Anything outside these categories can be considered of secondary importance and should be 

collected only if resources allow. Such limitations, when properly applied to the entire information collection process (i.e., prioritization of 

the checklist before data is collected) can benefit the risk analysis by eliminating unnecessary 

types of information (e.g., details concerning 

damage from the least likely events) before effort is expended on its collection and analysis. 

2.3.4 Assembly of the Information Obtained 

from the Hazards Analysis 

Data that are systematically assembled as they 

become available during the three major steps 

of the hazards analysis can be easily evaluated 

as the risk analysis progresses and can be used 

to identify missing data as well as information 

that is complete. As has been discussed earlier 

in this chapter, a hazards analysis is first performed during the screening of reporting facilities using “credible worst case assumptions” for 

establishing priorities among facilities. The hazards analysis of each facility is then reevaluated 

according to priority based on a careful reassessment of the assumptions used in the 

screening process. A list of these steps is 

shown in Exhibit 2-11. 

Information obtained during both the screening 

process and the reevaluation process can be 

stored in a hazards analysis matrix. The hazards 

12/87 2-25 
EXHIBIT 2-11 

STEPS IN HAZARDS ANALYSIS 

INITIAL SCREENING 

1. HAZARDS IDENTIFICATION 

A. List facilities that have reported EHSs in the community in excess of the threshold planning quantity TPQ 

B. Contact each facility on the list for information on the EHSs present 

i. Chemical identities 

ii. Quantities and location of chemicals present 

iii. Properties of the chemicals if identity is trade secret 

iv. Conditions under which chemicals are used, produced, processed, or stored 

C. Obtain information on transportation routes of EHSs, if possible 

D. Obtain information on hazardous materials, facilities, and transportation routes (other 

than for those with EHSs above the TPQ) listed by SERCs (optional) 

2. VULNERABILITY ANALYSIS 

A. Estimate vulnerable zone for screening using credible worst case assumptions 

i. Determine rate of release to air using information from the facility concerning quantity 

likely to be released from a vessel or interconnected vessels and fixed assumptions 

about time of release 

ii. Use LOC from Appendix C 

iii. Determine zone using Exhibit 3-l and fixed conditions 

B. Identify characteristics of human population (e.g., number, concentration, general

health) within estimated vulnerable zone

C. Identify critical facilities within estimated vulnerable zone 

3. RISK ANALYSIS 

A. Collect information obtained in hazards identification and vulnerability analysis 

B. Make rough estimate of risks posed by each based on readily available information on 

the likelihood of a release and severity of consequences 

C. Identify those facilities with higher priority due to the estimated risks they pose 

12/87 2-26 
PLANNING FOR FACILITIES BY PRIORITY 

4. HAZARDS IDENTIFICATION 

A. Contact each facility on the list and other expert sources for additional information on 

the EHSs present and what conditions might be present during a release 

i. Reevaluate estimate of quantity likely to be present 

ii. Reevaluate estimate of rate of release 

iii. Consider typical weather and wind conditions 

B. Obtain additional information on typical transportation conditions, if possible 

5. VULNERABILITY ANALYSIS 

A. Reestimate vulnerable zone using reevaluated assumptions gathered from conversations 

with the facility and other expert sources 

B. Identify characteristics of human population within estimated vulnerable zone 

C. Identify critical facilities within estimated vulnerable zone 

6. RISK ANALYSIS 

A. Collect all information obtained in hazards identification and vulnerability analysis into a 

table 

B. Obtain additional information on community and facility safeguards, response

capabilities, and accident records

C. Make judgment of probability of release and severity of consequences 

D. Organize all information (from A, B, and C) in a matrix format 

E. Rank risks 

F. Develop, or revise emergency plans for higher priority facilities 

INTEGRATING HAZARDS ANALYSIS INTO THE PLAN. 

See Exhibit 4-1 Emergency Planning Information Section. 

12/87 2-27 


Exhibit 2-13 

EXAMPLE QUALITATIVE DEFINITIONS OF

PROBABILITY OF OCCURRENCE

zoning

Providing a basic for requesting additional

In general, the events with likelihood-consequence rankings of high-high, high-medium, 

medium-high, and medium-medium will require 

some additional attention and possible mitigating 

measures. However, other less likely scenarios 

may also have serious consequences and be of 

high concern to a particular community and 

would warrant the focus of emergency planning. 

This initial approach to ranking hazards can enable the best use of the available planning resources. 

The planning and decision-making situations in 

which risk analysis information may prove valuable include: 

summarizes routing requirements at the 

Federal, State, and local levels consistent 

with the Hazardous Materials Transportation Act (HMTA) of 1975); 

emergency response resources (e.g . , fire 

department vehicles equipped for hazardous materials incidents); and 

� Developing new training materials or selecting available materials. 

The application of the results of a risk analysis to 

the emergency planning process will be described in detail in Chapter 4. 

Development of a comprehensive local

emergency plan;

Updating of facility emergency response

plans:

Planning major transportation routes for

hazardous chemicals (it should be emphasized that the Federal Highway Administration publication FHWA-IP-80-15,

Guidelines for Applying Criteria to Designate Routes for Transporting Hazardous

Materials, should be used. This document

The summary description of the components of 

hazards analysis presented in this chapter and 

Appendices I and J will provide a sound basis for 

understanding the next chapter of this guidance. 

Chapter 3 leads planners step by step through a 

hazards analysis, beginning with the initial 

screening of reporting facilities to establish priorities, and followed by a subsequent reevaluation of the estimated vulnerable zones and hazards analysis by priority of potential hazard. 

12/87 2-33 
3. Step-by-Step Procedures for Conducting a

Hazards Analysis of Extremely Hazardous Substances

Introduction 

Chapter 2 provided an overview of the 

underlying concepts and application of the three 

major steps in conducting a hazards analysis of 

extremely hazardous substances (EHSs) . These 

steps are hazards identification, vulnerability 

analysis, and risk assessment. 

This chapter provides procedures that can be 

used in a stepwise fashion to actually conduct a 

hazards analysis for a specific EHS as reported 

by a facility under Title Ill of the Superfund 

Amendments and Reauthorization Act of 1986 

(SARA). This chapter contains only minimal 

information on the background and concepts of 

the hazards analysis. Effective use of these 

procedures requires that all information 

presented in Chapter 2 and Appendices I and J 

be reviewed and understood. 

General Overview 

Because of time and resource limitations, 

planners will likely not be able to analyze 

3.1.1 Hazards Identification 

The hazards identification for initial screening is 

based primarily on those facilities in the planning 

district that have reported EHSs in excess of the 

TPQs under Section 302, Title Ill of SARA. 

Identification of hazards from EHSs present in 

amounts lower than the TPQ and from other 

hazardous substances may be undertaken but is 

not mandatory under this Act. 

Step 1. Prepare a list of all facilities in the 

planning district that have reported EHSs 

under Section 302 of Title Ill. Include any 

additional facilities specified by the State 

emergency response commission (SERC). 

Step 2. Prepare a list of all EHSs at each facility 

that exceed the TPQs. Chemical identity 

hazards and plan in detail for all facilities 

immediately. Resources should be 

concentrated first on those situations that 

present the greatest potential risk should an 

accident occur. To accomplish this, the hazards 

analysis is separated into two phases. The first 

phase is the initial screening of all facilities 

reporting EHSs on their premises in excess of 

their threshold planning quantities (TPQs). The 

initial screening is performed to establish 

priorities among reporting facilities using 

credible worst case assumptions. The second 

phase represents a reassessment by order of 

priority of the potential hazards posed by the 

reporting facilities. This is accomplished 

through the reevaluation of the assumptions 

used for the initial screening. Both the initial 

screening and the reevaluation phases utilize the 

three basic steps of a hazards analysis: hazards 

identification, vulnerability analysis, and risk 

analysis. 

should include chemical name and Chemical 

Abstract Service (CAS) registry number. 

Although it is not required under Title Ill of 

SARA, a list of EHSs below the TPQ could 

also be considered for hazards analysis. 

This information can be obtained from the 

facility representative. 

Step 3. Using chemical name or CAS number, 

find ambient physical state of substance in 

Appendix C. 

Step 4. Obtain from the facility representative 

information concerning the total quantity 

present, the average daily quantity, and 

maximum quantity in a single vessel or group 

of interconnected vessels for each EHS that 

exceeds the TPQ. 

3.1 Initial Screening to Set Priorities Among Sites 

3-1 
(If the EHS is a solid, these two steps (3 and 4) guidance and close approximations of the 

should establish the quantity of solid in each of following properties for each EHS: 

the following forms: powdered (less than 100 i. Physical state at ambient conditions microns particle diameter), molten (liquid), or in ii. For liquids: the vapor pressure at solution .) ambient conditions and boiling point 

Step 5. Obtain from the facility representative temperature 

additional information on liquids, solids, and iii. For molten solids: the melting point 

mixtures or solutions: temperature and vapor pressure at the 

i. For liquids: temperature of liquid in melting point temperature 

each vessel and whether or not the Approximation should be sufficiently close so 

vessel is located in a diked area. as not to significantly affect the size of the 

Information provided on temperature estimated zones.

may be specific or may be stated Step 7. If the local emergency planning generally as ambient or above/below committee (LEPC) deems it necessary, ambient. For purposes of this guidance, obtain information in steps 1 through 6 for liquids at ambient or below ambient other EHSs that are present in quantities that temperature are evaluated at ambient, do not exceed the TPQ.

and those at temperatures greater than 

ambient are evaluated at their boiling (NOTE: This step is not mandatory under Title Ill 

temperature. of SARA, but EHSs could pose a hazard to the 

community in quantities less than the TPQ.) ii. For molten solids: whether or not each 

vessel is in a diked area. Solid materials Step 8. Organize and record essential 

other than those in powdered or molten information and data. A discussion on the 

form, or in solution, may be considered assembly of information is provided in 

as low priority for hazards analysis. Section 2.3.4. 

iii. For mixtures, solutions, or solids as

powders: concentration of each EHS in a 3.1.2 Estimate Vulnerable Zones for

mixture or solution, or fraction of a solid Screening Purposes

with particle size less than 100 microns, For screening purposes, the vulnerable zone is on a weight percent basis. The hazards an estimate of the area potentially affected by analysis will be conducted using only the 

quantity of EHS present in the mixture or the release of an EHS using a set of fixed 

solution, or the quantity of solid with assumptions about the release and airborne 

particle size less than 100 microns. (For dispersion of the substance. 

example, 10,000 pounds of a solution of Step 1. For each EHS, use the maximum acrylamide in water at a concentration of quantity of material in a vessel or group of 30 percent by weight represents 3,000 interconnected vessels.

pounds of acrylamide for hazards

analysis.) For an EHS that is not in a mixture, solution, 

or partially powdered solid, this quantity is (NOTE: for the purposes of this guidance, the the maximum quantity that could be state (solid, liquid, gas) of the EHS is assumed released (QS). Use this value and proceed to be that for which it is listed at ambient to Step 3. To determine QS for an EHS in a 

conditions in Appendix C. The specific handling mixture or solution, or as a powder, proceed 

condition may place the EHS in a different state to Step 2. 

than listed, e.g., liquid handled as a gas. If the Step 2. For each EHS in a mixture, solution, or 

EHS is handled at other than ambient conditions, that is partially powdered or molten, 

the calculations should reflect the ambient state, determine the QS of EHS by multiplying the 

as explained in this guide.) maximum quantity of mixture, solution, or 

solid in a single vessel or interconnected 

Step 6. If facilities make confidentiality claims vessels by the concentration and/or portion 

for chemical identity, obtain from the facility that is molten or powdered as follows: 

representative close approximations of the QS (Ibs) level of concern (LOC) as defined in this 

3-2 
= Total Quantity of Mixture, Solution, 

or Solid (Ibs) x Concentration 

and/or portion molten or powdered 

(wt%) /100 

Example: A facility has 1000 pounds of a 

50 percent by weight solution of ammonia 

in water. The quantity of ammonia that 

could be released is: 

QS = 1000 pounds x 50/100 

= 500 pounds 

Step 3. Determine the rate (in pounds per 

minute) of release of the EHS to air. Note 

that the calculation of the rate at which a 

substance becomes airborne is dependent 

upon its physical state and the temperature 

of the liquid or molten solid at the time of 

release. If the physical state at ambient 

temperature is a gas, continue as described 

below in Section A. If the physical state is 

liquid, proceed to Section B. For soiids, 

refer to Section C. Once the rate of release 

(QR) is determined for each substance, 

proceed to step 4 to determine the 

vulnerable zone for each facility. 

A. Gases 

A-1. Determine the rate of release to air 

(QR) by dividing the maximum quantity of 

EHS that could be released from a vessel or 

group of interconnected vessels (QS) by 10: 

QR (Ibs/min) = QS (Ibs)/lO minutes 

Example: 2000 pounds (QS) of chlorine is 

stored in a single 1 ton container. 

The rate of release to air (QR) is: 

QR = 2000 Ibs/lO minutes 

QR = 200 Ibs per minute. 

B. Liquids 

B-1. If the liquid is handled only at or below 

ambient conditions, use the Liquid Factor 

Ambient (LFA) from the list of EHSs in 

Appendix C (see Exhibit C-1 and C-2). If 

the liquid is handled at temperatures greater 

than ambient, use the Liquid Factor Boiling 

(LFB) from the list in Appendix C. If the 

chemical identity is claimed confidential and 

the facility representative has provided a 

close approximation of the vapor pressure 

and boiling point at the handling temperature 

for the confidential liquid, use Appendix G to 

calculate an LFA or LFB. 

3-3 

B-2. If the area surrounding the vessel(s) is 

not diked, go directly to B-6. If the area is 

diked, determine the area bounded by the 

dike in square feet (ft2

). 

B-3. To determine if using the diked area is 

appropriate, estimate the area of the pool 

that might be formed by the spilled liquid if 

the area were not diked as follows: 

Area of Pool (ft2 ) = QS (Ibs) x 0.49 

B-4. Compare this area to the diked area. 

If the estimated area of the pool is smaller 

than the diked area, go to B-6 and do not 

use the diked area. If the diked area is 

smaller, continue to B-5. 

Example: 10,000 pounds of acrolein is 

stored in a tank in a diked area of 1600 

square feet. The pool area is derived as 

follows: 

Area of Pool = 10,000 x 0.49 

= 4900 ft2 

Since the diked area (1600 ft2) is less than 

the calculated area of the pool (4900 ft2

), 

use the diked area for further calculations. 

B-5. Determine the Rate of Release to air 

(QR) for a liquid spilled in a diked area using 

the following formula: 

QR (Ibs/min) = LFA or LFB x Diked 

Area (ft2

) x 2.8 

(NOTE: the factors 2.8 and 1.4 in B-5 and 

B-6, respectively, take into account the low 

wind speed of 1.5 m/set (3.4 miles/hour); 

see Appendix G.) 

Example: 50,000 pounds of pure, hot 

acrolein is spilled in a diked area of 1600 

square feet. Using the liquid factor boiling 

(LFB) of 0.02, the rate of release to air 

(QR) is: 

QR = 0.02 x 1600 ft2 x 2.8 

QR = 90 Ibs/min 

B-6. Determine the Rate of Release to air 

(QR) for a liquid spilled in an undiked area 

using this formula: 

QR (Ibs/min) = QS (Ibs) x LFA or 

LFB x 1.4 

Example: 50,000 pounds of pure, hot 

acrolein is spilled in an undiked area. 
Using the liquid factor boiling (LFB) of 

0.02, the rate of release to air (QR) is: 

QR = 50,000 Ibs x 0.02 x 1.4 

QR = 1400 Ibs/min 

C. Solids 

C-1. If the solid is powdered (particles less 

than 100 microns in diameter) or in solution, 

go to C-2. 

If the solid is molten, go to C-3. 

If the solid is not powdered, not in solution, 

nor molten, defer hazards analysis of this 

chemical and begin with another chemical at 

this facility, or proceed to another facility. 

Solids other than in powdered, molten, or 

dissolved form are less likely to become 

airborne. 

C-2. It is assumed that the maximum 

quantity of a solid that might be released 

(QS) is the quantity finely powdered or in 

solution. The QR of a powder or solution of 

a solid is QS divided by 10 or: 

QR (Ibs/min) = QS (Ibs)/lO minutes 

C-3. For molten solids, find the Liquid 

Factor Molten (LFM) from the list of EHSs in 

Appendix C (see Exhibit C-1 or C-2). If no 

LFM is available on the list, consult with 

facility personnel to obtain the necessary 

data to calculate the LFM as described in 

Appendix G. For molten solids claimed 

confidential, obtain a close approximation of 

the vapor pressure and melting point 

temperature from the facility representative 

and calculate an LFM using the formulae in 

Appendix G. 

C-4. If the area around the vessel(s) 

holding the molten solid is not diked, 

proceed to C-6. If the area around the 

vessel(s) is diked, determine if it is 

appropriate to use the diked area by 

comparing it to the liquid pool area as 

described in steps B-3 to B-5. 

C-5. Determine the QR for a molten 

material in a diked area as follows: 

QR (Ib/min) = LFM x Diked Area 

(ft 2

) x 2.8 

C-6. Determine the QR for a molten 

material in an undiked area as follows: 

QR (Ib/min) = quantity actually 

molten (Ibs) x LFM x 1.4 

Step 4. Select the LOC for the chemical from 

the list of EHSs in Appendix C (see Exhibit 

C-1 or C-2). In instances of confidentiality 

claims, obtain this value or close 

approximation from the reporting facility. 

Step 5. Estimate the distance (radius) of the 

screening zone using Exhibit 3-1 as follows: 

i. Locate across the top of the table the 

LOC value that most closely 

approximates the LOC for the EHS in 

question. If the LOC value falls halfway 

between two values on the table, use the 

value on the table that is smaller (to the 

left). 

ii. Locate the value in the left hand column 

that most closely approximates the 

calculated QR (Ibs/min) . If the calculated 

OR is halfway between two values on the 

table, use the value which is larger (lower 

on the table). 

iii Read across and down to the distance 

given in tenths of a mile. This value is the 

calculated radius of a circle 

encompassing the potential release site 

and represents the size (in tenths of a 

mile) of the estimated vulnerable zone for 

the initial screening of reporting facilities. 

Example: The LOC for nitrobenzene 

is 0.10 grams per cubic meter and 

the estimated rate of release to air 

(QR) is 15 pounds per minute. The 

radius of the estimated vulnerable 

zone is 0.4 miles. 

Step 6. Using a local map of appropriate scale, 

draw a circle to scale around the potential 

release site with the potential release site as 

the center and the estimated vulnerable 

zone distance as the radius. This represents 

the estimated vulnerable zone for initial 

screening of reporting facilities. 

Step 7. Identify populations and essential service 

facilities that are located within the estimated 

vulnerable zone. 

Step 8. Record essential data. A discussion of 

the assembly of information and an example 

format are provided in Section 2.3.4. 

3-4 
I 

I 

Worked Examples for Initial Screening 

Example 1. Gas Release (Chlorine) 

An 800 pound tank of chlorine, which is normally 

a gas, is stored at a water treatment plant. No 

other tanks are nearby and it is not 

interconnected to any other storage vessels 

containing chlorine. For screening purposes, it 

is assumed that the total quantity in the tank can 

be released, and the release will take place over 

a ten minute period. Therefore, 

OR = QS/lO 

QR = 800 pounds/l0 minutes = 80 

pounds per minute. 

The LOC for chlorine is 0.0073 grams per cubic 

meter (g/m3

) (from Exhibit C-1 or C-2 in 

Appendix C) . 

Locate the LOC listed along the top row of 

Exhibit 3-1. The LOC of chlorine falls between 

two values on the table: the lower value is used 

(i.e., LOC = 0.005 g/m 3). Locate the OR (80 

pounds per minute) in the left hand column. 

Read across from QR = 80 and down front LOC = 

0.005 to the distance. The estimated vulnerable 

zone has a radius of greater than 10 miles from 

the chlorine storage tank. 

Example 2. Gas Release (Ammonia) 

A tank truck contains 3.000 pounds of ammonia. 

For screening purposes it is assumed that the 

entire 3,000 pounds is released during a 

ten-minute period following an accident: the 

airborne quantity released per minute (QR) is 

calculated as follows: 

QR = 3,000 pounds110 minutes = 

300 pounds per minute 

The LOC for ammonia (from Exhibit C-1 or C-2 

in Appendix C) is 0.035 g/m3

. 

Locate the LOC in the top row of Exhibit 3-l. 

Locate the QR, 300 pounds per minute, in the 

left-hand column. Using Exhibit 3-1 and reading 

across from 300 pounds per minute and down 

from 0.035 g/m3 to the intersection of the row 

and column, the radius of the vulnerable zone or 

the distance over which the concentration of 

ammonia may reach the LOC is estimated to be 

7.6 miles. 

Example 3. Pure Liquid at Elevated Temperature, Undiked Area 

Pure methyl isocyanate is handled in an undiked 

1000 pound reactor in a pesticide plant. The 

chemical is handled at warm temperatures 

(39°C). The LFB from Exhibit C-1 is 0.02. The 

quantity released to air per minute is calculated 

as follows: 

QR = QS (Ibs) x LFB x 1.4 

QR = 1000 pounds x 0.02 x 1.4 = 28 

pounds per minute 

The LOC for methyl isocyanate is 0.0047 g/m3 

(see Exhibit C-1 or C-2 in Appendix C). 

Using Exhibit 3-l the radius of the vulnerable 

zone is estimated. Locate the LOC in the top 

row. The LOC of methyl isocyanate falls 

between two values. Use the lower value, 

0.0035 g/m3

 . Locate the QR, 28 pounds per 

minute, in the left hand column. The QR falls 

between two values. Use the higher value, 30 

pounds per minute. Read across from the rate 

of release of 30 pounds per minute and down 

from the LOC of 0.0035 g/m3

 to find the 

distance. The vulnerable zone distance is 

estimated to be 7.6 miles. 

3-5 
(Note that for methyl isocyanate, there is a large fraction of the chemical would become a 

possibility that a runaway polymerization solid and stay in the reactor while the remainder 

reaction could produce very high temperatures would be quickly released to the atmosphere as 

and pressures in the reactor. In this case, a a gas.) 

Example 4. Liquid at Ambient Temperature in 

Acrolein in a 50 percent solution by weight, at 

ambient temperature, is stored in an undiked 

50,000 pound tank. The LFA from Exhibit C-l is 

0.007. The airborne quantity released per unit 

time to air is calculated as follows: 

OS = 50,000 pounds x 50/100 

QS = 25,000 pounds 

QR = 25,000 pounds x 0.007 x 1.4 

QR = 245 pounds per minute 

The LOC for acrolein is 0.0011 g/m 3

 (see 

Exhibit C-1 or C-2 in Appendix C) . The distance 

Mixture or Solution in an Undiked Area 

over which the concentration of acrolein in air 

may reach the LOC is estimated from Exhibit 

3-1. Read across from 250 pounds per minute, 

and down from the LOC of 0.0007 to the 

distance. The vulnerable zone radius is 

estimated to be greater than 10 miles. (10 

miles is the maximum radius that can be 

estimated by this method.) 

Locate the LOC in the top row. The closest 

value lower than 0.0011 is 0.001. Locate the QR 

in the left hand column. The closest value 

higher than 245 pounds per minute is 250. 

Example 5. Liquid in Diked Area 

About 50,000 pounds of pure, hot acrolein is 

stored in a reactor. Since the liquid is hot, the 

LFB from Exhibit C-1, 0.02, is used in the 

calculation of the quantity released. The area 

around the reactor is diked and it is 40 feet 

square (1,600 ft2

). 

Check this against the area of the pool 

generated by the reactor contents: 

Area of pool = QS x 0.49 = 50,000 x 

0.49 = 24,500 ft2 

Since the diked area is smaller the OR is: 

QR (Ibslmin) = LFB x diked area 

(ft2

) x 2.8 

QR = 0.02 x 1600 x 2.8 = 90 

pounds per minute 

Using Exhibit 3-1 locate the LOC of 0.0011 g/m3 

for acrolein in the top row. The closest value 

lower than 0.0011 is 0.001. Locate the release 

rate of 90 pounds per minute in the left hand 

column. Read across from 90 pounds per 

minute and down from 0.001 g/m3

 to find the 

distance. The distance over which the airborne 

concentration of acrolein could exceed the LOC 

(i.e., the radius of the estimated vulnerable 

zone) is estimated to be greater than 10 miles. 

Example 6. Finely Powdered Solid 

A site has 10,000 pounds of acrylamide stored The rate of release to air is: 

in a large bin. About 20 percent of it has a 

particle size less than 100 microns. The QR = OS/l0 minutes = 2,000/10 

maximum quantity that could be released (QS) = 200 Ibs per minute 

is: The LOC for acrylamide is 0.11 g/m 3

 (see 

OS = 10,000 Ibs x 20/100 = 2,000 Exhibit C-1 or C-2 in Appendix C). Exhibit 3-1 is 

used to determine the distance over which the Ibs. 

3-6 
concentration of acrylamide in air may reach the across from the OR of 200 pounds per minute 

LOC . Locate the LOC in the top row. The and down from the LQC of 0.1 g/m 3, the 

closest value lower than 0.11 is 0.1 g/m 3. distance is estimated to be 2.1 miles. 

Locate the QR in the left hand column. Reading 

3.1.3 Risk Analysis for Initial Screening of 

Reporting Facilities 

For purposes of initial screening, the risk 

analysis is limited to a very rough estimate of the 

likelihood or probability of an incident and the 

severity of consequences to humans. 

Step 1. Evaluate populations at risk in the 

estimated vulnerable zone. This should 

include estimated number of individuals, 

types of populations such as elderly, 

children, infirm, incarcerated, residents, and 

transients such as daily workers, audiences, 

and spectators. 

Step 2. Evaluate critical facilities at risk in the 

estimated vulnerable zone. This should 

include hospitals or other health care 

facilities, fire and police stations, other 

emergency response facilities, and 

communications facilities. 

Step 3. Establish a relative ranking system for 

the potential consequences posed by 

hazards from reporting facilities. This may 

be qualitative such as high, medium, or low, 

or may be a simple numerical system. For 

further information, see Section 2.3.1. 

Step 4. If available, use known historical 

information about incidents in the area, 

estimate the likelihood of a release. 

(NOTE: for most hazards, the probability of 

occurrence will be assumed to be the same.) 

Step 5. Record the judgements made in steps 3 

and 4. 

3.2 Reevaluation; Planning for Facilities by Priority

The reevaluation process provides the 

opportunity to analyze further the potential 

hazards of reporting facilities by order of priority. 

This effort is characterized by the stepwise 

reevaluation of certain of the credible worst case 

assumptions used to estimate vulnerable zones 

during the initial screening process. It is 

important to emphasize that changes in 

assumptions resulting in a reduction in size of 

the zone should be considered with extreme 

care and prudence. Less conservative 

assumptions will decrease the estimated zone. 

In the event of a release under less favorable 

conditions, a greater area and perhaps a greater 

population may be affected. 

3.2.1 Hazards ldentification 

Step 1. Review the priority list of reporting 

facilities developed during the initial 

screening process and, starting with the 

highest priority facilities, begin reevaluation 

of assumptions that were used to estimate 

the credible worst case vulnerable zones. 

Step 2. List potential hazards other than those 

associated with acute lethality. (This step is 

not mandatory.) 

3.2.2 Reevaluation of the Vulnerable Zones 

step 1. Reevaluate the assumptions used to 

estimate the quantity of EHS likely to be 

released from a vessel or vessels. Planners 

should seek advice from appropriate experts 

including representatives of the facility. 

Estimates by the facility or other sources of 

the total quantity of EHS that could be 

released from a vessel and supporting 

rationale should be reviewed carefully. 

These may include revised estimates of the 

quantity of a liquid likely to be spilled based 

on actual quantities present or processed 

and the capabilities to mitigate a release. 

step 2. Reevaluate the assumptions used to 

estimate the rate at which the EHS becomes 

3-7 
have calculations or data on the actual 

amount of substance that could be released 

when solids are molten, in solution, in 

powdered form, or vaporized. If there is no 

way for powders or solutions to become 

airborne due to explosions or problems with 

pneumatic systems, release of the 

substance beyond the boundaries of the 

facility is not likely. This information should 

be included in the risk analysis (below). 

Similarly, molten solids may “freeze” upon 

contact with air at ambient temperatures and 

may not evaporate, or conditions may differ 

from those used to calculate the LFM. 

Obtain appropriate input from facility 

representatives and calculate a new LFM or 

use other data from the facility or other 

sources to estimate the rate at which the 

solid becomes airborne. As for liquids, the 

rate at which a molten solid evaporates from 

the pool depends upon the wind speed at 

the time of release. Consult Appendix G to 

calculate a factor to account for wind in the 

calculation of the rate of release to air of a 

molten solid. 

Once more realistic site-specific information 

has been collected and reevaluated 

regarding the release rate to air of gases, 

liquids, and solids, be sure to record the 

new data and the justification for changes. 

Then proceed to the next step (Step 3) in 

the reevaluation of the vulnerable zones. 

Step 3. Determine if the area around the facility 

is predominately rural or urban, as follows: 

If more than 50% of the land within a mile 

(1.6 km) radius is used as: 

1. Heavy industrial (large chemical, other 

manufacturing facilities, 3-5 story 

buildings, flat roofs, grass and trees 

extremely rare), or 

2. Light to moderate industrial (rail yards, 

truck depots, warehouses, industrial 

parks, minor fabrication, l-3 story 

buildings, flat roofs, limited grass and 

trees), or 

3. Commercial (office and apartments, 

hotels, 10 story heights, flat roofs, limited 

grass and trees), or 

4. Compact residential (single and some 

multiple family dwellings closely spaced, 

2 story or less, alleys, pitched or flat 

roofs, limited lawns and few old 

established shade trees, no driveways), 

then the area should be classified as urban. 

Otherwise use rural conditions. Select 

appropriate tables for use under Step 4. 

Guidance may be sought from appropriate 

experts. 

Step 4. Consider the principal meteorological 

conditions of wind speed and atmospheric 

stability. Consult local, State, or regional 

sources for information on frequency 

distributions of wind speed, direction, and 

atmospheric stability. 

This guidance provides tables for four 

different conditions (NOTE: Exhibits for 

Chapter 3 are at the end of the Chapter): 

a. The worst case conditions of rural 

topography, moderately stable 

atmospheric conditions (F stability) and 

low wind speed of 1.5 meters per 

second (3.4 mph) (Exhibit 3-1); 

b. Urban area, low wind speed of 1.5 

meters per second (3.4 mph), and 

moderately stable atmospheric 

conditions (F stability) predominate 

(Exhibit 3-2) ; 

c . Rural area, moderate wind speed of 5.2 

meters per second (about 12 mph), and 

less stable atmospheric conditions (D 

stability) (Exhibit 3-3); and 

d. Urban area, moderate wind speed of 5.2 

meters per second (about 12 mph), and 

less stable atmospheric conditions (D 

stability) (Exhibit 3-4). 

Step 5. Evaluate the effect of varying wind 

speed and atmospheric stability on the 

estimated vulnerable zone by using Exhibits 

3-3 and 3-4 (wind speed of 5.2 meters per 

second (12 mph) and D stability). For 

evaluation of other wind speeds and 

stabilities, refer to instructions in Appendix 

G. Decide to retain or change values for 

wind speed and stability and record final 

decision. If values for the assumptions used 

are not found in this guidance, consult 

experts including representatives of the 

facility. 

Step 6. Consider the value of the LOC used to 

estimate the vulnerable zone during the 

initial screening process. The one-tenth of 

the National Institute for Occupational Safety 

and Health (NIOSH) Immediately Dangerous 

to Life or Health (IDLH) value or its 

approximation represents a credible worst 

case exposure level. Other exposure 

guidelines may be obtained from Appendix 

3-9 
D, from the facility in question, or from 

appropriate experts. 

step 7. Evaluate the effect of changing the 

value of the LOC on the estimated zone and 

its impact on the risk analysis. After careful 

consideration of the impact on the risk 

analysis, retain or change the value of the 

LOC and record it. 

Step 8. Using all revised data and assumptions, 

estimate new vulnerable zones and decide 

whether to utilize the reevaluated zones in 

the risk analysis process. This may be an 

iterative process. 

3.2.3 Risk Analysis 

The risk analysis performed during the 

reevaluation process includes an assessment of 

the likelihood as well as the severity of an 

accidental release. This relative risk analysis is 

qualitative in nature, although LEPCs have the 

option to develop a relative ranking on a 

numerical basis. 

step 1. Based on information obtained from 

Chapter 2 and Appendices I and J of this 

guide, the facility representative, historical 

records, and appropriate experts, carefully 

evaluate the likelihood (probability) that an 

accidental release of a particular EHS will 

occur and not be contained or mitigated. 

Step 2. Assign a high, medium, or low ranking 

for the probability in Step 1 and record the 

decision as discussed in Section 2.3. 

Step 3. Using the reevaluated vulnerable zones, 

again evaluate populations at risk. This 

should include an estimated number of 

individuals, as well as types of populations 

such as elderly, children, infirm, and 

incarcerated. The evaluation should also 

consider transient populations (e.g., daily 

workers, audiences, and spectators), 

Step 4. Evaluate critical facilities at risk within 

the reevaluated zone. This should include 

hospitals or other health care facilities, fire 

and police stations, other emergency 

response facilities, and communications 

facilities. 

Step 5. Based on Steps 3 and 4, establish a 

relative ranking system, for the severity of 

consequences to humans associated with 

potential hazards posed by reporting 

facilities. This may be simply qualitative 

(high, medium, low) as discussed in Section 

2.3, or it may be a simple numerical 

system. 

Step 6. Using Steps 2 and 5, establish an 

overall relative risk for each facility, and 

record the relative rankings of facilities (see 

Section 2.3.1). This completes the hazards 

analysis as presented in this guidance 

document, This information can also be 

used for the development of site-specific 

release scenarios for training exercises and 

for refining response plans. 

3-10 








4. Using the Results of a Hazards Analysis

As noted in Chapter 1, hazards analysis is a necessary first step in developing a comprehensive 

emergency plan; it is a decision-making process that helps planners screen and decide which 

facilities to plan for. After local planners have 

completed a hazards identification, vulnerability 

analysis, and risk analysis, they should develop 

appropriate response procedures and organize 

all this material into an emergency response 

plan. This information can also be used for the 

development of site-specific release scenarios 

for training exercises and for refining response 

plans. This chapter summarizes the plan contents required by Title Ill of the Superfund 

Amendments and Reauthorization Act (SARA), 

lists the information provided by by a hazards 

analysis, briefly discusses three case studies for 

planning purposes, and describes how computers can be helpful to the planning process. 

Planners should use the National Response 

Team’s Hazardous Materials Energency Planning 

Guide (NRT-1) guidance document and the information generated by using this guidance to 

develop emergency plans for their district. 

4.1 What the Plan Must Contain

Title Ill of SARA requires each emergency plan to 

include at least each of the following: 

(1) Identification of facilities within the local 

emergency planning district (LEPD) subject 

to the Title Ill requirements: identification of 

routes likely to be used for the transportation of substances on the list of extremely 

hazardous substances (EHSs) ; and identification of additional facilities contributing 

or subjected to additional risk due to their 

proximity to facilities subject to Title Ill of 

SARA, such as hospitals or natural gas facilities. 

(2) Methods and procedures to be followed by 

facility owners and operators and local 

emergency and medical personnel to respond to any releases of EHSs. 

(3) Designation of a community emergency 

coordinator and facility emergency coordinators, who shall make determinations 

necessary to implement the plan. 

(4) Procedures providing reliable, effective, 

and timely notification by the emergency 

coordinators and the community emergency coordinator to persons designated 

in the emergency plan, and to the public, 

that a release has occurred. 

(5) Methods for determining the occurrence of 

a release, and the area or population likely 

to be affected by such release. 

(6) A description of facilities in the community 

subject to Title Ill requirements and emergency equipment at each facility in the 

community. 

(7) Evacuation plans, including provisions for a 

precautionary evacuation and alternative 

traffic routes. 

(8) Training programs, including schedules for 

training of local emergency response and 

medical personnel. 

(9) Methods and schedules for exercising the 

emergency plan. 

The information gathered in the hazards analysis 

will be useful in fulfilling several of these requirements, in particular (l), (4), (5) and (6). 

NRT-1 (page 38, Planning Element G) discusses 

the integration of the hazards analysis into emergency planning, and should be used as a complement to this guide. NRT-1 discusses approaches to the planning process, whether a 

community chooses to develop a multi-hazard 

12/87 4-l 
emergency operations plan (EOP) or incorporate hazardous materials plan. Sample formats for 

hazardous materials planning into an existing emergency plans are outlined and planning eleEOP, or to develop or revise a single-hazard ments are discussed in detail. 

4.2 Planning Information Provided by the Hazards Analysis

As a result of the hazards analysis, the following 

types of information concerning EHSs should be 

available during the initial stages of the planning 

process : 

� Location 

(1) What facilities have EHSs 

(2) What transportation routes have EHSs 

(1) The maximum quantity likely to be released at a facility 

(2) The maximum quantity likely to be transported at one time per transportation vehicle 

� Potential risks 

(1) Likelihood of release 

(2) Consequences of release 

� Other hazards to consider 

(1) Whether the material is flammable 

(2) Whether water can be used on it 

(3) Reactivity with other materials present to 

form other hazardous substances and/or 

to release heat 

(4) Likelihood of damage to property 

(5) Likelihood of damage to the environment 

� Emergency response information 

(1) Size of the vulnerable zone in case of a 

release 

(2) How many people are likely to be within 

the vulnerable zones 

(3) Sensitive populations within the vulnerable 

zones 

(4) Essential service facilities within the vulnerable zones 

(5) What emergency medical procedures 

should be followed 

(6) What specialized equipment emergency 

medical response personnel or local hospitals need to treat victims of exposure 

and whether they have such equipment 

(7) Type of protective gear (clothing and 

equipment) needed by emergency response personnel 

- Is it available at the facility? 

- Is it available to emergency responders? 

(8) What sampling and monitoring devices 

can be used to determine concentration 

levels 

- Are such devices available? 

(9) Containment/cleanup procedures 

(10) What materials are needed for containment, neutralization, and cleanup 

- Are these materials available? 

12/87 4-2 
4.3 Case Studies from Hazards Analysis 

To illustrate the planning process, and the use of 

hazards analysis in this process, the same hypothetical releases of chlorine, ammonia, and 

methyl isocyanate as described in Chapter 2 

(Exhibit 2-12) and Chapter 3 are used as examples. Exhibit 4-1 presents relevant data on the 

three example chemicals and considerations 

that the planning committee needs to address. 

This information can be used in the planning 

process to ensure that all needs can be accommodated should an emergency arise. 

In each of the case studies, a release of a hazardous substance is possible and both the responsible party and local government must be 

prepared to handle the resulting hazards and associated problems. In order to respond in an 

effective and safe manner, local emergency responders (and private sector managers in the 

cases of fixed facilities such as the water treatment plant and the pesticide manufacturing 

plant portrayed in these case studies) must work 

together to create a comprehensive hazardous 

materials emergency plan. In order to be effective, the plan must be tested and updated at 

least annually and more often as needed if conditions change after establishment of the plan. 

In each of the case studies, planners must first 

consider the safety of people within the estimated vulnerable zones. Not only must planners address evacuation but also in-place sheltering, as vapor clouds may move into populated areas too quickly to allow for a safe evacuation. Adequate warning systems must be in 

place to notify the public of a release. Persons 

who will require protection from hazardous releases include: a) people located in ‘the immediate area of the release (plant employees in the 

case studies involving chlorine and methyl 

isocyanate, and motorists in the case of an anhydrous ammonia tank truck accident), b) people in areas threatened by hazards resulting 

from the released materials, and c) emergency 

responders. (Appendix H presents a detailed 

discussion on evacuation and in-place sheltering, including decision-making, planning, conducting an evacuation, sheltering of evacuees, 

and re-entry.) 

A second planning consideration is hazard control and containment operations. Procedures for 

controlling and containing a hazardous release 

must be established and identified within the 

plan and exercised regularly. In each of the 

case studies, the hazardous material has multiple hazards associated with it. (Chlorine is poisonous, corrosive, and can act as an oxidizer; 

anhydrous ammonia is corrosive and can be fatal if inhaled: and methyl isocyanate is poisonous and extremely flammable.) Multiple hazards 

require special expertise in control and containment procedures. Regarding incidents where local government and private industry are both involved in remedial actions (such as the cases of 

the water treatment plant and the pesticide 

plant), planners must set forth provisions for cooperation between the two groups to ensure that 

response actions are coordinated and that direction and control are centralized. 

Another key planning consideration is that of 

emergency medical care. Provisions must be 

made for on-scene emergency medical care 

(establishment of a triage area may be necessary) t transport of victims to hospitals, and 

emergency room treatment. In order for this 

emergency care system to function properly, 

the hazardous materials plan should establish 

procedures coordinating the activities of the local emergency medical services (e.g., fire/rescue department, rescue squad, ambulance 

service) and local hospital(s) to ensure that victims are treated quickly and effectively. 

Specialized medical supplies to treat exposures 

to certain chemicals should be identified during 

the planning process so that adequate and current supplies will be available. 

Planners must address several other areas of 

community response as well. These include incident command; communications: search and 

rescue: detection, monitoring, sampling and 

analysis: damage assessment: cleanup: decontamination: and cost recovery. The hazardous 

12/87 4-3 



materials plan must address each of these areas 

of community response by delegating specific 

responsibilities to appropriate agencies of the local government. The plan also should include 

assistance available from regional, State, and 

Federal agencies as well as private industry and 

volunteer organizations. 

In addition to addressing emergency procedures, the hazardous materials plan must also 

address what equipment is needed to contain 

and control hazardous materials spills and fires. 

The plan must identify the equipment, its location, how to get it to the incident scene, and how 

to use it safely and effectively. The most important specialized equipment that will be needed is 

protective gear for the emergency responders. 

This includes fully encapsulated chemical protective suits, thermal protection, and positive 

pressure self-contained breathing apparatus. In 

terms of equipment needed to stop a leak, specialized plugging and/or patching devices are 

likely to be needed, unless the opening in the 

Title Ill requires each planning committee “to 

evaluate the resources necessary to develop, 

implement and exercise the emergency plan” 

and to “make recommendations with respect to 

additional resources that may be required and 

the means for providing such additional resources.” 

The NRT believes that it would be very useful to 

have these resource evaluations and recommendations available for the Regional Response 

Teams (RRTs) at the time of the plan reviews. 

Many of the suggested plan changes may be 

rather modest and are not likely to require the 

expenditure of significant local emergency planning committee (LEPC) resources. Other 

changes may be more difficult to accomplish 

and may require substantially more resources 

than are available to the LEPC. RRT comments 

may be more useful if the RRTs can formulate 

them in a way that takes into consideration the 

LEPC’s resource base. RRTs may wish to identify those suggestions for improvement that 

could be made with available resources and 

those that might require additional resources. 

4.4 Plan Reviews in the Context of Local Resource Needs 

damaged tank is too large to seal off. In order 

to keep track of hazardous material concentration levels, specialized monitoring devices will 

be needed. Monitoring is extremely important in 

the case of methyl isocyanate due to its vapors 

being odorless (but still highly dangerous) in low 

concentrations. Specialized cleanup and neutralizing materials (e.g., soda ash, caustic soda, 

activated carbon, diatomaceous earth) likely will 

be needed as well. Containment equipment 

also must be available at the accident scene. 

Materials (e.g., soil, sand) and heavy equipment (e.g., bulldozers, back hoes, dump 

trucks) likely will be used to construct dikes to 

contain spilled material or contaminated runoff 

from vapor knockdown and fire suppression operations. The heavy equipment also will be 

needed following the incident to remove contaminated soils and pavement. Lack of information concerning these specialized resources 

could make response efforts for a hazardous 

materials release unnecessarily difficult. 

LEPCs may include their resource requirements 

in a separate section of their plans, provide information in a separate report or present requirements in a formal request for additional resources submitted to the cognizant State emergency response commission (SERC) . Regardless of the method used, RRTs would be interested in information on: 

the personnel resources required by the 

LEPC in the preparation of the plan, including man-months of effort, and technical 

expertise provided and the additional resources that the LEPC would like to have 

available to revise and strengthen this 

plan: 

the financial resources required to develop 

the plan and the financial resources that 

the LEPC would like to have available in the 

future: 

the personnel and financial resources that 

would be required to exercise the plan, as 

proposed by the LEPC in the section on exercises: and 

12/87 4-7 
the means by which the LEPC generated lieves that the necessary additional rethe resources necessary to develop the sources could be secured. 

plan and the means by which the LEPC be4.5 Use of Computerized Systems in Planning

Computerized systems have many applications 

that would be useful to the LEPC as it incorporates hazards analysis information into a comprehensive emergency plan. They could be 

used for: 

• Listing the facilities and the major transportation routes that handle or carry hazardous substances through the planning district and for storing and reporting chemical 

and hazards analysis information. This 

could facilitate data management associated with hazards identification. 

• Modelling the release of chemicals and estimating vulnerable zones (vulnerability 

analysis). The system’s capabilities could 

be restricted to the simplified methods outlined in Chapters 2 and 3 or could include a 

more sophisticated analysis. A further 

level of sophistication which considers meteorological, topographical, and other sitespecific release scenario variables could 

also be developed according to the level of 

detail the local planning committee considers appropriate. 

� Identifying the regulatory requirements of 

Title Ill as they relate to chemical emergency preparedness. 

In addition, computerized systems could be 

used to provide emergency management and 

response information. Appendix K provides an 

evaluation guide in the form of a checklist for 

hazardous chemical inventory, planning, and response computerized systems. This checklist 

was developed to assist local emergency planning groups in evaluating and selecting computer systems and software that will have capabilities relevant to their environmental management and planning needs. 

12/87 4-8 
AAR/BOE 

ACGIH 

AlChE 

AIHA 

ATSDR 

BLEVE 

CAER 

CAS 

CEPP 

CERCLA 

CHLOREP 

CHRIS 

CMA 

DOD 

DOT 

EEC 

EEG 

EEGL 

EHS 

EOP 

EPA 

ERPG 

FDA 

FEMA 

FIFRA 

FMEA 

FMECA 

FTA 

HAZOP 

APPENDIX A 

ACRONYMS AND GLOSSARY OF TERMS 

ACRONYMS 

Association of American Railroads/Bureau of Explosives 

American Conference of Governmental Industrial Hygienists 

American Institute of Chemical Engineers 

American Industrial Hygiene Association 

Agency for Toxic Substances and Disease Registry 

Boiling Liquid Expanding Vapor Explosion 

Community Awareness and Emergency Response (a CMA program) 

Chemical Abstract Service 

Chemical Emergency Preparedness Program (EPA) 

Comprehensive Environmental Response, Compensation, and Liability Act of 

1980 (“Superfund”)

Chlorine Emergency Plan (developed by the Chlorine Institute)

Chemical Hazard Response Information System

Chemical Manufacturers Association

Department of Defense

Department of Transportation

European Economic Community

Emergency Exposure Guideline (developed by Dow Chemical)

Emergency Exposure Guidance Level (developed by the NRC)

Extremely Hazardous Substance

Emergency Operation Plan

Environmental Protection Agency

Emergency Response Planning Guideline

Food and Drug Administration

Federal Emergency Management Agency

Federal Insecticide, Fungicide, and Rodenticide Act

Failure Modes and Effects Analysis

Failure Modes, Effects, and Criticality Analysis

Fault Tree Analysis

Hazard and Operability Study

A-l 
HMTA Hazardous Materials Transportation Act 

IDLH Immediately Dangerous to Life or Health 

LC50 Median Lethal Concentration 

LCLO Lethal Concentration Low 

LD50 Median Lethal Dose 

LDLO Lethal Dose Low 

LEPC Local Emergency Planning Committee 

LEPD Local Emergency Planning District 

LFA Liquid Factor Ambient 

LFB Liquid Factor Boiling 

LFM Liquid Factor Molten 

LOC Level of Concern 

MSDS Material Safety Data Sheet 

NAS National Academy of Sciences 

NCP National Oil and Hazardous Substances Contingency Plan 

NFPA National Fire Protection Association 

NRC National Response Center or National Research Council 

NRT National Response Team 

NRT-1 Hazardous Materials Emergency Planning Guide, prepared by the National 

Response Team 

NIOSH National Institute for Occupational Safety and Health 

OPP Office of Pesticide Programs (EPA) 

OSC On-Scene Coordinator 

OSHA Occupational Safety and Health Administration 

OSWER Office of Solid Waste and Emergency Response (EPA) 

PEL Permissible Exposure Limit 

PMN Premanufacture Notice 

PRA Probabilistic Risk Assessment 

QR Rate of Release of EHS to Air 

QS Maximum Quantity of Chemical that Could Be Released 

RCRA Resource Conservation and Recovery Act 

REL Recommended Exposure Limits 

RQ Reportable Quantity 

RSPA Research and Special Programs Administration (DOT) 

A-2 
RRT Regional Response Team 

RTECS Registry of Toxic Effects of Chemical Substances 

SARA Superfund Amendments and Reauthorization Act of 1986 

SERC State Emergency Response Commission 

SPCC Spill Prevention Control and Countermeasures (Plan) 

SPEGL Short-term Public Exposure Guidance Level (developed by the NRC) 

Title III Emergency Planning and Community Right-to-Know Act of 1986 (Part of the 

Superfund Amendments and Reauthorization Act of 1986) 

TLVs* Threshold Limit Value 

TWA Time Weighted Average 

TPQ Threshold Planning Quantity 

TSCA Toxic Substances Control Act 

USCG United States Coast Guard 

USGS United States Geological Survey 

VP Vapor Pressure 

VSD Virtually Safe Dose 

Vz Vulnerable Zone 

WB World Bank 

*TLVs is a registered trademark 

A-3
GLOSSARY OF TERMS 

Accident Site 

The location of an unexpected occurrence, failure, or loss, either at a facility or along a 

transportation route, resulting in a release of hazardous materials: an incident site. 

Acute 

Severe but of short duration. Acute health effects are those that occur immediately after 

exposure to hazardous chemicals. 

Acutely Toxic Chemicals 

Chemicals that can cause severe short- and long-term health effects after a single, brief 

exposure (short duration). These chemicals (when ingested, inhaled, or absorbed through the 

skin) can cause damage to living tissue, impairment of the central nervous system, severe 

illness, or, in extreme cases, death. 

Airborne Release 

Release of any chemical into the air. 

Ambient 

Surrounding. Ambient temperatures are temperatures of the surrounding area (e.g., air or 

water). 

By-Product 

Material, other than the principal product, that is produced or generated as a consequence of 

an industrial process. 

Chemical Process 

A particular method of manufacturing or making a chemical, usually involving a number of 

steps or operations. 

Chronic 

Of long duration or having frequent recurrence. Chronic health effects are those that become 

apparent or continue for some time after exposure to hazardous chemicals. 

Combustion Product 

Material produced or generated during the burning or oxidation of a material, 

Command Post 

Facility located at a safe distance upwind from an accident site, where the on-scene 

coordinator, responders, and technical representatives can make response decisions, deploy 

manpower and equipment, maintain liaison with media, and handle communications. 

Community Awareness and Emergency Response (CAER) Program 

Program developed by the Chemical Manufacturers Association (CMA), to assist chemical 

plant managers in taking the initiative in cooperating with local communities to develop 

integrated (community/industry) plans for responding to releases of hazardous materials. 

Contingency Plan 

A document to identify and catalog the elements required to respond to an emergency, to 

define responsibilities and specific tasks, and to serve as a response guide. 

Critical Facilities 

Facilities essential to emergency response, such as fire stations, police stations, hospitals, 

and communication centers. 

Decomposition Product 

Material produced or generated as a result of the physical or chemical degradation of a parent 

material. 

A-4 
Dike 

A barrier such as a low wall or embankment designed to prevent a spill from spreading or 

flooding. 

Disposal 

The removal of waste material to a site or facility that is specifically designed and permitted to 

receive such wastes. 

Emergency 

A situation created by an accidental release or spill of hazardous chemicals which poses a 

threat to the safety of workers, residents, the environment, or property. 

Evacuation 

Removal of residents and other persons from an area of danger. 

Exercise 

A simulated accident or release set up to test emergency response methods and for use as a 

training tool. 

Extremely Hazardous Substances (EHSs) 

A list of chemicals identified by EPA on the basis of toxicity, and listed under Title Ill of SARA. 

These chemicals are listed in Appendix C. The list is subject to revision. 

Facility 

Defined for Section 302 of Title Ill of SARA as all buildings, equipment, structures, and other 

stationary items which are located on a single site or on contiguous or adjacent sites and 

which are owned or operated by the same person (or by any person which controls, is 

controlled by, or under common control with, such person). For purposes of emergency 

release notification, the term includes motor vehicles, rolling stock, and aircraft. 

Facility Emergency Coordinator 

Facility representative for each facility with an extremely hazardous substance (EHS) in a 

quantity exceeding its threshold planning quantity (TPQ), who participates in the emergency 

planning process. 

Fenceline 

Outermost perimeter of a facility property. 

Hazard 

Any situation that has the potential for causing damage to life, property, and/or the 

environment. 

Hazardous Chemical 

Any chemical which is a physical hazard or a health hazard as defined under OSHA 29 CFR 

1910.1201. 

Hazardous Material 

Any substance or material in a quantity or form which may be harmful to humans, animals, 

crops, water systems, or other elements of the environment if accidentally released. 

Hazardous materials include: explosives, gases (compressed, liquefied, or dissolved), 

flammable and combustible liquids, flammable solids or substances, oxidizing substances, 

poisonous and infectious substances, radioactive materials, and corrosives. 

Hazardous Substances (Superfund) 

Substances designated as hazardous under CERCLA (also known as Superfund); CERCLA 

incorporates substances listed under the Clean Water Act, the Clean Air Act, RCRA, and TSCA 

Section 7. 

A-5 
Hazards Analysis 

The procedure for identifying potential sources of a hazardous materials release, determining 

the vulnerability of an area to a hazardous materials release, and comparing hazards to 

determine risks to a community. 

Hazards Identification 

Provides information on which facilities have extremely hazardous substances (EHSs), what 

those chemicals are, and how much there is at each facility. Also provides information on how 

the chemicals are stored and whether they are used at high temperatures, Mandatory facility 

reporting under Title Ill will provide most of the information needed for a hazards identification, 

Immediately Dangerous to Life and Health (IDLH) 

The maximum level to which a healthy worker can be exposed for 30 minutes and escape 

without suffering irreversible health effects or escape-impairing symptoms, 

Lethal 

Causing or capable of causing death. 

Lethal Concentration Low (LCLO) 

The lowest concentration of a chemical at which some test animals died following inhalation 

exposure. 

Lethal Dose Low (LDLO) 

The lowest dose of chemical at which some test animals died following exposure. 

Level of Concern (LOC) 

The concentration of an extremely hazardous substance (EHS) in the air above which there 

may be serious irreversible health effects or death as a result of a single exposure for a 

relatively short period of time. 

Local Emergency Planning Committee (LEPC) 

A committee appointed by the State emergency response commission (SERC), as required by 

Title Ill of SARA, to formulate a comprehensive emergency plan for its district. 

Material Safety Data Sheet (MSDS) 

A compilation of information required under the OSHA Hazard Communication Standard on the 

identity of hazardous chemicals, health and physical hazards, exposure limits, and 

precautions. Section 311 of Title Ill of SARA requires facilities to submit MSDSs under certain 

conditions. 

Median Lethal Concentration (LC50) 

Concentration level at which 50 percent of the test animals died when exposed by inhalation I for a specified time period. 

Median Lethal Dose (LDSO) 

Dose at which 50 percent of test animals died following exposure. Dose is usually given in 

milligrams per kilogram of body weight of the test animal. 

Morbidity 

Ability to cause illness or disease. 

National Response Center 

A communications center for activities related to response actions: it is located at Coast 

Gaurd headquarters in Washington, DC. The National Response Center receives and relays 

notices of discharges or releases to the appropriate On-Scene Coordinator, disseminates 

On-Scene Coordinator and Regional Response Team (RRT) reports to the National Response 

Team (NRT) when appropriate, and provides facilities for the NRT to use in coordinating a 

national response action when required. The toll-free number (800-424-8802, or 

202-426-2675 or 202-267-2675 in the Washington, DC area) can be reached 24 hours a day 

for reporting actual or potential pollution incidents. 

A-6 
On-Scene Coordinator 

The pre-designated local, State, or Federal official responsible for the coordination of a 

hazardous materials response action, as outlined in the pertinent Emergency Response Plan. 

Plume 

Effluent cloud resulting from a continuous source release. 

Radius of the Vulnerable Zone 

The maximum distance from the point of release of a hazardous substance at which the 

airborne concentration could reach the level of concern (LOC) under specified weather 

conditions. 

Reportable Quantity (RQ) 

The quantity of a hazardous substance that triggers reporting under CERCLA; if a substance is 

released in a quantity that exceeds its RQ, the release must be reported to the National 

Response Center (NRC), as well as to the State emergency response commission (SERC) and 

the community emergency coordinator for areas likely to be affected by the release. 

Response 

The efforts to minimize the risks created in an emergency by protecting the people, the 

environment, and property, and the efforts to return the scene to normal pre-emergency 

conditions. 

Risk 

A measure of the probability that damage to life, property, and/or the environment will occur if 

a hazard manifests itself: this measure includes the severity of anticipated consequences to 

people. 

Risk Analysis 

Assessment of the probable damage that may be caused to the community by a hazardous 

substance release. 

Special Populations 

Groups of people that may be more susceptible than the general population (due to 

preexisting health conditions (e.g., asthmatics) or age (e.g., infants and the elderly)) to the 

toxic effects of an accidental release. 

Spill Prevention Control and Countermeasures (SPCC) Plan 

Plan covering the release of hazardous substances as defined under authority of the Clean 

Water Act. 

Stability Classes, Atmospheric 

Pasquill stability classes (ranging from “A” to “F”) are meteorological categories of 

atmospheric conditions. Pasquill stability class A represents unstable conditions under which 

there are strong sunlight, clear skies, and high levels of turbulence in the atmosphere, 

conditions that promote rapid mixing and dispersal of airborne contaminants. At the other 

extreme, class F represents light, steady winds, fairly clear nighttime skies, and low levels of 

turbulence. Airborne contaminants mix and disperse far more slowly with air under these 

conditions, and may travel further downwind at hazardous concentrations than in other cases. 

Stability class D, midway between A and F, is used for neutral conditions, applicable to heavy 

overcast, daytime or nighttime. 

State Emergency Response Commission (SERC) 

Commission appointed by each State governor according to the requirements of Title Ill of 

SARA: duties of the commission include designating emergency planning districts, appointing 

local emergency planning committees (LEPCs), supervising and coordinating the activities of 

planning committees, reviewing emergency plans, receiving chemical release notifications, and 

establishing procedures for receiving and processing requests from the public for information. 

A-7 
Storage 

Methods of keeping raw materials, finished goods, or products while awaiting use, shipment, 

or consumption. 

Threshold Planning Quantity (TPQ) 

A quantity designated for each chemical on the list of extremely hazardous substances (EHSs) 

that triggers notification by facilities of the State emergency response commission (SERC) that 

such facilities are subject to emergency planning under Title Ill of SARA. 

Toxic Chemical Release Form 

Information form required to be submitted by facilities that manufacture, process, or use (in 

quantities above a specified amount) chemicals listed in Section 313 of Title Ill of SARA. 

Toxic Cloud 

Airborne mass of gases, vapors, fumes, or aerosols of toxic materials. 

Toxicity 

The ability of a substance to cause damage to living tissue, impairment of the central nervous 

system, severe illness, or death when ingested, inhaled, or absorbed by the skin. 

Toxicology 

The study of the adverse effects of chemical agents on biological systems. 

Transfer 

Loading and unloading of chemicals between transport vehicles and storage vessels, and 

sending chemicals via pipes between storage vessels and process reactors. 

Transport Mode 

Method of transportation: highway: rail (trains); water (ships/barges); pipelines: air (planes). 

Vapor Dispersion 

The movement of vapor clouds or plumes in air due to wind, gravity spreading, and mixing. 

Vulnerability Analysis 

Assessment of elements in the community that are subject to damage should a hazardous 

materials release occur; includes gathering information on the extent of the vulnerable zone, 

conditions that influence the zone, size and type of the population within the zone, private and 

public property that might be damaged, and the environment that might be affected. 

Vulnerable Zone 

An area over which the airborne concentration of a chemical involved in an accidental release 

could reach the level of concern (LOC). 

A-8 
APPENDIX B 

THE CRITERIA USED TO IDENTIFY

EXTREMELY HAZARDOUS SUBSTANCES

B.1 BASIS FOR THE CRITERIA 

Introduction. In an effort to direct community 

planning efforts to those chemicals that, because of their inherent toxicity, are most likely to 

cause severe toxic effects in humans who are 

exposed to them due to an accidental release, 

EPA has specified toxicity criteria that can be 

used to screen chemical information sources 

and to identify acutely toxic chemicals. These 

criteria were used to identify the chemicals on 

the list of extremely hazardous substances 

(EHSs) required by Title Ill. While the criteria 

focus on animal lethality data, EPA is also concerned about a wide array of human toxic or 

clinical effects other than death (e.g., lung 

edema, liver or kidney damage, reproductive 

and developmental toxicity, neurological disorders, cardiac effects, dermal irritation and corrosion, and ocular damage). Such effects may 

be considered if suitable data are available when 

the list of EHSs is revised. 

Use of Animal Data. In defining criteria, EPA 

had to identify the health effects of concern and 

the data to be used. EPA elected to use animal 

acute toxicity data derived from controlled experiments to infer potential for acute toxic effects in humans. EPA has assumed that humans and animals (mammals) are similar, on 

the average, in intrinsic susceptibility to toxic 

chemicals and that animal data can be used as 

surrogates for human data. This assumption is 

one of the basic premises of modern toxicology 

and is an important component in the regulation 

of toxic chemicals. An additional benefit of using animal data is that there exists a large data 

base that is accessible to the public and government agencies such as EPA. Because human 

populations are diverse (e.g., individuals differ 

in age, health, and genetic background) and individuals are expected to vary considerably in 

their sensitivity to chemical substances, EPA assumed that humans are at least as sensitive to 

each toxic chemical as the most sensitive animal 

species tested. 

Type of Toxicity Data Used. Complete toxicological information on all potential concerns 

about the consequences of an acute chemical 

exposure is not available on all chemicals. EPA 

initially focused on lethality, not only because 

EPA wishes to avoid accidents resulting in human death, but also because lethality data are 

the most available and commonly reported information provided from animal toxicity testing. 

EPA determined that the most appropriate animal test data to use as surrogates for human 

acute toxicity are those data from animal acute 

toxicity tests expressed as the median lethal 

concentration (LC50) when the substance has 

been administered by inhalation (via the lungs), 

or the median lethal dose (LD50) when the substance has been administered orally (via the 

mouth) or dermally (via the skin). These data 

represent dose levels or concentrations of a 

chemical that are expected to result in the death 

of 50 percent of the test animals. Exposure to 

EHSs released during an accident is expected 

primarily to involve chemicals that are airborne. 

Thus, the inhalation route of human exposure is 

of primary concern during or following an accident. However, it should be borne in mind that 

humans could be exposed to an EHS by any or 

all of these routes after its accidental release. In 

using data on oral and dermal acute lethality, 

EPA was not specifically concerned with these 

routes of exposure in humans, but rather with 

identifying compounds with inherent high potential for acute toxicity. 

Use of LDLO and LCLO Data. Even with the 

amount of animal data that is available, there exist chemicals for which there are no standard 

acute toxicity test data. In those cases where 

toxicity testing has not determined an LD50 or 

LC50 value, EPA selected an alternative measure of acute toxicity: the lowest dose or concentration at which some animals died following exposure (LDLO or LCLO). EPA used LDLO or 

LCLO values in those instances where there are 

no median toxicity values available for a chemical. Data from these tests may be more Variable than those provided from median lethality 

tests, but for the purposes of screening large 
numbers of chemicals it was deemed necessary 

to provide a second level screening tool in preference to missing potentially toxic chemicals not 

adequately tested. However, it is expected that 

there are chemicals that may be acutely toxic, 

but for which there are no toxicity test data available in the public literature. It is expected that 

planners may obtain data that are not available 

in the open literature from firms manufacturing 

chemicals. By knowing whether chemical firms 

and other facilities have any chemicals that are 

on the list of EHSs or that meet the criteria, planners should be able to identify all potentially 

acute toxicants used in their community, 

B.2 THE CRITERIA 

Criteria Values Adopted. EPA adopted the criteria shown in Exhibit B-l to identify EHSs that 

may present severe health hazards to humans 

exposed to them during an accident or other 

emergency. The specific values chosen are 

consistent with toxicity values judged by the scientific community as indicative of potential for 

acute toxicity. The values shown in Exhibit B-l 

are lower than those for highly toxic chemicals in 

the health hazard definitions mandated by OSHA 

in its Hazard Communication Standard (FR Vol. 

48, No. 248, p. 53346). 

A chemical was identified as an EHS if animal 

test data with a value less than or equal to that 

stated for the LD50 or LC50 criteria for any one 

of three exposure routes were found. A chemical without LD50 or LC50 test data was evaluated using the alternate LDLO or LCLO criteria. 

EPA has prepared a list of chemicals that meet 

these criteria: these chemicals are included on 

the list of EHSs under Title Ill of SARA. 

EPA Criteria Compared with European Economic Community/World Bank Criteria. The 

screening criteria selected by EPA were consistent with internationally accepted criteria used 

by both the European Economic Community 

(EEC) and the World Bank (WB). EPA’s criteria 

recognized precedents set by these two organizations; however, in a conservative effort to 

avoid missing or excluding any potentially toxic 

chemicals, EPA modified the basic toxic substances criteria used by these organizations in 

three ways: 

1. Lethality data are not limited to data on 

rats, but include data on the most sensitive mammalian species tested: 

2. Data from tests with inhalation exposure 

time up to 8 hours is accepted instead of 

data from 4-hour exposure tests only: 

and 

3. LDLO and LCLO data are used when 

LD50 or LC50 data are not available. 

The criteria were designed to take maximum advantage of the kinds of animal data available for 

screening and to limit the potential for overlooking chemicals that may be potentially acutely 

toxic. The criteria should maximize the potential 

for planners to identify toxic chemicals. 

8.3 APPLICATION OF THE CRITERIA 

RTECS Data Base. The screening criteria can 

be applied to any experimental data or data 

base on chemical substances that includes 

acute animal toxicity data. EPA applied the criteria to a specific toxicity data repository, Registry of Toxic Effects of Chemical Substances 

(RTECS), maintained by the National Institute for 

Occupational Safety and Health (NIOSH). The 

RTECS data base was used as the source of toxicity data for identifying acutely toxic chemicals 

because it has the largest computerized set of 

acute toxicity information available, with information on more than 79,000 chemicals. RTECS is 

designed to be a single-source document for 

basic toxicity information and other data. It is 

widely accepted and used as a toxicity data 

source, as indicated by the fact that some organizations (e.g., health agencies and chemical 

companies) include RTECS numbers as a toxicity reference on the lists of chemicals in their 

files. While RTECS is not formally peer reviewed, the data presented are from scientific 

literature that has been edited by the scientific 

community before publication. In addition, the 

RTECS Editorial Review Board is responsible for 

reviewing a limited number of citations to remove ambiguities or errors. Them are limitations associated with the use of the RTECS data 

base, but for the purposes of screening acute 

12/87 B-2 
Exhibit B-I 

Criteria to Identify Extremely Hazardous Substances that

May Present Severe Health Hazards to Humans

Exposed During a Chemical Accident or Other Emergency

Route of 

a Exposure Acute Toxicity Measure b Value 

Inhalation Median Lethal Concentration Less than or equal to 0.5 milli­ in Air (LC50) grams per liter of air for

exposure time of 8 hours or less 

Dermal Median Lethal Dose (LD50) Less than or equal to 50

milligrams per kilogram of

body weight 

Oral Median Lethal Dose (LD50) Less than or equal to 25

milligrams per kilogram of

body weight 

a

The route by which the test animals absorbed the chemical, i.e., by 

breathing it in air (inhalation), by absorbing it through the skin 

(dermal), or by ingestion (oral). 

b

 LC50: The concentration of the chemical in air at which 50 percent of 

the test animals died. LD50: The dose that killed 50 percent of the test 

animals. In the absence of LC50 or LD50 data, LCLO or LDLO data should 

be used. LCLO: Lethal Concentration Low, the lowest concentration in air 

at which any test animals died. LDLO: Lethal Dose Low, the lowest dose 

at which any test animals died. 

12/87 B-3 
toxicity data, RTECS provides a large and easily 

searchable data file. It is important to emphasize that the purpose of the criteria was to provide a screening tool for the initial identification 

of chemicals that may be acutely toxic to humans. Additional information on the toxicity of 

specific chemicals may be available from the facility emergency coordinator. 

TSCA Inventory, Active Pesticide Ingredients, 

and PMN Chemicals. EPA selected only those 

chemical substances in current production by 

referring to the 1977 Toxic Substances Control 

Act (TSCA) Inventory and the current EPA list of 

active pesticide ingredients. The TSCA Inventory is a list of chemical substances in production at the time the Inventory was compiled. 

Chemical substances entering commerce since 

1977 through the Premanufacturing Notice 

(PMN) review process under Section 5 of TSCA 

were screened for acute toxicity data and compared to the criteria for possible inclusion on the 

list. 

Radioactive materials, chemical substances in 

research and development stages, and those 

manufactured, processed, or distributed in commerce for use as food, food additives, drugs, or 

cosmetics are not listed in the TSCA Inventory 

and, hence, were not considered. If research 

chemicals that meet the criteria are produced 

for commercial use under TSCA or for pesticide 

use under the Federal Insecticide, Fungicide, 

and Rodenticide Act (FIFRA), EPA will identify 

such chemicals through its PMN review program 

and pesticide registration program and list them 

under future rulemakings. 

8.4 OTHER EXTREMELY HAZARDOUS SUBSTANCES 

Chemicals that do not meet the criteria for acute 

toxicity discussed in the previous section are not 

necessarily safe. In fact, some are toxic to humans and may pose threats to the community if 

accidents occur. EPA identified and included on 

the list of EHSs some of these chemicals using 

criteria based on the following factors: large volume production, acute lethality values, and 

known risk, as indicated by the fact that some of 

the chemicals have caused death and injury in 

accidents. 

Candidates for listing were identified from the 

high-production capacity chemicals listed in the 

SRI International publication, 1985 Directory of 

Chemical Producers, United States of America, 

pp. 388-389, or from the World Bank List Group 

B: Other Toxic Substances. The toxicity criteria 

shown in Exhibit B-2 were used to aid in deciding 

which chemicals to list. In addition to high-production chemicals meeting these criteria, several other slightly less toxic chemicals were 

listed because of their known hazards: for example, several of them have caused death or injury 

in accidents. Exhibit B-3 lists these other 

chemicals included on the list of EHSs. 

12/87 B-4 
Exhibit B-2 

Criteria to Identify Other Hazardous Substances Produced in Large

Quantities that May Present Severe Health Hazards to Humans

Exposed During a Chemical Accident or Other Emergency

Route of 

Exposure a Acute Toxicity Measure b Value 

Inhalation Median Lethal Concentration Less than or equal to 2 milli­ in Air (LC50) grams per liter of air for

exposure time of 8 hours or less 

Dermal Median Lethal Dose (LD50) Less than or equal to 400

milligrams per kilogram of

body weight 

Oral Median Lethal Dose (LD50) Less than or equal to 200

milligrams per kilogram of

body weight 

a

The route by which the test animals absorbed the chemical, i.e., by 

breathing it in air (inhalation), by absorbing it through the skin 

(dermal), or by ingestion (oral). 

b

 LC50: The concentration of the chemical in air at which 50 percent of 

the test animals died. LD50: The dose that killed 50 percent of the test 

animals. In the absence of LEO or LD50 data, LCLO or LDLO data should 

be used. LCLO: Lethal Concentration Low, the lowest concentration in air 

at which any test animals died. LDLO: Lethal Dose Low, the lowest dose 

at which any test animals died. 

12/81 B-5 
Exhibit B-3 

Other Extremely Hazardous Substances 

Chemicals on the following list were judged to be extremely hazardous substances (EHSs) on the 

basis of high production capacity and the criteria summarized in Exhibit B-2 or known 

hazards (see Section 8.4). 

Name CAS Number 

Acrylamide 79-06-1 

Acrylonitrile 107-13-1 

Adiponitrile 111-69-3 

Ammonia 7664-41-7 

Aniline 62-53-3 

Bromine 7726-95-6 

Carbon disulfide 75-15-0 

Chloroform 67-66-3 

Cyclohexylamine 108-91-8 

Epichlorohydrin 106-89-8 

Ethylene oxide 75-21-8 

Formaldehyde 50-00-0 

Hydrogen chloride (gas only) 7647-01-0 

* Hydrogen peroxide 7722-84-1 

Hydrogen sulfide 7783-06-4 

Hydroquinone 123-31-9 

Methyl bromide 74-83-9 

Nitrobenzene 98-95-3 

Phosgene 75-44-5 

Propylene oxide 75-56-9 

Sulfur dioxide 7446-09-5 

Tetramethyl lead 75-74-1 

Vinyl acetate monomer 108-05-4 

* Concentration greater than 52 percent. 

12/87 B-6 
APPENDIX C 

THE LIST OF EXTREMELY HAZARDOUS SUBSTANCES 

EPA identified chemicals that meet the criteria ent physical state, molecular weight, boilfor extremely hazardous substances (EHSs) dis- ing point, vapor pressure, level of concern 

cussed in Section B.2. In addition, other chemi- (LOC), and liquid factors, 

cals were identified as EHSs as described in 

Section B.4. The chemicals are listed by their � Exhibit C-2: Same list as that in Exhibit 

common names and also by their Chemical Ab- C-1, in CAS number order. 

stract Service (CAS) numbers. While a chemical 

may be known by several different names, the Note that the value for the LOC given in these 

CAS number provides a unique and unambigu- Exhibits is one tenth the Immediately Dangerous 

ous identification. The list of EHSs is presented to Life and Health (IDLH) level or an estimation 

in the following forms: of that level for chemicals which do not have a 

specific IDLH assigned to them. Refer to AppenExhibit C-1 : List of common names, in al- dix D for a more detailed discussion of the LOC 

phabetical order, with CAS number, ambi- and other values that planners may wish to use. 

C-l 


















APPENDIX D 

ADDITIONAL INFORMATION ON LEVELS OF CONCERN 

D. 1 INTRODUCTION 

Levels of concern (LOCs), for purposes of this 

document, are defined as the concentrations of 

an extremely hazardous substance (EHS) in air 

above which there may be serious irreversible 

health effects or death as a result of a single 

exposure for a relatively short period of time. 

There is at present no precise measure of LOCs 

for the chemicals listed as EHSs. Various organizations have been developing for the past 

several years acute exposure guidelines for a 

limited number of hazardous chemicals: the 

methodology, however, is still in the developmental stages. Certain of the guidelines under 

development and the progress to date are described in detail below. Until more precise 

measures are developed, surrogate or estimated measures of LOCs have been identified 

for the listed EHSs. Local officials may choose 

values for LOCs different from those estimated 

in this guidance, depending upon their requirements and the specific characteristics of the 

planning district or site and the level of protection deemed appropriate. 

For the purposes of this guidance, the LOC has 

been estimated by using one-tenth of the “Immediately Dangerous to Life and Health” (IDLH) 

level published by the National Institute for Occupational Safety and Health (NIOSH) or an approximation of the IDLH from animal toxicity data 

(See Appendix B). Other exposure guidelines 

that may be used to estimate LOC include the 

“Threshold Limit Values” (TLVs1

), published by 

the American Conference of Governmental Industrial Hygienists (ACGIH), guidelines developed by the National Research Council (NRC) of 

the National Academy of Sciences, (NAS), and 

Emergency Response Planning Guidelines 

(ERPGs) under development by a consortium of 

chemical companies. Descriptions of the development and uses of these exposure guidelines 

will be given in the following sections. 

TLVs is a registered trademark. 

LOCs may be given in units of parts per million 

(ppm), milligrams per cubic meter (mg/m3), 

milligrams per liter (mg/L), or grams per liter 

(g/L). 

The equations for determining LOC in this guidance use the units grams per cubic meter, 

(g/m3), so any other units, such as ppm, must 

be converted to g/m3. Levels given in parts per 

million can be converted to grams per cubic meter (g/m3) as follows: 

where MW is the substance’s molecular weight. 

For example, chlorine has an LOC (0.1 IDLH) of 

2.5 ppm and a molecular weight of about 71 g/ 

mole. Thus, the LOC in grams per cubic meter 

is: 

LOC given in milligrams per cubic meter 

(mg/m3) can be converted to g/m3 as follows: 

LOC (in g/m3) = LOC (in mg/m3)/1000 

LOC given in grams per liter (g/L) can be converted to g/m3 as follows: 

LOC (in g/m3) = LOC (in g/L) x 1000 

LOC given in milligrams per liter (mg/L) is 

equivalent to LOC in g/m3: 

LOC (in g/m3) = LOC (In mg/L) 

D.2 LEVEL OF CONCERN BASED ON 

ONE-TENTH IDLH OR ONE-TENTH THE 

ESTIMATED IDLH 

About ten years ago, NIOSH developed IDLH levels for approximately 390 chemicals from the 

Occupational Safety and Health Administration 

(OSHA) Z-1 and Z-2 lists. These are lists of 

toxic and hazardous substances to which 

12/87 D-l 

1
employee exposure must be limited as required 

by the Code of Federal Regulations 29, Chapter 

17, Part 1910. IDLHs were developed exclusively 

for respirator selection in the workplace. The 

definition of IDLH provided in 30 CFR 11.3 (the 

Occupational Safety and Health Act of 1970, PL 

91-596) is: "Immediately dangerous to life or 

health means conditions that pose an immediate 

threat to life or health or conditions that pose an 

immediate threat of severe exposure to contaminants, such as radioactive materials, which 

are likely to have an adverse cumulative or delayed effect on health.” The IDLH concentration 

represents the maximum concentration of a substance in air from which healthy male workers 

can escape without loss of life or irreversible 

health effects under conditions of a maximum 

30-minute exposure time. Practically, IDLH’s 

are concentrations above which a highly reliable 

breathing apparatus is required with provisions 

for escape. 

The methodology in developing IDLHs takes into 

account immediate reactions that could prevent 

escape without injury, such as severe eye irritation or lung edema. The procedure used to derive IDLH’s from data from mammalian toxicity 

studies is outlined below: 

1. Where acute exposure data are available

(30 minute to 4 hour exposures), the lowest exposure concentration causing death

or irreversible health effects in any species

is used as the IDLH concentration. These

data are often reported as lethal concentration, low (LCLO).

2. Chronic exposure data are generally not

considered in developing IDLH levels for

the following reason: “Chronic exposure

data may have no relevance to the acute

effects and should be used in determining

the IDLH concentration only upon competent toxicological judgment.” (NIOSH

19782),

See Section D.7 for all references in Appendix D. 

3. Where there are no toxicity data to derive 

an IDLH concentration, 500 times the Permissible Exposure Limit (PEL) shall be 

used as the IDLH level. 

EPA recognizes that the IDLH was not designed 

as a measure of the exposure level required to 

protect general populations. First, the IDLH is 

based upon the response of a healthy, male 

worker population and does not take into account exposure of more sensitive individuals 

such as the elderly, children, or people with various health problems. Second, the IDLH is based 

upon a maximum 30-minute exposure period, 

which may not be realistic for accidental airborne releases. IDLH values have been developed for about one-fourth of the EHSs on the 

list. The IDLH may not indicate the concentration that could result in serious but reversible injury. Based on these conditions, one-tenth the 

IDLH level or an estimation of this value for substances that do not have a published IDLH, has 

been selected as one approximation of an LOC 

available for planning purposes. These IDLH values have been developed with human acute toxicity as the principal consideration and represent 

exposure concentrations that are one to two orders of magnitude below the median lethal concentration (LC50) or the median lethal dose 

(LD50) levels reported for mammalian species 

under experimental conditions. IDLHs were estimated from acute animal toxicity test data for 

substances without IDLH values. In these instances, the concentration used is determined 

from LC50, LCLO, LD50, or LDLO data. Inhalation data were used, if available, in preference 

to other data, and median lethality data were 

preferred to other types. The following equations show how these data are converted to air 

concentrations comparable to the IDLH level: 

(1) estimated IDLH = LC50 x 0.1; 

(2) estimated IDLH = LCLO 

(3) estimated IDLH = LD50 x 0.01 

(4) estimated IDLH = LDLO x 0.1 

12/87 D-2 

2
D.3 LEVELS OF CONCERN BASED ON

THRESHOLD LIMIT VALUES (TLVs3

)

ACGIH publishes an annual list of three types of 

workplace exposure limits for several hundred 

compounds. ACGIH has published three TLVs 

as guidelines since 1941: Threshold limit valueTime-weighted average (TLV-TWA), TLV-Short 

term exposure limit (TLV-STEL), and TLV-Ceiling (TLV-C). 

1. The TLV-TWA is defined as the time 

weighted average concentration limit for a 

normal eight hour workday and 40 hours 

per week, to which nearly all workers may 

be repeatedly exposed, day after day, 

without adverse effect. 

2. The TLV-STEL is a 15-minute timeweighted average concentration for a normal eight-hour workday and forty-hour 

workweek. All workers should be able to 

withstand up to four exposures per day of 

concentrations as high as the TLV-STEL 

with no ill effects if the TLV-TWA is not also 

exceeded. TLV-STELs are applied to supplement the TLV-TWA when there are recognized acute effects from a substance 

whose toxic effects are primarily of a 

chronic nature. 

3. The TLV-C is the airborne concentration 

that should not be exceeded in the 

workplace under any circumstances. Ceiling limits may supplement other limits or 

stand alone. In many cases, ACGIH could 

not find sufficient toxicological data to derive TLV-STELs or TLV-Cs for chemicals 

which had already been assigned a TLVTWA. In these instances, the ACGIH recommends that five times the TLV-TWA be 

used in place of the TLV-C and that shortterm exposures not exceed 3 times- the 

TLV-TWA for more than a total of 30 minutes during the day. 

TLVs are based primarily on acute toxicity data 

(LC5Os and LD50s) and irritation data (irritation 

of the cornea and respiratory tract). Irritation 

effects that are considered range from barely 

TLVs is a registered trademark. 

detectable to irreversible, in laboratory animals 

and human subjects documented in industrial exposures. Only some TLVs consider neurotoxic 

and mutagenic effects. Although TLVs are derived for the protection of healthy male workers, 

they occasionally consider special impacts on 

workers with chronic respiratory problems, 

TLVs do not consider reproductive effects (ACGIH 1966). ACGIH advises against using or applying the TLV levels outside the workplace. 

D.4 LEVELS OF CONCERN BASED ON 

NATIONAL ACADEMY OF SCIENCES 

SHORT-TERM EXPOSURE LEVELS 

For the last forty years, the NRC’s Committee on 

Toxicology has submitted emergency exposure 

guidelines for chemicals of concern to the Department of Defense (DOD) (NRC 1986), These 

guidelines are used in planning for sudden contamination of air during military and space operations; specifically, they are used to choose 

protective equipment and response plans after 

non-routine but predictable occurrences such 

as line breaks, spills, and fires. These guidelines are for peak levels of exposure considered 

acceptable for rare situations, but are not to be 

applied in instances of repeated exposure. 

An Emergency Exposure Guidance Level (EEGL) 

is defined as a concentration of a substance in 

air (gas, vapor, or aerosol) judged by DOD to be 

acceptable for the performance of specific tasks 

by military personnel during emergency conditions lasting 1-24 hours. Exposure to an EEGL is 

not considered safe, but acceptable during 

tasks which are necessary to prevent greater 

risks, such as fire or explosion. Exposures at 

the EEGLs may produce transient central nervous system effects and eye or respiratory irritation, but nothing serious enough to prevent 

proper responses to emergency conditions. 

Since the 1940’s, the NRC has developed EEGLs 

for 41 chemicals, 15 of which are listed in Section 302 of Title Ill of SARA as EHSs. Although 

acute toxicity is the primary basis for selecting 

EEGLs, long term effects from a single acute exposure are also evaluated for developmental, 

reproductive (in both sexes), carcinogenic, 

neurotoxic, respiratory and other organ-related 

12/87 D-3 

3
effects. The effect determined to be the most 

seriously debilitating, work-limiting, or sensitive 

is selected as the basis for deriving the EEGL. 

This concentration is intended to be sufficiently 

low to protect against other toxic effects that 

may occur at higher concentrations. Factors 

such as age of the exposed population, length of 

exposure, and susceptibility or sensitivity of the 

exposed population are also considered in determining EEGLs. 

Safety factors are used in developing EEGLs to 

reflect the nature and quality of the data. Safety 

factors for single exposures may differ from 

those used in chronic studies. In the absence of 

better information, a safety factor of 10 is suggested for EEGLs (i.e., the reported toxicity 

value should be divided by 10) if only animal 

data are available and extrapolation from animals to humans is necessary for acute, shortterm effects (NRC 1986). The safety factor of 

10 takes into account the possibility that some 

individuals might be more sensitive than the animal species tested. A factor of 10 is also suggested if the likely route of human exposure differs from the route reported experimentally 

(NRC 1986) (e.g., if oral data are reported and 

inhalation is the most likely exposure route for 

humans). 

As noted by NRC (1986, p. 7), development of 

an EEGL for different durations of exposure usually begins with the shortest exposure anticipated - i.e., 10-15 minutes - and works up to 

the longest, such as 24 hours. Under the simplest framework, Haber’s law is assumed to operate, with the product of concentration (C) and 

time (t) as a constant (k) for all the short periods used (Ct=k) (Casarett and Doull 1986). If Ct 

is 30 and t is 10, then C is 3; if Ct is 30 and t is 

30, then C is 1. If detoxification or recovery occurs and data are available on 24-hour exposures, this is taken into account in modifying Ct. 

In some instances, the Ct concept will be inappropriate, as for materials such as ammonia that 

can be more toxic with high concentrations over 

short periods. Each material is considered in 

relation to the applicability of Haber’s law. 

Generally, EEGLs have been developed for exposure to single substances, although emergency exposures often involve complex mixtures 

of substances and, thus, present the possibility 

of toxic effects resulting from several substances. In the absence of other information, 

guidance levels for complex mixtures can be developed from EEGLs by assuming as a first approximation that the toxic effects are additive. 

When the chemical under evaluation for development of an EEGL is an animal or human carcinogen, a separate qualitative risk assessment 

is undertaken in recognition of the fact that even 

limited exposure to such an agent can theoretically increase the risk of cancer. The risk assessment is performed with the aim of providing 

an estimate of the acute exposure that would not 

lead to an excess risk of cancer greater than 1 in 

10,000 exposed persons. The following mathematical approach, taken directly from NRC 

(1986, pp. 26-27), is applicable for EEGL cornputations for carcinogens: 

1. If there has been computed an exposure 

level d (usually in ppm in air), which after a 

lifetime of exposure is estimated to produce some "acceptable” level of excess 

risk of cancer -- say, 1x10-6 -- this has 

been called a “virtually safe dose” (VSD). 

Computation of the dose d, if not already 

done by a regulatory agency, will be computed by the Committee on Toxicology in 

accordance with generally accepted procedures used by the major regulatory 

agencies, i.e., using the multistage nothreshold model for carcinogenesis and 

the appropriate body weight/surface area 

adjustments when extrapolating from an 

animal species to humans. 

2. If carcinogenic effect is assumed to be a 

linear function of the total (cumulative) 

dose, then for a single 1-day human exposure an acceptable dose (to yield the 

same total lifetime exposure) would be d 

times 25,600 (there being approximately 

25,600 days in an average lifetime); the allowable 1-day (24-h) dose rate would be 

d x 25,600 

3. Because of uncertainties about which of 

several stages in the carcinogenic process 

a material may operate in, and because of 

the likely low age of military persons, it can 

be shown from data of Crump and Howe 

(1984) that the maximal additional risk that 

12/87 D-4 
these considerations contribute is a factor 

of 2.8. As a conservative approach, the 

acceptable dose is divided by 2.8, i.e., 

d x 25,600 

2.8 

If a lifetime excess risk, R, is established 

by DOD (for example, at 1x10-4, as has 

been suggested by the International Council on Radiation Protection for nuclear 

power plant workers), then the appropriate 

extent of risk at the EEGL would be 

(In the example given here, the level of risk 

at d was no more than 1x10-6.) If R is 

1 x10-4, then R/risk at d = 10-4 /10-6 = 100 

(NRC 1986). 

4. If a further element of conservatism is required (for example, where animal data 

need to be extrapolated to estimate human 

risk), an additional safety factor can be 

used as a divisor. 

The NRC’s Committee on Toxicology has also 

developed special public exposure guidelines 

upon request from Department of Defense. The 

Short-term Public Exposure Guidance Level 

(SPEGL) is defined as an acceptable ceiling concentration for a single, unpredicted short-term 

exposure to the public. The exposure period is 

usually calculated to be one hour or less and 

never more than 24 hours. SPEGLs are generally set at 0.1 to 0.5 times the EEGL. A safety 

factor of 2 is often used to take into account effects on sensitive subpopulations, such as children, the aged, and people with debilitating diseases. A safety factor of 10 may be used to 

take into account the effects of an exposure on 

fetuses and newborns. Effects on the reproductive capacity of both men and women are also 

considered. Five SPEGLs (for hydrazine, 

dimethylhydrazine, monomethyl hydrazine, nitrogen dioxide, and hydrogen chloride) have 

been developed by the NRC: all five chemicals 

are on the list of EHSs. 

D.5 LEVELS OF CONCERN BASED ON 

EMERGENCY RESPONSE PLANNING 

GUIDELINES 

A consortium of twenty-five chemical firms has 

developed a uniform protocol for community exposure guidelines based upon the NRC/NAS 

guidelines, EEGLs, and SPEGLs. The American 

Industrial Hygiene Association (AIHA) is providing technical review. These guidelines are not 

intended for repeated exposures and their adoption and use by individual companies is intended 

to be voluntary. 

The consortium members have identified 100 

chemicals of concern: for fifteen chemicals, 

draft Emergency Response Planning Guidelines 

(ERPGs) have been developed. None of these 

as yet is available for review. Briefly, the recommended procedure for developing ERPGs is as 

follows: 

1) Companies should use a multi-disciplinary 

team, including members from the toxicological, medical, and industrial hygiene 

fields, to collect and review data and draft 

ERPG documentation. The protocol recommends identifying producers and users 

of the material and requesting unpublished 

data on human health effects. Literature 

searches of computer databases are also 

recommended. 

2) Acute toxicity data, as well as possible 

long-term effects from a single acute exposure, including carcinogenicity, 

neurotoxicity, and reproductive and developmental effects are considered. Adjustments may be made, based upon informed judgment, for the increased susceptibility of sensitive subgroups in the 

population. ERPGs for carcinogens may 

be derived using the carcinogenicity risk 

assessment methodology for acute exposures employed by the NRC (1986). 

3) The protocol specifies that three concentration levels are needed for each chemi12/87 D-5 
cal. The ERPG-1 is defined as the “maximum airborne concentration below which it 

is believed that nearly all individuals could 

be exposed for up to one hour without experiencing other than mild transient adverse health effects or perceiving a clearly 

defined objectionable odor.” The ERPG-2 

is the concentration below which it is believed that “nearly all individuals” would 

come to no permanent harm after a onehour exposure period. The ERPG-3 is the 

“maximum concentration below 

which...nearly all individuals could be exposed for up to one hour without.. life 

threatening health effects.” (See Exhibit 

D-1) 

4) After the ERPG Task Force reviews and edits the documentation, the guidelines and 

their rationales are reviewed by a Toxicology Committee within the AIHA. The committee is comprised of experts from government, industry, and academia. 

5) When they are approved, the guidelines 

and their documentation are filed at the 

AIHA headquarters in Akron and will be 

available to the public upon request. 

D.6 OSHA PERMISSIBLE EXPOSURE LIMITS 

AND NIOSH RECOMMENDED EXPOSURE 

LIMITS 

OSHA Permissable Exposure Limits (PELs) are 

workplace exposure standards listed in 29 CFR 

1910, Subpart Z, General Industry Standards for 

Toxic and Hazardous Chemicals. 

Most of the PELs listed in 29 CFR 1910 were 

based on ACGIH TLVs, about 450 of which OSHA 

adopted in 1971 as interim standards under section 6(a) of the Occupational Safety and Health 

Act. Between 1972 and 1984, OSHA promulgated 9 permanent major health standards regulating worker exposure to 21 toxic chemicals or 

mixtures. These standards, besides establishing 

PELs for these chemicals or mixtures, also provided guidance on exposure monitoring, regulated areas, methods of compliance, respiratory 

protection, protective clothing, and hazard communication. 

Chemicals and substances listed in Subpart Z 

were divided into 3 tables. PELs for chemicals 

on the first table are usually 8-hour timeweighted average (TWA) concentrations, not to 

be exceeded in an 8-hour workday. For chemicals on the second table, ceiling concentrations 

and maximum peak concentrations were given in 

addition to 8-hour TWA concentrations. The 

maximum peak concentrations have associated 

with them exposure durations (e.g. five minute 

maximum peak concentration in any 2 hour period). These concentrations should never exceed the maximum peak, and should fall between the ceiling and the maximum peak concentration for the duration indicated. The third 

table provided 8-hour TWA concentrations for 

mineral dusts. 

The majority of OSHA PELs were adopted from 

the ACGIH TLVs available in 1971. PELs are enforceable by law, whereas the ACGIH TLVs are 

recommendations. It should be noted that there 

have been no revisions of the PELs since their 

adoption, although the corresponding ACGIH 

TLVs may have been revised. 

For chemicals which NIOSH has published recommendations, the NIOSH recommended exposure limits (RELs) are found in the Pocket Guide 

to Chemical Hazards. RELs are 8- or 10- hour 

TWA concentrations and/or ceiling concentrations. 

D.7 GUIDELINES AVAILABLE FOR 

EXTREMELY HAZARDOUS SUBSTANCES 

As local planning committees may consider the 

use of one tenth of the IDLH inappropriate for 

their specific situation, Exhibits D-2 and D-3 list 

the guidelines that have been discussed in this 

appendix that are available for each chemical on 

the List of Extremely Hazardous Substances. 

Planners may wish to use these values, but 

should do so only after discussion of the potential implications with qualified technical personnel. 

12/87 D-6 
D. 8 REFERENCES Crump, KS. and R.S. Howe. 1984. The multistage model with a time-dependent dose patAmerican Conference of Governmental Indus- tern: applications to carcinogenic risk assesstrial Hygienists. 1986. Threshold Limit Values ment. Risk Analysis 4: 163-176.

and Biological Exposure Indices for 1986-87.

Cincinnati, Ohio.

Casarett and Doull. 1986. Toxicology. Edited 

by C.D. Klassen, M.O. Amdur, and J. Doull. 

New York, Macmillan Publishing. 

12/87 D-7 
Exhibit D-l 

Emergency Response Planning Guidelines 

Adapted from Organization Resources Counselors, 1987. 

12/87 D-8
NIOSH. 1978. National Institute for Occupational Safety and Health. The Standards Completion Program Draft Technical Standards 

Analysis and Decision Logics. NIOSH Library, 

Cincinnati, Ohio. Copy courtesy of Dr. Howard 

Ludwig, NIOSH. 

NIOSH. 1985. National Institute for Occupational Safety and Health. Pocket Guide to 

Chemical Hazards. Washington, D.C.: U.S. 

Government Printing Office, DHEW (NIOSH) 

Publication No. 78-210. 

NRC. 1979. The National Research Council. 

Criteria for Short-term Exposures to Air Pollutants. November 1979. 

NRC. 1986, National Research Council, Committee on Toxicology. Criteria and Methods for 

Preparing Emergency Exposure Guidance Level 

(EEGL), Short-Term Public Emergency Guidance Level (SPEGL), and Continuous Exposure 

Guidance Level (CEGL) Documents. Washington, D.C.: National Academy Press. 

Organization Resources Counselors. 1987. 

Memorandum to ORC Occupational Safety and 

Health Group from Darrell K. Mattheis and 

Rebecca L. Daiss, update on Emergency Response Planning Guidelines (ERPG) Task 

Force.. July 20, 1987. 

Swank, M.G., Branson, D.R., Rampy, L.W. 

1986. The Dow Program to Develop Emergency Exposure Guideline Concentrations 

(EEGs), February 12, 1986. 

12/87 D-9 


















APPENDIX E 

SAMPLE PROFILE AND EMERGENCY FIRST AID TREATMENT 

EPA has prepared chemical profiles of the ex- and, in some cases, an emergency first aid 

tremely hazardous substances (EHSs) listed in treatment guide, are available in hard copy or on 

Exhibits C-1 and C-2. Emergency first aid treat- IBM compatible floppy disks. This appendix proment guides are also available for a number of vides, as an example, the profile and emerEHSs. A chemical profile for each substance gency first aid treatment guide for acrolein. 

12/87 E-l 
EPA Chemical Profile

CHEMICAL IDENTITY -- ACROLEIN

CAS Registry Number: 107-02-8

Page 1 of 4

Date: October 31, 1985

Revision: November 30, 1987

CAS Registry Number: 107-02-8

Synonyms: Acraldehyde; Acrylaldehyde; Acrylic Aldehyde; Ally1 Aldehyde;

Aqualin; Aqualine; Ethylene Aldehyde; Magnacide H; NSC 8819; Propenal;

2-Propenal; Prop-2-en-l-al; 2-Propen-l-one

Chemical Formula: C3H40

Molecular Weight: 56.06

SECTION I -- REGULATORY INFORMATION

CERCLA (SARA) 1986:

Toxicity Value Used for Listing Under Section 302: LC50 inhalation

(mouse) 0.15 mg/liter/6 hours (*NIOSH/RTECS 1985)

TPQ: 500 (pounds)

RQ: 1 (pounds)

Section 313 Listed (Yes or No): Yes

SECTION II -- PHYSICAL/CHEMICAL CHARACTERISTICS

Physical State: Liquid

Boiling Point: 126F, 52.5C (*Merck 1983)

Specific Gravity (H20-1): 0.8389 at 20C; 0.8621 at 0C (*Merck 1983)

Vapor Pressure (mmHg): 210 at 68F, 20C; 135.71 at 50F, 10C (*Weed

Science Society of America 1974)

Melting Point: -126F, -88C (*Merck 1983)

Vapor Density (AIR-l): 1.94 (*Encyc Occupat Health and Safety 1983)

Evaporation Rate (Butyl acetate-l): Not Found

12/87 E-2 
CAS Registry Number: 107-02-8

Page 2 of 4

ACROLEIN

SECTION II -- PHYSICAL/CHEMICAL CHARACTERISTICS (continued)

Solubility in Water: Soluble in 2-3 parts water (*Merck 1983)

Appearance and Odor: Colorless or yellowish liquid with extremely sharp,

disagreeable, acrid, irritating odor (*Sax 1979, *CHRIS 1980)

SECTION III -- HEALTH HAZARD DATA

OSHA PEL: TWA 0.1 ppm ( 0.25 mg/m3) (NIOSH 1987, p. 44)

ACGIH TLV: TWA 0.1 ppm (0.25 mg/m3); STEL 0.3 ppm (0.8 mg/m3) (ACGIH

1986-87, p. 9)

IDLH: 5 ppm (NIOSH 1987, p. 44)

Other Limits Recommended: EEGL 0.05 ppm (60 minutes) (NRC 1984a, pp. 27-34)

Routes of Entry: Inhalation: Yes (*NIOSH/RTECS 1985)

Skin: Yes (*NIOSH/RTECS 1985)

Ingestion: Yes (*Gosselin 1984)

Health Hazards (Acute, Delayed, and Chronic): Extremely toxic; probable

oral human lethal dose is S-50 mg/kg, between 7 drops and one teaspoon for

a 70 kg (150 lb.) person (*Gosselin 1984). Inhalation of air containing 10

ppm of acrolein may be fatal in a few minutes (*NRC 1981). Death from

cardiac failure accompanied by hyperemia and hemorrhage of the lungs and

degeneration of the bronchial epithelium is possible. Acrolein causes

acute respiratory and eye irritation; severe gastrointestinal distress with

slowly developing pulmonary edema (lungs fill up with fluid); and skin

irritation (Gosselin 1984, p. 11-186).

Medical Conditions Generally Aggravated by Exposure: Not Found

SECTION IV -- FIRE AND EXPLOSION HAZARD DATA

Flash Point (Method Used): -15F, -26C (CC); less than OF, -18C (OC)

(*NFPA 1978)

Flammable Limits:

LEL: 2.8% (*NFPA 1978)

UEL: 31% (*NFPA 1978)

Extinguishing Methods: Dry chemical, alcohol foam, or carbon dioxide.

Water may be ineffective, but can be used to keep containers cool (*NFPA

1978).

12/87 E-3 
CAS Registry Number: 107-02-8

Page 3 of 4

ACROLEIN

SECTION IV -- FIRE AND -EXPLOSION HAZARD DATA (continued)

Special Fire Fighting Procedures: In advanced or massive fires, fire

fighting should be done from safe distance or from protected location. Use

dry chemical, alcohol foam, or carbon dioxide. Water may be ineffective,

but should be used to keep fire-exposed containers cool. If a leak or

spill has not ignited, use water spray to disperse vapors. If it is

necessary to stop a leak, use water spray to protect men attempting to do

so. Water spray may be used to flush spills away from exposures and to

dilute spills to nonflammable mixtures (*NFPA 1978). Withdraw immediately

in case of rising sound from venting safety device or any discoloration of

tank due to fire. Isolate for l/2 mile in all directions if tank car or

truck is involved in fire (DOT 1987, Guide 30).

Unusual Fire and Explosion Hazards: Under fire conditions, polymerization

may occur. If inside a container, violent rupture of the container may

take place (*NFPA 1978).

NFPA Flammability Rating: 3

SECTION V -- REACTIVITY DATA

Stability: Unstable: Yes (*Merck 1983)

Stable:

Conditions to Avoid: Exposure to alkalis or strong acids (*Encyc

Occupat Safety and Health 1983) or to oxygen (*NFPA 1978).

Incompatibility (Materials to Avoid): Alkalis or strong acids act as

catalysts, causing a condensation reaction and liberating energy. Reaction

may be very rapid and violent (*Encyc Occupat Health and Safety 1983).

Readily converted by oxygen to hazardous peroxides and acids (*NFPA 1978).

Hazardous Decomposition or Byproducts: When heated to decomposition, it

emits highly toxic fumes (*Sax 1975).

Hazardous Polymerization: May Occur: Yes (*NFPA 1978)

May Not Occur:

Conditions to Avoid: Elevated temperatures, such as fire conditions.

(Polymerization inside container could cause violent rupture of

container under fire conditions.) (*NFPA 1978)

12/87 E-4 
CAS Registry Number: 107-02-8

Page 4 of 4

ACROLEIN

SECTION VI -- USE INFORMATION

Acrolein is used in manufacture of colloidal forms of metals; making

plastics, perfumes: as a warning agent in methyl chloride refrigerant; and

has been used in military poison gas mixtures (*Merck 1983). It is also

used as an intermediate in the production of glycerine, methionine, acrylic

acid, and esters (*SRI). Acrolein is also an intermediate for glycerol,

polyurethane, polyester resins, and pharmaceuticals (*Hawley 1981).

Additionally, acrolein is used as an aquatic herbicide, biocide, slimicide

(*Farm Chemicals Handbook 1984) and molluscicide (*Kearney and Kaufman 1975).

SECTION VII -- PRECAUTIONS FOR SAFE HANDLING AND USE 

(Steps to be Taken in Case Material is Released or Spilled)

When handling acrolein, no skin surface should be exposed (*NFPA 1978).

Remove all ignition sources. Ventilate area of spill or leak. For large

quantities, cover with sodium bisulfite, add small amount of water and mix.

Then, after 1 hour, flush with large amounts of water and wash site with

soap solution. Liquid should not be allowed to enter confined space, such

as sewer, because of possibility of explosion. Take up spill for disposal

by absorbing it in vermiculite, dry sand, or earth and disposing in a

secured landfill or combustion chamber (*NIOSH 1981).

SECTION VIII -- PROTECTIVE EQUIPMENT FOR EMERGENGY SITUATIONS

For emergency situations, wear a positive pressure, pressure-demand, full

facepiece self-contained breathing apparatus (SCBA) or pressure-demand

supplied air respirator with escape SCBA and a fully-encapsulating, chemical

resistant suit. See the introduction and comment section at the beginning

of the profiles for additional information.

Suit Material Performance (based on EPA/USCG "Guidelines", 1987)

(Chemical Resistance/Amount of Data):

Butyl: Good/Limited

Butyl/Neoprene: Poor/Many

CPE: Poor/Many

Nitrile: Poor/Many

Viton: Poor/Many

Viton/Chlorobutyl: Good/Limited

SECTION IX -- EMERGENGY TREATMENT INFORMATION

See Emergency First Aid Treatment Guide

E-5
Emergency First Aid Treatment Guide

for

ACROLEIN

(107-02-8)

This guide should not be construed to authorize emergency personnel to

perform the procedures or activities indicated or implied. Care of persons

exposed to toxic chemicals must be directed by a physician or other competent

authority.

Substances Characteristics:

Pure Form - Colorless or slightly yellow liquid.

Odor - Extremely sharp.

Commercial Forms - 92 to 99% pure liquid.

Uses - Chemical intermediate, manufacture of plastics, perfumes, paper, colloidal

forms of metals; component of military poison gas mixture, liquid fuel,

antimicrobial agent, aquatic pesticide; warning agent in methyl chloride

refrigerant.

Materials to Avoid - Strong acid, alkali, caustic soda, oxidizers, oxygen (except

for use in emergency life support).

Other Names - Acquinite, acraldehyde, acrylaldehyde, acrylic aldehyde, ally1

aldehyde, ethylene aldehyde, Magnacide H, 2-Propenal.

Personal Protective Equipment: See Chemical Profile Section VIII.

Emergency Life-Support Equipment and Supplies That May Be Required:

Compressed oxygen, forced-oxygen mask, soap, water, milk, activated charcoal,

saline cathartic or sorbitol.

Signs and Symptoms of Acute Acrolein Exposure:

Warning: Acrolein is highly irritating to skin and mucous membranes. Caution is

advised.

Signs and symptoms of acute exposure to acrolein may be severe and include

shortness of breath, tightness of chest, pulmonary edema, and coma. Lacrimation

(tearing), nausea, vomiting, and diarrhea may occur. Acrolein will irritate or

burn the skin and mucous membranes. Eye contact may cause irritation, swelling,

discharge and/or cornea1 injury.

12/87 E-6 
ACROLEIN

Emergency Life-Support Procedures:

Acute exposure to acrolein may require decontamination and life support for the

victims. Emergency personnel should wear protective clothing appropriate to the

type and degree of contamination. Air-purifying or supplied-air respiratory

equipment should also be worn, as necessary. Rescue vehicles should carry

supplies such as plastic sheeting and disposable plastic bags to assist in

preventing spread of contamination.

Inhalation Exposure:

1. Move victims to fresh air. Emergency personnel should avoid self-exposure

to acrolein.

2. Evaluate vital signs including pulse and respiratory rate and note any

trauma. If no pulse is detected, provide CPR. If not breathing, provide

artificial respiration. If breathing is labored, administer oxygen or other

respiratory support.

3. Obtain authorization and/or further instructions from the local hospital for

administration of an antidote or performance of other invasive procedures.

4. RUSH to a health care facility.

Dermal/Eye Exposure:

1. Remove victims from exposure. Emergency personnel should avoid selfexposure to acrolein.

2 . Evaluate vital signs including pulse and respiratory rate and note any

trauma. If no pulse is detected, provide CPR. If not breathing, provide

artificial respiration. If breathing is labored, administer oxygen or

other respiratory support.

3 . Remove contaminated clothing as soon as possible (and place in plastic

bag).

4. If eye exposure has occurred, eyes must be flushed with lukewarm water for

at least 15 minutes.

5 . Wash exposed skin areas THOROUGHLY with soap and water.

6 . Obtain authorization and/or further instructions from the local hospital for

administration of an antidote or performance of other invasive procedures.

7. RUSH to a health care facility.

12/87 E-7 
ACROLEIN

Ingestion Exposure:

1. Evaluate vital signs including pulse and respiratory rate and note any

trauma. If no pulse is detected, provide CPR. If not breathing, provide

artificial respiration. If breathing is labored, administer oxygen or other

respiratory support.

2 . Obtain authorization and/or further instructions from the local hospital for

administration of an antidote or performance of other invasive procedures.

3 . Give the victims water or milk: children up to 1 year old, 125 mL (4 oz

or l/2 cup); children 1 to 12 years old, 200 mL (6 oz or 3/4 cup); adults,

250 mL (8 oz or 1 cup). Water or milk should not be given if victims are

not conscious and alert.

4. Activated charcoal may be administered if victims are conscious and alert.

Use 15 to 30 gm (l/2 to 1 oz) for children, 50 to 100 gm (l-3/4 to 3-l/2 oz)

for adults, with 125 to 250 mL (l/2 to 1 cup) of water.

5. Promote excretion by administering a saline cathartic or sorbitol to

conscious and alert victims. Children require 15 to 30 gm (l/2 to 1 oz)

of cathartic; 50 to 100 gm (l-3/4 to 3-l/2 oz) is recommended for adults.

6 . RUSH to a health care facility.

E-8
APPENDIX F 

FIRE AND REACTIVITY HAZARDS 

Congress mandated in Title Ill of SARA that local 

emergency planning committees (LEPCs) focus 

initially on acute toxicity hazards related to extremely hazardous substances (EHSs). Other 

hazards may warrant consideration in emergency preparedness and response planning. 

This appendix is a brief discussion of fire and reactivity hazards. 

Fire Hazards. Flammable materials, particularly 

those that will ignite at a relatively low temperature (i.e., that have low flash points), clearly 

may be a hazard to communities. There are 

several major types of fires that may be associated with hazardous material discharges, with 

the type of fire being a function not only of the 

characteristics and properties of the spilled substance but the circumstances surrounding the 

accident. The types are: 

• Flame Jets. Tanks, cylinders, and 

pipelines which contain gases under 

pressure (i.e., compressed gases or 

liquefied gases) may discharge gases 

at a high speed if they are somehow 

punctured or broken during an accident. If the gas is flammable and encounters an ignition source, a flame jet 

of considerable length (possibly hundreds of feet) may form from a hole 

less than a foot in diameter. 

• BLEVEs. Boiling Liquid Expanding Vapor Explosions (BLEVEs) are among 

the most feared events when tanks of 

hazardous materials are exposed to 

fire or physical damage or other events 

that cause excessive pressures within 

the tank. A BLEVE could occur when 

flames impinge upon the vapor space 

(unwetted internal surface) of the tank 

where there is no liquid to absorb heat. 

As the vapor space is heated, the 

pressure inside the tank (even after 

the relief valve opens) becomes so 

great that it eventually vents itself 

through the weakest area of the tank. 

As the pressure inside is increasing, 

the flames weaken the structural integrity of the tank, thus creating the conditions for venting. This sudden venting of pressure and vaporization of 

product involves the violent rupture of 

the container, with rocketing fragments. If the container stored a flammable liquid or gas, a large rising fireball will form, the size of which will vary 

with the amount of hazardous material 

present. 

Vapor or Dust Cloud Fires and Explosions. Vapors evolved from a pool of 

volatile liquid or gases venting from a 

punctured or otherwise damaged container, if not ignited immediately, will 

form a plume or cloud of gas or vapor 

that moves in the downwind direction. 

If this cloud or plume contacts an ignition source, a wall of flame may flash 

back towards the source of the gas or 

vapor, sometimes with explosive force. 

Similarly, fires may flash through airborne clouds of combustible dusts. 

Dusts may explode under some conditions (e.g., grain elevator explosions). 

Liquid Pool Fires. A liquid pool fire is 

a fire involving a quantity of liquid fuel 

such as gasoline spilled on the surface 

of the land or water. An added complication is that the liquid fuel, depending 

on terrain, may flow downslope from 

the accident site and into sewers, 

drains, surface waters, and other 

catchments. 

Flammable Solid Fires. A “flammable 

solid” may cause fires through friction 

or retained heat from manufacturing or 

processing. It can be ignited readily 

and when ignited burns vigorously and 

persistently. Included in this class are 

spontaneously combustible 

(pyrophoric) and water-reactive materials. Fires involving these materials 

present a difficult challenge to firefighters, particularly when water cannot be 

used. 

12/87 F-1 
Reactivity Hazards. Some of the more common 

and/or dangerous types of reactions, and how 

they may alter the outcome of an accidental release, are outlined below: 

• Reactions with Water or Moist Air. 

Some substances generate heat when 

mixed with water. Some strong acids 

may evolve large amounts of fumes 

when in contact with water or moisture 

in the air. These fumes, which may 

consist of a mixture of fine droplets of 

acid in air and acid vapors, are usually 

highly irritating, corrosive, and heavier 

than air. Other materials may ignite, 

evolve flammable gases, or otherwise 

react violently when in contact with 

water. Knowledge of the reactivity of 

any substance with water is especially 

important when water is present in the 

spill area. Uninformed firefighters can 

worsen a situation by applying water to 

the water-reactive chemicals. 

• Reactions with Combustible Organic 

Materials. Strong oxidizing or reducing 

agents have the common characteristic of being able to decompose organic 

materials and react with a variety of inorganic materials while generating 

heat, flammable gases, and possibly 

toxic gases. If the heat generated is 

sufficient to ignite a combustible material or a flammable gas (when confined), either a fire or explosion may 

occur. 

• Polymerization Reactions. Many plastics are manufactured by means of a 

polymerization reaction in which molecules are linked together into long 

chains. Some of the chemicals capable of polymerizing have a strong tendency to do so even under normal ambient conditions and are especially 

prone to polymerize if heated above a 

certain temperature or if contaminated. Once polymerization starts, a 

chain reaction may occur that develops high pressures and temperatures 

within containers and can lead to possible rupture of the container and discharge of flammable and/or toxic 

gases if safety and control systems 

malfunction or are lacking. 

• Decomposition Reactions. Some 

chemical molecules are unstable and 

can break apart in a runaway reaction 

once the process is initiated. Various 

contaminants or heat may start a reaction. Containers may rupture or vent 

various flammable and/or toxic gases. 

Decomposition and polymerization reactions are hazardous only if they become uncontrolled and start a chain 

reaction that cannot be stopped with 

available equipment, materials, or 

safety systems. 

• Corrosivity. The process by which a 

chemical gradually eats away or dissolves another material is referred to 

as corrosion. It represents yet another 

type of chemical reactivity that must 

be considered in assessing the hazards of any given material. The word 

“corrosive” is also used descriptively 

to indicate that a substance may cause 

chemical burns of the skin, eyes, or 

other bodily tissues. 

• Other Reactivity Hazards. In addition 

to the types of reactions discussed 

above, hazards can result from the following situations: 

The combination of various chemicals may produce new chemicals 

with hazards quite different and 

possibly more severe than those 

associated with the original materials. 

Some combinations may result in 

spontaneous fires: spontaneous 

explosions: formation of substances which will ignite or explode if shocked, heated or subjected to friction: generation of 

toxic gases, liquids, or solids; or 

generation of flammable gases, 

liquids, or solids. 

12/87 F-2 
APPENDIX G 

EQUATIONS USED FOR THE ESTIMATION OF VULNERABLE ZONES 

G. 1 INTRODUCTION 

Chapter 3 presents a tabular method for estimation of the radius of the vulnerable zone (VZ) for 

releases of gases, liquids, and solids. This appendix contains the equations used to derive the tables 

found in Chapter 3. Section G.2 discusses the derivation of the release rate term of the vulnerable 

zone calculation. For liquids, a liquid factor including many of the variables that affect rate of evaporation is used for the estimate: this factor is also described in Section G.2. 

Section G.3 discusses the derivation of the relationship between downwind distance, as a function of 

rate of release, and level of concern (LOC) as presented in Exhibits 3-1 to 3-4 in Chapter 3. 

The calculations are based on applications of the dispersion model described in the Workbook of 

Atmospheric Dispersion Estimates, Public Health Service Publication No. 999-AP-26, 1970 (popularly 

known as Turner’s Workbook). Estimates of dispersion distribution parameters are those of Briggs, 

based on McElroy and Pooler’s experiments, given in the Handbook of Atmospheric Diffusion, Department of Energy Publication No. DOE/TIC-11223, 1982. 

The following assumptions are made concerning the circumstances of the credible worst case release 

(these assumptions are designed to be conservative and represent adverse conditions for screening 

purposes) : 

Rural flat terrain with no obstacles (e.g., hills) that would interfere with the downwind movement of the plumes (obstacles would increase the dispersion capability of the plume); 

Ground level release (releases from elevated sources tend to disperse more readily than 

ground level releases); 

F Stability and 1.5 meters per second (3.4 miles per hour) wind speed, representing stable 

air and low wind speed (the VZ calculated under these conditions is larger than that calculated under conditions usually considered typical); and 

Continuous release (consistent with a catastrophic loss) rather than a brief “puff.” 

The following assumptions are made concerning the substance released: 

There is no phase change and the plume is at ambient temperature (phase changes and 

temperature changes would cause variations in dispersion and evaporation (volatilization) 

rates). 

The substance released is neutrally buoyant in air. Dense gases are treated the same way as 

neutrally buoyant gases in this analysis. (The behavior of a dense gas is different, but for the 

calculations presented in this appendix, the concentrations along the centerline of the plume 

are considered. These concentrations are comparable for dense gases and neutrally buoyant gases); 

A Gaussian distribution of the plume’s spread, in both horizontal and vertical planes, was 

assumed in the dispersion estimates: 

Gases are released over a ten minute period:

Liquids are instantaneously spilled from containment onto a flat, level surface forming a

0.033 ft (1 cm) deep pool and are allowed to evaporate at ambient or boiling conditions: 

Solids in powder form (<100 microns particle size) behave like gases and are also released in 

ten minutes: 

12/87 G-1 
Solids in solution are assumed to behave as a finely dispersed aerosol and are released in 

ten minutes: 

Solids in molten form are assumed to behave as liquids. The quantity molten is assumed to 

lose containment instantaneously, forming a 0.033 ft (1 cm) deep pool on a flat, level surface 

and volatilizing at its melting point temperature: and 

Solids in “brick” form (i.e., not powdered, in solution, vaporized, or molten) are not likely to 

be released. 

G.2 ESTIMATION OF AIRBORNE QUANTITY RELEASED FOR LIQUIDS 

The rate of release of a chemical is needed for calculation of the radius of the VZ. It is dependent on 

the quantity of chemical released, the nature of the release scenario (i.e., pool of liquid, release of 

pressure relief valve, etc.), and the properties of the chemical released. For spilled pools of chemicals, the rate of release is usually taken to be the evaporation rate (rate of volatilization). Using the 

assumptions presented above, the following equation is used to calculate the rate of release to air for 

liquids (in Ibs/min) : 

(1) QR = (60 sec/min x MW x K x A x VP x (929cm2/ft2, (Clement 1981) 

R x (T1+273) x (760 mm Hg/atm) x 454 g/lb 

where: QR = Rate of release to air (Ibs/min); 

MW = Molecular weight (g/g mole); 

K = Gas phase mass transfer coefficient (cm/sec); 

A = Surface area of spilled material (ft2

); 

VP = Vapor pressure of material at temperature T1 (mm Hg); 

R = 82.05 atm cm3

/g mole K; and 

T1 = Temperature at which the chemical is stored (0

C). 

The equation for the evaporation rate (rate of volatilization) can be rewritten as follows: 

(2) QR= 0.162 x MW x K x A x VP

R (T1+273)

K can be estimated based on a known value for a reference compound as follows: 

(3) K = Kref x (MWref/MW) 1/3 (Clement 1981) 

Using water as the reference compound: 

(4) K K water=0.25 x (u)0.78 (Mackay and Matsugo 1973) ref

where: u = Windspeed (m/sec) 

12/87 G-2 
Combining Equations 3 and 4: 

(5) K = 0.25 (u) 078 x (18/MW) 1/3 

Combining equations for QR and K yields the following equations: 

0.162 x 0.25 x (u)0.78 x (18)1/3 x MW2/3 x Ax VP 

(6) QR = R x (T1 + 273) 

0.106 x (u) 0,78 x MW2/3x Ax VP 

(7) QR = R x (T1 + 273) 

Calculation of the surface area (A) of the spilled material is carried out as described in the following 

sections. 

G.2.1 CALCULATION OF SURFACE AREAS OF POOLS OF SPILLED LIQUIDS 

For diked areas, the surface area is assumed to be the area inside the dike (unless the surface area of 

the spill is smaller than the diked area). If the area is not diked, the following assumptions are used to 

calculate the surface area of the spill: 

Density = 62.4 Ib/ft3

 (i.e., all liquids are assumed to have the same density as water) 

Depth of pool is 0.033 ft (I cm) 

The surface area of the spilled liquid (ft2

) is: 

QS (Ibs) (8) A = 62.4 lb/f3

 x 0.033ft = 0.49 x QS 

where: QS = Quantity spilled (Ibs); and 

A = Surface area (ft2

). 

Substituting for A in Equation 7, the quantity released to air per minute (QR) can be estimated as 

follows: 

0.106 x (u)0.78 x MW 2/3 x 0.49 x QS x VP 

(9) QR = 82.05 x (T1 + 273) 

12/87 G-3 
G. 2.2 LIQUID FACTORS 

Equation (9) may be simplified by separating all the chemical specific parameters, such as vapor 

pressure and molecular weight, and the temperature into a “liquid factor.” The “liquid factor” therefore includes all the terms of Equation (9), except the quantity spilled (QS) and the wind speed term. 

For ambient temperatures, VP is the vapor pressure measured at T1 (ambient temperature). The 

liquid factor at ambient conditions (LFA) is calculated as: 

0.106 x MW2/3x 0.49 x VP 

(10) LFA = 

82.05 x (T1 + 273) 

For a liquid at its boiling temperature, VP is assumed to be 760 mm Hg at T1, the normal boiling point 

of the liquid. The liquid factor at the boiling point (LFB) is calculated as: 

0.106 x MW2/3 x 0.49 x 760 

(11) LFB = 82.05 x (Boiling point + 273) 

For a solid at its melting point, VP is the vapor pressure measured at T1 (melting point). The liquid 

factor at the melting point (LFM) is calculated as: 

0.106 x MW2/3 x 0.49 x VP melting (12) LFM = 82.05 x (melting point + 273) 

The liquid factor multiplied by the quantity spilled and the wind speed term (u0.78) gives the airborne 

quantity release rate: 

(13) QR = QS x u0.78 x (LFA, LFB, or LFM) 

For diked areas: 

(LFA, LFB, or LFM) x Diked Area (ft2) x u0.78 

(14) QR = 0.49 

Liquid factors for listed substances that are liquid at ambient conditions, or solid with potential for 

handling at molten state, are listed in Appendix C. 

G.3 ESTIMATION OF A VULNERABLE ZONE 

The following equation, based on Turner’s Workbook, was used to derive the vulnerable zone radius. 

The concentration downwind of a release is given by: 

(Turner 1970, Equation 3.4) 

12/87 G-4 
for a ground level release with no effective plume rise where: 

C = Airborne concentration, gm/m3

QR = Rate of release to air, gm/sec

= 3.141 

= dispersion deviation, horizontal (y), and vertical (z) 

u = windspeed, m/sec 

This equation represents the steady state concentration at some distance downwind and is applicable 

for release ranging from 10 minutes to one hour. 

QR (g/sec) 

3.141 x u x c 

0.318 x QR (g/sec) 

u x c 

QR (Ib/min) = QR (g/sec) x (60 sec/min x 1 lb/454 g) 

QR (Ib/min) = 0.132 x (QR g/sec) 

QR (g/sec) = (QR g/sec) / 0.132 

0.318 x QR (Ibs/min)

 0.312 x u x C 

2.41 x QR (Ib/min) 

(17) u x c 

As downwind distance increases, the product increases. For practical use to be made of the 

diffusion formula, numerical values of the diffusion coefficients must be determined. To 

deal with the resulting wide variations in turbulent properties, meteorologists have introduced stability 

classes into which atmospheric conditions are classified. Briggs (1973) used McElroy and Pooler’s 

G-1. To use these equations to determine distances, it will be necessary to use trial and error methods or a computer. For the development of this guidance, both rural (open country) and urban conditions for F atmospheric stability (the most stable class used for this guidance) and D atmospheric 

stability (neutral class assumed for overcast conditions during day or night, regardless of wind speed) 

were used. 

12/87 G-5 
EXHIBIT G-1 

FORMULAS RECOMMENDED BY BRIGGS (1973) 

Pasquill 

Stability 

Type 

Open-Country Conditions 

0.22d(1+0.0001d)-1/2 0.20d 

0.16d(1+0.0001d)-1/2 0.12d 

0.11d(1+0.0001d)-1/2 0.08d(1+0.0002d)-1/2 

0.08d(1+0.0001d)-1/2 0.06d(1+0.0015d)-1/2 

0.06d(1+0.0001d)-1/2 0.03d(1+0.0003d)-1 

0.04d(1+0.0001d)-1/2 0.016d(1+0.0003d)-1 

Urban Conditions 

A-B 0.32d(1+0.0004d)-1/2 0.24d(l+0.001d)1/2 

C 0.22d(l+0.0004d)-1/2 0.20d 

D 0.16d(l+0.0004d)-1/2 0.14d(1+0.0003d)-1/2 

E-F 0.11d(1+0.0004d)-1/2 0.08d(l+0.00015d)-1/2 

NOTE: d = downwind distance. 

12/87 G-6 
G.4 REFERENCES 

Briggs, G.A. 1973. Diffusion Estimation for Small Emissions. ATDL Contribution File No. 79. Atmospheric Turbulence and Diffusion Laboratory. 

Clement Associates Inc. 1981. Mathematical Models for Estimating Workplace Concentration Levels: 

A Literature Review, EPA Contract 88-01-6065. Prepared for ETD/EPA. 

Hanna, F.R., Briggs, G.A. and Hosker, R.P. 1982. Handbook of Atmospheric Diffusion, Department of 

Energy Publication No. DOE/TIC-11223. 

Mackay, Douglas and Matsugo, Ronald S., “Evaporation Rates of Liquid Hydrocarbon Spills on Land 

and Water.” The Canadian Journal of Chemical Engineering, Vol. 51, August, 1973. 

McElroy, J.L. and Pooler, F. 1968. St. Louis Dispersion Study Report AP-53. U.S. Public Health 

Service, National Air Pollution Control Administration. 

Turner, B. 1970. Workbook of Atmospheric Dispersion Estimates. Public Health Service Publication 

No. 999-AP-26. 

12/87 G-7 
ocument will not give you evacuation distances nor provide definitive guidance on estimating evacuation zone.Decision about whether or not to evacuate

e time of an actual release. The estimated vulerable zones should be used for planning purposes only and should not be used as an evecuation zone

APPENDIX H 

GENERAL CONSIDERATIONS FOR EVACUATION

OR IN-PLACE SHELTERING

An accidental release of hazardous materials 

sometimes necessitates evacuation of people 

from certain areas to prevent injury or death. 

These areas can include those directly affected 

by toxic fumes and gases or fire and those areas 

that may be potentially affected during the 

course of the incident (e.g., through wind shift, 

a change in site conditions). Evacuation is a 

complex undertaking. Rather than attempting to 

provide specific step-by-step guidance for each 

possible scenario, we will discuss in this appendix general considerations that should be addressed in advance by the local emergency 

planning committee (LEPC). Specifically, this 

appendix will discuss: deciding whether evacuation is appropriate and necessary (Section 

H.1); steps in conducting an evacuation (Section H.2); and in-place sheltering as an alternative to evacuation (Section H.3). 

H.1 MAKING A DECISION ON EVACUATION 

The first evacuation consideration, determining 

whether an evacuation is necessary, involves a 

comprehensive effort to identify and consider 

both the nature of and circumstances surrounding the released hazardous material and its effect on people. No safe exposure levels have 

been established for the extremely hazardous 

substances (EHSs) and therefore it is not possible to calculate evacuation distances using the 

methods outlined in this guidance. Section H. 1.1 

discusses how hazardous conditions and inherent properties of the released materials affect 

evacuation decisions. Section H. 1.2 discusses 

how life safety factors affect the decision on 

whether or not to order an evacuation. 

The Department of Transportation’s (DOT’s) 

Emergency Response Guidebook provides initial 

isolation and evacuation distances for transportation incidents. The evacuation distances given 

in the guidebook are preceded by the following 

advice: “The [initial isolation/evacuation] table 

is useful only for the first twenty to thirty minutes 

of an incident.. . . There are several good reasons for suggesting that the use of the table be 

limited specifically to the initial phase of a nofire spill incident during transport. The best calculations for these tables are not reliable for 

long vapor travel times or distances. At their 

best they are estimates for a cool, overcast 

night with gentle and shifting winds moving a 

non-reactive, neutrally-buoyant vapor.” The 

DOT Emergency Response Guidebook is intended to help first responders to make informed judgments during the initial phases of a 

hazardous materials transportation incident. 

LEPCs are cautioned not to use it as a substitute 

for a specific plan for responses to hazardous 

materials incidents. 

H. 1.1 Hazardous Conditions Affecting 

Evacuation Decisions 

Numerous factors affect the spread of hazardous substances into the area surrounding a leaking/burning container or containment vessel. 

Evacuation decision-makers must carefully consider each of these factors in order to determine 

the conditions created by the release, the areas 

that have been or will be affected, and the 

health effects on people. The factors that affect 

evacuation include amount of released material(s), physical and chemical properties of the 

released material(s), health hazards, dispersion 

pattern, atmospheric conditions, dispersion medium, rate of release, and potential duration of 

release. Each of these factors is explained below. 
To begin with, it is necessary to know the material’s physical and chemical properties, including : 

Physical State - solid, liquid, or gas:

Odor, color, visibility;

Flammability: flashpoint, ignition temperature, flammable limits;

Specific Gravity: whether material sinks or

floats on water:

Vapor Density: whether vapors rise or remain near ground level;

Solubility: whether material readily mixes

with water;

Reactivity: whether material reacts with air,

water, or other materials: 

Crucial Temperatures: boiling point, freezing point. 

It is also necessary to know the health effects 

resulting from a short-term exposure: 

� Acute or chronic hazards: 

� Respiratory hazards: 

� Skin and eye hazards: and 

Ingestion hazards. 

Another consideration is the dispersion pattern 

of the released hazardous material, for example: 

• Does the release follow the contours of the 

ground? 

� Is it a plume (vapor cloud from a point 

source) ? 

• Does the release have a circular dispersion 

pattern (dispersing in all directions)? 

Atmospheric conditions must also be addressed 

when determining the appropriate evacuation response to a hazardous material release. Atmospheric conditions that may affect the movement 

of material and evacuation procedures include: 

� Wind (speed and direction); 

� Temperature: 

� Moisture (precipitation, humidity); 

• Air dispersion conditions (inversion or normal); and 

• Time of day (daylight or darkness). 

Other considerations important in making evacuation decisions include: 

Whether the hazardous material is being 

released into air, land, and/or water and its 

concentration in air or water: 

Size and potential duration of the release: 

and 

Rate of release of the material, as well as 

the projected rate (the rate of release may 

change during the incident). 

H.1.2 LIFE SAFETY FACTORS TO CONSIDER 

IN PLANNING AN EVACUATION 

Life safety factors to consider when planning an 

evacuation include the number and types of 

people that require evacuation and the resources needed to conduct a safe and effective 

evacuation. Whether the people are actually located in an area that contains hazards or are 

located in an area that is only threatened by hazards is a critical component of evacuation planning . 

Populations in a Hazardous Area 

When considering people who are actually located within a hazardous area, the LEPC must 

address whether responsible authorities should 

order people to remain indoors, rescue individuals from the area, or order a general evacuation. The “remain indoors” option should be 

considered when the hazards are too great to 

risk exposure of evacuees. (See Section H.3 for 

further discussion of in-place sheltering.) It may 

be necessary to rescue people from the hazardous area, but this would involve supplying protective equipment for evacuees to ensure their 

safety. The third option is to order a general 

evacuation. In this case people must evacuate 

by means of private transportation or by transportation provided by local or State government, 

a private sector company, or volunteer groups. 

Populations in a Threatened Area 

For an area that is only threatened by a hazardous release, it should be determined whether 

12/87 H-2 
potential evacuees can be evacuated before 

hazards reach the area. To safely evacuate the 

area, a significant amount of lead time may be 

required. Depending on the hazards and their 

movement (as described above), evacuation 

assistance personnel may not have much lead 

time. 

Identifying People to be Evacuated 

Numerous factors must be considered to ensure 

that an evacuation is conducted in a safe and 

effective manner, including how many people 

will be involved, where they are located, their 

degree of mobility, and whether there are any 

communication barriers to address. Potential 

evacuees may be found in many different locations: 

Residences 

Educational institutions 

Medical institutions 

Health care facilities 

Child care facilties 

Correctional facilities 

Offices 

Commercial establishments 

Manufacturing/industrial/research facilities 

Government facilities 

Places of public assembly 

Parks and other recreational areas 

Sporting arenas/stadiums 

Roadways 

In addition to the above considerations, the 

LEPC must determine what persons will require 

special assistance in evacuating the area and 

whether there exist any barriers to communication between evacuees and evacuation assistance personnel. Special consideration should 

be given to: 

� Persons lacking private transportation 

� The elderly 

� Children 

Handicapped persons

The infirm

Prisoners

Non-English speaking persons

Resources Needed 

To accomplish a safe and effective evacuation, 

the LEPC must provide for appropriate and sufficient resources, including personnel, vehicles, 

and equipment appropriate for emergency situations. 

Among the agencies that would likely supply personnel during an evacuation operation are the 

Red Cross, police department, fire department, 

and emergency medical service agencies. 

In addition to personnel, specially equipped vehicles may have to be put in service, including: 

Lift-equipped buses and taxi cabs for 

handicapped persons: 

Ambulances for infirm and handicapped 

persons: and 

Vehicles for transporting persons lacking 

private transportation. 

Making prior arrangements to ensure the availability of these vehicles in times of emergency 

will result in a more timely and effective evacuation. 

The type of equipment that will be necessary 

during an evacuation includes: 

Protective gear for evacuation assistance 

personnel (e.g., masks to protect the 

lungs, protective covering for the skin and 

eyes); 

Protective gear for evacuees who may 

have to be taken through an area of heavy 

chemical concentration: 

Communication equipment (e.g. portable 

and mobile radios, mobile public address 

systems, bull horns); and 

Evacuation tags (a tag or marker attached 

to a door to indicate that the occupants 

have been notified) for buildings that have 

been evacuated. 

H.2 CONDUCTING AN EVACUATION 

Should it be decided that an area is to be evacuated, the evacuation must be conducted in a 

12/87 H-3 
well-coordinated, thorough, and safe manner. 

Evacuation involves a number of steps, which 

include assigning tasks to evacuation assistance 

personnel, informing potential evacuees, providing transportation as necessary, providing emergency medical care as necessary, providing security for evacuated areas, and sheltering 

evacuees as necessary. 

H.2.1 Evacuation Tasks 

The first step is to assign tasks to evacuation 

assistance personnel. These tasks include information concerning: 

The specific area to evacuate 

Protective gear to be worn 

Instructions to be given to evacuees 

Transportation of evacuees who are without private transportation 

Assistance to special populations 

Shelter locations 

Security for evacuated areas 

Traffic and pedestrian control 

Communication procedures 

The progress of the evacuation efforts must be 

monitored by those in charge who should also 

provide continuous direction to evacuation assistance personnel. 

H.2.2 Evacuation Warning and Instruction 

The second step in an evacuation is to inform 

people that they must evacuate and to provide 

them with accurate instructions. This procedure 

can be accomplished in several ways: 

� Door-to-Door. Requires significant manpower; is a slow process but is very thorough. 

• Public Address System (from a mobile unit 

or within a building). Requires less manpower than a door-to-door evacuation and 

is quicker to accomplish but is not as thorough. 

� Combination of Door-to-Door and Public 

Address System. For some sections of an 

area door-to-door notification may be 

12/87 H-4 

more expeditious, whereas in other areas 

evacuation instructions given via a public 

address system may be adequate and less 

time consuming. 

The potential evacuees might also be alerted to 

the emergency by means of an alerting and 

warning system that prompts them to tune in to 

their radios for instructions from the Emergency 

Broadcast System or a similar broadcast system. 

H.2.3 Movement of Evacuees 

The third step in an evacuation is to provide 

movement assistance to evacuees. Movement 

assistance includes: 

Arranging transportation for evacuees who 

are without private transportation: 

Arranging for movement of the infirm and 

handicapped: 

Traffic control: 

Encouraging evacuees to move along in an 

expeditious manner. 

Buses and/or vans will be needed for transportation of large groups of evacuees. Evacuating 

the infirm and handicapped will involve liftequipped buses, vans, and/or ambulances. 

Traffic control involves restricting access of vehicles into the evacuated area and facilitating 

speedy vehicular movement out of the evacuation area. 

H.2.4 Emergency Medical Care for Evacuees 

Should evacuees become exposed to hazards 

during an evacuation, emergency medical care 

must be provided. If a hazardous vapor cloud 

were to move suddenly upon a large group of 

people being evacuated, numerous casualties 

would be possible. For this reason, it is advantageous to have emergency medical service 

(basic and advanced life support) units standing 

by in case they are needed. 

H.2.5 Security in Evacuated Areas 

Once an area is evacuated, law enforcement 

personnel must guard the area to prevent looting and other unauthorized actions. Security 

forces operating in or around an evacuated area 

must be dressed in appropriate chemical protective gear. 
H.2.6 Sheltering of Evacuees 

The final step in the evacuation process is to 

provide shelter to the evacuees. Merely advising people to evacuate an area is inadequate. 

Providing shelter for them in a safe and comfortable building is of great importance, particularly 

at night or during inclement weather. In order to 

effectively serve the needs of evacuees, a shelter should have the following facilities, services, 

and characteristics: 

One qualified person to serve as Shelter 

Manager -- usually a Red Cross or local 

government representative 

Sufficient space to avoid overcrowding 

Restroom facilities 

Shower facilities 

Specialized facilities for the handicapped 

Chairs, tables, and other furniture 

Adequate lighting, temperature control, 

ventilation, and uncontaminated water 

Telephone system and/or two-way radio 

Food and refreshments 

Adequate safety features to meet fire, 

building, and health requirements 

Medical surveillance and care 

Care for the young, elderly, and handicapped 

Information available for evacuees concerning the emergency 

Sufficient parking near the shelter 

Shelters should be identified and management 

and operational procedures should be established as part of a preparedness plan. When 

selecting shelters, locations must be chosen 

that are in areas beyond current and projected 

areas of hazard contamination. To ensure that 

evacuees are continuously sheltered in safe areas, the following actions are necessary: 

• Collect and evaluate data on the spread of 

hazards toward shelters. 

� Establish and maintain communications 

with shelters. 

• Make provisions for the monitoring of hazards in and around each shelter and evaluate the resulting data. 

• Advise shelter managers when shelters will 

have to be evacuated because of approaching hazards. 

Should shelters have to be evacuated, alternate 

locations must be identified and shelter coordinators notified. 

To ensure the health and safety of evacuees at 

shelters, provisions should be made for evacuee 

medical surveillance and care. This is especially 

important for evacuees who may have been exposed to hazardous materials vapors. Ideally, 

each shelter should have medical professionals 

assigned to care for evacuees. They must be 

alert to symptoms caused by hazardous materials and be responsible for treating victims or 

calling for emergency medical assistance. 

Evacuees showing symptoms should be separated from those unaffected. The medical professional can also assist evacuees who need 

prescription medicines. 

H.2.7 Re-entry into Evacuated Areas 

Before making the decision to authorize reentry, data collected by the monitoring crews 

must be verified and the advice of health officials considered. 

Once the decision to authorize re-entry has 

been made, re-entry operations must be coordinated. These operations may be looked upon 

as an evacuation in reverse, as many of the 

same steps must be undertaken. Re-entry operations involve: 

Notifying people that they can return to 

evacuated areas. 

Providing evacuees with special information or instructions. 

Coordinating transportation for evacuees 

who require it. 

Providing traffic control and security in areas being re-entered. 

Advising people to report lingering vapors 

or other hazards to emergency services. 

Advising people to seek medical treatment 

for unusual symptoms that may be attributable to the hazardous materials release. 

12/87 H-5 
H.3 IN-PLACE SHELTERING 

Evacuation decisions are of necessity very incident-specific and the use of judgment will be 

necessary. If the release occurs over an extended period of time, or if there is a fire that 

cannot be controlled within a short time, then 

evacuation may be the sensible option. Evacuation during incidents involving the airborne release of EHSs is sometimes, but by no means 

always, necessary. Airborne toxicants can be 

released and move downwind so rapidly that 

there would be no time to evacuate residents. 

For short-term releases, often the most prudent 

course of action for the protection of the nearby 

residents would be to remain inside with the 

doors and windows closed and the heating and 

air conditioning systems shut off. An airborne 

cloud will frequently move past quickly. Vulnerable populations, such as the elderly and sick, 

may sustain more injury during evacuation, than 

they would by staying inside and putting simple 

countermeasures into effect. 

There are other disadvantages associated with 

evacuation during incidents involving airborne 

releases of EHSs. Changes in wind velocity and 

direction are difficult to predict and could be 

very important if evacuation were undertaken 

during a release. Differences in temperature 

between air layers could also cause the toxic 

cloud to disperse in ways that would be hard to 

predict. These factors and others make it difficult to estimate how long the community would 

be exposed to a toxic cloud. Also, no safe exposure or concentration levels have been established for the general population with regard to 

releases of chemicals included on the list of 

EHSs. 

In-place sheltering, therefore, may be a sensible course of action, when the risks associated 

with an evacuation are outweighed by the benefits of in-place sheltering. In order for this protection measure to be effective, the affected 

population must be advised to follow the guidelines listed below: 

Close all doors to the outside and close 

and lock all windows. (Windows seal better when locked). Seal gaps under doorways and windows with wet towels and 

those around doorways and windows with 

duct tape or similar thick tape. 

Building superintendents should set all ventilation systems to 100 percent recirculation so that no outside air is drawn into the 

structure. Where this is not possible, ventilation systems should be turned off. 

Turn off all heating systems and air conditioners. 

Seal any gaps around window type air-conditioners, bathroom exhaust fan grilles, 

range vents, dryer vents, etc. with tape 

and plastic sheeting, wax paper, or aluminum wrap. 

Turn off and cover all exhaust fans in kitchens, bathrooms, and other spaces. 

Close all fireplace dampers. 

Close as many internal doors as possible in 

homes or other buildings. 

If an outdoor explosion is possible, close 

drapes, curtains, and shades over windows. Stay away from windows to prevent 

potential injury from flying glass. 

If you suspect that the gas or vapor has 

entered the structure you are in, hold a wet 

cloth over your nose and mouth. 

Tune in to the Emergency Broadcast System channel on the radio or television for 

information concerning the hazardous materials incident and in-place sheltering. 

It should be understood that following the above 

guidelines will increase the effectiveness of inplace sheltering as a protective action. Following these guidelines does not ensure that this 

type of protective action will indeed be effective. 

12/87 H-6 
APPENDIX I 

INFORMATION COLLECTION TO EVALUATE SITES

FOR EMERGENCY PLANNING

1.1 OVERVIEW 

This appendix presents a process for collecting 

information that will be needed to assess the 

hazards posed by particular sites and to develop 

community emergency plans. The National Response Team’s Hazardous Materials Emergency 

Planning Guide (NRT-1) should be consulted 

when preparing such plans. The process focuses on an examination of the sites that use, 

produce, process, or store extremely hazardous 

substances (EHSs). The types of information to 

be collected include descriptions of the chemicals present, ongoing measures for the control 

of potential releases, and the available response 

resources and capabilities at the site and within 

the community, including existing emergency 

plans. Initial requests for information should be 

made in a way that promotes continued cooperation between the personnel at the sites and 

the community planners. The information 

should be sought in a way that encourages facilities to participate actively in the planning process along with local government and other community groups. Title Ill of the Superfund 

Amendments and Reauthorization Act of 1986 

(SARA) requires facilities to assist local planning committees by supplying information and 

designating an emergency planning coordinator 

(see Chapter 1). The Chemical Manufacturers 

Association (CMA) has published A Manager’s 

Guide to Title Ill that suggests ways for participants in the Community Awareness and Emergency Response (CAER) program to cooperate 

with local planning committees. 

Many sites will already have safety and contingency plans in response to regulatory requirements or as part of normal operating procedures. The community should learn what the facility is doing to identify and deal with the possible release of acutely toxic chemicals. The plant 

site may have identified community impacts resulting from accidental chemical releases and 

have taken measures to reduce risks. The planners can then identify what additional steps and 

resources, such as personnel, training, and 

12/87 I-1 

equipment, might be needed at the facility or in 

the community. 

The information collection process is outlined 

here as a series of discussion points, which are 

presented as examples of the types of information that a community may want to use to assess 

potential hazards. A community planning committee may use some, all, or none of these discussion points. Depending on the community’s 

initial perception of potential risks, the discussion points can be tailored by the committee to 

meet specific local needs. Some of these 

points will be rather simple and direct, such as 

those used to determine what EHSs are located 

at a site, and their quantity. Other points should 

generate additional discussion, for example, 

whether any EHSs are handled or stored near 

other chemicals that are flammable, explosive, 

or reactive. If such a situation does exist, subsequent discussions should be designed to: (1) 

identify these chemicals, (2) determine how the 

facility isolates the chemical of concern (e.g., 

the chemical of concern is stored in fire-proof 

containers, or the adjacent flammable, explosive, or reactive chemical is stored under conditions to prevent leakage or explosion), and (3) 

what additional precautions are taken to ensure 

that a release will not affect the surrounding 

community. 

Planners should always be aware that: 

The specific identity of an EHS may sometimes be withheld as a trade secret. In the 

absence of specific chemical identity, however, important information such as the 

physical state and the levels of concern 

(LOCs), as defined in this document, 

should be provided. 

The information-gathering effort should not 

be adversarial but rather an attempt by all 

concerned to cooperate in describing and 

solving a potential problem facing the entire community: 

Facilities may be sensitive concerning what 

they consider proprietary business information: 
Asking a particular question does not imply 

that there is a definite problem, but rather 

shows a desire to identify and address potential problems: and 

Title Ill of SARA requires facilities to provide 

information to planners that will enable 

hazards analysis. 

1.2 ORGANIZATION 

The suggested discussion points for gathering 

and analyzing information for a hazard assessment are presented in four sections: 

Site activities and management programs: 

� Site location information; 

Site measures for managing and controlling chemical releases; and 

Site interface with community response 

and preparedness programs. 

Information obtained from these discussion 

points and the information sources discussed in 

Chapter 2 will assist the planners in assessing 

site-specific hazards and should be considered 

along with the factors used for assessing chemical releases outlined in Chapter 2 and detailed in 

Appendix H. Even if the sites have safety and 

contingency plans in place, the community planners should not neglect the procedures suggested in Chapters 2 and 3, as they will enable 

the community to assess hazards posed by different sites and to develop contingency plans in 

order of priority. 

The discussion points outlined here are far ranging. Not all of them will be necessary to elicit 

information required for site-specific assessment. However, most will need to be discussed 

for the final phase of this program, the formulation of emergency plans. For this reason they 

are included here. Planners may select those 

points that best suit their needs for each phase 

of the process. 

The first section outlines the points of information that the community planners will want to obtain about the type and quantity of chemicals 

used, produced, processed, or stored and to 

evaluate the appropriateness and timeliness of 

any planning that may already have been done 

at the site. If little emergency preparedness 

work has been done, the planners need to know 

the site’s chemical handling and processing activities, related management programs, and capability for responding to chemical release 

emergencies. 

Next, the planners will want to find out about 

those physical, topographic, meteorological, 

and demographic factors that, although external 

to the facility itself, have an important bearing on 

how to prepare for an emergency involving a release from the facility. The facility may already 

have assembled this kind of information as part 

of its internal planning process. 

Most companies, for reasons of plant and employee safety, community concern, regulatory 

requirements, or as a matter of corporate policy, have analyzed the potential on-site and offsite impact of a chemical release. Plans for promoting on-site safety, emergency plans, and 

liquid spill and hazardous waste release prevention plans may already have been developed as 

a result of standard industrial practice or regulatory requirements. If such plans are available, 

they can be a valuable starting point for the 

larger task facing the planners, that is, developing an up-to-date comprehensive community 

emergency plan, in addition to the initial task of 

ranking the site-specific hazards. 

The final step for the community planners is that 

of developing, or updating, the community 

emergency plan. NRT-1 should be consulted for 

this step. Based on emergency planning efforts 

that may already have been undertaken at the 

site, as well as on the planners’ assessment of 

the site’s activities and management programs, 

the planners can assess the adequacy of the 

site’s emergency plans and those of the community. A solid foundation will now exist upon 

which future cooperative planning and updating 

can occur. 

1.3 SITE ACTIVITIES AND MANAGEMENT 

PROGRAMS 

This section contains example discussion points 

that will assist planners in collecting basic information about the site’s processes and related 

management programs. With this information 

and using the procedures outlined in Chapter 2 

and 3, the planners can assess a site’s potential 
hazards as well as evaluate its emergency response resources and capabilities. This information will also be useful in developing a community emergency plan. The planners first need 

information about the hazardous materials that 

exist at the site and then about how these materials are handled and managed. 

1 . Chemicals of Concern That Could Be Released: 

Chemicals used, produced, processed, 

or stored that meet the criteria (see Appendix B) or are on EPA’s EHS list (see 

Appendix C), whether or not they exceed the threshold planning quantities 

(TPQs). (The specific chemical identity 

of an EHS may sometimes be withheld 

as a trade secret. In the absence of the 

specific identity, however, important information such as the physical state and 

the LOC, as defined in this document, 

should be obtained.) 

Chemicals that could result from reaction, combustion, or decomposition of 

chemicals at the site. 

High temperature, high pressure processing and storage of chemicals. 

2 . Shipping and Transfer of EHSs: 

� Frequency of shipments (daily, weekly, 

irregular schedule). 

� Quantity of shipments (tons, gallons, 

number of drums, tanks, and vats). 

� Form of shipment (e.g., tank truck, rail 

car, drums, boxes, carboys, pipelines, 

barges). 

� Transportation routes through the community (roads, railroads, pipelines). 

� Unloading systems: 

o pumping versus gravity feed systems, and 

o underground versus aboveground 

pipelines.

� Unloading procedures:

o monitoring by plant personnel, and 

o remote monitoring by tank level 

gauges, alarms, automatic cut-off 

valves, and similar means. 

3. Storage Conditions: 

Quantities normally stored in aboveground tanks and underground tanks. 

Drum storage areas (indoors and outdoors). 

Storage of gas cylinders. 

Use and operation of secondary spillcontainment systems. 

Techniques used for the separation of 

incompatible chemicals. 

Special systems used for the storage of 

reactive, flammable, and explosive 

chemicals. 

4. Handling Procedures for EHSs: 

Special safety systems used in connection with high temperature or high pressure operations. 

Secondary equipment containment systems for reactor and other processes. 

Pumping versus gravity-feed systems. 

Materials handling by automatic systems 

versus manual systems. 

Use of alarm systems for tank level 

gauging, temperature and pressure 

sensing. 

Redundancy for critical process (i.e., 

availability of back-up equipment in 

case of failure, or automatic system 

shut-down after a system failure). 

Frequency of inspection and testing of 

critical process equipment, alarm systems and similar equipment. 

5. Site Management Characteristics: 

� Hours of operation and production rates 

during different shifts (planning needs 

may differ between day and night 

shifts), 

� Degree of around-the-clock coverage 

by trained, responsible, and fully authorized technical and management staff. 

12/87 I-3 
Plant security (e.g., fencing, guards on 

duty, remote sensing by TV monitors, 

alarm connections to local police and 

fire departments). 

Plant wastewater and stormwater drainage: direct discharges to local surface 

water versus discharge to on-site or offsite treatment plants. 

Site emissions to the air covered by Federal and State environmental regulations. 

Hazardous and non-hazardous solid 

wastes generated, treated, stored, or 

disposed on-site. Wastes transported 

off-site. 

6. Site Process Design and General Operations: 

Listing and description of relevant site 

processes for synthesis, manufacture, 

formulation, repackaging, distribution, 

and handling of EHSs. 

Design and construction specifications 

covering such aspects as handling temperature and pressure, and materials’ 

compatibility. 

Process design to consider safety devices, alarms, and back-up systems to 

ensure the integrity of the process and 

to protect the facility during normal and 

unusual conditions of operation. 

Programs for managing changes in the 

design or operation of process equipment and changes in chemical component amounts, concentrations, or types. 

Preventive maintenance programs for 

facilities and equipment critical to safe 

process operation. 

Maintenance training and implementation that addresses the potential for preventing or controlling the release of 

EHSG. 

Description of “best engineering practice” and “state-of-the-art” process 

design, construction, operation, and 

12/87 I-4 

maintenance for similar facilities within 

the industry. 

1.4 SITE LOCATION INFORMATION 

These example discussion points allow the community planners to describe the vulnerable zone 

in greater detail and to assess the adequacy of 

both site and community preparedness programs. 

1. Significant Physical, Topographic, and Meteorological Features: 

Distance to site fenceline or boundaries 

from Chemical storage and process areas. 

Transportation access/egress including 

surface, air, and water routes. 

Terrain characteristics of importance 

such as mountains, hills, canyons, valleys, and plains. 

Meteorological features, including profiles of wind speed and direction, precipitation, and temperature. 

Distance to nearest surface-water body, 

including drainage ditches and other 

conduits, and flood plains. 

2. Site Demographic Characteristics: 

Distance to nearby populations such as 

communities, subdivisions, commercial 

or industrial sites, and transportation 

corridors. 

Distance to public facilities such as 

schools, hospitals, parks, playgrounds 

and stadiums. 

Numbers of people within vulnerable 

zone distances and a characterization of 

how those numbers can fluctuate hourly, 

daily, and seasonally. 

Value of property and commercial goods 

located within potential vulnerable zone. 

1.5 SITE MEASURES FOR MANAGING AND 

CONTROLLING CHEMICAL RELEASES 

This section contains example discussion points 

to help the community understand those actions 
already taken by a facility to identify hazardous 

situations and to describe the potential effects 

on people, property, and the environment. The 

planners should identify the control measures 

site management has put in place to control releases of EHSs, their by-products and decomposition products, or other chemicals that meet 

the criteria. Facilities are defined under Section 

302 of Title Ill of SARA (see glossary). 

1 . Site, Community, and Environmental Impacts of Potential Emergencies: 

Site analyses or models to predict location, intensity, and duration of hazards 

related to chemical releases. 

Community, State, or Federal activities 

or studies that the site has integrated 

with their own release modeling efforts. 

Past experiences or incidents at the site. 

Past experiences with similar chemicals 

and processes. 

Past facility and transportation incidents 

in the community involving hazardous 

materials. Relationship of past response 

efforts to possible future needs. Note 

that transporters are not required to 

keep historical records. 

Activities or studies by trade groups, 

professional societies, or academia that 

could be of value. 

2. Control and Response Plans in Operation, 

under Development, or on File: 

� Spill Prevention Control and Countermeasures (SPCC) Plan covering the release of hazardous substances as defined under authority of the Clean Water 

Act. 

� General site safety plan covering routine 

and non-routine operations, maintenance, emergencies, training, and inspections. 

� Site emergency response and preparedness plans. 

� Resource Conservation and Recovery 

Act of 1976 (RCRA) Part B Emergency 

Response Plan covering site and community response procedures and contingencies for release to the environment 

of hazardous wastes as required by the 

regulations under RCRA in 1976 and as 

amended in 1980 and 1984. 

� Site and corporate policies for developing, implementing, and updating all such 

plans. 

3. Equipment Available On-Site for Emergency Response: 

Basis for having such equipment onsite.

Description of “good practice” and

“state-of-the-art” equipment for similar

facilities within and chemicals handled

by the industry.

Fire-fighting systems (fire hydrants,

sprinklers, extinguishers, chemical fire

retardants, protective clothing).

Fogging or misting systems for vapor release control.

Neutralization materials for acids or

caustics.

Dedicated dump tanks, absorbers,

scrubbers, or flares for liquid/vapor release control.

Absorbants, foams, and specialized

Chemical agents for containing and controlling releases.

Emergency power systems in case of

power outage.

Containment booms for surface-water

spills.

4. Leak and Spill Detection Systems: 

� Basis for installation of these systems. 

� Description of “good practice” and 

“state-of-the-art” systems for similar 

chemicals handled by the industry. 

� Gas detection monitors or explosimeters 

for determining sources and severity of 

leaks. 

� Oil spill detection devices for nearby 

sewers or drains to surface-water bodies. 

12/87 I-5 
Wind direction indicators for determining 

the direction of released chemical aerosols or vapors. 

Chemical spill detection systems for corrosives, organics, and other volatilizable 

liquid spills. 

Degree to which such systems are remotely monitored and can initiate an 

automatic response. 

Activation sensors for rupture disks and 

relief valves. 

Sensors to detect overfilling of tanks and 

initiate automatic response. 

Site Emergency Response Procedures: 

Chain of command for leak or spill notification within the plant (24-hour notification system). 

Employee evacuation plan. 

Response procedures for operations and 

staff personnel. 

6. Community Notification Procedures: 

Criteria for notifying the community of a 

release. 

Procedures for notification, such as 

sounding alarms and contacting community officials, local police and fire departments, nearby populations, and the media. 

Ongoing education of citizens and workers to inform them of the exact meaning 

of notification alarms. 

7. Outside Emergency Response Resources: 

Contracts with local cleanup contractors.

Arrangements with local hospitals or

other medical facilities.

Mutual aid agreement with other local industries. 

8. Training and Preparedness: 

Frequency of employee training in emergency response procedures.

Extent of emergency response training

(training sessions, emergency drills, involvement of local police and fire departments in emergency training and drills,

which employees receive training).

Frequency of updating of contingency

plans (regular basis or only after

changes in plant operating procedures).

Inspection of emergency equipment

(frequency and extent).

Description of “good practice” and

“state-of-the-art” practices for similar

facilities within the industry.

I.6 SITE INTERACTIONS WITH COMMUNITY 

RESPONSE AND PREPAREDNESS 

PROGRAMS 

These discussion points help the community 

evaluate its emergency response resources and 

capabilities and those of the facilities. They are 

designed to identify planning activities, resources used, and response capabilities established within the community. Information will be 

required from a Variety of local emergency response agencies and government agencies. 

These discussion points may need to be addressed only once for the entire community. 

This information will be used directly to develop 

the community emergency plan and will assist 

the planners in evaluating what emergency response resources may be needed in addition to 

those already in place or planned by the facility 

or community. 

1. Planning Documents and Activities: 

Existing community hazardous chemical 

emergency plans. 

Current status of community emergency 

plan or planning process for EHSs or other 

hazardous chemical emergencies. 

Status of technical reference library or 

other information systems for response 

procedures for chemicals. 

Structure and authority of existing community planning and coordination body (e.g., 

12/87 I-6 
task force, advisory board, interagency 

committee) to plan for and deal with emergencies. 

Status of previous surveys or assessments 

of potential risks to the community from facility or transportation accidents involving 

hazardous chemicals. 

Status of any existing assessments of prevention and response capabilities within the 

community’s own local emergency response network. 

Frequency of training seminars, exercises, 

or mock accidents performed by the community in conjunction with local industry or 

other organizations. 

Integration of any existing hazardous 

chemical plans into any existing community 

contingency plans for other emergencies. 

2. Planning Review and Update: 

Community personnel and programs for 

periodic analysis, review, and update of 

the community contingency plan. 

Corporate and on-site facility officials designated to maintain and update the site 

contingency plan and to interact with the 

local emergency planning group. 

Corporate and facility policies in this regard. 

3 Training and Preparedness: 

Capacity and level of expertise of the community’s emergency medical facilities, 

equipment, and personnel. 

Arrangements for assistance from or mutual aid agreements with other jurisdictions 

or organizations (e.g., other communities, 

counties, or States; industry; military installations; Federal facilities; response organizations ). 

Availability of any specific chemical or toxicological expertise in the community -­

either in industry, colleges and universities, or on a consultant basis. 

Availability of equipment and materials on 

the local level to respond to emergencies. 

Accessibility of equipment, materials, and 

manpower in emergency situations. 

Completeness of a list of important resources and their availability for speedy response activities: wreck clearing, transfer, 

transport, cleanup, disposal, analytical 

sampling laboratories, and detoxifying 

agents. 

Training and equipment available to the local emergency services (fire, police, 

medical). 

Proximity of specialized industry response 

teams (e.g.) CHLOREP, AAR/BOE), State/ 

Federal response teams, or contractor response teams available to the community. 

Average time for them to arrive on the 

scene. 

Definition of community emergency transportation network. 

Designation of specific evacuation routes; 

public awareness of evacuation routes. 

Designation of specific access routes designated for emergency response and services personnel to reach facilities or accident sites. 

Other procedures for protecting citizens 

during emergencies (e.g., remain indoors, 

wear gas masks). 

4. Community, State, and Federal Agencies and 

Other Organizations that Can Contribute to or 

Should Have a Role in the Contingency Planning 

Process : 

Fire Department. 

Police/Sheriff/Highway Patrol. 

Emergency Medical/Paramedic Services 

associated with local hospitals or fire or police departments. 

Emergency Management Agency/Civil Defense. 

Public Health Agency. 

Environmental Agency.. 

12/87 I-7 
Red Cross. 

Other local community resources such as 

transportation department, public housing, 

communications. 

5. Communications: 

A list of specific community points of contact and a description of what their duties 

and responsibilities are in an emergency. 

Agencies involved, areas of responsibility 

(e.g., emergency response, evacuation, 

emergency shelter, medical/health care, 

food distribution, control of access to accident site, public/media liaison, liaison with 

Federal and State responders, locating and 

manning the command center), the name 

of the contact, position, 24-hour telephone 

number, and the chain of command. 

Status of the emergency communications 

network in the community to alert the public, keep the public informed with up-todate information, and provide communications between the command center, the 

accident site, and off-scene support. 

Components available for the communications network (e.g., special radio frequency, network channel, siren, dedicated 

phone lines, computer hook-up). 

Status of community source list with the 

name, position, and phone number of a 

contact person for technical information 

assistance. This can be Federal, State, industry associations, and local professional 

groups. 

I-8 
APPENDiX J 

METHODS FOR EVALUATING HAZARDS USED BY FACILITIES 

J.1 INTRODUCTION 

Many facilities will have undertaken detailed 

analyses of their plant operations. This appendix 

describes three procedures which they may 

have used to evaluate hazards in everyday operating procedures. They are Hazard and Operability Study (HAZOP), Event Tree Analysis, and 

Fault Tree Analysis. Some community planners 

may wish to use these methods or at least be 

familiar with them. It may be possible for planners to use such studies if they are available for 

the facilities of concern. The prodcures discussed below, as well as others, are described 

in detail in Guidelines for Hazard Evaluation Procedures prepared by Battelle Columbus Division 

for the Center for Chemical Plant Safety of the 

American Institute of Chemical Engineers 

(AIChE). These methods for risk analysis are 

highly complex and the methodologies employed are under continual development by experts in the field. It is therefore suggested that 

planners intending to use these methodologies 

seek appropriate technical support. 

J.2 HAZARD AND OPERABILITY STUDY 

A HAZOP is a technique commonly used by 

chemical process facilities to identify hazards 

and difficulties that prevent efficient operation. 

There are two versions of the technique, one 

which deals with “deviations” and the other with 

"disturbances.” “Deviations” are caused by 

malfunction or maloperation of a specific production system. ‘Disturbances” include problems caused by influences outside the specified 

system, including other activities and the environment. 

The first version of HAZOP to be developed and 

the most widely known was aimed at deviations 

and is called a “Guide Word” HAZOP. Each element of the process is evaluated separately. 

The purpose of the element is specified and 

notational deviations are generated by associating this purpose of the element with distinctive 

words or phrases called “guide words.” These 

guide words are “no” or “not," “more,” “less,” 

“as well as," " part of,” "reverse,” and “other 

than” which, broadly speaking, cover all possible types of deviation. 

For each notational deviation, a determination 

must be made whether this is a possible situation (e.g., no flow or reverse flow in a transfer 

line that should have forward flow). If this is 

possible, the conditions in which that situation 

might occur and the possible hazardous consequences must be identified. The guide words 

are applied to all materials and all operating parameters (e.g., flow, temperature, pressure). 

The guide words are applied not only to the 

equipment, but also to the operating procedures. All phases of operation (e.g., startup, 

normal operation, shutdown, backwash) must 

also be included. As would be expected, this 

approach can be time-consuming and the time 

taken can vary from several days for a small 

production unit, to several months for a complex 

facility. 

The second version of HAZOP studies is called a 

“creative checklist” HAZOP. This version has 

been developed as a complement to the guide 

word HAZOP to cover “disturbances." It is of 

particular value in two situations. These are to 

enable a HAZOP study to be carried out very 

early in the design process, even before the detailed design necessary for a “guide word” 

HAZOP is available; and to cover hazards which 

may be caused by interactions between units 

which could be perfectly safe if built in isolation, 

but may be capable of adverse interactions. 

This second method uses a checklist of known 

major hazards and nuisances. The checklist 

would contain words such as “fire,” “explosion," “toxicity,” “corrosion,” ”dust,” and 

“smell.” The checklist is initially applied to 

every material likely to be present; raw materials, intermediates, finished products, byproducts and effluents. This establishes qualitatively whether hazards and nuisances exist and 

also provides a quantitative data base of the numerical intensities of different hazards. Thus 

“fire” would result in not only a note that a material is flammable but numerical measurements 

such as a “flash point” and “flammable limits.” 
Any missing data are pinpointed and timely 3. Track what the actors will do under the cursteps taken to collect such data. rent conditions: and 

The Second method continues with the association of the same checklist with each item of 

equipment. The materials present in such 

equipment, together with the inventories, are 

known as the “materials hazards.” As the 

analysis proceeds, the potential for all major 

hazards including interactions between units or 

the unit and its environment are identified. The 

flow of hazards can be in both directions. For 

example, the environment may pose hazards to 

the unit (e.g., flooding and earthquakes), which 

would have to be considered in the siting, design, and layout of the unit. Although less well 

known than the guide word HAZOP, the creative 

checklist HAZOP has been found to be a quick 

and valuable complementary approach. 

While local emergency planners will not possess 

the resources or need to perform a HAZOP on 

all facilities in the community, the concept of 

analyzing deviations from normal performance 

could be the best way to analyze the most hazardous elements found in the community. For 

example, if a shipping error caused a volume of 

a hazardous chemical to be delivered to a local 

facility that exceeded the capacity of the chemical material loading area, where would the excess material be placed? If part of a train stored 

on the local rail siding caught fire, is there sufficient space available to segregate the chlorine 

tank cars that are often kept there? 

J.3 EVENT TREE ANALYSIS 

Event tree analysis is a systematic approach that 

focuses primarily on a chain of events or occurrences. While the possible outcome of some 

events may be intuitive, complex situations must 

be broken down into a series of sequential 

events. 

The steps in event tree analysis are: 

1. Identify the actors in an emergency (e.g.,

hazardous materials, response personnel);

2. Identify the conditions present; 

12/87 J-2 

4. Visualize the effect of the activities on the 

outcome of the event. 

The following example analysis from Analysis of 

Hazardous Materials emergencies for Emergency Program Managers: Student Manual 

FEMA SM-110 (see Appendix L) visualizes the 

potential outcome of a leaking vessel (in this 

case a drum) of flammable liquid engulfed in a 

fire. In this situation, the actors and their activities include: 

• Burning fuel is heating the drum: 

� Drum is absorbing heat from the burning 

fuel and heating the contents; and 

• Contents of drum are absorbing heat from 

the drum. 

The complex activities of the emergency are divided into sequential events in which the burning 

fuel generates heat, causing the drum contents 

to change physical state (liquid to gas). This 

expansion of the contents will raise the pressure 

in the drum and stress the drum components. 

The possible activities of the drum can then be 

evaluated. Possibilities include: 

• The flat drum head will begin to round out 

as the internal pressure continues to rise: 

• The weld between the drum head and the 

drum wall will begin to yield: and 

• The drum head will separate from the drum 

wall. 

When the drum head breaks away from the side 

wall, activities of the contents could include: 

� As the pressure is relieved through the 

breach in the drum, the heated contents 

will expand and flow through the breach. 

� Drum contents will escape to the atmosphere, creating a new actor -- vaporized 

flammable contents. 

� Escaping contents will produce a propulsive effect on the drum, propelling it like a 

rocket. 
If the drum is still surrounded by the burning fuel, the vaporized contents will ignite, 

forming a fireball and escalating the problem. 

When the drum is open, possible activities of the 

drum and contents include: 

The drum, propelled by the escaping contents, may fly along a trajectory that is dependent upon where the drum was heated. 

Obstructions may change the direction or 

distance of travel. 

• The released contents may fall along the 

flight path of the drum, leaving a trail of 

burning material along the ground. 

The third step in event tree analysis visualizes 

the sequential interrelationship of the actors. 

Each event is broken down and placed in logical 

sequence to make the possible points of intervention readily apparent. In this way, the application of event tree analysis provides a detailed 

understanding of the mechanical, chemical, and 

thermal interactions that affect the behavior of 

actors in an emergency. 

Four general factors that affect the behavior of 

hazardous materials in an emergency are: 

• Inherent properties and quantity of the hazardous material: 

• Built-in characteristics of the container; 

• Natural laws of physics and chemistry; and 

� Environment, including the physical surroundings (terrain) and the conditions 

(weather). 

These factors and their interrelationships can 

provide a basis for visualizing what will happen in 

an emergency involving hazardous materials. 

For most events involving hazardous materials, 

the scenario begins with a container (e.g., tank, 

pipe, drum, cylinder, bag) that under normal 

conditions holds a hazardous material. The 

event begins when the container is disturbed or 

stressed in some way. When the stress exceeds the capacity of the container, a breach of 

the container’s integrity occurs and some type 

of release will occur. The escaping matter and/ 

or energy will follow the patterns governed by 

the natural laws of physics and chemistry to disperse into the surrounding environment. As the 

material comes in contact with vulnerable elements in the environment, the duration and intensity of the exposure influences the type of 

event that results. These basic elements of hazardous events are combined to form a model for 

the behavior of hazardous materials. 

Stress Stage of the Behavior Model 

Stress is an applied force or system of forces 

that tends to strain or deform a container and 

may trigger a change in the condition of the contents. There are three basic forms of stress: 

thermal, mechanical, and chemical. Thermal 

stress results from the effects of extreme temperature changes which may be caused by fire, 

sparks, friction, electricity, radiative transfer, or 

extremes of cold or heat. 

Mechanical stress is caused by an object which 

physically contacts the container. The object 

may puncture, gouge, bend, break, tear or split 

the container. A chemical stress is caused by a 

chemical action such as acids corroding the 

container, pressure generated by decomposition, polymerization, or runaway reactions. 

Breach Stage of the Behavior Model 

If the container is stressed beyond its structural 

limits, it will open or breach. Different containers breach in different ways: 

Disintegration, which is the total loss of integrity (e.g., a glass jar shattering). 

Attachments open up (e.g., a pressure relief device malfunctions). 

Punctures from external sources. 

A split, tear or crack of a container (e.g., 

torn bags or boxes, or split or cracked 

drums). 

Release Stage of the Behavior Model 

Once the container is breached, the material 

can escape to the environment. There are four 

types of release: 

• Violent rupture causes runaway cracking of 

closed containers and Boiling Liquid Ex12/87 J-3 
panding Vapor Explosion (BLEVE), and occurs in less than one second. 

Rapid release through pressure relief devices, damaged valves, punctures, or broken piping will take several seconds to several minutes. 

A spill or leak, which is a non-violent flow 

through opening in fittings, splits or tears, 

and punctures may take minutes to days. 

Detonation is an explosive chemical reaction which occurs in less than 1 /100th of a 

second. Examples are military munitions, 

dynamite, and organic peroxides. 

Dispersal Stage of the Behavior Model 

Once the hazardous material is released into the 

surrounding environment, the event is likely to 

escalate in intensity. The properties and characteristics of the material, in combination with 

the laws of physics and chemistry, will determine the pattern of the distribution of matter and 

energy. The forms that the matter or energy 

may take include: fragments, powder, dust, 

schrapnel, liquid, vapor, vaporizing liquid, 

gases, infared rays, and shock waves. Factors 

that will affect the movement of materials include temperature differentials, density with respect to water and air, wind speed and direction, and gravity. The dispersion path that is followed may be linear, radial, random, or could 

follow the contour, upward or outward. The dispersion pattern may be in the form of a cloud, 

cone, plume, stream, or irregular deposits. 

Dispersion patterns will also depend on the 

physical form of the material (i.e., gas, liquid, or 

solid). Gases escaping under pressure (e.g., 

leaks from a cylinder) form a cloud or plume. If 

enclosed, the cloud will fill the available space: if 

not enclosed, it may be carried by the wind as a 

plume. If the vapor’s density is greater than air, 

the material may settle into depressions or travel 

along the ground as a plume. 

Liquids may flow along the ground as a stream 

while simultaneously vaporizing and acting as a 

gas (stream with plume) or may be absorbed 

into the ground or onto clothing worn at the 

scene (irregular deposits). Solids may scatter 

(irregular deposits), form dust clouds that are 

carried by the wind (plume), or stick to surfaces 

(irregular deposits). 

Exposure Stage of the Behavior Model 

As the hazardous material moves away from the 

point of release, exposure to the surrounding 

environment may occur through a variety of 

pathways including: ingestion, physical contact, 

and inhalation. Duration of the exposure and 

Concentration of the material are particularly important aspects of the exposure event. 

Damage Stage of the Behavior Model 

Damage due to the exposure to the hazardous 

material includes aspects of the susceptibility of 

the environment or population. Such susceptibility will differ markedly depending on the time 

of day, season of the year, age of the population, and ability of the population to escape or 

otherwise mitigate the event. 

The types of damage which may occur include: 

thermal (heat and cold), radioactive, asphyxiation, toxic or poison, corrosive or chemical, 

disease (viral or bacterial), and physical or mechanical. 

Damage can be expressed in terms of: fatalities, injuries, property destruction, critical system disruption, and environmental disruption. 

As shown in Exhibit J-1, event tree analysis 

traces each event, as it occurs or does not occur, and each safety or control equipment or 

procedure to identify the possible outcome. 

Note that several paths through the event tree 

can have similar or identical outcomes. It is important to trace all possible events through all 

paths that can affect the outcome. In addition to 

identifying the possible outcomes and their relative severity, an event tree can visually represent the potential importance of possible equipment or procedures in mitigating the severity of 

damage. In the example in Exhibit J-1, if both 

hazardous events occur and procedure A fails, 

the control procedure B is completely ineffective 

in altering the outcome or severity of damage. 

5.4 FAULT TREE ANALYSIS 

Fault tree analysis (FTA) is an analytical technique used to determine the means by which an 

12/87 J-4 
Exhibit J-l 

Sample Event Tree Analysis 

12/87 J-5
unwanted event, such as a release of toxic materials, could possibly occur. The technique, 

which in structure is similar to the event analysis 

technique, involves the development of fault 

tree diagrams which illustrate the “chain of 

events” required for a particular event to occur. 

Fault tree analysis reverses the normal sequence of events and places the undesirable 

event under study (i.e., head event) at the top 

of the diagram. The incident is assumed to have 

occurred and sub-events which represent the 

means by which this event could occur are inserted below. Sub-events which are interrelated (i.e., dependent incidents), in that they 

must both occur before the subsequent event 

can occur, are related by a logical “and.” Subevents which are unrelated in that the occurrence of any one sub-event would cause the 

subsequent event, are connected with a logical 

"or.” For example, in the analysis of the overflow of a storage tank that is being filled with 

gasoline, in which the storage tank has a highlevel alarm, the associated fault tree might be 

constructed as in Exhibit J-2. The head event is 

that the tank overflows. 

The fault tree technique only considers those actions which must occur for the head event to occur, and therefore isolates the events of importance from the many possible events. In the example, in order for the tank to overfill, there 

must be an increase in the tank level of the flammable liquid (gasoline) (sub-event 1) and no 

corrective action taken before overfilling (subevent 2). 

Since both sub-event 1 and sub-event 2 must 

occur before the head event occurs, the two 

events are connected to the head event by an 

“and” (i.e., sub-event 1 and sub-event 2 must 

occur to have the head event occur). 

The fault tree analysis continues down the tree 

and breaks each of the sub-events into their 

components in a similar manner (i.e., if no corrective action occurs, there must be a high level 

alarm failure or an operator failure). 

Sub-event 2 would then be divided into: 

Sub-event 2.1. High Level Alarm Fails 

Sub-event 2.2. Operator Fails 

12/87 J-6 

The analysis continues until the sub-events can 

not be practically subdivided further. The determination of this point is left to the judgement of 

the analyst. Exhibit J-2 illustrates an example of 

the beginning of a simple fault tree: however, 

this event might need to be subdivided further to 

reach the practical limits of the analysis. 

As the number of sub-events increases due to 

system complexity, the fault tree can become 

very complex. The analyst can limit the effort 

involved by carefully selecting the scope of the 

head event and by limiting the level of detail 

considered in the analysis. 

Fault tree analysis is useful for describing the interrelationship of events or components of a 

system which must “fail” for an accident to occur. Since only the negative actions (i.e., failures), and only those actions related to the actual head event are considered, the technique is 

often an efficient means of analyzing complex 

scenarios or systems. 

J.5 FAILURE MODES, EFFECTS, AND 

CRITICALITY ANALYSIS 

As described in the AlChE document, Guidelines 

for Hazard Evaluation Procedure, Failure 

Modes, Effects, and Criticality Analysis (FMECA) 

and Failure Modes and Effects Analysis (FMEA) 

identify and tabulate equipment and system failure modes and the potential effects on the system or plant for each failure mode. The failure 

mode is a description of how equipment fails 

(e.g., open, closed, on, off, or leaks). The effect is the accident or system response resulting 

from the failure. The FMECA also includes a 

criticality ranking for each failure mode. Single 

failure modes that result in or contribute to a 

major accident are identified; however, FMECA 

is not efficient for identifying combinations of 

equipment failures that lead to accidents. 

FMECA may be used to supplement more detailed hazard assessments such as HAZOP or 

Fault Tree Analysis. Results of this type of 

analysis include worst-case estimates of the 

consequences of single failures and a relative 

ranking of equipment failures based on estimates of failure probability and/or hazard severity. 
Exhibit J-2 

Example Fault Tree 

12/87 J-7

APPENDIX K 

EVALUATION GUIDE FOR AVAILABLE COMPUTER

APPLICATIONS ADDRESSING HAZARDOUS MATERIALS

EMERGENCY RESPONSE PLANNING

PURPOSE OF THIS CHECKLIST 

This appendix contains a checklist of criteria developed to help local emergency planning committees (LEPCs), or other groups considering 

purchasing software, to identify computerized 

applications to assist in emergency response 

planning as outlined in the chapters of this document. The checklist identifies many of the ways 

that software applications can be of assistance. 

The priorities and needs of the local planning 

district will dictate which criteria are to be considered and may require development of additional criteria. 

SOURCES OF INFORMATION USED TO 

DEVELOP THE CHECKLIST 

The checklist criteria were developed from information in the National Response Team’s Hazardous Materials Emergency Planning Guide 

(NRT-1) and this technical guidance document. 

NRT-1 was designed to help local communities 

respond to potential incidents involving hazardous materials. This guidance document supplements NRT-1 by identifying the facility and transportation route information necessary for hazards analysis and emergency planning, providing 

guidelines for determining vulnerable zones, and 

outlining the process for analyzing risks. 

Understanding the planning processes described 

in these documents and how the information being assembled will be used is a prerequisite for 

determining which computer application will best 

address the specific set of needs involved. 

STRUCTURE OF THE CHECKLIST 

Section 1. Provides a checklist for evaluating 

the computer hardware (equipment) and additional software (programs) required to operate the system. The flexibility and ease of 

use of the system and the availability of 

training and other types of vendor support 

are also addressed. 

The next sections of the checklist are based on 

the structure of this Guidance Document, and 

include: 

Section 2. Hazards Identification (assembling 

facility, transportation route, and chemical 

data); 

Section 3. Vulnerability Analysis (modeling of 

releases); 

Section 4. Risk Analysis (ranking of hazards); 

and 

Section 5. Emergency Response Planning (assembling hazards identification, vulnerability 

analysis, and risk analysis information). 

Section 6. Regulatory Requirements. This section describes a few of the ways that a software application can explain the requirements under Title Ill and assist in compliance 

with requirements, such as tracking deadlines and responding to requests for information. 

NOTE: This checklist highlights some important user costs to be considered, however the 

total system cost is difficult to represent. Some 

software applications may require the purchase 

of specialized hardware or additional software 

from other manufacturers. Vendors may include fees for tailoring of the software application to meet a user’s needs in the original price. 

Training, manuals, technical support services, 

additional data entry, software updates, and additional copies of the software may be included 

or may need to be purchased separately. 

1 National Response Team. Hazardous Materials Emergency Planning Guide. NRT-1 (March 1987). 

12/87 K-l 
In addition to the initial purchase costs of the application, the long-term investment required to 

install, maintain, and operate the full working 

system must be considered. Such costs will include: assembling the required data: validating 

and entering the data: training new personnel; 

purchasing updated software: and correcting 

and amending the data as changes occur. 

These costs will apply to some extent to any application purchased. Assistance in estimating 

some of these costs may be available from data 

processing professionals within the State government or from computer-oriented firms located within the district. 

SUGGESTED PROCEDURE FOR EVALUATING 

EMERGENCY RESPONSE PLANNING SOFTWARE APPLICATIONS 

The suggested procedure for LEPCs to use the 

checklist is as follows: 

1. Identify the local district’s need to manage 

emergency response planning information 

under NRT-1 and this Guidance Document. 

Understanding how the information is to be 

used in the planning process is an essential first step to focusing the evaluation on 

the needs. 

2. Select the criteria on the checklist which 

most closely represent the local district’s 

needs and priorities for emergency response planning. It is not expected that all 

criteria listed will apply. 

3. Develop any additional criteria required to 

address local needs and priorities (e.g., 

consistency with the type of computer 

equipment that is already available). 

4. Rank the criteria according to levels of importance (e.g., must be met, would be 

valuable, can be delayed). 

5. Identify vendors and their emergency response software from the available literature, advertising, and other sources. An 

initial list of commercial software applications will be made available through the Environmental Protection Agency (EPA) 

emergency preparedness coordinator in 

each EPA regional office. 

6. Request information from the vendors 

(e.g., sales literature, demonstration software, cost information, and current users 

of the application who can be contacted as 

references). 

7. Review the information and complete a 

checklist for each software application. 

6. Contact vendors to request any additional 

information and to clarify data on the applications which seem best suited to the 

need. 

CAUTIONS: An evaluation include the specific priorities and needs of the individual jurisdiction. 

Any comparison of the cost of computer applications requires the assessment of many factors 

in addition to the purchase price identified by the 

vendor. (See NOTE on previous page for a detailed discussion of costs.) 

Computer systems are continually being modified and refined. The results of the evaluation 

will become out-of-date and should be repeated 

if the purchase of a system is delayed. 

12/87 K-2 
CRITERIA FOR THE REVIEW OF COMMERCIALLY AVAILABLE 

SOFTWARE APPLICATIONS FOR EMERGENCY RESPONSE PLANNING 

Computer System Requirements (Hardware, Software, Support, Etc.) 

Objective: Provide a basis to evaluate the functional capabilities, design limitations, and operational requirements of the system, and to evaluate the vendor’s ability and willingness to support 

the system. 

Criteria Explanation/Examples 

1. Demonstrations of the software 

application are available? 

2. Documentation of the software 

is available for review? 

3. Software application is available 

for a trial evaluation? 

4. Vendor is willing to modify the 

application? 

5. Software is compatible with 

hardware that is already available 

or hardware that can be easily 

obtained? 

6. Computer system hardware memory 

can be expanded to meet the 

anticipated needs? 

7. Requires additional software to 

be purchased from other companies 

to function? 

8. Sold as modular components which 

are priced separately? 

9. Total system cost is consistent with 

budget capabilities of user? 

Either a professional sales demo or

current user demo may be available.

User’s manuals and other explanatory 

material from the vendor. 

30-day free trial may be available

from the vendor.

The application may require changes

by the vendor to allow specific community

needs to be addressed.

Microcomputer; monitor: graphics board:

modem: phone line: math co-processor:

data storage space: digitizer:

printer or plotter.

Hardware can accept additional memory

required to load the software

and modify the largest data file needed.

Operating system: printer interface:

graphics package.

Modules may be selected and 

assembled to meet specific 

requirements (NOTE: the software may 

require purchasing several modules 

to function properly.) 

Costs of hardware, software, training, 

and data input may be hidden. 

12/87 K-3 
Computer System Requirements (Continued) 

Criteria Explanation/Examples 

10. Limits hardware and data access by 

unauthorized users? 

11. User friendly and requires a 

minimal amount of user training? 

12. Vendor provides additional training 

which may be required? 

13. Allows data that was entered 

by the system vendor to be 

updated by the user? 

14. Allows new types of data to be 

entered by the user which were 

not included in the vendor’s 

application? 

15. Limits copying or distribution 

by copyright or copy protection? 

16. Validates data as it is entered 

or stored in the application? 

17. In addition to using established keywords, 

allows searches to be performed with 

criteria chosen by the user? 

18. Quality data sources were used 

and updates will be available 

as source information changes? 

19. Allows reports or graphs to be 

designed by the user? 

Access may be limited through passwords 

and/or encryption of stored data. 

Menu driven: provides help screens: 

clearly presented instructions: uses a 

mouse or touch screen. 

Training classes and materials may 

be required when the system is installed 

and as employees are hired: cost of training 

should be considered. 

Allows modification of procedures 

for handling a spill or release according 

to facility or community practices. 

A new field of data can be added to 

the database (e.g., new type of chemical 

information: facility response procedures). 

Some vendors limit the ability to 

make copies of the software and require 

copies to be purchased for each user. 

Tests data against valid ranges (e.g., pH <14) 

or lists of acceptable data (e.g., chemical 

names). 

Data can be identified by other 

than preset criteria such as through a menu 

(e.g., user defined searches). 

Chemical data content is current and 

generally accepted by science and 

health agencies such as EPA, OSHA, NIH, 

NOAA, U.S.Coast Guard, DOT, and others: 

cost and timeliness of updates should be 

considered. 

User can specify data to be included, 

physical layout, and headings for 

columns of data. 

12/87 K-4 
Computer System Requirements (Continued) 

Criteria Explanatiorn/Examples 

20. Allows data to be transferred System can communicate with other systems 

(input and output) with other (e.g., Lotus, dBASE, ASCII and DIF data 

types of software packages and formats: Macintosh and IBM equipment). 

hardware systems? 

21 Is in use by others who are Vendors may provide names of current 

willing to provide information users of the system who would be 

on their experience? willing to discuss their experience. 

22 Will the system software and New capabilities that are compatible 

data be updated by the vendor? with the current system may be added. 

23 Vendor provides continued service If this type of service is available, a 

and support if the user experiences maintenance and support fee will probably 

any type of difficulties in operating be charged. 

the system? 

HAZARDS IDENTIFICATION 

Objective: Provide information on the identity, quantity, location, physical properties, and toxicity 

of chemicals at sites within the planning district. 

Criteria Explanation/Examples 

Facilities 

1. Accepts data on one or more 

manufacturing and storage facilities? 

2. Accepts chemical inventory and 

storage data? 

3. Accepts information concerning 

facility accident potential or 

history? 

4. Records or describes engineering 

controls and safeguards at 

specific facilities? 

Locations: activities: and inspection records. 

Chemical names; quantities: site 

location(s); storage methods, temperature, 

and pressure. 

Events that could result in damage; 

anticipated damage and consequences: 

and historical accident records. 

Detection, fire suppression, and 

security systems: containment and 

drainage systems: and utility shutoffs. 

12/87 K-5 
HAZARDS IDENTIFICATION (Continued) 

Criteria Explanation/Examples 

Transportation Routes 

1. Records shipping routes taken to Identifies route taken and materials 

deliver materials to facilities transported. 

(e.g., highway, rail, and air)? 

2. Accepts information on the Routes may create problems because of: 

major safety characteristics width: access: traffic patterns: and 

of routes? jurisdictions. 

3. Logs transportation data, Tracks planned cargo shipments for 

schedules, and exceptions? location and time expected. 

Chemical Information 

1. Database contains information As required by the Title Ill regulations 

concerning the extremely (i.e., threshold planning quantities). 

hazardous substances? 

2. Contains information about the Flammability; reactivity; corrosivity; 

chemical and physical properties? vapor pressures: physical states: boiling and 

melting points. 

3. Contains the health hazards and Exposure routes and limits: signs and 

risks, toxicological data, and symptoms: target organs: and medical 

first aid procedures? conditions aggravated by exposure. 

4. Contains methods for the safe Identifies the equipment, clothing 

handling and use of the chemical, and procedures required. 

and emergency response? 

5. Indicates if notification Identifies notification requirements 

requirements apply to the for release of reportable quantities 

chemical released? of chemicals (e.g., CERCLA, SARA). 

12/87 K-4 
VULNERABILITY ANALYSIS 

Objective: Identify geographic zone of the community that may be affected by an airborne release 

and populations that may be subject to harm. 

Criteria Explanation/Examples 

1. Accepts information on critical areas 

around facilities and routes? 

Drinking water supplies: cropland; 

livestock: sensitive natural areas. 

2. Accepts information on the 

characteristics of populations located in 

areas that could be in the vulnerable 

zone? 

Location of special populations 

(e.g., elderly: handicapped: hospitals: 

prisons; schools) and population density. 

3. Calculates the vulnerability 

zone based on the maximum quantity 

present for screening? 

Calculations are based on credible worst 

case assumptions identified in this technical 

guidance document. 

4. Allows site-specific inputs to the 

calculation of vulnerability zones 

and provides release scenarios? 

Calculations are based on site-specific 

planning factors such as wind speed, 

stability class, and chemical toxicity. 

Modeling the Release of Chemicals (predicting the path, the effect, and the area of impact of the 

chemical release using mathematical analysis) 

Inputs (information that drives the model) 

1. Accommodates physical 

characteristics of the chemical? 

2. Addresses different types of 

releases? 

3. Supports multiple point sources? 

4. Address releases from any source 

or only pre-selected sources? 

Liquids at boiling point or ambient temperature;. 

powdered solids: solids in solution: 

molten solids: gas density. 

Instantaneous and continuous releases 

including spills, leaks, fires, explosions, 

and BLEVEs. 

Several release sources operating concurrently. 

Modeling ability may be limited to a specific set 

of pre-established sites or may be capable of 

representing releases from any possible location 

(e. g., transportation accident). 

12/87 K-7 
VULNERABILITY ANALYSIS (Continued) 

Criteria Explanation/Examples 

5. Accepts data on meteorological 

conditions? 

Wind velocity and direction: 

temperature: stability class: precipitation. 

a. Allows observed data to be 

manually input? 

Data are typed into the system using 

the keyboard. 

b. Allows a modem link for 

direct data entry? 

Accepts data directly from 

laboratories or weather stations. 

c. Requires a meteorological 

tower for data input? 

Facility or community meteorologic 

tower is required for data collection. 

6. Accepts data input for the 

level of concern? 

Uses the data entered to calculate 

the vulnerable zones. 

Algorithms (equation(s) and assumptions used to calculate the results such as the concentration 

of the plume of released chemicals) 

1. Employs dispersion models that 

are consistent with those used 

in this technical guidance 

document? 

2. Identifies the types of assumptions 

used? 

3. Calculates chemical dispersion 

rates and routes? 

4. Supports terrain modeling and 

considers complex terrain? 

Gaussian dispersion models based on 

Turner’s Workbook of Atmospheric 

Dispersion Estimates, PHS Pub. No. 

999-AP-26. Different air stabilities and wind 

speeds are used. 

Some models are not documented to provide 

information on the assumptions used to 

perform calculations and their effect on the 

model’s results, or the limits of the model’s 

ability. 

Provides information on the plume size, 

motion, and concentration over time: and 

predicts toxic corridors. 

The ability to accommodate site-specific 

effects of terrain can be significant under 

some circumstances. 

Outputs (the results of the calculations performed) 

1. Presents pictorial representation Presents model output as dispersion 

of dispersion plumes? plume overlaid on a map of the area. 

12/87 K-8 
2. Produces line, bar, or pie graphs? Presents model output in graphical format 

(e.g., concentrations experienced at a 

location over time). 

3. Retains the results of calculations Systems differ in their ability to re-enact a 

in final form for future review or stores series of calculations or to reproduce a 

the input parameters to allow the specific output. 

results to be reproduced? 

RISK ANALYSIS 

Objective: Provide a basis to judge the relative likelihood (probability) and severity of various possible events. Risks can be expressed in qualitative terms (high, medium, low) based on subjective, common-sense evaluations, or in quantitative terms (numerical and statistical calculations). 

Criteria Explanation/Examples 

1. Allows judgement to be made 

concerning facilities and routes, 

for probable hazard and severity 

of consequences? 

Judgement may be based on the accident 

history, type of facility, storage conditions, 

control technologies in place, and other 

factors. 

2. Assembles quantitative facility 

information concerning possible 

release scenarios? 

Recognized systematic approaches include: 

hazard operability study (HAZOP): 

event tree analysis: fault tree analysis. 

3. Allows priorities to be recorded 

according to community concerns 

and opinions? 

Judgement and concerns of the 

community can be entered into the 

ranking and prioritization for community hazards. 

12/87 K-9 
EMERGENCY RESPONSE PLANNING 

Objective: Assemble detailed information concerning hazards, vulnerability, and risk; provide 

action outlines for responders and criteria for plan review; present maps of the local area; and 

provide simulation capabilities for training. 

Criteria Explanation/Examples 

1. Provides detailed methods for promptly 

identifying the affected area and 

population based on release 

information? 

a. Maps facility locations and

transportation routes?

b. Plans routes for hazardous

chemical shipments?

2. Accepts emergency information and 

plans provided by chemical facilities? 

a. Records facility emergency

contacts?

b. Generates floor plans of

facility storage sites?

c. Indicates location of

engineering controls/safeguards?

3. Provides an action outline for 

emergency responders? 

4. Identifies the needed emergency 

response equipment for various 

types of emergencies? 

5. Stores the inventory of local 

response equipment and provides 

location and availability 

information? 

Mapping: modeling; demographical 

statistics: worst case release. 

Provides details of relative

locations of hazards and vulnerable zones.

Based on characteristics of routes

available, selects the least dangerous route.

Plans; procedures: site diagrams:

emergency checklists.

Provides names, titles, and 24-hr. phone

numbers for emergency purposes.

Shows building layout and chemical

locations graphically.

Identifies safeguards such as

emergency shut-offs graphically, or

by detailed description of the location.

Provides a chain of events or considerations

that is based on the site-specific conditions

involved.

Provides a decision aid for choosing

proper equipment and required medical

supplies based on the chemicals involved.

Assists in the identification of equipment

available from chemical facilities, local

emergency responders, hospitals,

other communities, and private

contractors.

12/87 K-1O 
EMERGENCY RESPONSE PLANNING (Continued) 

Criteria Explanation/Examples 

6. Stores information on community 

emergency procedures and plans? 

7. Provides criteria for evaluating 

existing emergency response 

functions? 

8. Prompts for information to update 

emergency response plans? 

9. Identifies hazardous material 

training program requirements 

and stores training information 

and schedules? 

10. Provides simulation capabilities 

for training? 

Direction and control; communications:

evacuation and sheltering: medical

treatment facilities: resource management:

cleanup and disposal: decontamination: and

documentation.

Identifies the essential elements that

should be present in the plans based

on regulatory requirements and local

community priorities.

Flags information that changes frequently

(e.g., emergency contacts, telephone

numbers, and addresses).

Provides criteria for evaluation of training

programs and stores information on

training completed per regulatory

requirements.

Provides example test emergencies to

exercise the plan and train response personnel.

12/87 K-11 
IDENTIFICATION OF REGULATORY REQUIREMENTS

Obiective: Track regulatory deadlines and assist in the assessment of compliance with reporting 

requirements, as well as record the status of required information and log requests for information. 

NOTE: These criteria concentrate on planning and response requirements of Title Ill of SARA. The 

following is only a partial list of the possible capabilities that computer applications may possess 

with 

regard to the identification of regulatory requirements. 

Criteria Explanation/Examples 

1. Tracks deadlines for reporting Deadlines for reporting as required 

requirements under Title Ill of under Title 111 of SARA Sections 302, 304, 

SARA? 311-312, and 313. 

2. Provides a means to respond to Report capabilities may include 

information reporting requirements production of the submission forms or 

of Title III of SARA? letters or partial assembly of the needed 

information. 

3. Has the capability to store and Data manipulation including cross 

manage MSDS and chemical indexing lists to identify all facilities 

inventory form data? using a particular chemical. 

4. Addresses public requests for Record type and number of requests 

information under Title Ill of SARA? and provide information to answer them. 

5. Tracks the status of planning Identify when a plan was developed 

in the local districts? and when it was last updated. 

12/87 K-12 
APPENDIX L 

SELECTED BIBLIOGRAPHY 

This appendix lists some other documents that may prove helpful to anyone organizing a community 

awareness and preparedness program for responding to releases of extremely hazardous substances 

(EHSs). 

1. Hazardous Materials Emergency Planning Guide (NRT-1). Washington, D.C.: National Response 

Team: prepared by ICF Incorporated, 1987. 

NRT-1 was prepared to comply with the requirement in Section 303(f) of SARA. It contains general 

guidance on selecting and organizing the planning team, and describes how to carry out fundamental 

planning tasks (e.g., review existing plans, assess response capabilities, conduct a hazards analysis). 

The guide describes in detail what should be included in a hazardous materials emergency plan and 

suggests how this material could be organized. 

NRT-1 can be obtained free of charge from:. 

Hazmat Planning Guide WH-562A

401 M Street, S.W.

Washington, D.C. 20460

2. Community Teamwork: Working Together to Promote Hazardous Materials Transportation Safety. 

Washington, D.C.: U.S. Department of Transportation (DOT), Research and Special Programs 

Administration; prepared by Cambridge Systematics, Inc. 1983. 

This publication provides State and local (i.e., fire, police, emergency service/civil defense, transportation, public safety, and environmental protection) officials with guidance on the most efficient use of 

their resources to develop effective hazardous materials programs. The bulk of the guide describes 

how one can, with a limited budget (1) perform a risk analysis: (2) obtain and mobilize emergency 

response services: (3) perform hazardous materials inspections: and (4) obtain hazardous materials 

training. 

Deliberate and detailed attention to minimizing costs is a- consistent aspect of DOT’s Community 

Teamwork. Because most communities must take into consideration strict budget limitations when 

devising preparedness plans, Community Teamwork should be of interest for this reason alone. Community Teamwork will also prove helpful to those planning to provide personnel safety equipment and 

clothing. Copies of Community Teamwork can be obtained by calling (202) 426-2301 or writing to: 

Office of Hazardous Materials Transportation, Attn.: DHM-50

Research and Special Programs Administration

Department of Transportation

400 7th Street, S.W.

Washington, D.C. 20590

3. Hazardous Materials Management System: A Guide for Local Emergency Managers. Portland: 

Multnomah County Office of Emergency Management, 1983. 

This handbook is a detailed guidance document prepared at the local level and published by the 

Multnomah County Office of Emergency Management in Portland, Oregon. This handbook guides the 

local emergency manager in the development and implementation of a comprehensive system approach for dealing with hazardous materials incidents within a specific geographic area. It is written 

from the perspective that such a system is multi-disciplinary and requires a team effort under the 

leadership of a local “emergency manager.” 

12/87 L-1 
4. 

Information on availability of the Multnomah County guide can be obtained by calling (503) 255-3600 or

writing to:

Multnomah County Emergency Management

12240 N.E. Glizan

Portland, Oregon 97230

4. Community Awareness and Emergency Response Program Handbook. Washington, D.C.: Chemical 

Manufacturers Association (CMA), 1985. 

This private sector planning document is similar to those prepared by government agencies. However, 

the CMA document addresses two areas of chemical plant management: 

Community awareness: developing a community outreach program and providing the public 

with information on chemicals manufactured or used at local chemical plants: and 

Emergency response planning: combining chemical plant emergency plans with other local 

planning. 

This CMA document presumes that the key organizing person might have no experience in contingency planning; hence, the information is provided in elementary detail to help just such an organizer. 

Pages 1-40 will prove helpful to any community preparing to develop an emergency plan to respond to 

EHS incidents. Appendix 1 lists typical components of a chemical plant emergency response plan: 

Appendix 2 provides highlights of interrelated plant, community, and State plans. 

Copies of the CMA guide are available for $10.00 and can be obtained by calling (202) 887-1100 or 

writing to: 

Chemical Manufacturers Association

2501 M Street, N.W.

Washington, D.C. 20037

5. An Unconstrained Overview of the Critical Elements in a Model Stare System for Emergency Responses to Radiological Transportation Incidents. Washington, D.C.: U.S. Nuclear Regulatory

Commission and U.S. Environmental Protection Agency; prepared by Rockwell International, 

1981. 

6. Atmospheric Emergencies: Existing Capabilities and Future Needs. Washington, D.C.: Transportation Research Board, 1983. 

7. Chemical Hazards Response Information System (CHRIS), Manual II: Hazardous Chemical Data. 

Washington, D.C.: United States Coast Guard, Department of Transportation, 1984. 

8. Criteria and Methods for Preparing Emergency Exposure Guidance Level (EEGL) Documents. 

Washington, D.C.: National Research Council, May 1985. 

9. Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants. Washington, D. C. : U.S. Nuclear Regulatory Commission 

and Federal Emergency Management Agency, 1980. (NUREG 0654/FEMA-REP-1). 

10. Emergency Planning, Student Manual. Washington, D.C.: Federal Emergency Management 

Agency, August 1983. 

11. Disaster Operations: A Handbook for Local Governments. Washington, D.C.: Federal Emergency 

Management Agency, 1981. 

12/87 L-2 
12. 1987 Emergency Response Guidebook. Washington, D.C.: U.S. Department of Transportation, 

1987. This guidebook is available at: 

Office of Hazardous Materials Transportation, Attn. : DHM-50

Research and Special Programs Administration

Department of Transportation

400 7th Street, S.W.

Washington, D.C. 20590

13. Guidance for Developing State and Local Radiological Emergency Response Plans and Preparedness 

for Transportation Accidents. Washington, D.C.: Federal Emergency Management Agency, 1983. 

(FEMA-REP-5) 

14. Guide and Checklist for the Development and Evaluation of State and Local Government Radiological Emergency Response Plans in Support of Fixed Nuclear Facilities. Washington, D.C.: U.S. 

Nuclear Regulatory Commission, Office of International and State Programs, 1974. 

15. Guide for Development of State and Local Emergency Operations Plans, CPG 1-8. Washington, 

D.C.: Federal Emergency Management Agency, October 1985. 

16. Multi-Media Compliance Inspection: Union Carbide Corporation, Institute, WV. Philadelphia: 

Environmental Protection Agency, Region Ill, 1985. 

17. The National Oil and Hazardous Substances Pollution Contingency Plan. Washington, D.C.: U.S. 

Environmental Protection Agency, 40 CFR Part 300. (Usually referred to as the National Contingency Plan). 

18. Objectives for Local Emergency Management, CPG 1-5. Washington, D.C.: Federal Emergency 

Management Agency, July 1984. 

19. Risk Assessment/Vulnerability Users Manual for Small Communities and Rural Areas. Washington, 

D.C.: U.S. Department of Transportation, Research and Special Programs Administration; Prepared by Department of Civil Engineering, Kansas State University, 1981. 

20. Emergency Handling of Hazardous Materials in Surface Transportation, Student, Patrick J. (ed). 

Washington, D.C.: Association of American Railroads, Bureau of Explosives, 1981, 

21. Overview of Environmental Pollution in the Kanawha Valley, Vincent, James R,. Denver: EPA 

Office of Enforcement and Compliance Monitoring, 1984. 

22. Highly Hazardous Materials Spills and Emergency Planning, Zajic, J.E., and Himmelman, N.A. 

New York: Marcel Dekker, Inc., 1978. 

23. Hazardous Materials Transportation: A Synthesis of Lessons Learned from the DOT Demonstration 

Projects. Washington, D.C.: ICF Incorporated. This report summarizes seven DOT-sponsored 

demonstration projects on prevention and preparedness planning. Appendix F contains a discussion of the lessons learned so that other communities can benefit from the experience. 

24. Hazardous Materials Response Guide, Kelty, J. Emergency Response Unit, Illinois Environmental 

Protection Agency. This guide is designed to provide rapid access to information on hazardous 

properties of chemicals involved in emergency incidents. 

25. Safeguards Report. University of Charleston, Charleston, West Virginia: National Institute for 

Chemical Studies, November 1986. A Community Hazard Assessment for the Kanawha Valley of 

West Virginia. 

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26. Criteria and Methods for Preparing Emergency Exposure Guidance Level (EEGL), Short-Term Public Emergency Guidance Level (SPEGL), and Continuous Exposure Guidance Level (CEGL) Documents. Washington, D.C.: National Academy Press, 1986. This document was developed by the 

Board on Toxicology and Environmental Health Hazards of the National Research Council. It is 

designed exclusively for the use of the Department of Defense (DOD) for the chemicals of interest 

to it. 

27. The Workbook of Atmospheric Dispersion Estimates, Turner, B., Public Health Service Publication 

No. 999-AP-26, 1970. 

28. Analysis of Hazardous Materials Emergencies for Emergency Program Managers: Student Manual. 

FEMA SM-110. 

29. DOT Hazardous Materials Table. 49 CFR 172.101. 

30. Fire Protection Guide on Hazardous Materials. Quincy, MA.: National Fire Protection Association, 

1986. 

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APPENDIX M 

EPA AND FEMA REGIONAL CONTACTS 

A. EPA Regional Preparedness Contacts 

Region I

(Maine, Vermont, New Hampshire, Massachusetts, 

Rhode Island, Connecticut) 

60 Westview Street 

Lexington, MA 02173 

Region II

(New York, New Jersey, Puerto Rico, Virgin Islands)

26 Federal Plaza

Room 900

New York, NY 10278

Region Ill 

(Pennsylvania, Maryland, D.C., Delaware, Virginia, 

West Virginia)

841 Chestnut Street

Philadelphia, PA 19107

Region IV

(North Carolina, South Carolina, Georgia, 

Florida, Mississippi, Alabama, Tennessee, Kentucky)

345 Courtland Street, N.E.

Atlanta, GA 30365

Region V

(Wisconsin, Illinois, Indiana, Michigan, 

Ohio, Minnesota)

230 South Dearborn Street

Chicago, IL 60604

Region VI

(New Mexico, Texas, Oklahoma, Louisiana, Arkansas)

1445 Ross Avenue

Allied Bank Tower at Fountain Place

Dallas, TX 75202

Region VII

(Nebraska, Kansas, Iowa, Missouri)

726 Minnesota Avenue

Kansas City, KS 66101

Environmental Services Division 

(617) 861-6700, ext. 221

Response and Prevention Branch

New Jersey: (201) 321-6657

New York: (212) 264-2525

Office of Emergency Response 

(215) 597-8907

Emergency Response and Control 

Section 

(404) 347-3931

Emergency Response Section 

(312) 886-1964

Regional Information Center 

(214) 655-2270

Preparedness Coordinator 

(9 13) 236-2806

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Region VIII 

(Montana, Wyoming, Utah, Colorado, 

North Dakota, South Dakota)

One Denver Place

999 18th Street

Suite 500 Denver, CO 80202

Region IX

(California, Nevada, Arizona, Hawaii, 

American Samoa, Guam)

215 Fremont Street

San Francisco, CA 94105

Region X

(Washington, Oregon, Idaho, Alaska)

1200 Sixth Avenue

Seattle, WA 98101

Title III/CEPP Information HOTLINE NUMBER 

Emergency Response Branch 

(303) 293-1723

Toxics Division 

(415) 974-7460

Hazardous Waste Division 

Emergency Response Team 

(206) 442-1263

1-800-535-0202 (in Washington, D.C.: (202) 479-2449) 

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B. FEMA Regional Offices 

(Note: Direct all requests to the “Hazmat Program Staff” of the appropriate FEMA 

Regional office.) 

Region I 

(Connecticut, Maine, Massachusettes, 

New Hampshire, Rhode Island, Vermont) 

442 J. W. McCormack POCH 

Boston, MA 02109 

(617) 223-9540 

Region II 

(New Jersey, New York, Puerto Rico, 

Virgin Islands) 

Room 1337 

26 Federal Plaza 

New York, NY 10278 

(212) 238-8208 

Region Ill 

(Delaware, Washington DC, Maryland, 

Pennsylvania, Virginia, West Virginia) 

Liberty Square Building 

105 S. 7th Street 

Philadelphia, PA 19106 

(215) 597-9416 

Region IV 

(Alabama, Florida, Georgia, Kentucky,

Mississippi, North Carolina,

South Carolina, Tennessee)

Suite 700

1371 Peachtree Street, N.E.

Atlanta, GA 30309

(404) 347-2400 

Region V 

(Illinois, Indiana, Michigan,

Minnesota, Ohio, Wisconsin)

4th Floor

175 W. Jackson Blvd.

Chicago, IL 60604

(312) 431-5501 

Region VI 

(Arkansas, Louisiana, New Mexico, 

Oklahoma, Texas) 

Federal Regional Center, Room 206 

800 N. Loop 288 

Denton, TX 76201-3698 

(817) 898-9399 

Region VII 

(Iowa, Kansas, Missouri, Nebraska) 

911 Walnut Street, Room 300 

Kansas City, MO 64106 

(816) 283-7060 

Region VIII 

(Colorado, Montana, North Dakota, 

South Dakota, Utah, Wyoming) 

Denver Federal Center, Building 710 

Box 25267 

Denver, CO 80225-0267 

(303) 235-4811 

Region IX 

(Arizona, California, Hawaii, Nevada,

American Samoa, Guam)

Building 105

Presidio of San Francisco, CA 94129

(415) 923-7100 

Region X 

(Alaska, Idaho, Oregon, Washington)

Federal Regional Center

130 228th St., S.W.

Bothell, WA 98021-9796

(206) 481-8800

 US GOVERNMENT PRlNTlNG OFFlCE 1991- 5 17- 003/ 4 7004 

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