Federal Register / Vol. 58, No. 11 / Tuesday, January 19, 1993 / Proposed Rules

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 68

[A-91-7468: FRL-4553-3]

List of Regulated Substances and

Thresholds for Accidental Release

Prevention; Requirements for Petitions

under Section 112(r) of the Clean Air

Act as Amended

AGENCY: Environmental Protection

Agency (EPA).

ACION: Proposed rule.

SUMMARY: The Clean Air Act

Amendments of 1990, signed into law

on November 15, 1990, include

provisions for chemical accident

prevention. The Environmental

Protection Agency is proposing a list of

regulated substances and threshold

quantities as required under section

112(r) of the Clean Air Act as amended.

The list is composed of three distinct

categories: list of 100 toxic substances,

list of 62 flammable substances (gases

and volatile liquids), and commercial

explosives as defined by the Department

of Transportation (DOT) in Division 1.1

(explosives with mass explosion

hazard); individual explosives are not

included. The list and threshold

quantities will determine the need for

owners and operators of facilities to

comply with future regulations

addressing the prevention and detection

of accidental releases to be proposed

later. EPA is also publishing the

requirements for the petition process

that will be used to add or delete

chemicals from the final list.

DATES: Comments must be submitted on

or before March 22, 1993. EPA plans to

hold at least one public hearing; date,

time and location will be published

shortly in the Federal Register.

ADDRESSES: Comments may be mailed

or submitted to: Environmental

Protection Agency, Air Docket (LE-131),

Attn: Docket No. A-91-74, Waterside

Mall, 401 M St. SW., Washington, DC

20460. Comments must be submitted in

duplicate.

Docket: Supporting information used

in developing this proposed rule is

contained in Docket No. A-91-74. This

docket is available for public inspection

and copying between 8:30 a.m. and 12

noon, and between 1:30 and 3:30 p.m..

Monday through Friday at the address

listed below. A reasonable fee may be

charged for copying.

FOR FURTHER INFORMATION CONTACT:

Vanessa Rodriguez, (202) 260-7913,

Chemical Emergency Preparedness and

Prevention Office, OS-120,

Environmental Protection Agency, 401

M St. SW., Washington, DC 20460, or

the Emergency Planning and

Community Right-to-Know Hot Line at

1-800-535-0202.

SUPPLEMENTARY INFORMATION:

I. Introduction

A. Statutory Authority

B. Background

I. Clean Air Act Amendments of 1990

(CAAA)

III. List of Substances and Thresholds

A. Introduction

B. Factors Considered in Defining List

Criteria

C. Criteria Options Considered

D. List of Substances

E. Threshold Quantities

IV. Other Issues

A. State Programs

B. OSHA's List of Highly Hazardous

Chemicals

C. Relationship to EPCRA (SARA Title III)

Section 302/303

D. Agricultural Nutrient Exemption

E. Information Gathering Efforts

V. Petitions for Additions and Deletions

A. Information Required fron Petitioner

B. Petition Process

VI. Discussion of the Proposed Rule

VII. Required Analyses

A. E.O. 12291

B. Regulatory Flexibility Act

C. Paperwork Reduction Act

I. Introduction

A. Statutory Authority

This notice of proposed rulemaking

(NPRM) is being issued under section

112(r) of the Clean Air Act (CAA or Act)

as amended (42 U.S.C. 7412, 7601).

B. Background

Public awareness of the potential

danger from accidental releases of

hazardous chemicals has increased over

the years as serious chemical accidents

have occurred around the world (e.g.,

the 1974 explosion in Flixborough,

England, and the 1976 release of dioxin

in Seveso, Italy). Public concern

intensified following the 1984 release of

methyl isocyanate in Bhopal, India,

which killed more than 2,000 people

living near the facility. A subsequent

release from a chemical facility in

Institute, West Virginia, sent more than

100 people to the hospital and made

Americans aware that such incidents

can and do happen in the United States.

In response to this public concern and

the hazards that exist, the U.S.

Environmental Protection Agency (EPA)

began its Chemical Emergency

Preparedness Program (CEPP) in 1985,

as part of the Agency's Air Toxics

Strategy. CEPP was a voluntary program

to encourage state and local authorities

to identity hazards in their areas and to

plan for chemical emergency response

actions. In 1986, Congress adopted

many of the elements of CEPP in the

Emergency Planning and Community

Right-to-Know Act of 1986 (EPCRA),

also known as Title I of the Superfund

Amendments and Reauthorization Act

of 1986 (SARA Title II). EPCPA (SARA

Title Ill) requires states to establish state

and local emergency planning groups,

namely, the State Emergency Response

Commissions (SERCs) and the Local

Emergency Planning Committees

(LEPCs), to develop emergency response

plans for each community. EPCRA

(SARA Title I) requires facilities to

provide information on the hazardous

chemicals they have on site; the

information collected is available to the

public through the SERC/LEPC

structure. This information forms the

foundation of both the emergency

response plans and the public-industry

dialogue on risks and risk reduction.

EPCRA (SARA Title III) did not

mandate that facilities establish

accident prevention programs. However,

Congress acknowledged the importance

of accident prevention by requiring

EPA, under EPCRA (SARA Title 11I)

section 305(b), to conduct a review of

emergency systems to monitor, detect,

and prevent chemical accidents. The

final report to Congress, Review of

Emergency Systems (EPA, 1988),

concluded that the prevention of

accidental releases requires an

integrated approach that considers

technologies, operations, and

management practices. The report

emphasized the importance of

management commitment to safety. Although EPCRA (SARA Title II) did

not directly address accident

prevention, EPA recognized that

prevention, preparedness, and response

form a continuum. Therefore, in 1986,

EPA established a chemical accident

prevention program to collect

information on chemical accidents and'

work with other groups to increase

knowledge of prevention practices and

encourage industry to improve safety at

facilities. Under this program, EPA

developed its Accidental Release

Information Program (ARIP) to collect

data on the causes of chemical accidents

and the steps facilities take to prevent

recurrences. EPA also developed a

program for conducting chemical safety

audits at facilities. Through the audit

program, EPA headquarters and regional

staff as well as state and local officials

learned about integrated approaches to

process safety from facilities. EPA has

also worked with trade associations,

professional organizations, labor.

environmental groups, and other

Federal agencies to determine how best

to reach smaller operations, which the

section 305(b) study indicated are less

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aware of risks than larger facilities. EPA

has also been an active participant in

international efforts related to chemical

accident prevention, particularly

through the Organization for Economic

Cooperation and Development (OECD),

which has held five international

workshops from 1989 through 1991 to

discuss issues related to accident

prevention, preparedness, and response,

and has developed guidelines for

member countries.

In addition to EPA's work in this area,

other agencies and states have

developed programs related to chemical

accident prevention. Recently, the

Occupational Safety and Health

Administration (OSHA) has

promulgated a final rule on chemical

process safety management (57 FR 6356,

February 24, 1992). Three states-New

Jersey, California, and Delaware-have

adopted regulations requiring facilities

to prepare and implement risk

management plans. A fourth state,

Nevada,. has recently enacted legislation on chemical process safety management.

Professional and trade organizations

have also developed programs in this

area. For example, the Center for

Chemical Process Safety of the

American Institute of Chemical

Engineers has published guidance on

the management of chemical process

safety. The Chemical Manufacturers'

Association has adopted a Responsible

CareTm program, which all members

must comply with to maintain

membership. The American Petroleum

Institute has developed a similar

program, Management of Process

Hazards; Recommended Practice 750

(RP 750), for its members. In 1982, the

European Community adopted the

Seveso Directive (82/501/EEC, as amended), which requires facilities

handling certain chemicals to develop a

safety report that is similar to a risk

management plan.

II. Clean Air Act Amendments of 1990

(CAAA)

In the Clean Air Act Amendments of

1990 (CAAA), signed into law on

November 15, 1990, Congress added

paragraph (r) to section 112 for the

prevention of chemical accidents. The

goals of the chemical accident

prevention provisions are to focus on chemicals that pose a significant hazard

to the community should an accident

occur, to prevent their accidental release

and to minimize the consequences of

such releases.

Section 112(r) of the CAA has a

number of provisions. It establishes a general duty for owners and operators of

stationary sources, who produce,

process, handle, or store substances

listed under section 112(r)(3) and any

other extremely hazardous substances,

to comply and perform specific

activities to prevent and mitigate

accidental releases. The general duty

requirements apply to stationary sources

regardless of the quantity oj substances

managed at the facility. Activities such

as hazards identification using

appropriate hazard assessment

techniques, designing, maintaining and

operating a safe facility, and minimizing

the consequences of accidental releases

if they occur would be essential

activities that must be performed to

satisfy the general duty requirements.

Owners and operators of these

stationary sources are required in the

CAA to conduct, in the same manner

and to the same extent as OSHA's

general duty clause in section 654 of

title 29 of the United States Code, these

activities as a matter of general business

practice.

Section 112(r)(3) of the CAA requires EPA to promulgate, by November 15,

1992, a list of at least 100 substances

("regulated substances") that are known

to cause, or may be reasonably

anticipated to cause, death, injury, or

serious adverse effects to human health

or the environment if accidentally

released. EPA is required to set

threshold quantities for each listed

substance. Under CAA section 112(r)(7),

the Act requires EPA to promulgate, by

November 15, 1993, reasonable

regulations and appropriate guidance to

provide for the prevention and detection

of accidental releases and for responses

to such releases. The accident

prevention regulations will apply to

stationary sources that have present

more than a threshold quantity of a

regulated substance. These regulations

shall address, as appropriate, the use,

operation, repair, and maintenance of

equipment to monitor, detect, inspect,

and control releases, including training of personnel in the use and maintenance

of equipment or in the conduct of

periodic inspections. The regulations

shall include requirements for a risk

management plan (RMP). The RMP shall

include a hazard assessment, a

prevention program, and a response

program. The proposed rule for the Risk

Management Program requirements will

be published in the Federal Register in

the future.

The Act establishes a Chemical Safety

and Hazard Investigation Board to

investigate (or cause to be investigated)

chemical accidents at facilities and

recommend to Congress, Federal, state,

local authorities, and the public actions

that can be taken to improve chemical

safety. Under the Act, EPA is authorized

to conduct studies related to accidental

releases, including research on hazard

assessments, hydrogen fluoride, and air

dispersion modeling.

The CAAA also require OSHA to

promulgate a chemical process safety

rule (CAAA section 304) to protect

empl6yees from hazards associated with

accidental releases of highly hazardous

chemicals in the workplace. OSHA

promulgated a final rule (57 FR 6356,

February 24, 1992) requiring a chemical

process safety management program for

any process involving a highly

hazardous chemical at or above a

specified threshold quantity. The rule

applies to a list of highly hazardous

toxic and reactive substances at

particular threshold quantities,

flammable liquids or flammable gases in

quantities of 10,000 pounds or more and

to the manufacture of explosives and

pyrotechnics.

III. List of Substances and Thresholds

A. Introduction

The Act requires EPA to promulgate,

no later than November 15, 1992, an

initial list of at least 100 substances that,

in the event of an accidental release, are

known to cause or may reasonably be

anticipated to cause death, injury, or

serious adverse effects to human health

or the environment. An accidental

release is defined under the Act as "an

unanticipated emission * ' * into the

ambient air from a stationary source." In

developing this list, EPA shall use, but

is not limited to, the list of extremely

hazardous substances (EHSs)

promulgated under EPCRA (SARA Title

III) section 302.

Congress listed the following 16

substances to be included in the initial

list (the Chemical Abstracts Service

(CAS) Registry number is provided in

parentheses):

chlorine (7782-50-5),

ammonia and anhydrous ammonia

(7664-41-7),

methyl chloride (74-87-3),

ethylene oxide (75-21-8),

vinyl chloride (75-01-4),

methyl isocyanate (624-83-9),

hydrogen cyanide (74-90-8),

'hydrogen sulfide (7783-06-4),

toluene diisocyanate, represented by: -toluene 2.4-diisocyanate (584-84-9)

-toluene 2,6-diisocyanate (91-08-7)

-toluene diisocyanate, mixed

isomers (26471-62-5)

phosgene (75-44-5),

bromine (7726-95-6).

anhydrous hydrogen chloride (7647-01-

0),. hydrogen fluoride (7664-39-3),

anhydrous sulfur dioxide (7446-09-5),

and

sulfur trioxide (7446-11-9).

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No air pollutant for which a national

E rimary ambient air quality standard

as been established shall be included

on the list, with the exception of

anhydrous sulfur dioxide and sulfur

trioxide, which must be included. No

substances regulated under title VI of

the Act as amended shall be included

on the list. Title VI covers ozone

depleters, primarily chlorofluorocarbons

(CFCs) and halons.

The list of chemicals proposed today

will, when final. identstationary

sources that will be covered by chemical

accident prevention regulations

subsequently adopted under section

112(r) of the Act. The list of substances

is intended to focus accidental release

prevention efforts on those stationary

sources and substances that pose

significant hazards to the community.

EPA strongly emphasizes, however, that

the chemicals proposed today for listing

are not the only substances that may

pose a threat to communities upon

release. There are large numbers of

compounds and mixtures in commerce

in the United States that in specific

circumstances could be considered toxic

or otherwise dangerous; however, it

would not be feasible to Include all such

substances and circumstanoes. The

proposed list represents only the first

step toward development of an effective

accidental release prevention effort by

facilities. Without a preliminary list of

this kind, It would be more difficult for

facilities to identify chemical hazards

with the potential to affect the

community. This list should serve as a

focus in initiating prevention efforts; it

is not a list of all substances that could

be considered for chemical accident

prevention. Similarly, the threshold

quantities being proposed may not

always represent a level below which no

hazard exists. Although stationary

sources will be required to comply with

the provisions for accidental release

prevention only if they have listed

substances in quantities exceeding the

threshold quantity, it does not mean

that these substances in smaller

quantities represent no potential hazard

to the community. Also. stationary

sources have a general duty to comply

and perform activities to prevent and

mitigate accidental releass regardless of

the quantity of the substance handled

on site.

EPA is proposing a list of 100 acutely

t oxic substances, 62 flammnable gases

and volatile flammable liquids, and high

explosives as a category. Proposed

threshold quantities for toxic substances

are based on a ranking method that

considers each substance' tocicity and

potential to become airborne and

disperse. The proposed threshold

quantity for flammable substances Is

based on the quantity that potentially

might be involved in a vapor cloud

explosion. The proposed threshold

quantity for high explosives is based on

the quantity that could produce

potentially lethal blast waves from an

explosion at a distance of 100 meters.

The presence of a threshold quantity at

a stationary source would be

determined based on the maximum

quantity in a single process.

B. Factors Considered in Defining List

Criteria

Under CAA section 112(rX4), the

factors to be considered in listing

substances are: (a) The severity of acute

adverse health effects associated with

accidental releases of the substance, (4)

the likelihood of accidental releases of

the substance, and (c) the potential

magnitude of human exposure to

accidental releases of the substance. The

Act specifies that the Administrator

shall use, but is not limited to, the list

of extremely hazardous substances

(EHSs) under EPCRA (SARA Title III)

section 302 for purposes of

promulgating the list. The Act also

requires that regulations establishing the

list shall include an explanation of the

basis for establishing the list.

EPA reviewed a number of existing or

proposed chemical lists associated with

other accident prevention, preparedness

and response programs to evaluate

criteria for listing regulated substances.

These lists, which are related to safety

and the protection of human health and

the environment, included several EPA

lists, lists developed by other Federal

agencies, lists developed under state

programs, and lists developed under

international programs.

The chemical lists reviewed were:

* The EPCRA (SARA Title II) Section

302 List of Extremely Hazardous

Substances

9 The EPCRA (SARA Title II) Section

313 List of Toxic Chemicals

9 The Comprehensive Environmental

Response, Compensation, and Liability

Act (CERCLA) Section 102 Hazardous

Substances List

a The Clean Air Act Section 112(b)

List of Hazardous Air Pollutants

e The Department of Transportation's

(DOT) Toxic by Inhalation Lists

o OSHA's Proposed List for Process

Safety Management Regulations1

* The New Jersey Acute Toxic

Catastrophe List

SEPA's analysis was based on OSHA's proposed

reISS PR 29150, Muy 7, 1"go. OSHA bA since

publ~eG Bad .mad7 sr R63S6, f ry

24Ae

* The List from the European

Community's (EC) Seviso Directive

(subsequently revised)

* The Delaware Prevention

Regulations List

* The National Fire Protection

Association's (NFPA) Fire Hazard

Properties of Flammable Liquids, Gases,

and Volatile Solids

* Flammable Gases and Volatile

Flammable Liquids from the DOT

Hazardous Materials Table

The criteria used for the development

of these lists were reviewed to

determine whether they were related to

the factors mandated by Congress for list

development under CAA section 112(r).

Acute toxicity was generally considered

in developing these lists of chemicals.

but soew also used flammability and

explosivity as criteria for regulating

chemicals. Several lists used a measure

of dispersibility (equilibrium vapor

pressure) in combination with acute

toxicity. Furthermore, some programs

used, either exclusively or in part,

criteria rather than lists to define

covered chemicals.

The EPCRA ISARA Title 11) section

302 list, the DOT toxic by inhalation

list, the New Jersey acute toxic

catastrophe list, the Delaware

prevention regulations list. and the list

from the European Community's (EC}

Seveso Directive are all based on some

measures of toxicity and the potential

for a chemical to become airborne. The

CERCLA list is not based solely on an

airborne citerion, but rather Is based on

a combination of statutory requirements

and criteria. OSHA's list is based on a

review of chemical lists compiled by a

number of Federal and state agencies

and other organizations [LB.. EPA. DOT,

the World Bank, NFPA, the Health and

Safety Commission of the United

Kingdom. and the states of Delaware

and New Jersey) and it includes

chemicals listed for toxicity and

reactivity, as well as criteria listings for

flammability and explosivity. NFPA~s

list was developed by committee and

includes a compilation of date from

various sources. Listed chemicals are

ranked according to their flammability.

reactivity, and health hazards, the

flammability rankings am based

primarily on flash point ad boiling

point. EPA reviewed the DOT

Hazardous Materials Table, which lists

materials regulated in transportation, to

identify flammable substances The

Hazardous Materials Table includes

hazard classes and packing

assigned according to the majcwIrs

of the vabst .For fmomble

ds. gogmpsarassied

primarily by flash point and beiing

point.

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EPA's review of the CAA section

112(b) list of hazardous air pollutants

and of the EPCRA (SARA Title III)

section 313 list of toxic chemicals

indicated that both of these lists focus

on routine emissions rather than

accidental releases. The CAA section

112(b) list is aimed at controlling

routine emissions of hazardous air

pollutants; the EPCRA (SARA Title III)

section 313 list focuses on all emissions,

and is aimed at development of

information on releases to the

environment over time. Although both

of these lists include chemicals that

have adverse health effects from shortterm exposure, the majority of the

chemicals listed have the potential for

producing adverse effects from longterm exposure rather than short-term

exposure. Adverse health effects from

long-term exposure are an important

consideration when dealing with

routine emissions, but are not the

primary concern in the event of an accidental release. Therefore, EPA

determined that the CAA section 112(b)

'list and the EPCRA (SARA Title I)

section 313 list were not of particulr

relevance to the development of the list

under CAA section 112(r), which

focuses on the prevention of

catastrophic accidental releases.

The factors specified for consideration

in list development cover a broad

spectrum (see CAA section 112(r)(4));

therefore, the Agency set out to define

these factors more specifically in

relation to accidental releases. The

Agency's definitions are discussed

below.

Severity of Acute Adverse Health Effects

The severity of acute adverse health

effects can be related to the inherent

hazards of the substances of interest,

such as the toxicity of a substance

resulting in lethal effects. Accidental

releases would most likely lead to shortterm exposure of the public, which

could cause both immediate and

delayed toxic effects. Acute adverse

health effects also could result from

other inherent hazards, such as the

flammability of the substance, or whether the substance is highly

reactive. The phenomena associated

with these hazards could be, for

example, radiant heat from a chemical

fire or blast waves from an explosion of

a chemical.

As confirmed by a review of death

and injury events in EPA's Acute

Hazardous Events (AHE) database, the

Emergency Response Notification

System (ERNS) database, the Accidental

Release Information Program (ARIP)

database, and other accident data, the

physical state (liquid, solid, gas) and

physical/chemical properties (toxicity,

flammability, explosivity, and volatility)

of released substances are important

factors in the actual severity of the

release. These data show that deaths

and injuries from accidental releases of

chemicals are strongly correlated with

these factors. Because physical state and

physical/chemical properties are linked

to severity as well as likelihood and

potential magnitude of human exposure

(discussed below), EPA is proposing to

give these factors substantial weight in

selecting its proposed list of regulated

substances.

Likelihood of Release

There are many measures and

surrogates that can be used to define the

likelihood of an accidental release. The

likelihood of a chemical being

accidentally released can be related to

typical usage and handling scenarios,

such as equipment commonly used in

typical facility operations. Ubiquitous

substances, because of greater handling

and use, may have a greater potential for

an accidental release. A history of a

large number of accidents in the past,

for example, may be an indicator of an

existing hazard related to a particular

substance and its potential to be

involved in accidental releases in the

future. Chemicals that are found in large

volumes at many locations and

chemicals that are particularly prevalent

(commodity chemicals, for example)

may be more likely to be involved in

accidental releases than small-volume,

less commonly used chemicals. All of

these factors may be relevant in

determining the likelihood of accidental

release for particular chemical

substances. However, the Agency also

believes that there may be limitations to

reliance on these factors, questions on

the amount, validity, and reliability of

existing accident history data, and

questions about the practicability of

incorporating factors that may vary from

site to site (e.g., facility operations or

type of equipment) in criteria for a

national list.

Likelihood can also be related to the

possibility of the chemical becoming

airborne and having an effect beyond

the facility fenceline in the event of an

accidental release. This likelihood can

be related to its physical/chemical

properties. Specific data indicators can include physical state (gas, liquid, or

solid) and vapor pressure. Although it is

not impossible for solids and non- volatile liquids to become airborne in an

explosion, gaseous substances and

vapors from volatile liquids are more

likely to be released to air and have an

effect beyond the facility fenceline.

Because the chemical and physical

properties of the substances under

review are linked to both the likelihood

and the severity of chemical accidents,

EPA believes that these two factors

deserve the greatest weight in

determining its proposed list of

substances. EPA solicits comments on

other factors accounting for severity and

likelihood of a release that might be

used to determine the list of substances.

EPA also solicits comments on the

availability of data to support the use of

such factors.

Magnitude of Human Exposure

For purposes of today's proposal EPA

considers the magnitude of human

exposure associated with accidental

releases to be related to the severity of

the health effects (hazards) and the

likelihood of a release (the likelihood

that a release will have an effect on the

population or environment beyond the

facility fenceline). This definition of

magnitude of exposure Is somewhat

different from the traditional risk

assessment definition of human

exposure, which relates magnitude of

exposure to the population and

sensitive environments that may be

affected by a release from a specific site.

EPA solicits comments on the relative

merits of using the Agency's approach

as a surrogate measure of the magnitude

of human and environmental exposure

and requests commenters to submit any suggested method for determining

magnitude of human or environmental

exposure to accidental releases of

hazardous substances.

The Agency recognizes factors that

might affect the magnitude of human

exposure could be site-specific or

accident-specific, and could vary widely

by location and incident. Proximity to

population centers and weather

conditions, for example, may play a role

in the magnitude of accidental releases.

EPA believes that these and other sitespecific factors are difficult to use in

determining national criteria. EPA

solicits comments on these and any

other factors and any supporting data

which may be useful in selecting the list

of substances.

EPA has also estimated, through

analysis of information collected

through the Accidental Release

Information Program (ARIP) database for

some of the listed toxics, the likelihood

that releases of those toxics reported

will result in human or environmental

impacts including injury,

hospitalization, death, soil

contamination, vegetation damage,

groundwater contamination, fire,

evacuations, and sheltering in place. In

these events, the actual human or

environmental exposure level is not

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precisely known and is not predictable

with any degree of confidence because

of many site-specific factors that

influence the result. However, for

purposes of this proposal, the level of

severity or degree of hazard for the

particular substance that generated the

off-site impact is known such that the

severity of the health effect and the

likelihood of release has been used as a

surrogate for the actual human exposure

level. EPA requests comments and any

additional data which could improve

our assessment of human exposure.

C. Criteria Options Considered

The CAA mandates EPA to develop a

list of substances based on specified

criteria, namely severity of adverse

health effects, likelihood of accidental

releases, and potential magnitude of

human exposure. The Act also mandates

the inclusion of 16 substances in this

list; these substances serve as the

starting point for the development of the

full -list of regulated-substances. The

Agency identified additional substances

based on similarities with the mandated

substances and the selection criteria

specified in the Act. The options

considered for the selection criteria

accounted for the inherent hazards of

the substances to be listed, as well as for

the potential these hazards have to

affect the community in case of an

accidental release. The hazards

considered include toxicity,

flammability, reactivity, explosivity,

and radioactivity, all of which can result

in acute effects from short term

exposures. Substances were identified

for each of these hazards, but, in

addition, the Agency considered the

potential impact that the identified

substances would have on the

community in case of a release. Each

hazard, and its potential to pose a threat

to the community, was evaluated

independently of any other hazard,

because of the difficulties of addressing

all possible combinations of hazards. A

.group of toxic substances, a group of

flammable substances, and a group of

explosive substances are being proposed

in today's rule for addition to the 16

mandated substances in the Act.

EPA is proposing to focus on acute

effects from short-term exposure to

toxics as one priority for development of

this list because these effects are

believed to be of immediate concern

beyond the fenceline in case of an

accidental release. EPA is proposing to

list 100 acutely toxic substances. EPA is

also proposing to consider the physical

hazards of flammable and explosive

substances because these effects may

have an impact on the community

beyond the fnameine in the event of an

accidental release. For flammable

chemicals, EPA is focusing on the

effects of blast waves from vapor cloud

explosions, because such effects appear

to have the potential to affect the

community beyond the fenceline. A list

of 62 flammable gases and volatile

flammable liquids is proposed. EPA

considers commercial high explosives,

which have the potential to detonate, to

be the explosive substances with the

greatest potential to affect the

community; commercial high explosives

are proposed for listing as a category.

EPA also considered, based on analyses

of accident history data, the relationship

between past accidental releases of

toxic, flammable, and explosive

substances and their associated human

and environmental effects, as a tool to

determine the likelihood that future

events could have similar impacts. EPA

seeks comments on this approach. EPA

has also attempted to exclude

substances from the list that are not in

production (or imported) or that are not

handled in commercial quantities.

1. Toxicity.

To account for the severity of acute

health effects from accidental releases of

toxic chemicals, EPA is proposing to list

a subset of the chemicals already

identified as EHSs on the basis of acute

toxicity (lethality) under EPCRA (SARA

Title Il) section 302. For purposes of

criteria for listing, severity of acute

adverse health effects from toxic

chemicals was considered to be best

measured by the concentration or dose

level that could cause death or serious,

irreversible health effects after a short

exposure. Chemicals not on the EHS

list, but listed under other programs,

also were reviewed to determine

whether there were other chemicals that

should be considered for listing on the

basis of the ENS acute toxicity criteria.

EPA believes that using the EHS list

to identify priority chemicals for the

accidental release prevention provisions

is a reasonable approach. The statute

directed EPA to use the EHS list as a

starting point for the regulated

substance list. The EHS list is intended

to identify chemicals that could cause

serious irreversible health effects from

accidental releases because of their

acute toxicity. The list has been revised

over the years based on reviews of

toxicity data. EPA believes that the EHS

list provides an appropriate basis for

identifying acutely toxic chemicals for

the list for accidental release

prevention.

Chemicals are listed under section

302 on the basis of animal test data,

using the criteria listed below. These

criteria are discussed in more detail in

Technical Guidance for Hazards

Analysis (December 1987). a guidance

document developed by EPA in

conjunction with the Federal Emergency

Management Agency (FEMA) and DOT.

EPA also included on the EPCRA

(SARA Title 11) section 302 list

chemicals that are less toxic than those

meeting these criteria but, because of

their known toxicity and high

production volume, may pose a threat to

the community.

The acute toxicity criteria are:

Inhalation LCse-0.5 milligrams per liter

of air (for-exposure time!8 hours),

or

Dermal LDWe50 milligrams per

kilogram of body weight, or

Oral LDs:e.25 milligrams per kilogram of

body weight where LCso is the median lethal

concentration, or the concentration in

air at which 50 percent of the test

animals died, and LD59 is the median

lethal dose, or the dose that killed 50

percent of the test animals. In the

absence of LC5 o or LDo data, LCLo or

LD data were used for listing, where

LCLo L the lethal concentration low, or

the lowest concentration in air at which

any test animals died, and LD.is the

lethal dose low, or the lowest dose that

killed any test animals.

In addition, EPA chose to focus on

physical state, vapor pressure, and

accident history in setting criteria

related to the likelihood of accidental

releases for toxic chemicals. A vapor

pressure criterion of 0.5 millimeters of

mercury (mim Hg) under ambient

conditions is proposed for toxic liquids.

This criterion captures most toxic

substances that have relatively low

volatility but may still pose an airborne

hazard in case of an accidental release.

Congress mandated the listing of

toluene diisocyanate, which has a

relatively low ambient vapor pressure;

therefore, EPA believes it is appropriate

to set the vapor pressure criterion at a

level that would include on the list

other toxic liquids with relatively low

volatility, similar to toluene

diisocyanate that also have accident

history. Chemicals on the EHS list that

are gases under ambient conditions and

liquids meeting the vapor pressure

criterion of 0.5 mm Hg were considered

for listing. Additional chemicals were

identified on the basis of high

production volume and history of

accidents involving death or injury. EPA also analyzed data in the ARIP

database and attempted to establish a

relationship between the presence or

absence of accident prevention

measures at facilities that have had

significant accidental releases and the

probability that the release will result in

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damaging and environmental effects.

Using the ARIP data, EPA developed

estimates of the probabilities that

releases of those toxic substances

reported through ARIP would result in

human or environmental impacts. In

this way, EPA attempted to measure the

potential magnitude of the impacts

resulting from an accidental release of a

listed toxic substance as it relates to

certain chemical accident prevention

requirements at facilities that handle

these substances. EPA seeks comments

on which type of data (i.e., relationship

between accidental releases and human

and environmental impacts, accident

history, physical/chemical properties)

or combination of data could be used to

evaluate the magnitude of human

exposure for toxics.

EPA is focusing on acute toxicity to

identity toxic chemicals as a priority for

listing, because acute toxicity is of the

most immediate concern in an

accidental release. However, there are a

number of other possible health effects

criteria that might be considered at a

future time for listing hazardous

substances, including non-lethal acute

health effects and chronic health effects,

e.g., lung damage, reproductive and

developmental toxicity, and

neurological effects. EPA invites

comments on methods to evaluate

substances on the basis of these health

effects and on how to rank substances

listed on these bases.

2. Flammability

EPA also considered physical hazards

of chemicals in relation to acute health

effects. EPA Is currently reviewing the

EPCRA (SARA Title M) section 302 list

of chemicals and considering the

addition of chemicals to that list based

on explosivity, flammability, and

reactivity. EPA has published an

advance notice of proposed rulemaking

(55 FR 35012, August 27,1990) on

physical/chemical property criteria for

adding chemicals to the section 302 list.

The notice announced the availability of

technical background documents on the

potential criteria for listing explosives

and flammables. The Agency is

proposing substances for listing today

based on the analysis conducted in its

review of the EPCRA (SARA Title 11I)

section 302 list. The analysis of

flammables and explosives conducted

in support of listing under section 302

has been reviewed by EPA's Science

Advisory Board. Results of additional

analysis that may be carried out as a

result of that review in support of the

EPCRA (SARA Title III) section 302 list

review will be considered prior to

publication of a final rule.

EPA's analysis of historical data on

accidental releases of flammable

chemicals indicate that vapor cloud

explosions may pose the most serious

hazard from a flammable substance to

the community. The heat effects of a fire

involving a flammable liquid or gas, or

of a fireball from a boiling liquidexpanding vapor explosion (BLEVE), do

not have a severe impact for as great a

distance from the source as the blast

effects of a vapor cloud explosion of the

same quantity of a flammable substance.

For example, a 1988 vapor cloud

explosion at a refinery in Louisiana,

involving C3 hydrocarbons (primarily

propane), caused damage up to six miles

away. Based on the results of EPA

modeling of flammable hazards and

analysis of the literature, a clear

distinction can be made between the

results for flammable substances that

boil at temperatures below

approximately 370 C and higher boiling

flammable substances. Analysis of other

classification schemes and regulations

indicates that flammable gases and

volatile flammable liquids are the

flammable materials considered of

greatest concern by agencies and

organizations such as DOT, NFPA, and

EEC. The temperature at which clear

distinctions in consequences can be

made, based on modeling techniques,

corresponds to the temperature at which

DOT and NFPA have made distinctions

in categories of flammable materials

(boiling point below 380C and flash

point below 23*C for NFPA

flammability rating 4; boiling point

below 350C and flash point below 230C

for DOT packing group I). EPA decided

to use the criteria used by NFPA for

flammable gases and liquids with the

highest degree of hazard (a ranking of 4)

for flammability to identify flammable

substances. Flammable liquids with a

flash point below 730F (22.80C) and a

boiling point below 100'F (37.8°C), as

well as flammable gases, are included

under NFPA's highest flammability

hazard ranking.

EPA applied the same criteria used for

toxics when analyzing the likelihood of

releases related to flammable

substances. EPA chose to focus on

physical state, physical/chemical

properties, and accident history in

setting criteria related to the likelihood

of accidental releases of flammable

substances. The volatility of a

flammable substance is taken into

account by the flash point and boiling

point criteria. No additional substances

were added after consideration of

accident history, because the volatility

criterion already covered all substances

that otherwise would have been

proposed. EPA invites comments on

methods to evaluate substances on the

basis of these effects and on the ranking

of these substances.

EPA examined flammables based on

accident history, the inherent hazards of

the substances, and the physical/

chemical properties that make them

likely to be involved in an accident and

have an effect beyond the fenceline.

Hazard data, physical/chemical

properties data, and accident history

data were used for this basis. However,

unlike the accident database for toxic

substances, EPA does not have a

database from which to estimate directly

a relationship between the presence or

absence of accident prevention

measures at facilities where significant

accidental releases of flammables have

occurred and the probability that human

or environmental impacts will occur.

Nevertheless, historical data

demonstrate that flammables can be

involved in accidents with the potential

for devastating impacts to the

community. The Agency believes that

the accident prevention measures that

have proven effective at facilities that

handle toxic substances will be as

effective at facilities that handle

flammable substances. EPA requests

comments and any data that the public

can provide to directly estimate the

relationship between the presence or

absence of accident prevention

measures at facilities where accidental

releases of these substances have

occurred and the probability that human

and environmental Impacts will occur.

EPA also seeks comments on which

type of data (i.e., relationship between

accidental releases and human and

environmental impacts, accident

history, physical/chemical properties)

or combination of data could be used to

evaluate the magnitude of human

exposure for flammables.

3. Explosivity

Explosives are already regulated by

several agencies and organizations. The

Bureau of Alcohol, Tobacco, and

Firearms (BATF) regulates the

manufacture, processing, use,

distribution, and storage of explosive

materials; BATF regulations include

licensing, permitting, and recordkeeping

requirements and requirements for

storage of explosives. DOT regulates the

transportation of explosives, and other

agencies such as OSHA, the Mine Safety

and Health Administration (MSHA), the

Department of Defense (DOD), and the

International Maritime Organization

(IMO) regulate certain aspects of the

explosives industry. Many state and

local governments also have regulations

regarding licensing and safety

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requirements for explosives. EPA's

Acute Hazardous Events database and

other data on accidents show accidents

involving commercial explosive

materials that had an impact on the

neighboring community. BATF

regulations require that explosives be

stored at set distances from inhabited

buildings, highways, and railways,

limiting the potential impact of an

accidental explosion. Although

explosives are currently regulated by

Federal, state, and local governments,

these regulations do not uniformly

address the issue of identifying hazards

using appropriate hazard assessment.

techniques, designing and maintaining a

safe facility, and minimizing the

consequences of accidental releases

when they do occur. All of these

elements are to be addressed in the RMP

program regulations, which are

intended to help focus on accident

prevention. Therefore, the Agency

believes these substances should be

considered for purposes of list

development and accidental release

prevention regulations.

Blast waves from accidental

explosions have the potential to cause

damage to people and property beyond

the fenceline. EPA considered high

explosives, low explosives, and blasting

agents in its analysis of the hazards of

explosives. High explosives are

generally defined as those materials that

detonate if ignited, shocked, or

subjected to heat or friction. Detonations

result from chemical reactions that

proceed at supersonic velocities,

generating large volumes of high

pressure gas and heat instantaneously,

even though no confining vessel or

structure exists. In an explosion caused

by a high explosive, the rate of energy

release is particularly rapid and the

shock wave has a very short duration

time. In contrast, low explosives

deflagrate, or bum relatively slowly in

comparison to high explosives. A

deflagration generates lower pressures

and is less destructive than a

detonation. Blasting agents are relatively

low sensitivity explosives which cannot

be initiated by blasting caps and are

unlikely to explode except under

special conditions. DOT defines an

explosive as "any substance or article,

including a device, which is designed to

function by explosion (i.e., an extremely

rapid release of gas and heat) or which,

by chemical reaction within itself, is

able to function in a similar manner

even if not designed to function by

explosion * ...."High explosives are

classified by DOT in Division 1.1,

defined as explosives that have a mass

explosion hazard, where a mass

explosion hazard is one that affects

almost the entire load instantaneously.

Low explosives, Division 1.3 under

DOT, are defined as explosives that

have a fire hazard and either a minor

blast hazard or a minor projection

hazard or both, but not a mass explosion

hazard. Blasting agents, Division 1.5, are

defined as explosives that have a mass

explosion hazard but are so insensitive

that there is very little probability of

initiation or of transition from burning

to detonation under normal conditions

of transport.

EPA's analysis for revisions to the

EPCRA (SARA Title InI) section 302 list

indicates that blast waves caused by the

detonation of commercial high

explosives could potentially have an

impact on the community. However,

EPA's analysis indicates that low

explosives, which primarily pose a fire

hazard rather than a mass explosion

hazard, are less likely to cause a

catastrophic event when compared to

the same quantity of high explosives.

The deflagration or burning of a low

explosive generates lower pressures and

is less destructive than the detonation of

a high explosives, although the Agency

recognizes that it may be possible for

jome low explosives to detonate under

nusual conditions, with effects similar

to the detonation of a high explosive.

Another key distinction between

categories of explosives is the likelihood

of initiation of an explosion. Blasting

agents, for example, have a mass

explosion hazard, but it is much more

difficult to set off an explosion of a

blasting agent, making them less likely

to explode accidentally. The Agency

recognizes, however, that it is still

possible for a blasting agent to detonate

accidentally under some circumstances.

In this case, the distinctions between

blasting agents and high explosives may

not be apparent; effects on the

community could be felt from

explosions of both types of explosives. EPA examined explosives based on

accident history, the inherent hazards of

the substances, and the physical/

chemical properties that make them

likely to be involved in an accident and

have an effect beyond the fenceline.

Hazard data, physical/chemical

properties data, and accident history

data were used for this basis. However,

unlike the accident database for toxic

substances, EPA does not have a

database from which to estimate directly

a relationship between the presence or

absence of accident prevention

measures at facilities where significant

accidental releases of explosives have

occurred and the probability that human

or environmental impacts will occur.

Nevertheless, historical data

demonstrate that explosives can be

involved in accidents with the potential

for devastating impacts to the

community. The Agency believes that

the accident prevention measures that

have proven effective at facilities that

handle toxic substances will be as

effective at facilities that handle

explosive substances. EPA requests

comments and any data that the public

can provide to directly estimate the

relationship between the presence or

absence of accident prevention

measures at facilities where accidental

releases of these substances have

occurred and the probability that human

and environmental impacts will occur.

EPA also invites comments on methods

to evaluate substances on the basis of

these effects and on the ranking of these

substances. EPA also seeks comments

on which type of data (i.e., relationship

between accidental releases and human

and environmental impacts, accident

history, physical/chemical properties)

or combination of data could be used to

evaluate the magnitude of human

exposure for explosives.

4. Reactivity

In its analysis for EPCRA (SARA Title

Inl) section 302 list revisions, EPA is

currently working to identify

approaches for evaluating the hazards

associated with other types of

substances that may have explosive

properties, e.g., unstable substances

such as certain peroxides. To evaluate

the hazards of these substances, a

number of factors must be considered,

such as the energy of reaction and

whether a probable or possible result of

the decomposition of such substances

would be a deflagration, with heat

radiation the primary consequence, or a

detonation, with blast waves the

primary consequence. EPA also has

examined the chemicals that are highly

reactive with air or water; identifying

common characteristics or specific

properties that cause chemicals to be so

reactive with air or water as to pose a

hazard to the community requires

additional study. For example,

chemicals that are reactive with water

may react to produce a flammable gas,

creating a fire or explosion hazard, or to

produce a toxic gas, or they may

decompose explosively on contact with

water; the consequences of these

reactions would be very different. At

present, EPA is attempting to evaluate

the hazards of reactive chemicals and to

develop an adequate technical basis to

determine the potential effects on the

community. EPA is investigating, for

example, computer models that estimate

heats of reaction, and the possible use

of the heats of reaction to compare the

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effects of an explosion of an unstable

substance to the effects of an explosion

of trinitrotoluene (TNT). This

methodology would only be appropriate

for substances that detonate, which

appears to be unlikely for many

unstable substances. Unstable and

reactive substances will be considered

for listing for accidental release

prevention if the evaluation indicates

potential consequences involving the

community. Thus, any decision relating

to this type of hazard will be deferred

pending additional Agency review. EPA

requests comments on methods that

might be used to evaluate the potential

consequences of accidents involving

reactive substances.

5. Radioactivity

EPA Is requesting Information to

determine the need and appropriateness

of listing radionuclides under this

proposed rulerhaking. There are several

issues that the Agency considers of

importance in making such a

determination. Do any or all

radionuclides at facilities not licensed

by the Nuclear Regulatory Commission

(NRC) pose risks of severe health effects

in case of an accidental release? If some

jtiionuclides were listed, should they

be listed a class of substances, or is it

more appropriate to prioritize their

hazards and list specific radionuclides

of concern? What specific approaches

could be taken to develop a

methodology that sets thresholds for

radionuclides that would represent

equivalent hazards to those posed by

other substances listed under this rule?

Is the volatility of radionuclides

relevant to their potential to be

released? The Agency is interested in

obtaining information on the universe of

facilities potentially affected by listing

radionuclides; the baseline considered

by the Agency is listing of radionuclides

as a class with levels similar to those

established for NRC-licensed facilities

under NUREG 1140, A Regulatory

Analysis on Emergency Preparedness

for Fuel Cycle and Other Radioactive

Materials Licensees (NRC-licensed

facilities are exempt from these

provisions under the CAA

amendments). Finally, the Agency

requests comments on how regulations

that may be in place for the accidental

release prevention of radionuclides at

the Federal, state, or local levels would

interact with the accident prevention

requirements applicable to these

substances.

D. List of Substances

1. Proposed List

EPA is proposing a list of 100 toxic

chemicals based on the criteria

discussed above and the list of

chemicals mandated for inclusion. EPA

is also proposing a list of 62 flammable

gases and volatile flammable liquids.

The lists of toxic and flammable

chemicals are set forth in § 67.130 of the

proposed rule. EPA is also proposing

the commercial explosives in Division

1.1 (explosives with a mass explosion

hazard), as defined by DOT; individual

commercial explosives are not included

on the proposed list. In proposing this

list, EPA considered the factors

specified in the Act: severity of acute

adverse health effects associated with

accidental releases, the likelihood of

accidental releases, and the potential

magnitude of human exposure to

accidental releases (albeit not directly as

function of factors such as population

exposed). As noted above, each hazard

was evaluated independently. The final

list adopted by the Agency may consist

of a combination of any of these

substances. Substances will be placed

on the final list according the statutory

criteria and based upon public comment

and additional information provided by

the public or developed by the Agency

as a result of public comment.

a. Toxic Substances. All of the 93

EHSs on the list of 100 toxic chemicals

proposed for listing are reported to be

toxic by inhalation; inhalation toxicity

would be expected to be the greatest

hazard to the public from an accidental

release to air. The list includes the

following categories of chemicals:

* Gases on the EHS list. The list

includes 22 gases that meet the toxicity

criteria based on their presence on the

EHS list and meet the criteria for

likelihood of accidental releases based

on their physical state and the fact that

they are in commercial production. Two

other gases meeting these criteria, ozone

and nitrogen dioxide, have primary

national ambient air quality standards

and are, therefore, excluded from the list b statute.

* Liquids on the EHS list with vapor

pressure of 0.5 mm Hg or greater. There

are 65 liquids that meet the toxicity

criteria by virtue of Inclusion on the

EHS list and meet the criteria for

likelihood of accidental releases because

their vapor pressure under ambient

conditions is 0.5 mm Hg or higher, and

they are in commercial production. Two

additional chemicals meeting these

criteria, methyl vinyl ketone and

methacryloyl chloride, were not

included because the toxicity data used

for listing are based on inhalation

studies that may contain flawed

scientific methods. EPA requested

comments on these two chemicals in a

proposed rule to delete several

chemicals from the EHS list. No

comments were received, and no

additional toxicity data were obtained;

therefore, these chemicals were not

deleted from the EHS list. However,

EPA does not believe it is appropriate to

include methyl vinyl ketone and

methacryloyl chloride on this proposed

list based on toxicity data that may be

questionable.

* Other liquids on the EHS list.

Toluene 2,4-diisocyanate (584-84-9)

and toluene 2,6-diisocyanate (91-08-7)

are included on the list because

Congress mandated the listing of

toluene diisocyanate. Four liquids from

the EHS list are included because they

are produced in high volumes and have

been involved in a number of accidents

in the past in which deaths or injuries

have occurred, based on Information

from several databases, including the

AHE, ERNS, and ARIP databases;

therefore, they meet the likelihood

criteria, although they have ambient

vapor pressures less than 0.5 mm Hg,

These chemicals (CAS numbers in

parentheses) are: nitrobenzene (98-95-

3), parathion (56-38-2), phenol (108-

95-2), and sulfuric acid (7664-93-9).

(EPA is proposing to include phenol in

liquid form only; phenol is a lowmelting solid under ambient conditions

but is frequently stored and shipped as

a liquid above its melting point.) The

accident history data and high

production volume indicate that these

substances pose a great risk to human

health and the environment from

accidental releases.

Releases to air are reported for all of

these substances in EPA's AHE

database, even though their vapor

pressure is less than 0.5 mm Hg.

Sulfuric acid is one of the most

frequently reported chemicals involved

in incidents with death and injury in

EPA's AHE database, and the most

frequently reported in all accidents; in

addition, it is the highest-volume

chemical in commerce in the U.S. The

AHE database includes nearly 200

reports of Incidents involving sulfuric

acid, more than half of them involving

releases to air and 60 of them involving

deaths or injuries. Air releases were

reported in more than half of the

incidents with deaths or injuries,

including four where explosions were

reported. The ARIP database Includes

nearly 150 reports for sulfuric acid.

Migration of sulfuric acid beyond the

facility boundaries was reported in a

significant number (32) of incidents. In

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two of these cases, migration of sulfuric

acid as a vapor or gas was reported. For phenol, the AHE database

includes reports of 24 incidents, with

one-third of them involving releases to

air. Deaths or injuries were reported in

five phenol incidents, with air releases

reported in two of them. The ARIP

database includes 10 reports for phenol,

with migration beyond the fenceline

reported in four of them. In two of these

cases, migration beyond the fenceline

was reported for phenol vapor.

Parathion incidents were reported 11

times in the AHE database, with releases

to air reported in most of them, and

deaths or injuries reported in eight of

them. Recent regulations have restricted

the use of parathion; as a result of the

restrictions, the likelihood of accidents

involving parathion may decrease. EPA

requests comments on whether

parathion should be included on the list

of regulated substances or whether

current regulations are sufficient to

prevent accidents involving parathion.

For nitrobenzene, there were four

incidents reported in the AHE database,

all with releases to air. Two of the

incidents involved deaths or injuries,

with a large number of deaths reported

in one incident, in which an explosion

and fire were reported. * Non-EHSs. Two gases proposed for

listing, methyl chloride (74-87-3) and

vinyl chloride (75-01--4), are not on the

EHS list but are mandated for listing.

Both of these chemicals have a history

of accidents involving death or injury.

Both of these chemicals are also highly

flammable and would meet the listing

criteria for flammability. No other gases,

chlorine dioxide (10049-04-4) and

cyanogen chloride (506-77-4), were

recommended for listing by OSHA, and

are included because of their toxicity,

potential for airborne release, and

production volume. Chlorine dioxide

appears to meet the criteria for "other"

chemicals on the EHS list, based on

toxicity and production volume.

Cyanogen chloride does not strictly

meet the listing criteria, primarily

because the available data are for

extremely short exposure periods;

however, data indicate that this

substance is highly toxic and would

probably meet the EHS criteria if

adjustments were made for duration of

exposure. EPA concluded that listing is

appropriate, based on available data.

Congress mandated the listing of both

anhydrous ammonia and ammonia; the

EHS list includes only one listing for

ammonia, with no form specified. EPA

is proposing to include both ammonia

(anhydrous) (7664-41-7) and

ammonia-aqueous (solutions with total

ammonia concentration in water of 20

percent by weight or greater). The

concentration cut-off was chosen so that

commonly used commercial solutions of

ammonia would be covered.

Congress also mandated the listing of

toluene diisocyanate, without specifying

an isomer; EPA is proposing to list

toluene diisocyanate (unspecified

isomer) (26471-62-5), which is not on

the EHS list, in addition to toluene 2,4-

diisocyanate (584-84-9) and toluene

2,6-diisocyanate (91-08-7), which are

EHSs. The TSCA Inventory includes

these three listings for toluene

diisocyanate (and no other listings).

Including unspecified isomers on the

list should help to ensure that all forms

of toluene diisocyanate are covered, in

conformance with the intent of

Congress. Hydrochloric acid (solution,

concentration 25 percent by weight or

greater) (7647-01-0), which is not an

EHS, is proposed for listing, in addition

to anhydrous hydrogen chloride, which

is an EHS. The concentration cut-off of

25 percent is intended to cover

commonly-used commercial solutions

of hydrochloric acid; solutions of

hydrochloric acid in these

concentrations could release hydrogen

chloride gas in the event of a spill.

Listing of the solution is proposed on

the basis of its potential to release

hydrogen chloride, high volume use,

and accident history. Hydrochloric acid

is one of the most frequently reported

chemicals in death and injury events

and in all events in the AHE database;

the ARIP database also includes many

reports of incidents involving

hydrochloric acid.

b. Flammable Substances. The

proposed list of 62 flammable

substances includes 43 flammable gases

and 19 volatile flammable liquids that

meet the criteria for NFPA's highest

flammability hazard- ranking. These

substances were identified from NFPA's

Properties of Flammable Liquids, Gases

and Volatile Solids and DOT's

Hazardous Materials Table; in addition,

there was evidence of production of

these substances in commercial

quantities. EPA is not proposing to

cover any of these substances when they

are used solely for facility consumption

as fuel. Two additional chemicals that

met the criteria for listing were

excluded from the list because they are

covered under title VI of the Act as

amended. Some of the substances listed

on the basis of toxicity also.meet the

flammability criteria; they are listed as

toxic substances, however, and were not

considered for listing as flammables.

c. Explosive Substances. EPA is

proposing to include all explosives that

meet the criteria specified by DOT for

Division 1.1 (55 FR 52402, December

21,1990; 49 CFR part 172), which are

based on the United Nations

Recommendations on the Transport of

Dangerous Goods. High explosives are

proposed for listing as a class, rather

than as individual substances, because

explosives are usually mixtures or

formulations rather than specific

chemicals. An individual chemical

could be a component of a high

explosive or a low explosive, or could

be non-explosive, depending on various

factors; e.g., particle size, concentration,

and other components of the

formulation. EPA is not proposing to list

any individual explosive substances.

d. Toxic Substances Not Proposed for

Listing. Several toxic substances that

initially appeared to meet the listing

criteria are not proposed for listing at

this time. These substances include two

that were listed as EHSs on the basis of

toxicity data based on inhalation studies

that may contain flawed scientific

methods. These two substances, methyl

vinyl ketone (78-94-4) and

methacryloyl chloride (920-46-7), are

not proposed for listing today because of

the questionable nature of the toxicity.

data. Two additional substances on the

EHS list that did not meet the vapor

pressure criterion were considered for

listing because they have been involved 0

in a number of accidents with death or

injury. These substances, chlordane

(57-74-9) and tetraethyllead (78-00-2),

are not proposed for listing because

recent regulatory developments make it

unlikely that they will be produced in

commercial quantities in the future;

therefore, they are unlikely to be

involved in potentially catastrophic

accidents. EPA requests comments on

the exclusion of these chemicals from

the proposed list of substances.

2. Other List Options

As discussed above, the Agency is

proposing a list of substances comprised

of three distinct categories: toxics,

flammables, and explosives. The

substances listed under each category

conform to the discussed criteria for the

particular hazard it presents, and reflect

a measure of likelihood of off-site

impacts in case of accidental release.

Because these categories have been

developed independently of each other,

the Agency may choose, at the time of

final promulgation, to adopt any of

these hazard options, or any individual

substance covered by these options

based on public comment and any

additional information provided or

developed by the Agency as a result of

public comment.

In addition to those options that

would be variations of the proposed list

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*of substances (e.g., toxics only; toxics

and flammables only; a subset including

toxics, flammables and explosives), the

Agency also considered an additional

option for the list of regulated

substances that would meet the

statutory criteria. This option is

discussed below. The Agency requests

comments on any variation of the

proposed list, as well as on the

additional option for comment.

Entire EHS List. EPA considered the

option of adopting the entire list of 360

chemicals regulated under EPCRA

(SARA Title II) section 302 as the list

of toxic chemicals. These chemicals are

listed on the basis of acute toxicity, and,

therefore, meet the criterion of severity

of acute health effects. Since this list

was adopted in 1986, toxicity data for

many of the chemicals have been

reviewed or are currently under review,

data on other properties have been

collected and updated, and other

chemicals have been reviewed for

possible addition to the list. However,

the EHS list is based solely upon acute

toxicity for most of the substances,

without any consideration of their

volatility, which relates to the

likelihood of that substance being

involved in a catastrophic airborne

accidental release that carries beyond

the facility fenceline. For the initial list

of substances for accidental release

prevention, EPA proposes to focus on

those toxic chemicals posing the

greatest potential threat to the

community from airborne releases. In

this way, the initial list will reflect the

statutory criteria of likelihood and

magnitude of release. The EHS list

includes a number of solids and nonvolatile liquids that, although they meet

the toxicity criteria, are expected to be

much less likely to have an effect

beyond the fenceline in the event of an

accidental release than those EHSs that

are gases and volatile liquids.

E. Threshold Quantities

Under CAA section 112(r)(5), EPA

must establish threshold quantities for

each substance at the time of listing.

The threshold quantity should take into

account the toxicity, reactivity,

volatility, dispersibility, combustibility,

or flammability of the substance, and

the amount of the substance known or

anticipated to cause death, injury, or

serious adverse human health effects.

Substances used by farmers as

agricultural nutrients may be assigned

greater threshold quantities or

exempted. Two issues related to

threshold quantities were considered:

Development of an appropriate

threshold quantity for triggering the risk

management prevention regulations and

development of a method for

determining whether a stationary source

has present a quantity of a listed

chemical greater than the threshold

quantity. The Agency does not consider

any thresholds to be a precise measure

of a "safe" level; no such level can be

determined. The risk posed by any

chemical release depends on the

particular circumstances at the time of

the release; for example, releases of the

same quantity of the chemical may pose

very different threats depending on the

location of a facility, weather at the time

of the release, the elevation of the

source of the release (e.g., a release from

a smokestack versus a ground level

release), and the pressure and

temperature of the substance, among

other factors.

1. Review of Threshold Methodologies

In developing threshold quantities,

the reporting thresholds associated with

the other lists considered and the

methods used to develop them were

reviewed. This review is discussed

below.

Delaware Methodology. The Delaware

thresholds for toxic chemicals were

determined on the basis of dispersion

modeling and a combination of toxicity

and vapor pressure; the Delaware

"Sufficient Quantity" (SQ) for a toxic

chemical is defined as the quantity that

-would create a potentially lethal

concentration at the facility boundary if

released over a period of one hour. The

thresholds are calculated based on an

assumption of a 100-meter distance to

the fenceline. If the distance at a facility

is greater, the threshold is adjusted

upward. For flammable materials, Delaware

provides a calculation method for

determination of the SQ based on a

comparison with propane. The

Delaware calculation is based on the

release rate calculated for propane as

sufficient to cause death or permanent

disability from heat radiation resulting from a fireball at a distance of 100

meters from the point of release. SQs for

other flammable substances are

calculated based on the properties of the

substances compared to the properties

of propane. Thresholds can be adjusted

upward for fenceline distances greater

than 100 meters, as for toxics.

Delaware specifically excludes

commercial explosives from its list. For

potentially explosive chemicals that are

not commercial explosives, SQs are

determined by relating explosion energy

for a given mass of material to an

equivalent mass of TNT. The scaling

law, which relates blast overpressure,

distance, and mass of TNT, was used to

calculate SQs. The SQ for a reactive

substance was the quantity calculated to

create an overpressure of 2.3 pounds per

square inch (psi) at a distance of 100

meters.

New Jersey Methodology. New Jersey

thresholds for toxic chemicals are set

based on dispersion modeling and

mortality curves; a Registration Quantity

(RQ) is the quantity that will produce

one fatality in a location with 10,000

people per square mile. New Jersey does

not currently list flammable or

explosive substances.

ORC Methodology. The methodology

recommended by the Organization

Resources Counselors (ORC) for the

development of threshold quantities for

toxic cnemicals, presented by aRC to

OSHA in public hearings, was also

reviewed. This method uses dispersion

modeling, assuming the total quantity of

the substance released immediately

becomes airborne, to determine the

quantity of a toxic substance that would

lead to a concentration that could cause

death or permanent disability at a

distance of 100 meters from the point of

release from a one-hour exposure.

For reactive chemicals, the threshold

methodology recommended by ORC was

the same as that used by Delaware to

develop SQs for explosive chemicals,

described above.

EHS TPO Methodology. The threshold

planning quantities (TPQs) developed

for EHSs are based on a ranking of the

EHSs according to their potential to

become airboiine, dispersion potential,

and toxicological properties, with

adjustments based on chemical

reactivity and other factors. To develop

the TPQs for EHSs, the Immediately

Dangerous to Life and Health (IDLH)

level developed by the National

Institute of Occupational Safety and

Health (NIOSH), or an approximation of

the IDLH based on animal toxicity data,

was used as an index of toxicity.

Physical state and volatility were used

to derive an index of the chemical's

potential to become airborne and

disperse. The two indices were

combined to produce an overall risk "ranking factor" defined as IDLH/V,

where V is the index of potential to

become airborne and disperse. TPQs

were assigned to groups of EHSs

according to their relative ranking. The index of potential to become

airborne and disperse (V) was derived

based on physical state and volatility.

For EHSs that are gases under ambient

conditions, V was assumed to have a

value of 1, indicating that in an

accidental release, the total quantity ot

chemical involved in the release could

become airborne. For liquids, V was

calculated by estimating the rate of

volatilization from a pool (assumed to

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be one centimeter in depth) on a flat,

non-absorbing surface using equations

presented in Attachment I of the

Interim Final Rule of November 17,

1986, listing EHSs under EPCRA (SARA

Title 11) section 302 (51 FR 41580).

Liquids Were assumed to be at their

boiling point, and all liquids were

assumed to have the same density as

water. A mass transfer coefficient was

estimated by reference to water. Because

of these assumptions, the only variables

used in the calculation of V were the

molecular weight and boiling point of

the liquid,

The EHSs were ranked according to

the ranking factor IDLH/V and assigned

TPQs of 1, 10, 100, 500, 1,000, or 10,000

pounds based on order of magnitude

ranges in the ranking factor. The TPQs

assigned based on the ranking factors

were reviewed, and changes were made

based on other toxicity data, rapid

absorption, chemical reactivity, and

consideration of specific handling,

formulation, and use information.

2. Proposed Threshold Methodology

Relative Ranking for Toxic Chemicals.

To set thresholds for toxic chemicals,

EPA is proposing to use a ranking

method similar to that used in

developing the TPQs for EHSs, as

described above, modified to reflect the

different purposes of thresholds under

this rulemaking; i.e., under EPCRA

(SARA Title III) section 302, thresholds

only trigger reporting by facilities to

state and local planners, while under

CAA section 112, facilities with listed

substances in quantities exceeding the

threshold will be required to comply

with prevention requirements, such as

the development of risk management

plans. Using the revised threshold

methodology, a ranking factor based on

toxicity and potential to become

airborne and disperse was derived as

described above. In some cases, revised

toxicity data or IDLH values were used.

Thresholds were assigned by order of

magnitude ranges in the ranking factor,

threshold quantity categories are as

follows: 500 pounds, 1,000 pounds,

5,000 pounds, and 10,000 pounds. The

threshold quantities selected are, at the

minimum level of 500 pounds,

representative of drum-size containers,

and, at the maximum level of 10.000

pounds, consistent with reporting

requirements already in place for

EPCRA (SARA Title IM) under sections

311-312 and 302. Under EPCRA (SARA

Title III) sections 311-312, facilities

must submit material safety data sheets,

chemical lists, or inventory reports on

hazardous chemicals to state and local

agencies at a threshold for most

chemicals of 10,000 pounds. Under

EPCRA (SARA Title MI) section 302, the

maximum TPQ for EHSs is 10,000

pounds; the presence of a TPQ of an

EHS requires facilities to notify state

and local planners.

A relative ranking method to assign

thresholds has advantages over

developing substance-specific

thresholds based on dispersion

modeling because airborne dispersion

modeling involves many site-specific

and accident-specific parameters,

including the distance from the source

to the community or fenceline, the

conditions under which the chemical is

handled (e.g., temperature and

pressure), the topography of the area

around the facility, and meteorological

conditions at the time of the release.

The Agency's analysis showed that

assumptions made for modeling cause

wide variations in the results. In

addition, the relative ranking takes into

account both toxicity and volatility. Air

dispersion modeling alone does not take

into account the potential for a

substance to become airborne. This

relative ranking method also is

consistent with the methodology for

assigning TPQs under EPCRA (SARA

Title Ill) section 302.

This methodology has been applied to

develop thresholds for additional

substances that would be listed if EPA

chose the option, discussed above, of

adopting the entire list of EHSs

regulated under EPCRA (SARA Title M)

section 302. Refer to the technical

background documents in the docket for

more information on thresholds for

EHSs not proposed for listing.

Thresholds have been developed using

this methodology for the four toxic

chemicals discussed previously, that

appeared to meet the listing criteria but

have not been proposed for listing

because of questionable toxicity data or because they are not expected to be

produced in commercial quantities in

the future. The thresholds for these

chemicals would be: chlordane (57-74-

9), 5,000 pounds; methacryloyl chloride

(920-46-7), 500 pounds; methyl vinyl

ketone (78-94-4), 500 pounds;

tetraethyllead (78-00-2), 1,000 pounds.

Threshold Methodology for

Flammable Substances. EPA's analysis

of the hazards of flammable chemicals

indicates that the greatest hazard to the

public from these substances is from

vapor cloud explosions. Historical data indicate that vapor cloud explosions are

unlikely for vapor clouds containing

quantities less than 10,000 pounds. The

quantity in a vapor cloud resulting from an accidental release of a flammable gas

or volatile flammable liquid could vary

greatly depending on site-specific and

accident-specific conditions, as well as

properties of the chemical released.

Because it would be difficult to set

chemical-specific thresholds based on

all these factors, EPA is proposing to set

the thresholds for all the listed

flammable substances at 10,000 pounds.

EPA believes that this threshold is

conservative and protective of the

public because the vapor cloud resulting

from a release of 10,000 pounds would

probably contain a quantity less than

10,000 pounds, even though all of the

listed flammable substances are gases or

volatile liquids. Establishing one

threshold for all the flammable

substances on the list also simplifies the

regulatory process. Threshold Methodology for

Explosives. EPA's analysis of explosives

indicates that a blast wave overpressure

of 3.0 psi from a detonation could have

potentially lethal effects in the

community beyond the fenceline of a

facility. This overpressure level could

cause serious structural damage to

buildings, lead to serious wounds from

flying glass, and potentially cause

eardrum rupture. EPA used the scaling

law of distances, which relates quantity

of explosive material and distance for a

given overpressure, to estimate the

quantity of high explosives that would

produce an overpressure of 3.0 psi at a

distance of 100 meters in the event of

a detonation. Based on this calculation,

EPA decided to set the threshold for

high explosives at 5,000 pounds.

Although individual high explosives

may vary in their explosive power, the

variations are not very great; high

explosives function by detonation and

produce similar results for a given

weight. EPA believes, therefore, that it

is appropriate to apply one threshold

quantity to all high explosives. This is

consistent with the approach used by

BATF to set storage distances for high

explosives; BATF uses one table of

distances for all high explosives. EPA

believes that this threshold will a pply

primarily to manufacturers of high

explosives, who have larger quantities

available on site with the potential for

catastrophic releases. Users of

explosives (e.g., for industrial uses,

construction, or mining) would

probably not have enough high

explosives present at one time to meet

this threshold; lower quantities on site

and existing regulations would reduce

the likelihood of catastrophic events at

these facilities.

3. Other Threshold Options

The Agency's proposed options for

the threshold quantity methodology

relate to the physical/chemical

properties of the substances and the

specific hazard that each substance

I

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presents (i.e., toxicity, flammability,

explosivity). EPA recognizes however,

that the impact of a release in a

particular instance may be greater or

lesser depending upon site-specific

considerations and that there may be

other factors that can be accounted for

in a methodology to determine a

threshold quantity. These other factors

may include industry class or facility

type in which a particular chemical is

typically handled or used. For example,

a threshold quantity for a particular

chemical could be adjusted if it is

typically handled at elevated

temperatures and pressures. Other

factors that might be considered under

this approach include typical SIC codes

in which a particular chemical is

handled, typical population density and

sensitivity around types of facilities that

handle a partitular chemical (e.g., a

chemical may be typically used at

remote locations, far from dense

population centers or sensitive

ecosystems), or process type in which a

chemical is typically involved. The

advantages of this approach would be

that it would more specifically tailor

threshold quantities based on common

use patterns of a substance. The

disadvantage would be that this

approach would not apply to ubiquitous

chemicals that are used in a wide

variety of applications, such as chlorine,

ammonia, and sulfuric acid, which are

also chemicals that, according to

Agency data, are frequently involved in

accidental releases and incidents

involving deaths and injuries. A greater

disadvantage to this approach is that the

intrinsic hazard of a chemical will still

be present even when it is used outside

of a "typical" scenario; it would not

account for the potential for chemical

accidents in all possible handling or use

scenarios. Also, based on current data

limitations, EPA believes it is not

feasible to develop a methodology that

adopts a typical use factor and that

would still be applicable uniformly

nationwide. The Agency requests

comments on methods or supporting

data which would permit the use of the

aforementioned factors (or other factors)

to establish threshold quantities.

In developing the proposed threshold

methodologies, the Agency also

considered four additional options,

which are discussed below. Three of

these methodologies are based on

intrinsic properties of each substance

(i.e., physical/chemical properties,

toxicity, explosivity, flammability). The

fourth option is the adoption of

thresholds already developed by

another agency. EPA requests comments

on these methodologies.

Vapor Quantity Method (Toxics). EPA

considered a method similar to that

recommended by ORC for development

of threshold quantities for toxics, as

described above. To derive threshold

quantities by this method, a

concentration level equal to the IDLH or

its equivalent was assumed to be

reached at a distance of 100 meters from

the source of the release. A release rate

that would produce that concentration

level at 100 meters was calculated using

air dispersion modeling techniques. The

dispersion modeling used was based on

equations presented in Technical

Guidance for Hazards Analysis (EPA,

FEMA, and DOT, 1987). For the

calculations, moderate conditions of a

wind speed of 10 miles per hour (4.4

meters per second), atmospheric

stability D, and urban conditions were

assumed. The duration of the release

was assumed to be 30 minutes, and a

quantity was calculated by multiplying

the release rate by the duration.

Threshold quantities were assigned

based on the calculated quantity, with

500 pounds as the lower bound and

10,000 pounds as the upper bound.

Refer to the technical background

documents in the docket for more

information on thresholds developed

using this methodology.

This method of assigning thresholds

assumes that the total quantity of the

substance becomes airborne. It does not

consider the chemical properties that

might affect the likelihood of an

accidental release. The volatility of the

listed chemicals is not taken into

account; e.g., a gas could be assigned the

same threshold as a liquid with

relatively low volatility if the toxicity of

the substances were similar. Thus,

thresholds assigned by this method rank

the chemicals primarily by toxicity.

Because it seems probable that, under

most circumstances, a gas would be

more likely to be released to the air than

a liquid with a low vapor pressure, it

seems reasonable that gases should have

lower thresholds than liquids with the

same toxicity. In addition, the

assumptions (e.g., wind speed,

atmospheric conditions, duration of

release) used in the dispersion models

have a major effect on the results; many

different quantities could be calculated

for the same chemical, depending on the

modeling assumptions made. The

conditions affecting an actual release

could vary greatly; therefore, the results

of chemical-specific calculations such

as those used under this method may

have little relation to what might

happen during an actual release.

TPQ Method (Toxics). EPA also

considered using the TPQs under

EPCRA (SARA Title Ill) section 302 as

the thresholds for toxic substances

under this rulemaking. However, the

purpose of the TPQs is to trigger

reporting by the facility to state and

local emergency planners of the

presence of an EHS. The community

planners then carry out an analysis of

the hazards posed by the substance and

use this analysis to set priorities for

community planning. The primary

purpose of the threshold quantities

under this rule, however, is to trigger

mandatory prevention requirements to

prevent the catastrophic accidental

release of a regulated substance.

Therefore, thresholds under this rule

should represent quantities that are

sufficiently hazardous (i.e., pose a risk

of catastrophic event) to merit the

requirement for a risk management plan

on a site-specific basis. These quantities

should be higher than the TPQs. which

only represent a level where the hazard

should be considered for planning

purposes. EHSs on the proposed list

with TPQs of 1,10, or 100 pounds

generally have threshold quantities of

500 pounds in today's proposed rule,

based on the revised methodology; those

with TPQs of 500 pounds generally have

1,000-pound thresholds; and those with

TPQs of 1,000 pounds generally have

threshold quantities of 5,000 pounds. A

TPQ of 10,000 pounds generally

corresponds to a threshold of 10,000

pounds.

Alternative Overpressure Levels

(Explosives). EPA considered basing the

threshold quantity for explosives on

other overpressure levels; for example,

an overpressure of 2.0 psi, a level which

could cause the partial collapse of walls

and roofs of houses, would give a

threshold quantity of 2,000 pounds.

However, EPA believes threshold

quantities calculated using the

overpressure level of 3.0 psi are

consistent with quantities that might

have a catastrophic effect in case of an

accidental release.

Adopting OSHA's Thresholds

For chemicals listed under both

OSHA's chemical process safety

standard and the list of regulated

substances under CAA section 112(r),

EPA considered adopting thresholds

established by OSHA. Because the

OSHA standard is designed to protect

employees from hazards associated with

accidental releases of OSHA-listed

chemicals in the workplace, EPA

assumed that the OSHA thresholds

represent accepted quantities that, if

accidentally released, would be

reasonably anticipated to cause death,

injury, or serious adverse health effects

in the workplace. EPA's proposed

thresholds are intended to be protective

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of the public outside the workplace or

off site.

EPA reviewed the thresholds under

OSHA's standard for chemicals on both

lists and determined that EPA's

thresholds generally are greater than or

equal to OSHA's thresholds. EPA also

noted that there are 15 substances for

which EPA's thresholds are lower than

OSHA's. These substances (CAS

numbers in parentheses) and their

OSHA thresholds are: Ammonia

(anhydrous) (7664-41-7), 10,000

pounds; ammonia (aqueous solution,

concentration greater than 44 percent)

(7664-41-7), 15,000 pounds; boron

trichloride (10294-34-5), 2,500 pounds;

bromine (7726-95-6), 1,500 pounds;

chlorine (7782-50-5), 1,500 pounds;

chlorine dioxide (10049-04-4), 1,000

pounds; fluorine (7782-41-4), 1,000

pounds; formaldehyde (50-00-0), 1,000

pounds; hydrogen chloride (anhydrous)

(7647-01-01, 5,000 pounds; hydrogen

cyanide (anhydrous) (74-90-8), 1,000

pounds; hydrogen fluoride (7664-39-3),

1,000 pounds; hydrogen peroxide

(concentration 52 percent or greater)

(7722-84-1), 7,500 pounds; hydrogen

sulfide (7783-06-4), 1,500 pounds;

methyl chloride (74-87-3), 15,000

pounds; and methyl mercaptan (74-93-

1), 5,000 pounds.

The thresholds proposed today for the

list of regulated substances under CAA

section 112(r) generally are not equal to

those for the highly hazardous

substances listed under the OSHA

standard. Thresholds that are protective

of the worker may differ from levels that

are protective of the public. EPA

believes it is reasonable for the EPA

thresholds generally to be equal to or

greater than the OSHA thresholds

because workers generally are located

closer to the chemicals than the public.

EPA recognizes that OSHA's thresholds

for the 15 substances discussed above

were established by rulemaking, which

may indicate a consensus on the amount

that can be reasonably anticipated to

cause serious adverse effects not only

within the workplace but also on the

public. This consensus may support

raising EPA's thresholds for these 15

substances to OSHA's levels. However,

EPA has proposed thresholds lower

than OSHA's for these 15 substances

because EPA believes that the scientific

methodology applied to determine the

protective thresholds for these 15

chemicals should be consistent with

that used for the remaining substances

on the EPA list. By adopting a

consistent methodology, EPA can

ensure that there is a reasonable

relationship between the thresholds for

substances on EPA's list that are on

OSHA's list and those that are not, and

between substances listed in the initial

rulemaking and those added

subsequently by petition or other

revision. The Agency requests

comments on these issues and, given the

extent to which this rule and the rule

promulgated by OSHA overlap, the

degree that accidental releases of toxics,

flammables and explosives and their

corresponding offsite effects will be

reduced by the OSHA rule.

EPA requests comments on the

proposed methodologies for establishing

threshold quantities for toxic,

flammable, and explosive substances

covered in this proposed rule. EPA also

requests comments on options

considered for setting thresholds.

4. Determination of Presence of

Threshold Quantity

The purpose of the threshold

determination is to evaluate (a) whether

a facility is covered for a specific

regulated substance and Mb) whether a

particular location within the facility is

subject to regulations based on the

presence of the substance. In deciding

how the presence of a threshold

quantity of a listed substance at a

facility should be determined, EPA

considered several possibilities and

reviewed the methods used by other

agencies and programs. Under section

302 of EPCRA (SARA Title I1), a facility

is covered if the total quantity of an EHS

present on site at any one time is in

excess of its TPQ. New Jersey's

threshold also is applied to the

maximum quantity on site at any time.

Under Delaware's approach, facilities

must determine the maximum quantity

of a toxic chemical that could be

released at one time, using guidance

provided by the state to account for.

facility-specific factors. If this potential

release quantity is greater than the

threshold, the facility is covered by the

Delaware RMP regulations. OSHA

proposed that the threshold quantity be

based on the amount used in a process,

rather than the quantity on site. to

determine whether a threshold quantity

is present, where a process is defined as

"any use, storage, manufacturing,

handling, processing, or the on-site

movement. . .. or combination of these

activities." Vessels that are

interconnected or vessels that are not

interconnected but could be involved in

a potential release are considered a

single process. EPA is proposing to apply the

threshold quantity to the maximum total

quantity of a substance in a process,

using the same definition used by

OSHA. This definition would apply to

the maximum quantity, at any one time,

in a single vessel, or in several vessels

that could be involved at one time in a

potential release, or in a group of

interconnected vessels. Interconnected

vessels could include, for example,

storage tanks, surge tanks, or weigh

tanks that may be connected to another

vessel or processing system by pipes,

pumps, or other conveyance equipment

used to transfer a substance from one

vessel to another. The proposed

approach to determining whether a

facility or location is covered focuses on

the quantity of a substance that could be

released in a single accident. For

example, if a facility uses 300 pounds of

chlorine in one process, uses 150

pounds to treat wastewater, and stores

600 pounds, the facility would have a

total of 1,050 pounds quantity on site.

The proposed threshold quantity for

chlorine is 1,000 pounds. gall of the

chlorine is kept and used i1 a single

area, where a fire or explosion could

affect the chlorine cylinders, more than

1,000 pounds have the potential of

being released in a single incident,

thereby exceeding the threshold. If,

however, the process area, storage area.

and wastewater treatment facility are

widely separated (and not otherwise

interconnected by pipes, pumps, or

other conveyance equipment), a single

incident would be unlikely to lead to a

large chlorine release. EPA also believes

that considering only the quantity in

one vessel or interconnected vessels

would not be sufficiently protective in

some cases. For example, debris from an

explosion could puncture a nearby

container, or a fire could cause a

number of containers or pipes to

rupture. Therefore, EPA is also

proposing that threshold determination

consider all vessels located sufficiently

close to each other that they might be

involved in a release at one time. EPA

believes this approach is relatively

simple to implement and verify and also

reasonably approximates the potential

release quantity. The Agency

recognizes, however, that this method of

threshold determination would not

address some potentially hazardous

situations. Different materials with the

same characteristic (e.g., flammability),

or different materials with various

hazards, that are stored in close

proximity to each other but are all

stored in quantities below the threshold

quantity, might pose a potential hazard

to the community, but the threshold

quantity would not be exceeded because

each substance is considered

individually. EPA believes it is not

feasible to attempt to address all

potential hazards of combinations of

substances. EPA requests comments on

the proposed approach.

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EPA considered applying the

threshold quantity to the total quantity

on site at a facility, as under EPCRA

(SARA Title III) section 302. A facility

would be covered if it had present an

amount of a listed substance exceeding

its threshold quantity regardless of its

location or distribution on the site. This

method is clear and unambiguous; no

complicated formulas or definitions

need to be applied. The Agency

believes, however, that it is unlikely

that the contents of several vessels that

are not interconnected and that are

widely separated would be released

simultaneously, causing a catastrophic

event. Therefore, using the total

quantity on site for threshold quantity

determination appears to be an overly

conservative approach.

Another approach considered was to

base determination of the threshold on

the maximum quantity of the regulated

substance capable of being released in a

worst-case accidental release. This

approach is used by Delaware for toxic

chemicals. Under the Delaware

regulation, the facilities must calculate

a worst-case potential release quantity

based on formulas provided. Some

difficulties have been reported with this

approach; for example, the calculations

require a technical knowledge not

available at the full range of potentially

covered facilities. Again, EPA believes

this approach may present enforcement

and compliance problems due to the

lack of easily verifiable criteria. EPA

requests comments on the proposed

definition for threshold quantities and

the alternative approaches considered as

options.

5. Threshold Exemptions

EPA is proposing several exemptions

to limit the quantities of substances

included in the threshold

determination. EPA would adopt the

exemption applied under EPCRA

(SARA Title IM) which does not

consider substances in mixtures if they

represent less than one percent of the

mixture by weight Regulated

substances in such dilute solutions are

unlikely to pose a hazard to the

community in the event of an accidental

release. In addition, it might not be

feasible in many cases for facilities to

calculate small quantities of substances

that may be contained in mixtures.

EPA also is proposing to exempt

substances contained in "articles" from

the threshold determination. The OSHA

definition of an article would be used

(29 CFR 1910.1200(b)). Batteries (after

their manufacture) would be considered

articles under this definition. In

addition, EPA is proposing to exempt

substances used for the following

purposes from Inclusion in the

threshold determination: substances

that are a structural component of the

facility; substances used for routine

janitorial maintenance; substances in

consumer products; and substances in

water drawn from the environment or

municipal sources. EPA also would

exempt activities in laboratories when

under the supervision of a technically

qualified person. EPA considers it less

likely that substances stored in these

exempt forms could be involved in

accidental releases of a catastrophic

nature.

These proposed exemptions parallel

the exemptions provided under EPCRA

(SARA Title III) sections 311 and 312 for

threshold calculations. EPA recognizes that under EPCRA (SARA Title III)

section 302, there are no similar

exemptions from threshold

determination. However, as noted

previously, EPCRA (SARA Title 11)

section 302 does not require facilityspecific prevention measures, in

contrast to the requirements of CAA

section 112(r). EPA believes these

exemptions are necessary to avoid

covering facilities whose use of the

substances does not merit the

substantial regulations required under

the CAA and facilities who do not

directly use the substance because it is

contained in an article, in process water,

in other products, or in specific

supervised situations. For example, without the article exemption, car

dealers and service stations could'be

covered because of the acid in car

batteries. Under EPCRA (SARA Title MI)

section 302, facility notification to local

and state emergency planners may be

appropriate in order for them to

consider the risk to the community, but

mandatory prevention requirements in

all cases would be excessive.

In addition, EPA is proposing to

exempt listed flammable substances

used solely for facility consumption as

fuel. This exemption is consistent with

OSHA's approach in its proposed rule

for process safety management.

6. Considerations for Mixtures

EPA notes that certain listed

substances are covered only if they are

in concentrations by weight above

specified levels; for example, hydrochloric acid would be covered

only when it is in solution at a

concentration of 25 percent or greater,

aqueous solutions of ammonia must be

considered only if the concentration is

20 percent or greater, and hydrogen

peroxide solutions must be considered

if the concentration is greater than 52

percent. Stationary sources would not

be required to estimate quantities of

more dilute solutions of these

substances. These concentrations

represent typical industry handling of

these mixtures. For mixtures or

solutions of other listed substances,

determination of whether a threshold

quantity is present would be based on

the quantity of the listed substance in

the mixture or solution. For example,

for a 25 percent solution of a listed

substance with a threshold quantity of

500 pounds, more than 2,000 pounds of

the solution would be needed to exceed

the threshold for the listed substance.

IV. Other Issues

A. State Programs

The Act encourages states to develop

programs to implement CAA statute

requirements. EPA will be publishing

guidance to assist in the development of

state programs and in the

implementation of section 112(r)

requirements. Section 112(l)(1) indicates

that statis may submit State Program

Plans outlining the implementation and

enforcement of section 112(r)

requirements. The chemical list and

reporting thresholds EPA adopts will

provide a minimum set of requirements

for state programs to adopt. States,

however, are not restricted from having

a more stringent program than the one

EPA is proposing.

Several states have developed their

own chemical accident prevention

regulations. As previously noted,

California, Delaware, and New Jersey

already have chemical accident

prevention regulations that require

facilities to develop and implement risk

management plans. For each of these

programs, the applicability of the

regulations is determined by a list of

chemicals with reporting thresholds.

The California program uses! the list and

thresholds established under EPCRA

(SARA Title Ill) section 302; that is, the

California program covers all 360

extremely hazardous substances on the

EPCRA (SARA Title III) section 302 list

at their TPQs. New Jersey has developed

its own list of chemicals and thresholds.

Delaware has also developed a separate

list; Delaware's thresholds are

dependent on both the quantity of the

substance on site and the distance to the

nearest population. If an established

state program does not include all the

substances at the threshold quantity set

by EPA (or at a lower, more stringent

threshold), the program would have to

be revised to bring it into compliance

with the Federal requirements when

they are promulgated.

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B. OSHA's List of Highly Hazardous

Chemicals

In developing the proposed list of

substances and thresholds, EPA

considered the possibility of adopting

the list of highly hazardous chemicals

and thresholds OSHA lists for its

chemical process safety standard. EPA

conducted its analysis based on the

proposed OSHA standard available at

the time, with coordination with OSHA

between their proposal and final

versions. However, OSHA's list does not

include all the substances mandated for

listing by Congress. It does not include

all EHSs that meet EPA's proposed

criteria and includes several substances

that EPA cannot list under the Act. It

also includes a number of substances

that are not in commercial production.

EPA is required to consider likelihood

of a release; substances that are not in

commercial production would be

unlikely to be released in significant

quantities. Therefore, the OSHA list

does not meet EPA's Congressional

mandate. Approximately 20 percent of

OSHA's list is made up of reactive

chemicals. EPA is currently considering

whether reactive chemicals pose a

potential threat to the public health or

welfare (as opposed to worker safety),

and is deferring listing such substances

for the accidental release provisions

pending further analysis of their

hazards. For these reasons, EPA

determined the OSHA list could not be

adopted in its entirety. EPA and OSHA

continue to work together to coordinate

their lists to the extent possible.

EPA has proposed the same method

as OSHA for determining whether the

quantity of a substance at a facility

exceeds the threshold. However, EPA

and OSHA used different methods to

assign threshold quantities. EPA's

proposed list includes 61 chemicals that

also are listed by OSHA (50 on EPA's

list of toxic substances and 11 on the list

of flammable substances). Of the

substances that are listed by both OSHA

and EPA, 10 (9 toxics and I flammable)

have identical thresholds. EPA's

thresholds are higher than OSHA's for

36 substances (26 toxics and 10

flammables); because OSHA's

thresholds relate to worker protection,

while EPA's are intended to protect the

community, it is reasonable that EPA's

thresholds should be higher. However,

OSHA's thresholds are higher for 15

substances.

C. Relationship to EPCRA (SARA Title

III) Section 302/303

Under EPCRA (SARA Title III) section

302, EPA published a list of extremely

hazardous substances (EHSs) and

threshold planning quantities (TPQs).

Facilities with EHSs, in quantities

exceeding the TPQ must notify the State

Emergency Response Commission and

Local Emergency Planning Committees.

Identification of facilities with EHSs

above their TPQs Is intended to. provide

local emergency planners with a basis

for further analysis of the potential

danger posed by these facilities. The

TPQs do not trigger any specific

requirements, other than notification

and designation of a facility coordinator,

for facilities with EHSs, nor do they

trigger any specific emergency planning

requirements at the facility other than

cooperation with the state and local

planners in the planning process.

However, some facilities already may be

instituting prevention programs, based

especially on the heightened awareness

of hazards that has resulted from EPCRA

(SARA Title III) section 303 activities.

The main distinction between EPCRA

(SARA Title III) section 303

requirements and the CAA requirements

is that EPCRA (SARA Title III) section

303 focuses on community planning,

while the CAA focuses on planning at

the facility for accident prevention and

response. The list of substances and

threshold quantities being proposed

under CAA section 112(r) triggers

mandatory prevention requirements by

facilities for prevention of accidental

releases. EPA, therefore, believes it is

appropriate that the list of toxic

chemicals under CAA section 112(r)

should be limited to gases and volatile

liquids with evidence of production,

unlike the EHS list, which is based only

on toxicity, and that the thresholds for

toxic chemicals under CAA section

112(r) should be higher than the TPQs

under EPCRA (SARA Title I) section

302. In addition, determination of the

presence of a TPQ of an EHS under

EPCRA (SARA Title III) section 302 is

based on the total quantity of the EHS

at the facility, while under CAA section

112(r), the proposed method of

threshold determination is based on the

quantity of the regulated substance in a

process. EPA believes it is appropriate

under EPCRA (SARA Title I) section

302 to identify facilities based on the

total quantity on site; emergency

planners can then take factors such as

location and distribution of vessels into

account when setting priorities for

planning. On the other hand, EPA

believes it is more appropriate under

CAA section 112(r), because of the

associated requirements, to consider the

quantity that has the potential to be

released in a single accident and cause

serious effects beyond the fenceline.

EPA may decide to list flammable and

explosive substances under EPCRA

(SARA Title Ill) section 302, following

completion of its analysis of the hazards

of such chemicals. Because of the

different purposes of EPCRA (SARA

Title III) section 302 and CAA section

112(r), it may be appropriate to have

somewhat different lists and thresholds

under EPCRA (SARA Title I) section

302. For example, to provide local

emergency planners with sufficient

Information to allow them to set

planning priorities for their

communities, EPA may use less

stringent criteria for listing (e.g., blasting

agents as well as high explosives may be

listed) and set lower thresholds (e.g.,

thresholds for explosives may be set

using a lower overpressure level, such

as 1.0 psi or 2.0 psi) under EPCRA

(SARA Title III) section 302.

D. Agricultural Nutrient Exemption

Under CAA section 112(r), EPA is

authorized to establish higher threshold

quantities for, or exempt entirely,

chemicals used as agricultural nutrients

when held by farmers. EPA believes that

ammonia is the only chemical on the

proposed list of substances that would

be used as an agricultural nutrient and

thus could be subject to the higher

threshold or exemption. EPA is

proposing to exempt ammonia from the

requirements of this rule when held by

a farmer as an agricultural nutrient. EPA

is proposing this exclusion for two

reasons. First, the farms that use

ammonia as a fertilizer are primarily

growing corn, wheat, and cotton, and

involve large acreages and the ammonia

is intentionally released to the

environment. Second, many elements of

chemical accident prevention programs

may. not be directly relevant to the use

of ammonia as a fertilizer. EPA requests

comments on the proposed exemption.

EPA notes that farm contractors who

sell ammonia as a fertilizer would be

covered by today's proposed rule.

E. Information Gathering Efforts

Before EPA began writing its

proposed rules for accidental release

prevention, the Agency decided to seek

information from those already

implementing similar regulations. EPA

staff met extensively with officials in

three states and held interviews with

seven facilities that have developed

RMPs under state laws. To gather more

information, EPA held eight focus

groups, five with facilities (two each in

New Jersey and California, one in

Delaware), and three with administering

agency officials in California, to elicit

their opinions on the regulations and

their ideas about the most useful

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program components. After analyzing

the results of these meetings, EPA held

a two-day seminar on issues that have

arisen at the state level. Officials from

California, Delaware. and New Jersey, as

well as Minnesota, Texas, New York,

and Wisconsin, attended the meetings.

On the second day, other groups that

had expressed an interest, including

trade associations, labor unions,

environmentalists, and organizations of

public officials, joined the discussion.

Participants were concerned that to

the extent possible, the OSHA, EPA, and

state chemical lists and related

regulations should be consistent.

Several facilities indicated that they

would like the regulations arranged so

that if they are in compliance with one

rule, they would be in compliance with

all rules, at least for a specific chemical.

It was noted that the chemical list

should be based on criteria; thresholds

should be developed on a risk-based

system. In general, the focus group

participants found the thresholds used

in their states reasonable, regardless of

the actual threshold quantities, which

varied from state to state. A report on

this information gathering effort entitled

Clean Air Act of 1990, Chemical

Accident Release Provisions, Report on

Focus Groups and Round Table

Discussions, transcripts of the focus

group sessions, and a report on the twoday seminar are available in the docket.

V. Petitions for Additions and Deletions

A. Information Required from Petitioner

The Act requires EPA to review the

list at least every five years; EPA may

revise the list either through petitions or

by Agency initiative. EPA is required to

develop procedures for the addition and

deletion of substances from the list;

these procedures are to be consistent

with those applicable to the list in CAA

section 112(b).

EPA will consider and respond to

petitions to modify the list of regulated

substances for accidental release

prevention within 18 months of

submission of the petition. For EPA to

complete its review of petitions and

publish the results of its determinations

in a timely and efficient manner, the

data presented In the petition must be

complete and technically sound. EPA's

review would be facilitated if the

petitioner presents the information in

the order listed below.

* Name and address of the petitioner

and a brief description of the

organization(s) that the petitioner

represents, if applicable.

* Name, address, and telephone

number of a contact person for the

petition.

o Common chemical name(s),

common synonym(s), Chemical

Abstracts Service (GAS) number, and

chemical formula and structure. The

CAS number is a unique number

assigned to chemical substances by the

American Chemical Society Chemical

Abstracts Service Registry System. The

CAS numbers are independent of

nomenclature and have no chemical

significance. They are assigned as each

new chemical enters the CAS Registry

System. 9 Action requested. The petitioner

must identify whether the request is to

add to or delete from the list of

reulated substances for accidental

release prevention. • Rationale supporting the

petitioner's position. Each petition must

present a discussion of the rationale to

add or delete each substance based

upon the data presented and their

relationship to the criteria for addition

or deletion. A short summary of the

rationale must be submitted along with

a more detailed narrative that includes

a discussion of the available data on the

potential for acute adverse human

health effects that occur as a result of

exposure to the substance. Physical and

chemical data related to the likelihood

of accidental releases and the magnitude

of human exposure also should be

discussed. For a petition to add, data

must be submitted showing that the

criteria for listing are met. Chemicals

meet the criteria for listing if they meet

the mammalian toxicity criteria for

listing as EHSs (discussed in Section I

C of this preamble), are gases or liquids

with vapor pressure of 0.5 mm Hg or

higher under ambient conditions, and

are in production in commercial

quantities. Less volatile chemicals that

meet the toxicity criteria will be

considered for listing if they have a

history of involvement in accidents that

caused death or injury. For flammable

chemicals, data should indicate that the

substances are flammable gases under

ambient conditions, or that they are

liquids with boiling point below 100 OF

(37.8 0C) and flash point below 73 OF

(22.8 *C). For a petition to delete, data

must be submitted demonstrating that

the substance would not reasonably be

expected to cause death, injury, or

serious adverse effects to human health

or the environment in the event of an

accidental release. Available data on all

hazards presented by the chemical

should be included.

* Supporting data. The petitioner

must provide EPA with sufficient

information to support scientifically his

or her request to add to or delete from

the list of regulated substances for

accidental release prevention. Duplicate

copies of all material submitted and an

English translation of any Information

published in a foreign language should

be included with the petition in order

to expedite the review process. All data presented must meet basic

criteria for acceptable scientific quality.

These include, but are not limited to,

appropriate study design, quality of the

scientific approach/method, appropriate

quality assurance and quality control

procedures, and appropriate statistical

analyses.

The supporting data for the petition

must contain, at a minimum, te

following elements:

* List of supporting documents. The

petitioner must include a summary list

of all supporting documents included

with the petition. * Literature searches. The petitioner

must include a printed copy of all

literature searches conducted to Identify

data available for the substances,

including identification of the

database(s) searched, the search

strategy, dates covered, and printed

results. The literature searches must

have been conducted within six months

prior to submission of the petition. * Effects data. Each petition must

include summary tables identifying all

studies cited. The petitioner must

submit printed copies of the studies

cited on these tables. The reports of

effects data should include all available

reports on effects of short-term exposure

to the chemical and should not be

limited to reports on the effect for which

the chemical was listed. Human studies,

animal studies, other environmental

effects studies, and supplementary data

such as results from short-term in vitro

tests, toxicokinetic studies, comparative

metabolism studies, structure-activity

relationships, and other relevant

toxicological studies may be submitted.

Studies will be evaluated for

adequacy using standard EPA guidance

documents and basic toxicologic

principles. EPA will place greater

confidence in studies that have been

published in peer-reviewed scientific

journals or books. In addition, the

petitioner may be aware of supporting

studies, data, or reports that were not

Eublished in peer-reviewed journals or

ooks. In such cases, the petitioner

should submit a printed copy of each

relevant non-peer-reviewed citation.

Examples of such citations may include

proceedings of scientific meetings,

studies conducted at an industrial site

for internal purposes, and some

government-sponsored reports/

assessments.

* Exposure and accident history data.

The petition should include data related

to the potential for serious adverse

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human health or environmental effects.

Relevant physical and chemical

properties of the substance (e.g., boiling

point and vapor pressure) should be

included, with literature citations. Air

dispersion modeling results may be

included. Assumptions and data used

for the modeling should be presented

clearly, and documentation for the

model used should be included in the

submission. Historical data on accidents

involving the substance may be

included, clearly citing the sources of

the data.

B. Petition Process

The guidance presented in this

proposed rulemaking is intended to

provide a general framework for

determining petition adequacy. Because

most petitions will have specific issues

not covered by this guidance,

individuals wishing to petition EPA to

modify the list of regulated substances

for accidental release prevention are

encouraged to request a pre-petition

conference with EPA. Such a meeting

would facilitate submittal of complete

and technically sound petitions. To

arrange a pre-petition conference, please

contact CAA 112(r) Petition

Coordinator, Chemical Emergency

Preparedness and Prevention Office

(OS-120), 401 M Street SW.,

Washington DC 20460. At the time a

pre-petition conference is requested, the

potential petitioner must be prepared to

submit a proposed agenda for the

meeting and a list of participants.

A petition to modify the list of

regulated substances for accidental

release prevention under section 112(r)

of the Clean Air Act should be sent to

the following address to expedite its

review. Environmental Protection

Agency, Chemical Emergency

Preparedness and Prevention Office,

OS-120, 401 M Street, SW.,

Washington, DC 20460.

Upon receipt of a petition, EPA will

first review the petition for

completeness. If the petition is found to

be incomplete, EPA will return it to the

petitioner identifying the omissions.

The petitioner may correct the

deficiencies and resubmit the petition.

This action will be considered

equivalent to submitting a new petition;

thus, EPA will have 18 months to

review the petition contents and publish

a decision to grant or deny the petition.

If the petition is found to be complete, EPA proposes to publish the following

two notices in the Federal Register: 1. Notice of Petition Receipt and

Request for Comments: This notice will

announce that a complete petition has

been received and will identify the

following: the petitioner, the action

requested (regulated substance,

addition/deletion), the rationale and

summary of the key data submitted in

support of the petition, and the list of

studies submitted by the petitioner to

support the request. In response to this

notice, EPA will request that interested

parties submit additional, pertinent

scientific information that was not

identified by the petitioner if such

information might assist EPA in making

the decision to grant or deny the

petition. Additional data will be

accepted for sixty days following

publication of this notice. The request

for information will constitute a request

for public comments on the petition. All

pertinent information and comments

received will be addressed in the notice

granting or denying the petition. 2. Publication of Decision: This notice

will announce EPA's decision to grant

or deny a specific petition. EPA anticipates publishing the two

notices discussed above within 18

months of receiving a complete petition.

EPA will not accept additional petitions

on the same substance following

publication of a final notice of the

decision to grant or deny a petition

unless new data become available that

could significantly affect the basis for

the decision made by EPA. If significant

additional data are available, interested

persons may submit these data through

the petition procedures identified in

this notice. Reference should be made to

previous petitions for a specific

substance, identifying the date the

petition was submitted and the previous

petitioner. Information previously

submitted need not be resubmitted but

may be cited by reference for

reconsideration. EPA requests

comments on the proposed information

to be required from the petitioner and

the proposed petition process.

VI. Discussion of the Proposed Rule

EPA is proposing to add Part 67 to

Title 40 of the Code of Federal

Regulations, which would include the

list of regulated substances and

threshold quantities, as well as the

requirements for the petition process to

add regulated substances to the list or to

delete regulated substances from the

list.

Proposed § 68.5 would establish the

procedures to determine whether a

threshold quantity of a regulated

substance is present at a stationary

source. Specific exemptions to the

threshold determination procedure are

also included for mixture

concentrations, articles, and certain uses

and activities.

Proposed § 68.100 would establish the

purpose of the subpart as the

designation of regulated substances and

their threshold quantities, and

establishment of the requirements for

petitions to add substances or delete

substances from the list.

Proposed § 68.120 would specify the

requirements for petitions to the Agency

to add substances to the list, and to

delete substances from the list.

Proposed § 68.125 would exempt

ammonia used as an agricultural

nutrient when held by a farmer.

Proposed § 68.130 would establish the

list of regulated substances, including a

list of toxic substances, a list of

flammable substances, and a list

criterion for commercial high

explosives. This section also would

establish the threshold quantities for all

listed substances.

VII. Required Analyses

A. E.O. 12291

Under Executive Order 12201, the

Agency must judge whether a regulation

is "major" and thus subject to the

requirement for a Regulatory Impact

Analysis (RIA). Under E.O. 12291, a

major rule is one that is likely to result

in:

1. An adverse (cost) impact in the

economy of $100 million,

2. A major increase in cost or prices

to consumers, individual industries,

Federal, state, or local government, or

geographic region, or

3. Significant adverse effects on

competition, employment, investment,

productivity, innovation, or the ability

of U.S.-based enterprises in domestic or

export markets.

Based on the RIA, EPA estimates that

approximately 140,500 facilities will be

covered by the three proposed hazards

lists and thresholds (i.e., toxic,

flammables, and explosives). These

facilities include 22,440 manufacturers

(18,960 of whom are covered by the

OSHA rule); 33,250 public drinking

water and waste treatment systems

(15,400 covered by OSHA); 50,000 cold

storage facilities (42,500 covered by

OSHA); 4,460 wholesalers (2,240

covered by OSHA); 1,240 service

industry facilities (776 covered by

OSHA); 2,980 private utilities (3,000

covered by OSHA); and 20,000 propane

retailers. The average number of

regulated substances varies from one per

facility for cold storage facilities, to 13

per facility for highly complex

manufacturing facilities.

EPA has determined the proposed

rule is not a major rule for the purposes

of E.O. 12291 because the list, by itself,

imposes no cost on facilities. The cost

impact of the list and thresholds derives

from compliance with the risk

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management regulations and other

reasonable regulations, which are

triggered by the presence of a regulated

substance above its threshold quantity.

Because the impact of the list and

threshold decisions are felt through the

risk management regulations, EPA has

prepared a combined preliminary RIA

entitled, "Regulatory Impact Analysis in

Support of Listing Regulated Substances

and Thresholds and Mandating Risk

Management Programs for Chemical

Accident Prevention, as Required by

section 112(r) of the CAA," which

analyzes the impacts of various list and

threshold options on the risk

management requirements. The RIA is

available in the docket.

The petition process is the only aspect

of this rulemaking that is directly

attributed to the listing of substances.

EPA estimates that the petition process

under this rulemaking will cost a

facility submitting a petition an average

of $5,000. EPA estimates that there will

be 11 petitions a year. EPA anticipates

that the cost to the Federal government

for processing and reviewing the

petitions will be approximately equal to

the cost to facilities for filing a petition.

The total annual cost is estimated to be

$110,000 ($5,000 x 2 x 11 petitions).

B. Regulatory Flexibility Act

In accordance with the Regulatory

Flexibility Act of 1980, Federal agencies

must evaluate the effects of the rule on

small entities and examine alternatives

that may reduce these effects. Because

the proposed rule, by itself, has no cost

impact on facilities, a separate

Regulatory Flexibility analysis was not

conducted, but is included in the

combined RIA, available in the docket.

C. Paperwork Reduction Act

The information collection

requirements in this proposed rule have

been submitted for approval to the

Office of Management and Budget

(OMB) under the Paperwork Reduction

Act, 44 U.S.C. 3501 et seq. An

Information Collection Request

document has been prepared by EPA

(ICR No. 1601.1) and a copy may be

obtained from Sandy Farmer,

Information Policy Branch, EPA, 401 M

St. SW. (PM-22Y), Washington, DC

20460, or by calling (202) 260-2740.

Public reporting burden for this

collection of information in the petition

process, the only aspect of the proposed

rule involving reporting or

recordkeeping, is estimated to be

approximately 138 hours, including

time for reviewing instructions,

searching existing data sources,

gathering and maintaining data needed,

and completing and reviewing the

collection of information. EPA estimates

that there will be 11 petitions a year.

The total annual burden is estimated to

be 1,518 hours (138 hours x 11

petitions). Send comments regarding the burden

estimate or any other aspect of this

collection of information to Chief,

Information Policy Branch, PM-223Y,

U.S. EPA, 401 M St. SW., Washington,

DC 20460, and the Office of Information

and Regulatory Affairs, Office of

Management and Budget, Washington,

DC 20503, Attn: Desk Officer for EPA.

The final rule will respond to any OMB

or public comments on the information

collection requirements contained in

this proposal.

List of Subjects in 40 CFR Part 68

Chemicals, Hazardous substances,

Extremely hazardous substances,

Intergovernmental relations, Clean Air

Act, Chemical accident prevention.

Dated: December 30, 1992.

William K. Reilly,

Administrator.

For the reasons set out in the

preamble, title 40, chapter I, subchapter

C of the Code of Federal Regulations is

proposed to be amended by adding a

new part 68 to read as follows:

PART 68-CHEMICAL ACCIDENT

PREVENTION PROVISIONS

Subpart A-General

Sec.

68.1 Scope. 68.3 Definitions.

68.5 Threshold determination.

Subpart B-Risk Management Plan

Requiremeirts [Reserved]

Subpart C-Regulated Substances for

Accidental Release Prevention

68.100 Purpose. 68.120 Petition process. 68.125 Exemptions. 68.130 List of substances.

Authority: 42 U.S.C. 7412(r).

Subpart A-General

568.1 Scope.

This part sets forth requirements for

chemical accident prevention steps that

must be taken by the owner or operator

of stationary sources.

§68.3 Definitions.

For the purposes of this part: Accidental release means an

unanticipated emission of a regulated

substance or other extremely hazardous

substance into the ambient air from a

stationary source.

Administrator means the

administrator of the U.S. Environmental

Protection Agency.

Article means a manufactured item

that is formed to a specific shape or

design during manufacture,'that has end

use functions dependent in whole or in

part upon the shape or design during

end use, and that does not release or

otherwise result in exposure to a

regulated substance under normal

conditions of processing and use.

CAS means the Chemical Abstracts

Service.

Process means any activity involving

a regulated substance including any use,

storage, manufacturing, handling, or

onsite movement of such substances, or

combination of these activities. For the

purposes of this definition, any group of

vessels that are interconnected, or

separate vessels that are located such

that a regulated substance could be

involved in a potential release, shall be

considered a single process. Regulated substance is any substance

listed under section 112(r)(3) of the

Clean Air Act as amended, and § 68.130.

Stationary source means any

buildings, structures, equipment,

installations, or substance emitting

stationary activities which belong to the

same industrial group, which are

located on one or more contiguous

properties, which are under the control

of the same person (or persons under

common control), and from which an

accidental release may occur. A

stationary source includes

transportation containers that are no

longer under active shipping orders and

transportation containers that are

connected to equipment at the

stationary source for the purposes of

temporary storage, loading, or

unloading. Threshold quantity means the

quantity specified for regulated

substances under section 112(r)(5) of the

Clean Air Act as amended, and listed in

§ 68.130 and determined to be present at

a stationary source as specified in

§ 68.5.

Vessel means any reactor, tank, drum,

barrel, cylinder, vat, kettle, boiler, pipe,

hose, or other container.

§68.5 Threshold determination.

(a) A threshold quantity of a regulated

substance as listed in S 68.130 is present

at a stationary source if the total

quantity of the regulated substance

contained in a process exceeds the

threshold.

(b) For the purposes of determining

whether more than a threshold quantity

of a regulated substance is present at the

stationary source, the following

exemptions apply: (1) Concentrations of a regulated

substance in a mixture. If a regulated

substance is present In a mixture and

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the concentration of the substance is

below one percent by weight of the

mixture, the amount of the substance in

the mixture need not be considered

when determining whether more than a

threshold quantity is present at the

stationary source.

(2) Alices. Regulated substances

contained in articles need not be

considered when determining whether

more than a threshold quantity is

present at the stationary source.

(3) Uses. Regulated substances used

for the following purposes need not be

included when determining whether

more than a threshold quantity is

present at the stationary source:

(i) Use as a structural component of

the stationary source;

(ii) Use of products for routine

janitorial maintenance;

(iii) Use by employees of foods, drugs,

cosmetics, or other personal items

containing the regulated substance; (iv) Use of regulated substances

present in process water or non-contact

cooling water as drawn from the

environment or municipal sources, or

use of regulated substances present in

air used either as compressed air or as

part of combustion; and

(v) Use solely for consumption as fueL

(4) Activities in Laboratories. If a

regulated substance is manufactured,

processed, or used in a laboratory at a

stationary source under the supervision

of a technically qualified individual as

defined in § 720.3(ee) of this chapter,

the quantity of the substance need not

be considered in determining whether a

threshold quantity is present. This

exemption does not apply to:

(i) Specialty chemical production-

(ii) Manufacture, processing, or use of

substances in pilot plant scale

operations; and

(iii) Activities conducted outside the

laboratory.

Subpart B--Risk Management Plan

Requirements [Reserved)

Subpart C-Regulated Substances for

Accidental Release Prevention

168.100 Purpoae.

This subpart designates substances to

be listed under section 112(r) (3), (4),

and (5) of the Clean Air Act, as

amended, identifies their threshold

quantities, and establishes the

requirements for petitioning to add or

delete substances from the list.

S68.120 Petition process.

(a) Any person may petition the

Administrator to modify, by addition or

deletion, the list of regulated substances

identified in § 68.130. Based on the

information presented by the petitioner,

the Administrator may grant or deny a

petition.

(b) A substance may be added to the

list if, in the case of an accidental

release, it is known to cause or may be

reasonably anticipated to cause death,

injury, or serious adverse effects to

human health or the environment.

(c) A substance may be deleted from

the list if adequate data on the health

and environmental effects of the

substance are available to determine

that the substance, in the case of an

accidental release, will not cause death,

injury, or serious adverse effects to

human health or the environment.

(d) No substance for which a national

primary ambient air quality standard

has been established shall be added to

the list. No substance regulated under

title VI of the Clean Air Act, as

amended, shall be added to the list.

(e) The burden of proof is on the

petitioner to demonstrate that the

criteria for addition and deletion are

met. A petition will be denied if this

demonstration is not made.

(f) The Administrator will not accept

additional petitions on the same

substance following publication of a

final notice of the decision to grant or

deny a petition, unless new data become

available that could significantly affect

the basis for the decision.

(g) Petitions to modify the list of

regulated substances must contain the

following:

(1) Name and address of the petitioner

and a brief description of the

organization(s) that the petitioner

represents, if applicable;

(2) Name, address, and telephone

number of a contact person for the

petition;

(3) Common chemical name(s),

common synonym(s), Chemical

Abstracts Service number, and chemical

formula and structure;

(4) Action requested (add or delete a

substance);

(5) Rationale supporting the

petitioner's position; that is, how the

substance meets the criteria for addition

and deletion. A short summary of the

rationale must be submitted along with

a more detailed narrative; and

(6) Supporting data; that is, the

petition must include sufficient

information to scientifically support the

request to modify the list. Such

information shall include:

(i) A list of all support documents;

(ii) Documentation of literature

searches conducted, including, but not

limited to, identification of the

database(s) searched, the search

strategy, dates covered, and printed

results;

(ii) Effects data (animal, human, and

environmental test data) indicating the

potential for death, injury, or serious

adverse human and environmental

impacts from acute exposure following

an accidental release; printed copies of

the data sources, in English, should be

provided; and

(iv) Exposure data or previous

accident history data, indicating the

potential for serious adverse human

health or environmental effects from an

accidental release. These data may

include, but are not limited to, physical

and chemical properties of the'

substance, such as vapor pressure;

modeling results, Including data and

assumptions used and model

documentation; and historical accident

data, citing data sources.

§68.125 Exemptlons.

Agricultural nutrients. Ammonia used

as an agricultural nutrient, when held

by farmers, need not be included when

determining whether a threshold

quantity is present on site.

§68.130 Ustof subtarce.

(a) Explosives are covered under

section 112(r) of the Clean Air Act if

they are classified by DOT in Division

1.1(49 CFR part 172.102) defined as

explosives that have a mass explosion

hazard, and are present on site in

quantities greater than 5,000 pounds.

(b) Regulated toxic and flammable

substances under section 112(r) of the

Clean Air Act are the substances listed

in Tables 1, 2, 3, and 4 of this section.

Threshold quantities for listed toxic and

flammable substances are specified in

the tables.

(c) The bases for plarcng toxic and

flammable substances on the list of

regulated substances are explained in

the notes to the list.

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TABLE 1 TO § 68.130.-LIST OF REGULATED Toxic SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL RELEASE

PREVENTION

(Alphabetical Order-100 Substances)

Chemical name CAS No. Threshold Basis for

quantity (Ibs) listing

Acetone cyanohyddn 75-86-5 5.........................

5,000 (b)

Acrolen ............................................................................................................................................................................. 107-02-8 1.000 (b)

Acrylonitl0e ........................................................................................................................................................................ 107-13-1 10,000 (')

Acry ly chloride ................................................................................................................................................................... 814-68-4 1,000 (b)

Alyl alco hol ........................................................................................................................................................................ 107-18-6 5,000 (b)

Allylam ine ........................................................................................................................................................................... 107-1 -9 1,000 ()

Ammona (anhydrous) ....................................................................................................................................................... 7664-41-7 1,000 b)

Ammonia (aqueous solution. conc 20% or greater) .......................................................................................................... 7664-41-7 5,000 (" b)

A llne ................................................................................................................................................................................ 62-53-3 5,000 (b)

Antimony pentafluo de ...................................................................................................................................................... 7783-70-2 1,000 (b)

Arsenous trilo rIde ........................................................................................................................................................... 7784-34-1 5,000 (b)

Arsine ................................................................................................................................................................................. 7784-42-1 500 ()

Benzal chloide ................................................................................................................................................................. 98-87-3 1.000 (b)

Benzenamlne, 3-{tdfluoromethyl)- ..................................................................................................................................... 98-1 -8 1,000 (b)

Benzotlichlodde ................................................................................................................................................................. 98-07-7 500 ()

Benzy chloride d .................................................................................................................................................................. 100-44-7 1,000 C')

Benzyl cyande .................................................................................................................................................................. 140-29-4 1,000 ()

Boron trichlodde ................................................................................................................................................................. 10294-34-5 1,000 (b)

Boron trfluorde ................................................................................................................................................................. 7637-07-2 1,000 (b)

Boron trnfluorlde compound with methyl ether (1:1) ......................................................................................................... 353-42-4 5,000 () Bromi¢ne .............................................................................................................................................................................. 7726-95-6 1,000 (-. b)

Carton disulfide ................................................................................................................................................................. 75-15-0 10,000 (b) Chlorine .............................................................................................................................................................................. 7782-50-5 1,000 (, b) Chlorine dio de ................................................................................................................................................................. 10049-04-4 500 (d) Chloroethanol ..................................................................................................................................................................... 107-0 7-3 1,000 ()

Chloroform ......................................................................................................................................................................... 67-66--3 10,000 (b)

Chlorom thyl. ether ............................................................................................................................................................ 542-88-1 500 (b)

Chloromethyl methyl ether ................................................................................................................................................. 107-30-2 1000 (b)

Crotonaldehyde .................................................................................................................................................................. 4170-30-3 10,000 C')

Crotonaldehyde, (E)- ......................................................................................................................................................... . 123-73-9 10,000 (b)

Cyanogen chloride ............................................................................................................................................................. 506-77-4 1,000 (d)

Cyclohexylamine ............................................................................................................................................................... 108-91- 5,000 (b)

Diborane ............................................................................................................................................................................ 19287-45-7 500 (b)

Trans-1.4-dchloro.butene ................................................................................................................................................... 110-57-6 1,000 )

Dichloroethyl ether ............................................................................................................................................................. 111-44-4 10,000 (b)

Dimethyldichlorosllane ....................................................................................................................................................... 75-78-5 1,000 (b)

Dimethylhydrazne ............................................................................................................................................................. 57-14-7 5,000 (b)

Dimethyl phosphorochlondothloate ................................................................................................................................... 2524-03-0 1,000 (b)

Epchlorohydrin ................................................................................................................................................................. 106-89-8 10,000 C')

Ethylenediamine ................................................................................................................................................................ 107-15-3 10,000 (b)

Ethyleneim e .................................................................................................................................................................... 151-56-4 1,000 (,b) Ethylene oxidle ............................. I...................................................................................................................................... 75-21-8 5,000 (,- b)

Fluorine ............................................................................................................................................................................. 7782-4 1-4 500 ()

Formaldehyde .................................................................................................................................................................... 50-00-0 500 (b)

Formaldehyde cyanohydrin ............................................................................................................................................... 107-16-4 5,000 (b)

Furan .................................................................................................................................................................................. 110-00-9 1,000 ()

Hydrazine ........................................................................................................................................................................... 302-0 1-2 5,000 (b)

Hydrochloric acid (solution, conc 25% or greater) ............................. I ..... ............................................ 7647-01-0 5,000 (')

Hydrocyanc acid ............................................................................................................................................................... 74-90-8 500 ( b)

Hydrogen chloridde (anhyd rous) ......................................................................................................................................... 7647-0 1-0 1,000 b)

Hydrogen fluoridde .............................................................................................................................................................. 7664-39-3 500 ' b)

Hydrogen peroxide (conc 52% ) ...................................................................................................................................... 7722-84-1 5,000 ')

Hydrogen selende ............................................................................................................................................................. 7783-07-5 500 (b)

Hydrogen sulfide ................................................................................................................................................................ 7783-06-4 1,000 (' b)

Iron, pentacatonyl-.. .......................................................................................................................................................... 13463-40-6 500 (b) Isobutyronitdte .......................................................... .......................................................................................................... 78-82-0 10,000 (b) Isopropyl chlo ..................................................................................................................................................... .ofo.a.e 108-23-6 5,000 (b)

Lactonitnile .......................................................................................................................................................................... 78-97-7 5,000 ()

Methacrylon trile ................................................................................................................................................................. 126-98-7 1,000 (b) Methyl bromide .................................................................................................................................................................. 74--&3-9 5,000D O '

Methyl chloridde ................................................................................................................................................................... 74-87-3 10,000 ')

Methyl chlo oratmate .......................................................................................................................................................... 79-22-1 1,000 (b)

Methyl hy .............................................................................................................................................................. 60-34-4 5,000 (b)

Methyl Isocyanate .............................................................................................................................................................. 624-83-9 1,000 (', b)

Methyl mercaptan .............................................................................................................................................................. 74-93-1 1,000 (b)

Methyl thlocyanate ............................................................................................................................................................. 556-64-9 10,000 (b)

Methyltcb Nickel rosilane .......................................................................................................................................................... 75-79-6 1,000 (b) carbonyl ........................................................................................ ;......................................................................... 13463-39-3 500 M t,

Nitric acid .......................................................................................................................................................................... 7697-37-2 5,000 (b)

Nitric oxide ................................. : ....................................................................................................................................... 10102-4 3-9 1,000 (b)

Nitrobenzene ...................................................................................................................................................................... 98-95-3 10,000 )

Parathion ........................................................................................................................................................................... 56-38-2 1,000 )

Peracetic acid .................................................................................................................................................................... 79-21-0 1.000 )

Perchloromethylmrercaptan ................................................................................................................................................ 594-4 2-3 100( ) (b) Phenol (liquid) .................................................................................................................................................................... 108-95-2 10,000 M

Phosgene ........................................................................................................................................................................... 75-44-5 500 ( b)

Phosphine h7) .......................................................................................................................................................................... 7803-51-2 1,000 

Phosphorus oxychloridde .................................................................................................................................................... 10025-87-3 1,000 (b)

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TABLE I TO § 68.130.-LIST OF. REGULATED Toxic SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL RELEA'I;:

PREVENTION-Continued

(Alphabetical Order-l0a Substances)

Chemical name CAS No. Threshold Basis for

quantity (Ibs) listing

Phosphorus trichlodde ................................... ..... ............................................ 7719-12-2 5,000 (b)

Piperidine ........................................................ .. . .............................................. 110-89-4 5,000 (')

Proplonltle ....................................................................................................... ............ 107-12-0 1,000 (')

Propyl chloroformate ................................................. .............................. ............... 109-61-5 5,000 C') Propytenelrnine ...................................................................................................... 4.......................................................... 75-55-8 10,000 (h) Propylene oxide ...............................................................................................................

75-56-9 10,000 ()

Pyridlne, 2-m ethyl-5-vnyl- ..........................................................................................................

140-76-1 1,000 e)

Sulfur dioxide ......................................................................... 7446-09-5 1,000 ( )

Sulfuridc acid ..................................................................................................................

7664-93-9 5,000 () Suifur tetrafluo dde ..............................................................................................................

7783-60-0 11, 00 (b)

Sulfur ti doxide .................................................................................................................

7446-11-9 1,000 ( b)

Tetram ethyllead ...............................................................................................................

75-74-1 1,000 (b)

Tetranitm m et hane ..............................................................................................................

509-14-8 1,000 (b)

Thlophenol ..................................................................................................................

108-98-5 1,000 )

Titanium tetrachlorlede ............................................................................................................

7550-45-0 500 ()

Toluene 2,4-diisocyanate ..........................................................................................................

584-84-9 1,000 ()

Toluene 2,6-dllsocyanate ..........................................................................................................

91-08-7 1,0 0 (')

Toluene dilsocyanate (unspecified Isom er) ...............................................................................................

26471-62-5 1,000 )

Trichloroethylsllane .............................................................................................................

115- 21-9 1,000 ') Trim ethylchlorosilane ............................................................................................................

75-77-4 1,000 (b)

Vinyl acetate monom er ...........................................................................................................

108-05-4 5,000 (b) Vinyl chloride ................................................................................................................ 4.....................................................1 75-01-4 1 10,000 1(-)

Basis for Listing:

:Mandated for listing by Congress. bOn ENS ist, vapor pressure 0.5 mmHg or greater. .On EMS NL vapor pressure less than 0.5 mrnHg, but has been involved In accidents resulting in death or Injury. a Toxic gas.

Listed based on toxicity of hydrogen chloride, potential to release hydrogen chloride, and history of accidents.

TABLE 2 TO § 68.130.-LIST OF REGULATED Toxic SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL RELEASE

PREVENTION

(CAS Number Order-100 Substances)

CAS No. Chemical name Threshold Basis for

quantity (Ils) listing

50-00-0 .......... Form aldehyde .....................................................................................................

500 (b)

56-38-2 .......... Parathion ........................................................................................................

1,000 ()

57-14-7 .......... lm ethylhydrazine ..................................................................................................

5,000 (b)

60-34-4 .......... Methyl hydrazlne ...................................................................................................

5,000 C)

62-53-3 .......... Aniline .........................................................................................................

5,000 ) 67-66-3 .......... Chloroformn ...................... ...........................................................................................................

10,000 (b,)

74-83- 9 .......... M ethyl brom ide ....................................................................................................

5,000 ') 7 "- 7-3 .......... M ethyl chloride ...................................................................................................................

10,000 (,)

74-87-3......Methyl 74-90-8 ......... Hydrocyanic mhloide................................................................... acid ...................................................................................................

...................................... ....... 10,000 5000 (b) (. )

75-15-0 .......... Car onhy lide n.......................... ... .....................................................................................................

10,000 (b,) 75-9 1-1 .......... Et c ryle apotade ................................... ............................................................................. .................................................. . 1 0,000 (*)

75-15-0 .......... Car on disulfide. ...................................................................................................

500 (b)

7 5 5 21 ---8in ......- d e. ... ..... .... .... ..... .... .... ..... .... .... ..... .... .... ..... .... .... ..... .. ... ..... .... ..1 ,0 0 0 ('.b)

75- - .......... ylene oxide............................ ........................................................................................

000 (b)

75-44-5 . h. e h n.......... e . ....................................................................................................

.. 100 ( b)

75-55-8 .......... Propyleneim ine ............................................................................................

10,000 (b)

75-5-9 . Propylene oxide.... . . ......................................................................................

10,000 (b)

75-74-1 .......... Tet methyllead ....................................................................................................

1,000 (,)

75-77-4 .......... T m ethylchlo si lane ................................................................................................

,O0 (b)

75-78-5 .......... Dimethyld chorsil lane..... ...........................................................................................

1,000 (')

75-86-5 78- 7-7 .......... .......... Acetone M etoyltriclor cyano ......................................................................................................................

s hyd rin ..................................................................................................

5,000 ,000 (b) (b)

78-82-0 ......... Isobutyronll e.....................................................................................................

10,000 (b)

78-97-7 ......... Lactonie i ...................................................................................................

... ,000 ') 79-21-0 .......... Peracetic acid ............... .... ..................................................................................

.. . 1,000 (b)

79-22-1 .......... M ethyl chloroform ate ..... ...........................................................................................

.. 1,000 (b)

918- 73 .......... Tolen ea 2,h lsoy e ............................................................................................................

. 1,000 (b)

98-95-7 .......... Nyabenz o e ....................................................................................................

... 1 ,000 (,)

98-16-8 ....... Benzene m ne, 3-(tri luo om ethyl).... ... .................................................................................

... 1,000 (b)

98-87-3 ........ Ba nzai chlor ide. ....................................................................................................

1 ,000 (')

96-95-3 ........ Nitrobenzene . ......................................................................................................

1 ,000 (b)

100-44-7 ....... Benzyl chlor de .....................................................................................................

1,000 C') 106-89-8 ........ plchlom hydrin . ....................................................................................................

10,000 ()

107-02-8 ....... Acrolein .........................................................................................................

1,000 (b) 107-07-3 .... Chloroethanol........................................1,000 (b)

107-11-9 ........ A lylam lnee ........................................................................................................

1,000 (') 107-12-0 ...... Proopnltrnit e......................................................................................................................

.... ')

107-13-1 ..... Acrylyltoneit e...................................................................................................................10,000 ..... 1,00 ')

107-15-3 ........ Ethylenedlamine ...................................................................................................

10,000 ()

107-16-4 ........ Form aldehyde cyanohydrin ............................................................................................

5,000 C')

107-18-6 ........ Alyl alcohol ......................................................................................................

5,000 (b)

107-30-2 ....... Chlorom ethyl m ethyl ether .............................................................................................

............................ 1,000 C)

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TABLE 2 TO § 68.130.--LIsT OF REGULATED Toxic SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL RELEASE

PREVENTION-Continued

[CAS Number Order-100 Substances]

CAS No. Chemical name Threshold Basis for

Niquantity (lbs) listing

108-05-4 ......

108-23-6 ....... 108-91-8 .......

108-95-2 ........ 108--98-5 .......

109-61-5 ......

110-00-9 .......

110-57-6 .......

110-89-4 ......

111-44-4 ......

115-21-9 ......

123-73-9 ......

126-98--7 ......

140-29-4 ........

140-76-1.

151-56-4 ........

302-01-2 ........

353-42-4 .......

506-77-4 .......

509-14-8 .......

542-88-1 .......

556-64-9 ........

584-84-....

594-42-3 ......

624-83-9 ........

814-68-6

2524-03-0 .....

4170-30-3 ......

7446-09-5 ......

7446-11-9 ......

7550-45-0 ......

7637-07-2 ......

7647-01-0.

7647-01-0 ......

7664-39-3 ......

7664-41-7 ......

7664-41-7.

7664-93-9

7697-37-2 ......

7719-12-2.

7722-84-1 ......

7726-95-6 ......

7782-41-4.

7782-50-5

7783-06-4.

7783-07-5.

7783-60-0

7783-70-2.

7784-34-1 ......

7784-42-1 ......

7803-51-2

10025-87-3 ....

10049-04-4

10102-43-9

10294-34-5

13483-39-3 ....

13463-40-6 ....

19287-45-7 ....

26471--62-5 ....

'4K Vinyl acetate monomer ...................................................................................................................................................... Isopropyl chorofom ate ...................................................................................................

Cyciohexylamine ................................................................................................................................................................ P eno (l u ) .................................................................................................................................................................

Thiophenol ....... ........................................................................................................................................................... Propyl .hlorolo ate ........................................................................................ ...........................................................

T ran .4-d . tene.....................................................................................................................................................

Piper ine .................................................................................................................................................................... Dic roethyl ether ..................................................................................................................................................................... TDchloroethylal lane ............................................................................................................................. ............................. Crotonalr ehyde, (E) ............................................................................................................................. ............................. M hac onl . . . . . . . . . . . . . . . . . ........................................................................................................

Bent cyl on e ........................................................... ............................................................... .............................

Pyrd ne, 2-met y-5- nyl ............. ..................................................................................................................................... Etyldre elm l ........ v y .................. ........................................................................ .......................................................

Ethylenelmlne ................................................ . .................................................................................................................

Hydraz ne ......... .... . . ..... ... . . . .......................................................................................................

Boron trhfluo de com.ound .. with methyl ether (1:1) .................................................................................... .....................

Tetrang h e .......................................................................................................................................................... Chloromethyl e ter ............................................................................... .......................................................................

Toluene 2,4 isocyanate ........................................................................................................... ....................................... Me "rc h loometh le ............. ..... ........... ........ ....... ... ....................... .. .............................................................................

Tolen 2 iisocyana .... e ..................................... ............................ ................................................................................. . P r ch lor e . ... captan ............................................................................................................................................ M ethyl Isocyanate ................................................... .................................................................................

Cr tyla hyork e .... d.............................................................................. ............. .............................................................

C r t doadey de............. .................................................................................................................................... Sufur ioIdde ....................................................................................................................................................................

T ltan um te rach.orl e .....................................................................................................................................................

ron trifluodde .................................................................................................................................................................. Hydrogen chloride (anhydrous) ...........................................................................................................................................

Hyron fluode .......................................... ......................................... ..........................................................................

Hydrognalod (anhydrous) ...............................................................................................................................................

Ammooni Hydrogn (aueou (flu ie (solution, s t n, conc on 2% 20 ............................... or org greater) e er .................................. ...................... ................................................................

Sulfuric a d d ............................................................. .................... ..................................................................

Nitric acid ..........................................................................................................................................................................

Phosphorus tr lodde ..................... ................................. ........................................................................

Hydrogen peroxide (coc > 52%/6) .......................................................................................

Fluo ine .........................................................................................................................................................................

C lorine ............................................................................................................... ..........................................................

Hydrogen sl.de .................................................................. .............................................................................................

Hydrogen seleide .............................................................................................................................................................. SHy r t e eflo kle ............................................................................................................................................................

A imony pe al uodd e.....................................................................................................................................................

A imenous trch odde ............................................................................ .............................. . .........................................

Arsone.....hore............................................................................................ ,-- ...- - Prie...................................................n....................................................... Pho6ph ne ......................................................................................................................................................................... Phosphorus oxycanoree ...........................................................................................

CThoree d o e .... ........................................................................................................................................................... Nhtdc oxide ..... ... ...............................................................................................................................................................

Boron trlchlodde ..................................... ................................. ............. .... . .....................................................................

Nickel carbonyl .. .......................................... .............................................. ...................................................................... iron. pentacaronyl .............................................................................................................................................................

Diborane ..... .................................................................... ........... ............................................................... Toueeo is cy n teenseefedIomrd.........................s......................d......................).

5,000

5,000

5,000

10,000

1,000

5,000 1,000

1.000

5,000

10,000

1,000

10,000

1,000

1,000

1,000

1,000

5,0O0

5,000

1,000

1,000

500

10,000

1,000

1,000

1,000

1,000

1,000

10.000

1,000

1,000

500

1,000

1,000

5,000

500

1,0010

5,000

5,000

5,000

5.000

5,00C

1,000

500

1.000

1,000

500

1,000

1,00C

5,00C

50C

1,00C

1,000

50C

1,00

4.00C

5O(

500

50C

1,000

Basis for UsItg:

* Mandated for liting by Congress. On EHS list, vapor pressure 0.5 mmHg or greater

On EHS lot vapor essure Is than 0.5 mmlg, but has been nvolved In accld@nt resukig in death or I ,ury.

Ld based on ioxiclty of hydrogen chloide, potential to release hydrogen chloride. and histoy of socit

TABLE 3 TO § 68.130.-LIST OF REGULATED FLAMMABLE SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL

RELEASE PREVENTION

[Alphabetical Order--62 Substances)

Chemical name CAS No. Threshold J Basisl for I I quentliy (06) 1 flth'ng

I I I

Acetaldehyde

Acetylene ........ Bromoi- fluordhylene

1,3-Butadtene

1 75-07-0 10,000 (9)

74-86-2 10,000 ()

598-73-2 10,000 ('

106-99-0 10,0001

HeinOnline -- 58 Fed. Reg. 5123 1993
5124 Federal Register / Vol. 58, No. 11 / Tuesday, January 19, 1993 / Proposed Rules

TABLE 3 TO § 68.130.-LIST OF REGULATED FLAMMABLE SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTAL

RELEASE PREVENTION-Continued

[Alphabetical Order--62 Substances]

Threshold Basis for Chemical name CAS No. quantity (Ibs) listing

Butane .....................................................................................................................

106-97-8 10,000

1-Butane ...................................................................................................................

106-98-9 10,000 ( 2-But ne ....................................................................................................................................

107-01-7 10,000 (t

Butene .....................................................................................................................................

25167--67-3 10,000 ( 2-Butene-c .s .................................................................................................................

590-18-1 10,000

2-Butene-trans ................................................................................................................624-64-6 10,000 (

Carbon oxysuflde ..............................................................................................................463-58-1 10,000 (

Chlo ine r noxide .............................................................................................................7791-21-1 10,000 (

2-Chloropropylene .............................................................................................................................

557-98-2 10,000 () 1-Chloropropylene ..............................................................................................................

590-21-- 6 10,000 ()

Cyanogen ...................................................................................................................460-19-5 10,000 )

Cyclopropane ................................................................................................................75-19-4 10,000 (

D chlorosilane ................................................................................................................

4109-96-0 10,000

Difluoroethane ................................................................................................................75-37-6 10,000

Di lmethylamlne ...............................................................................................................124-40-3 10,000

2,2-Dlmethylpropane ............................................................................................................

463-82-1 10,000 (

Ethane .....................................................................................................................

74-84-0 10,000 (

Ethyl acetylene ...............................................................................................................

107-00-6 10,000

Ethylamine ..................................................................................................................

75-04-7 16,000 (

Ethyl chloride ................................................................................................................

75-. 00-3 10,000

Ethylene ......................................................................................................... ....................................................................... 74-85-1 10,000

Ethyl ether ..................................................................................................................

60-29-7 10,000 C)

Ethyl mercaptan ...............................................................................................................

75-08-1 10,000 )

Ethyl nitte ..................................................................................................................

109-95-5 10,000 Hydrogen ........................ .............................................. 1337-0 t00C) o e ....................... ..........................................................................................

1333-74 10,000 (9 Isobutanve ............................................................................................................................... :................................................. 75-28-5 10,000 (

Isopntane ..................................................................................................................................

78-78-4 10,000 (s)

Isoprene ...................................................................................................................

78-79-5 10,000 )

Isopropylamine ...............................................................................................................

75-31-0 10,000 ) Isopropyl chloride ..............................................................................................................................

75-29-6 10,000 (S)

Methane ...................................................................................................................74-82-8 10,000 (

Methylamine .................................................................................................................

74-89-5 10,000

3-Methyl-l-butene .............................................................................................................

.563-45-1 10,000

2-Methyl-i-butene .......................................... ...........................................................................................

5 3-46-2 10,000 (') Methyl ether ................................................... ".........................................................................................................

115-10-6 10,000 ( Methyl formate ...............................................................................................................

107-31-3 10,000 ()

2-Methylpropene ..............................................................................................................

115- 11-7 10,000

1,3-Pentadiene ...............................................................................................................

504- 0-9 10,000

Peantane ....................................................................................................................

109- 6-0 10,000 )

1-P ntene ...................................................................................................................

109-67-1 10,0001 )

2-Pentene, (E)- ................................................................................................................

646-04-8 10,000 )

2-Pentene, (Z)-. ...............................................................................................................

627-20-3 10,000 ')

Propadleane ..................................................................................................................

463-49-0 10,000

Propane ...................................................................................................................

74-98- 10,000 (1

Propylene ...................................................................................................................

115-0 7-1 10,000

Propyne ....................................................................................................................

74-99-7 10,000

Silane ....................... ...........................................................................................................

7803-62-3 10,000 (

Tetrafluoro thyl ene .............................................................................................................

116-14-3 10,000 ( Tetramethylsilane .............................................................................................................................

75- 76-3 10,000 ()

Trlchlorosilane ................................................................................................................

10025-78-2 10,000 )

Tdfluoro- chloroethylene .............................................................................. I ........................................................................ 79-38-9 10,000 (

Tdmethylamlne ...............................................................................................................

75-50--3 10,000

Vinyl acetylene ...............................................................................................................

689-97-4 10,000

Vinyl ethyl ether ...............................................................................................................

109-92-2 10,000 ) VInyl fluoride ..................................................................................................................... .75-02-5 10,000 Ct9

Vinylidene chloride .............................................................................................................

75-35 -4 10,000 ) Vinylldne fluoride .............................................................................................................................

75-38-7 10,000( (l 

Vinyl methyl ether .............................................................................................................................

107-25-5 10,000 (

Bass for Lwk

Flammable gas. 'Volatile flammable liquid.

TABLE 4 TO § 68.130.-LIST OF REGULATED FLAMMABLE SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTIAL

RELEASE PREVENTION

[CAS Number Order-62 Substances]

CAS No. Chemical name Threshold Basis for

quantity (Ibe) listing

60-29-7 .......... Ethyl ether ......................................................................................................

10,000 ()

74- -82-8 .......... Methane .......................................................................................................

10,000 ()

74-84-0 .......... Ethane .........................................................................................................

10,000 (

74-85-1 .......... Ethylene .......................................................................................................

10,000 (

74-86-2 .......... Acetylene ......................................................................................................

10,0001 ()

74-89-5 .......... Methylan ne ...................................................................................................................

10,000 (

74-98-6 .......... Propane .......................................................................................................

. 10,000

HeinOnline -- 58 Fed. Reg. 5124 1993
Federal Register / Vol. 58, No. 11 / Tuesday, January 19, 1993 / Proposed Rules 5125

TABLE 4 TO § 68.130.-LIST OF REGULATED FLAMMABLE SUBSTANCES AND THRESHOLD QUANTITIES FOR ACCIDENTIAL

RELEASE PREVENTION-Continued

[CAS Number Order-62 Substances]

Chemical name Threshold I Basis for

quantity (Ibs) I listing

Propyne .............................................................................................................................................................................. Ethyl chloride ......................................................................................................................................................................

Vinnyl fluoride ......................................................................................................................................................................

Ethylarnine .......................................................................................................................................................................... Acetaldehyde .......................................................................................................................................................... ........... Ethyl mercaptan .................................................................................................................................................................. Cyclopropane .............................................................................................................................................................................. Isobutane ...........................................................................................................................................................................

Isopropyl c o ........................................................................................................................................................... Iopropylam ne .................................................................................................................................................................... Vinylidene chlorde .............................................................................................................................................................

Difluoroethane .....................................................................................................................................................................

Vinyl ene fluoridde ..............................................................................................................................................................

Trlmetyla ne ...................................................................................................................................................................

Tetramethylsilane ...............................................................................................................................................................

Isopentane ..........................................................................................................................................................................

Isoprene .............................................................................................................................................................................

Trlfluorochloroethylene ....................................................................................................................................................... Mfl # ...

74-99-7 ..........

75-00-3 ..........

75-02-5 .......... 75-04-7 ..........

75-07-0 ..........

75-08-1 .......... 75-19-4 ..........

75-28-5 ..........

75-29-6 .......... 75-31-0 ..........

75-35-4 ..........

75-37-6 ..........

75-38-7 ..........

75-60-3 ..........

75-76-3 ..........

78-78-4 ..........

78-79-5 ..........

79-38-9 ..........

106-97-8 ........

106-98-9 ........ 106-99-0 ........ 107-00-6 ........

107-01-7 ........

107-25-5 ........

107-31-3 ........

109-66-0 ........ 109-67-1 ........ 109-92-2 ........ 109-95-5 ........

115-07-1 ........

115-10-6 ........

115-11-7 ........

116-14-3 ........

124-40-3 ........

460-19-5 ........

463-49-0 ........

463-68-1 ........

463-82-1 ........

504-60-9...

557-98-2 ........

563-45-1 ........

563-46-2 ........

590-18-1 ........

590-21-0 ........

598-73-2 ........

624-64-6.

627-20-3 ........

646-04-8 ........

689-97-4 ........

1333-74-0.

4109-96-0 ......

7791-21-1 ......

7803-62-5 ......

10025-78-2

25167-67-3 ....

1.-1lJ faOIOflA ...................................................................................

Ethyl acetylene ................................................................................................................................................................... 2-Butene ............................................................................................................................................................................. V lmethyl .. t.er................................... ................................................ Vnmthyrter ................................................................................................................................................................

Pentane .... . ...................................................................................................................................................................... I -Pentane ............................................................................................................................................................................... Vinyl ethyl ether .................................................................................................................................................................. Ethyl n otrlte . ..................................................................................................................................................................

Propylene ............................................................................................................................................................................ Methyl ether ........................................................................................................................................................................

2-M ethylpropene .................................................................................................................................................................

Tetrafluoroethylene .............................................................................................................................................................

Dimethylamine.........f... ......................................................................................................................................................

Cyanogen ......................... ...................................................................... . ........................................................................

Cyanogen ................................................................................................. . .. .. .. ................................. .....

Carbon oxysulie ...................................................................................................................................................................

2,2-D methylpropane ...........................................................................................................................................................

1,3-Pentadiene...............................................................................................................................................................

2-Chloropropylene ..............................................................................................................................................................

3-Methyl-l-butne ..............................................................................................................................................................

2-Methyl-1 -butene ...............................................................................................................................................................

2-Butene-cis ........................................................................................................ .......................................................

1-Chloropropylene

Brom otrifluore yle.ne .......................................................................................................................................................... 2-Butene-trans ....................................................................................................................................................................

2-Pentene, (Z) .....................................................................................................................................................................

2-Pentene, (E) .................................................................................................................................................................... Vinyl acetylene ....................................................................................................................................................................

Hydrogen ...........................................................................................................................................................................

Dichlorosilane ..................................................................................................................................................................... Chlorine monoxide ..............................................................................................................................................................

Slane .......................................................................................................................

Tdchlorosilane ..................................................................................................................................................................... Butane ...............................................................................................................................................................................

Basis for Ust:

'Vltiefa "al liquid

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10:000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

[FR Doc. 93-960 Filed 1-15-93; 8:45 am)

BILUNG CODE 6660-50-

4

CAS No.

1 -Butane o.o........................................................I.........................................................................o............+..............................

................................................................................................................................

HeinOnline -- 58 Fed. Reg. 5125 1993