Accidental Release Prevention Requirements: Risk Management Programs Under Clean Air Act Section 112(r)(7); Amendments to the Worst-Case Release Scenario Analysis for Flammable Substances

SUMMARY: This direct final action amends the Chemical Accident

Prevention Provisions, also known as the Risk Management Program (RMP)

regulations, codified in 40 CFR part 68. The revisions concern the

worst-case release scenario analysis for regulated flammable substances

in 40 CFR 68.25. EPA is issuing these revisions so that the regulated

community can treat regulated flammable substances in the same manner

as regulated toxic substances for determining the quantity released

when conducting a worst-case release scenario analysis. EPA is taking

this direct final action pursuant to a settlement agreement with the

American Petroleum Institute (API).

EPA is also clarifying its interpretation of Clean Air Act sections

112(l) and 112(r)(11), as they relate to Department of Transportation

(DOT) requirements under the Federal Hazardous Materials Transportation

Law under a settlement agreement with the Chlorine Institute (CI).

DATES: This rule is effective on June 21, 1999 without further notice,

unless EPA receives adverse comment by June 16, 1999 or, pursuant to

CAA section 113(g), declines to finalize the settlement agreement. If

we receive such comment, or decide to withdraw from the settlement

agreement, we will publish a timely withdrawal in the Federal Register

informing the public that this rule will not take effect.

ADDRESSES: Docket and Comments. Docket No. A-99-15, containing

supporting information used to develop these amendments, is available

for public inspection and copying from 8:00 a.m. to 5:30 p.m., Monday

through Friday (except government holidays) from EPA's Air Docket, at

Waterside Mall, Room M1500, 401 M Street, SW, Washington, D.C., 20460,

telephone 202-260-7548. Written comments should be submitted to the

same address. A reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT: Sicy Jacob or John Ferris, Chemical

Emergency Preparedness and Prevention Office, Environmental Protection

Agency (5104), 401 M Street SW, Washington, D.C., 20460, (202) 260-7249

or (202) 260-4043, respectively; or the Emergency Planning and

Community Right-to-Know Hotline at 800-424-9346 (in the Washington, DC

metropolitan area, (703) 412-9810). You may wish to visit the Chemical

Emergency Preparedness and Prevention Office (CEPPO) Internet site, at

www.epa.gov/ceppo.

SUPPLEMENTARY INFORMATION:

Regulated Entities

Entities potentially regulated by this action are those stationary

sources that have more than a threshold quantity of a regulated

substance in a process. Regulated categories and entities include:

------------------------------------------------------------------------

Example of regulated

Category entities

------------------------------------------------------------------------

Petrochemical............................. Refineries, Plastics,

Resins.

Chemical Manufacturing.................... Organics.

------------------------------------------------------------------------

This table is not meant to be exhaustive, but rather provides a

guide for readers to indicate some of those entities likely to be

regulated by this action. The table lists entities EPA is aware of that

could potentially be regulated by this action. Other entities not

listed in the table could also be regulated. To determine whether a

stationary source is regulated by this action, carefully examine the

provisions associated with the list of substances and thresholds under

Sec. 68.130 and the applicability criteria under Sec. 68.10. If you

have questions regarding applicability of this action to a particular

entity, consult the hotline or persons listed in the preceding FOR

FURTHER INFORMATION CONTACT section.

Table of Contents

I. Introduction and Background

A. Statutory Authority

B. Background

C. RMP Rule Litigation

II. Discussion of Revisions to Sec. 68.25

III. Clarification of Section 112(l) and 112(r)(11)

IV. Judicial Review

V. Administrative Requirements

A. Docket

B. Executive Order 12866

C. Executive Order 12875

D. Executive Order 13045

E. Executive Order 13084

F. Regulatory Flexibility

G. Paperwork Reduction

H. Unfunded Mandates Reform Act

I. National Technology Transfer and Advancement Act

J. Congressional Review Act

I. Introduction and Background

A. Statutory Authority

These amendments are being promulgated under sections 112(r) and

301(a)(1) of the Clean Air Act (CAA) as amended (42 U.S.C. 7412(r),

7601(a)(1)).

B. Background

The 1990 CAA Amendments added section 112(r) to provide for the

prevention and mitigation of accidental chemical releases. Section

112(r) mandates that EPA promulgate a list of ``regulated substances,''

with ``threshold quantities''. Processes at stationary sources that

contain a threshold quantity of a regulated substance are subject to

accidental release prevention regulations promulgated under CAA section

112(r)(7). EPA promulgated the list of regulated substances on January

31, 1994 (59 FR 4478) (the ``List Rule'') and the accidental release

prevention regulations creating the risk management program

requirements on June 20, 1996 (61 FR 31668) (the ``RMP Rule'').

Together, these two rules are codified at 40 CFR part 68. EPA has since

revised the rules in several respects, and these revisions are

reflected in the most recent codification of 40 CFR part 68.

Part 68 requires that any source with more than a threshold

quantity of a regulated substance in a process develop and implement a

risk management program that includes a five-year accident history,

offsite consequence analyses, a prevention program, and an emergency

response program. In part 68, processes are divided into three

categories (Programs 1 through 3). Processes that likely have no

potential impact on the public in the case of accidental releases have

minimal requirements (Program 1). Processes in Programs 2 and 3 have

additional requirements based on their potential for offsite

consequences as indicated by worst-case accidental release analysis and

their accident history. Program 3 is also triggered if the processes

are subject to OSHA's Process Safety Management (PSM) Standard. By June

21, 1999, any source with more than a threshold quantity of a regulated

substance in a process must submit to EPA a risk management plan (RMP)

that summarizes their implementation of the risk management program.

C. RMP Rule Litigation

The American Petroleum Institute (API) and the Chlorine Institute

(CI) filed petitions for judicial review of the

[[Page 28697]]

RMP Rule (The Chlorine Institute v. EPA, No. 94-1279 (D.C. Cir.) and

consolidated cases (Nos. 96-1284, 96-1288, 96-1289 & 96-1290)). In

court filings, API raised issues related to worst-case release scenario

analysis (Sec. 68.25 of the rule) for flammables.

In the final RMP rule issued on June 20, 1996, Sec. 68.25(e) states

that when conducting a worst-case scenario analysis for flammables, the

owner or operator shall assume that the quantity of the substance, as

determined under paragraph (b) of Sec. 68.25, vaporizes, resulting in a

vapor cloud explosion. This approach applies to all listed flammable

substances regardless of whether the flammable substance is normally a

liquid or liquefied by refrigeration. API suggested that flammable

liquids and those liquefied by refrigeration should be treated, for

modeling purposes, in the same manner as for toxic liquids or those

liquefied by refrigeration, as stated in Sec. 68.25 (c) and (d). EPA

agreed that flammable liquids (including those liquified by

refrigeration) could be appropriately treated in that manner.

Accordingly, EPA and API signed a proposed settlement agreement in May

1999. This settlement agreement is awaiting finalization pursuant to

section 113(g) of the CAA.

CI's primary litigation concern related to CAA sections 112(l) and

112(r)(11), as they relate to Department of Transportation (DOT)

requirements under the Federal Hazardous Materials Transportation Law

(``Federal Hazmat Law''). EPA and CI reached an agreement on this issue

and signed a proposed settlement agreement in May 1999. This settlement

agreement is awaiting finalization pursuant to section 113(g) of the

CAA.

II. Discussion of Revisions to Sec. 68.25

40 CFR 68.25 requires each stationary source subject to the RMP

rule to analyze at least one worst-case release scenario for regulated

flammables and at least one for regulated toxic substances that are

present in a process at the stationary source above the threshold

quantity. A worst-case release means the release of the largest

quantity of a regulated substance from a vessel or process line failure

that results in the greatest distance to an endpoint defined in

Sec. 68.22(a).

In the final rule promulgated on June 20, 1996, EPA established a

framework for the worst-case scenario analysis that considers the

physical state of the substance and the way in which it is stored or

handled (see 40 CFR 68.25):

(1) For toxic gases and gases liquefied by pressure, the worst-case

release scenario assumes that the largest quantity is released in 10

minutes and the rate of release to the air is the quantity divided by

10 minutes. Upon loss of containment (e.g. a catastrophic vessel

failure), a gaseous substance will be completely released to the air

within 10 minutes. Although gases liquefied by pressure will behave

initially like a liquid, they will rapidly become gases upon

catastrophic release because of the sudden release of pressure and

because the storage temperature of the liquid is often much higher than

the boiling point of the substance. The rate of flashing and

volatilization is generally great enough to vaporize the entire

quantity within 10 minutes.

(2) For toxic liquids, the worst-case scenario assumes an

instantaneous spill; the release rate to the air is the volatilization

rate from a pool that spreads out to a 1 centimeter (cm) depth unless

passive mitigation (e.g., a diked area) contains the substance in a

smaller area. The rate of volatilization to the air depends on the

surface area of the liquid pool and it may be adjusted to account for

the smaller surface in a contained area.

(3) For toxic substances liquefied by refrigeration, the scenario

assumes an instantaneous liquid spill followed by volatilization of the

pool at the substance's boiling point but only if the spilled liquid is

contained by passive mitigation at a liquid depth greater than 1 cm. If

passive mitigation is not present or is of such large capacity that the

refrigerated liquid spill can spread out to a depth of 1 cm, then the

quantity of refrigerated liquid is assumed to completely volatilize

within 10 minutes. Gases liquefied by refrigeration need time to

vaporize and become a gas because the storage temperature of the liquid

is less than its boiling point. Therefore, the rate of release to the

air is less than the total quantity released in 10 minutes. The liquid

must be contained by passive mitigation at a depth greater than 1 cm;

otherwise, the rate of warming and volatilization is great enough to

completely vaporize the spill within 10 minutes.

For all listed flammables however, the worst case assumes that the

quantity in the largest vessel or pipeline vaporizes to form a vapor

cloud, followed by a vapor cloud explosion. No consideration was given

for liquids or substances liquefied by refrigeration, primarily because

EPA assumed that passive mitigation or containment was typically not

used under flammable storage due to fire safety reasons. The American

Petroleum Institute (API) argued that, in many cases, spilled flammable

liquids are, in fact contained, but in a way that prevents a liquid

fire from impacting storage vessels and prevents release to the

environment. Such containment serves to reduce the quantity available

for a vapor cloud explosion in the same way that liquid toxics generate

a smaller toxic vapor cloud than gases. If the flammable worst-case

scenario were revised to account for liquids in the same way as toxics,

then the flammable worst-case scenario could distinguish flammable

gases from liquids to avoid generating a technically incorrect and

overly conservative result.

EPA agrees that the worst-case assessment for flammable liquids and

flammables liquefied by refrigeration is not consistent with the

approach for toxic liquids or toxics liquefied by refrigeration. EPA is

thus taking direct final action to revise Sec. 68.25(e) so that

flammables may be treated in a manner consistent with the treatment of

toxics.

Specifically, EPA is making the following changes to Sec. 68.25 for

flammables: (1) For regulated flammable substances that are normally

gases at ambient temperature and handled as a gas or as a liquid under

pressure, the owner or operator shall assume that the quantity in the

vessel or pipe, as determined under Sec. 68.25(b), is released as a gas

over 10 minutes. The total quantity shall be assumed to be involved in

the vapor cloud explosion. (2) For regulated flammable substances that

are normally liquids at ambient temperature, the owner or operator

shall assume that the entire quantity in the vessel or pipe, as

determined under Sec. 68.25(b), is spilled instantaneously to form a

liquid pool. For liquids at temperatures below their atmospheric

boiling point, the volatilization rate shall be calculated at the

conditions specified in Sec. 68.25(d). The owner or operator shall

assume that the quantity which becomes vapor in the first 10 minutes is

reported as the quantity released. (3) For flammable gases handled as

refrigerated liquids at ambient pressure, the owner or operator may

assume that the total quantity of the substance determined in

Sec. 68.25(b) instantaneously spills followed by volatilization of the

liquid pool at the substance's boiling point and under the conditions

specified in Sec. 68.25(d), provided the spilled liquid would be

contained by passive mitigation at a liquid depth greater than 1 cm.

The quantity of substance that becomes vapor in the first 10 minutes is

involved in the vapor cloud explosion. If passive mitigation is not

present or is of such large capacity that the refrigerated liquid spill

can spread out to a depth of 1 cm, then the quantity of refrigerated

[[Page 28698]]

liquid is assumed to completely volatilize within 10 minutes and the

total quantity is involved in the vapor cloud explosion.

This modification allows stationary sources to account for

volatilization of the liquid pool if flammables are liquefied by

refrigeration; however, sources are not required to use this added

assumption. Sources can still use the quantity determined under

Sec. 68.25(b) as the quantity released. Sources that have already

submitted their RMP may choose to use this revised approach, but are

not required to do so. Sources that choose to use this revised

approach, must revise and re-submit their RMP to EPA by June 21, 1999.

EPA will not be modifying RMP*SubmitTM (the computer

database used to report the RMPs) as a result of this rule at this

time. Instead, stationary sources reporting for flammables liquefied by

refrigeration would need to calculate the total quantity of the gas

generated (taking the volatilization rate into account) from the pool

in a 10-minute period. This value would be reported as ``Quantity

released'' in section 4.4 of RMP*SubmitTM. The passive

mitigation (dikes, berms, etc.) considered would be specified at

``Other'' in section 4.10. EPA also suggests that stationary sources

utilize the Executive Summary section of RMP*SubmitTM to

explain how they calculated the quantity released for the refrigerated

flammable substances.

Section 68.25(e) will be revised by adding (i) and (ii) and adding

a new (f); existing (f), (g), and (h) will become (g), (h), and (i).

EPA is publishing this rule without prior proposal because we view

this as consistent with the original rule as promulgated and as a

noncontroversial amendment. No adverse comment is anticipated. The sole

regulatory change contemplated under the settlement agreement

represents a narrow technical amendment designed to make the treatment

of flammables consistent with that of toxics. This amendment merely

adjusts the way in which releases of these substances are modeled and

does not alter the number of sources subject to RMP or the basic

obligations under the RMP. In light of the foregoing and the need to

promulgate the revision prior to the rule's June 21, 1999 compliance

date, the Agency believes a direct final rule is the most appropriate

vehicle for implementation of the settlement agreement.

In the ``Proposed Rules'' section of today's Federal Register

publication, we are publishing a separate document that will serve as

the proposal to revise Sec. 68.25 for flammables if adverse comments

are filed. This rule will be effective on June 21, 1999, without

further notice unless we receive adverse comment by June 16, 1999. If

EPA receives adverse comment, we will publish a timely withdrawal in

the Federal Register informing the public that the rule will not take

effect. We will address all public comments in a subsequent final rule

based on the proposed rule. We will not institute a second comment

period on this action. Any parties interested in commenting must do so

at this time.

III. Clarification of CAA Sections 112(l) and 112(r)(11)

Pursuant to the settlement agreement with CI, EPA is clarifying its

interpretation of CAA sections 112(l) and 112(r)(11), as they relate to

DOT requirements under the Federal Hazardous Materials Transportation

Law, 49 U.S.C. 5101-5127.

In our amendments to 40 CFR part 68 (63 FR 640, January 6, 1998) we

dealt with the issue of the relationship between part 68 and statutes

administered by and regulations promulgated by the Department of

Transportation (DOT), such as the Federal Hazardous Materials

Transportation Law (``Federal Hazmat Law'') and the Hazardous Materials

Regulations (``HMR''). We noted therein that: ``EPA's regulations do

not supersede or limit DOT's authorities and, therefore, are in

compliance with CAA section 310.''

The definition of stationary source finalized in that rule

generally provides that containers that are in transportation or

storage incident to transportation are not part of a stationary source

or a process at the stationary source. On the other hand, the

definition of stationary source does provide that such containers are

part of a stationary source under certain circumstances, most notably

when they are being loaded, unloaded or on site for storage not

incidental to transportation. Because a transportation container may at

times function as a storage container or a process at a stationary

source, or may function as part of operations at a stationary source,

EPA is specifically directed by statute to address these activities

(CAA section 112(r)(7)(B)(i)) (``The regulations shall cover storage,

as well as operations''). To the extent that DOT is also authorized

under the Federal Hazmat Law to regulate activities that are at a

stationary source, nothing in the CAA prohibits both agencies from

exercising concurrent jurisdiction over these activities. As EPA has

said in the context of the RMP Rule, compliance with Federal Hazmat Law

and HMR requirements may satisfy parallel requirements of part 68. This

approach to implementation reflects the coordination between the

agencies that is called for under CAA section 112(r)(7)(D). The

exercise of concurrent jurisdiction preserves the applicability of the

Federal Hazmat Law and HMR and does not supersede or limit DOT's

jurisdiction. CAA section 310 provides that the CAA shall not be

construed as superseding or limiting the authority or responsibilities

of any Federal agency. Thus, neither CAA section 112(r)(11) (which

provides that section 112(r) does not preempt state regulations that

are more stringent than EPA's) nor section 112(l) (which allows EPA to

delegate the accident prevention regulations to a state if the state's

program is no less stringent than EPA's) can be read to authorize a

state to regulate in a manner that would otherwise be preempted under

the Federal Hazmat Law. A state that, for purposes of obtaining

delegation under section 112(l), adopts Part 68 or a program that is

substantively the same as Part 68 will not be considered by EPA to

regulate in a manner that would otherwise be preempted under the

Federal Hazmat Law.

IV. Judicial Review

Under section 307(b)(1) of the Clean Air Act (CAA), judicial review

of this rule is available only by filing a petition for review in the

U.S. Court of Appeals for the District of Columbia Circuit within 60

days of this notice, unless EPA withdraws this rule as described

earlier in this notice. Under section 307(b)(2) of CAA, the

requirements that are the subject of today's document may not be

challenged later in civil or criminal proceedings brought by EPA to

enforce these requirements.

V. Administrative Requirements

A. Docket

The docket is an organized and complete file of all the information

considered by the EPA in the development of this rulemaking. The docket

is a dynamic file, because it allows members of the public and

industries involved to readily identify and locate documents so that

they can effectively participate in the rulmaking process. Along with

the proposed and promulgated rules and their preambles, the contents of

the docket serve as the record in the case of judicial review. (See

section 307(d)(7)(A) of the CAA.)

The official record for this rulemaking, as well as the public

version, has been established for this

[[Page 28699]]

rulemaking under Docket No. A-99-15, and is available for inspection

from 8:00 a.m. to 5:30 p.m., Monday through Friday, excluding legal

holidays. The official rulemaking record is located at the address in

ADDRESSES at the beginning of this document.

B. Executive Order 12866

Under Executive Order 12866, (58 Federal Register 51,735 (October

4, 1993)) the Agency must determine whether the regulatory action is

``significant'' and therefore subject to OMB review and the

requirements of the Executive Order.

The Order defines ``significant regulatory action'' as one that is

likely to result in a rule that may: (1) Have an annual effect on the

economy of $100 million or more or adversely affect in a material way

the economy, a sector of the economy, productivity, competition, jobs,

the environment, public health or safety, or State, local, or tribal

governments or communities; (2) Create a serious inconsistency or

otherwise interfere with an action taken or planned by another agency;

(3) Materially alter the budgetary impact of entitlements, grants, user

fees, or loan programs or the rights and obligations of recipients

thereof; or (4) Raise novel legal or policy issues arising out of legal

mandates, the President's priorities, or the principles set forth in

the Executive Order.''

It has been determined that today's action is not a ``significant

regulatory action'' under the terms of E.O. 12866 and is, therefore,

not subject to OMB review.

C. Executive Order 12875

Under Executive Order 12875, EPA may not issue a regulation that is

not required by statute and that creates a mandate upon a State, local

or tribal government, unless the Federal government provides the funds

necessary to pay the direct compliance costs incurred by those

governments, or EPA consults with those governments.

If EPA complies by consulting, Executive Order 12875 requires EPA

to provide to the Office of Management and Budget a description of the

extent of EPA's prior consultation with representatives of affected

State, local and tribal governments, the nature of their concerns, any

written communications from the governments, and a statement supporting

the need to issue the regulation.

In addition, Executive Order 12875 requires EPA to develop an

effective process permitting elected officials and other

representatives of State, local and tribal governments ``to provide

meaningful and timely input in the development of regulatory proposals

containing significant unfunded mandates.''

Today's rule does not create a mandate on State, local or tribal

governments. This rule change does not impose any enforceable duties on

these entities. Instead, it merely provides an alternative approach for

calculating the quantity released in the worst-case scenario.

Stationary sources already subject to the rule may use this approach

for conducting worst-case release scenarios for flammable substances in

the same manner as toxic substances. Accordingly, the requirements of

section 1(a) of Executive Order 12875 do not apply to this rule.

D. Executive Order 13045

Executive Order 13045: ``Protection of Children from Environmental

Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies

to any rule that: (1) is determined to be ``economically significant''

as defined under E.O. 12866, and (2) concerns an environmental health

or safety risk that EPA has reason to believe may have a

disproportionate effect on children. If the regulatory action meets

both criteria, the Agency must evaluate the environmental health or

safety effects of the planned rule on children, and explain why the

planned regulation is preferable to other potentially effective and

reasonably feasible alternatives considered by the Agency.

This action is not subject to the E.O. 13045 because it is not

``economically significant'' as defined in E.O. 12866, and because it

does not involve decisions based on environmental health or safety

risks.

E. Executive Order 13084

Under Executive Order 13084, EPA may not issue a regulation that is

not required by statute, that significantly or uniquely affects the

communities of Indian tribal governments, and that imposes substantial

direct compliance costs on those communities, unless the Federal

government provides the funds necessary to pay the direct compliance

costs incurred by the tribal governments, or EPA consults with those

governments.

If EPA complies by consulting, Executive Order 13084 requires EPA

to provide to the Office of Management and Budget, in a separately

identified section of the preamble to the rule, a description of the

extent of EPA's prior consultation with representatives of affected

tribal governments, a summary of the nature of their concerns, and a

statement supporting the need to issue the regulation. In addition,

Executive Order 13084 requires EPA to develop an effective process

permitting elected officials and other representatives of Indian tribal

governments ``to provide meaningful and timely input in the development

of regulatory policies on matters that significantly or uniquely affect

their communities.''

Today's rule does not significantly or uniquely affect the

communities of Indian tribal governments. This rule change merely

provides an alternative approach for calculating the quantity released

in the worst-case scenario. Stationary sources already subject to the

rule may use this approach for conducting worst-case release scenarios

for flammable substances in the same manner as toxic substances.

Accordingly, the requirements of section 3(b) of Executive Order 13084

do not apply to this rule.

F. Regulatory Flexibility

EPA has determined that it is not necessary to prepare a regulatory

flexibility analysis in connection with this direct final rule and that

this rule will not have a significant negative economic impact on small

entities. This rule change does not require any stationary source to

report additional elements in the risk management plan. It merely

provides an alternative approach for stationary sources already subject

to the rule to use for conducting worst-case release scenarios for

flammable substances.

G. Paperwork Reduction

The Office of Management and Budget (OMB) has approved the

information collection requirements contained in this rule under the

provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. and

has assigned OMB control number 2050-0144.

This rule does not include any new information collection

requirements for OMB review under the provisions of the Paperwork

Reduction Act. This revision of the rule does not impose any new

reporting, recordkeeping, or third party reporting requirements on

stationary sources, it merely provides an alternative approach for

sources to calculate the quantity released in the worst-case scenario

for flammables. The Office of Management and Budget (OMB) has approved

the information collection requirements contained in this rule under

the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq.

and has assigned OMB control number 2050-0144.

Burden means the total time, effort, or financial resources

expended by persons

[[Page 28700]]

to generate, maintain, retain, or disclose or provide information to or

for a Federal agency. This includes the time needed to review

instructions; develop, acquire, install, and utilize technology and

systems for the purposes of collecting, validating, and verifying

information, processing and maintaining information, and disclosing and

providing information; adjust the existing ways to comply with any

previously applicable instructions and requirements; train personnel to

be able to respond to a collection of information; search data sources;

complete and review the collection of information; and transmit or

otherwise disclose the information.

An Agency may not conduct or sponsor, and a person is not required

to respond to a collection of information unless it displays a

currently valid OMB control number. The OMB control numbers for EPA's

regulations are listed in 40 CFR part 9 and 48 CFR Chapter 15. EPA is

amending the table in 40 CFR part 9 of currently approved ICR control

numbers issued by OMB for various regulations to list the information

requirements contained in this final rule.

H. Unfunded Mandates Reform Act

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public

Law 104-4, establishes requirements for Federal agencies to assess the

effects of their regulatory actions on State, local, and tribal

governments and the private sector. Under section 202 of the UMRA, EPA

generally must prepare a written statement, including a cost-benefit

analysis, for proposed and final rules with ``Federal mandates'' that

may result in expenditures to State, local, and tribal governments, in

the aggregate, or to the private sector, of $100 million or more in any

one year. Before promulgating an EPA rule for which a written statement

is needed, section 205 of the UMRA generally requires EPA to identify

and consider a reasonable number of regulatory alternatives and adopt

the least costly, most cost-effective or least burdensome alternative

that achieves the objectives of the rule. The provisions of section 205

do not apply when they are inconsistent with applicable law. Moreover,

section 205 allows EPA to adopt an alternative other than the least

costly, most cost-effective or least burdensome alternative if the

Administrator publishes with the final rule an explanation why that

alternative was not adopted. Before EPA establishes any regulatory

requirements that may significantly or uniquely affect small

governments, including tribal governments, it must have developed under

section 203 of the UMRA a small government agency plan. The plan must

provide for notifying potentially affected small governments, enabling

officials of affected small governments to have meaningful and timely

input in the development of EPA regulatory proposals with significant

Federal intergovernmental mandates, and informing, educating, and

advising small governments on compliance with the regulatory

requirements.

EPA has determined that this rule does not contain a Federal

mandate that may result in expenditures of $100 million or more for

state, local, and tribal governments, in the aggregate, or the private

sector in any one year. Today's action is not subject to the

requirements of sections 202 and 205 of the Unfunded Mandates Act.

Today's rule contains no Federal mandates (under the regulatory

provisions of Title II of the UMRA) for state, local, or tribal

governments or the private sector. This rule change does not require

any stationary sources to report additional elements in the risk

management plan. It merely provides an alternative approach for

stationary sources already subject to the rule to use for conducting

worst-case release scenarios for flammable substances.

In addition, for the same reasons, EPA has determined that this

rule contains no regulatory requirements that might significantly or

uniquely affect small governments.

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement

Act of 1995 (``NTTAA''), Public Law 104-113, section 12(d) (15 U.S.C.

272 note), directs EPA to use voluntary consensus standards in its

regulatory activities unless to do so would be inconsistent with

applicable law or otherwise impractical. Voluntary consensus standards

are technical standards (e.g., materials specifications, test methods,

sampling procedures, business practices) that are developed or adopted

by voluntary consensus standards bodies. The NTTAA requires EPA to

provide Congress, through OMB, explanations when the Agency decides not

to use available and applicable voluntary consensus standards.

This action does not involve technical standards. Therefore, EPA

did not consider the use of any voluntary consensus standards.

J. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et. seq., as added by

the Small Business Regulatory Enforcement Fairness Act of 1996,

generally provides that before a rule may take effect, the agency

promulgating the rule must submit a rule report, which includes a copy

of the rule, to each House of the Congress and to the Comptroller

General of the United States. EPA will submit a report containing this

rule and other required information to the U.S. Senate, the U.S. House

of Representatives, and the Comptroller General of the United States

prior to publication of the rule in the Federal Register. This action

is not a ``major rule'' as defined by 5 U.S.C. 804(2). This rule will

be effective on June 21, 1999.

List of Subjects in 40 CFR Part 68

Environmental protection, Chemicals, Chemical accident prevention.

Dated: May 17, 1999.

Carol M. Browner,

Administrator.

For the reasons set out in the preamble, title 40, chapter I,

subchapter C, part 68 of the Code of Federal Regulations is amended to

read as follows:

PART 68--CHEMICAL ACCIDENT PREVENTION PROVISIONS

1. The authority citation for Part 68 continues to read as follows:

Authority: 42 U.S.C. 7412(r), 7601(a)(1), 7661-7661f.

Subpart B--Hazard Assessment

2. Section 68.25 is amended by redesignating paragraphs (f), (g),

and (h) as (g), (h), and (i), and by revising paragraph (e) and adding

a new paragraph (f) to read as follows:

Sec. 68.25 Worst-case release scenario analysis.

* * * * *

(e) Worst-case release scenario--flammable gases. The owner or

operator shall assume that the quantity of the substance, as determined

under paragraph (b) of this section and the provisions below, vaporizes

resulting in a vapor cloud explosion. A yield factor of 10 percent of

the available energy released in the explosion shall be used to

determine the distance to the explosion endpoint if the model used is

based on TNT equivalent methods.

(1) For regulated flammable substances that are normally gases at

ambient temperature and handled as a gas or as a liquid under pressure,

the owner or operator shall assume that the quantity in the vessel or

pipe, as determined under paragraph (b) of this section, is released as

a gas over 10 minutes. The total quantity shall be

[[Page 28701]]

assumed to be involved in the vapor cloud explosion.

(2) For flammable gases handled as refrigerated liquids at ambient

pressure:

(i) If the released substance is not contained by passive

mitigation systems or if the contained pool would have a depth of one

centimeter or less, the owner or operator shall assume that the total

quantity of the substance is released as a gas in 10 minutes, and the

total quantity will be involved in the vapor cloud explosion.

(ii) If the released substance is contained by passive mitigation

systems in a pool with a depth greater than 1 centimeter, the owner or

operator may assume that the quantity in the vessel or pipe, as

determined under paragraph (b) of this section, is spilled

instantaneously to form a liquid pool. The volatilization rate (release

rate) shall be calculated at the boiling point of the substance and at

the conditions specified in paragraph (d) of this section. The owner or

operator shall assume that the quantity which becomes vapor in the

first 10 minutes is involved in the vapor cloud explosion.

(f) Worst-case release scenario--flammable liquids. The owner or

operator shall assume that the quantity of the substance, as determined

under paragraph (b) of this section and the provisions below, vaporizes

resulting in a vapor cloud explosion. A yield factor of 10 percent of

the available energy released in the explosion shall be used to

determine the distance to the explosion endpoint if the model used is

based on TNT equivalent methods.

(1) For regulated flammable substances that are normally liquids at

ambient temperature, the owner or operator shall assume that the entire

quantity in the vessel or pipe, as determined under paragraph (b) of

this section, is spilled instantaneously to form a liquid pool. For

liquids at temperatures below their atmospheric boiling point, the

volatilization rate shall be calculated at the conditions specified in

paragraph (d) of this section.

(2) The owner or operator shall assume that the quantity which

becomes vapor in the first 10 minutes is involved in the vapor cloud

explosion.

* * * * *

[FR Doc. 99-12936 Filed 5-24-99; 10:57 am]

BILLING CODE 6560-50-P