*** E.O. 12866 Review – Draft – Do Not Cite, Quote, or Release During Review ***

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EO12866_Solids in Solution 2050-AF08 NPRM NPRM_20101108

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 355

[EPA-HQ-SFUND-2010-0586; FRL_XXXX-X]

RIN 2050-AF08

Emergency Planning and Community Right-to-Know Act; Amendments to Emergency 

Planning and Notification; Emergency Planning and List of Extremely Hazardous 

Substances and Threshold Planning Quantities.

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of Proposed Rulemaking.

_______________________________________________________________________

SUMMARY: EPA is proposing to revise the manner by which the regulated community would 

apply the threshold planning quantities (TPQs) for those Extremely Hazardous Substances (EHS) 

that are non-reactive solid chemicals in solution form. Specifically, facilities with a solid EHS in 

solution would be subject to the Emergency Planning requirements of 40 CFR 355 Subpart BEmergency Planning if the amount of the solid chemical on-site, when multiplied by 0.2, equaled 

or exceeded the lower published TPQ, based on data that shows less potential for the solid 
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chemical in solution to remain airborne in the event of an accidental release. Previously, EPA 

assumed that 100% of the chemical could become airborne in the event of an accidental release.

DATES: Comments: Comments must be submitted on or before [Insert date sixty (60) days 

from after publication in the Federal Register].

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQSFUND-2010-0586, by one of the following methods:

 • http://www.regulations.gov: Follow the on-line instructions for submitting comments.

 • E-mail: superfund.docket@epa.gov.

 • Fax: (202) 566-9744.

 • Mail: Superfund Docket, Environmental Protection Agency, Mail code: [2822T], 1200 

Pennsylvania Ave., N.W., Washington, DC 20460.

 • Hand Delivery: EPA West, Room 3334, 1301 Constitution Ave., N.W., Washington, DC. 

Such deliveries are only accepted during the Docket's normal hours of operation, and special 

arrangements should be made for deliveries of boxed information.

 Instructions: Direct your comments to Docket ID No. EPA-HQ-SFUND-2010-0586. EPA's 

policy is that all comments received will be included in the public docket without change and 

may be made available online at http://www.regulations.gov, including any personal information 

provided, unless the comment includes information claimed to be Confidential Business 

Information (CBI) or other information whose disclosure is restricted by statute. Do not submit 

information that you consider to be CBI or otherwise protected through 
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http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site is an 

``anonymous access'' system, which means EPA will not know your identity or contact 

information unless you provide it in the body of your comment. If you send an e-mail

comment directly to EPA without going through http://www.regulations.gov, your e-mail 

address will be automatically captured and included as part of the comment that is placed in the 

public docket and made available on the Internet. If you submit an electronic comment, EPA 

recommends that you include your name and other contact information in the body of your 

comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to 

technical difficulties and cannot contact you for clarification, EPA may not be able to consider 

your comment. Electronic files should avoid the use of special characters, any form of

encryption, and be free of any defects or viruses. For additional information about EPA's public 

docket, visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm. For 

additional instructions on submitting comments, go to Section I.B of the SUPPLEMENTARY 

INFORMATION section of this document.

 

Docket: All documents in the docket are listed in the http://www.regulations.gov index. 

Although listed in the index, some information is not publicly available, e.g., CBI or other 

information whose disclosure is restricted by statute. Certain other material, such as copyrighted 

material, will be publicly available only in hard copy. Publicly available docket materials are 

available either electronically http://www.regulations.gov/or in hard copy at the Superfund 

Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., N.W., Washington, DC. The 

Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 

legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the 
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telephone number for the Superfund Docket is (202) 566-0276.

FOR FURTHER INFORMATION CONTACT: Kathy Franklin, Office of Emergency 

Management, Mail Code 5104A, Environmental Protection Agency, 1200 Pennsylvania Avenue, 

NW, Washington DC 20004; telephone number: (202) 564-7987; fax number: (202) 564-2625; 

e-mail address: franklin.kathy@epa.gov You may also contact the Superfund, TRI, EPCRA,

RMP and Oil Information Center at (800) 424-9346 or (703) 412-9810 (in the Washington DC 

metropolitan area). The Telecommunications Device for the Deaf (TDD) number is (800) 553-

7672 or (703) 412-3323 (in the Washington, DC metropolitan area). You may wish to visit the 

Office of Emergency Management (OEM) Internet site at www.epa.gov/oem.

SUPPLEMENTARY INFORMATION: Here are the contents of today‘s preamble.

I. General Information

 A. Who is Affected by This Proposed Rule?

 B. What Should I Consider as I Prepare My Comments for EPA?

 C. What is the Statutory Authority for This Proposed Rule?

 D. What Is the Background for This Proposed Rule?

II. Summary of This Action

A. What is the Scope of This Proposed Rule?

B. What is EPA‘s Rationale for Proposing the TPQ Changes?

C. What Alternative Approaches Were Considered?

D. What are the Peer Review Results?
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E. What are the Economic Impacts of the TPQ Changes?

III. Statutory and Executive Orders

A. Executive Order 12866: Regulatory Planning and Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132 (Federalism)

F. Executive Order 13175 (Consultation and Coordination with Indian Tribal Governments)

G. Executive Order 13045 (Protection of Children From Environmental Health Risks and 

Safety Risks)

H. Executive Order 13211 (Energy Effects)

I. National Technology Transfer and Advancement Act (―NTAA‖)

J. Executive Order 12898: (Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations)

I. General Information

A. Who is Affected by This Proposed Rule?

Entities that would be affected by this proposed rule are those organizations and facilities 

subject to section 302 of the Emergency Planning and Community Right-to-Know Act (EPCRA) 
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and its implementing regulations found in 40 CFR part 355 Subpart B- Emergency Planning. To 

determine whether your facility is affected by this action, you should carefully examine the 

applicability provisions at 40 CFR part 355. If you have questions regarding the applicability of 

this action to a particular entity, consult the person listed in the preceding FOR FURTHER 

INFORMATION CONTACT section. 

B. What Should I Consider as I Prepare My Comments for EPA?

Tips for Preparing Your Comments. When submitting comments remember to:

Identify the rulemaking by docket number and other identifying information 

(subject heading, Federal Register date and page number).

Follow directions – The Agency may ask you to respond to specific questions 

or organize comments by referencing a Code of Federal Regulations (CFR) 

part or section number.

Explain why you agree or disagree, suggest alternatives, and substitute 

language for your requested changes.

Describe any assumptions and provide any technical information and/or data 

that you used.

If you estimate potential costs or burdens, explain how you arrived at your 

estimate in sufficient detail to allow for it to be reproduced.

Provide specific examples to illustrate your concerns, and suggest alternatives.

Explain your views as clearly as possible.
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Make sure to submit your comments by the comment period deadline 

identified.

C. What is the Statutory Authority for This Proposed Rule?

This proposed rule is being issued under the Emergency Planning and Community Rightto-Know Act of 1986 (EPCRA), which was enacted as Title III of the Superfund Amendments 

and Reauthorization Act of 1986 (Pub. L. 99-499), (SARA). The Agency relies on EPCRA 

section 328 for general rulemaking authority.

C. What is the Background of This Proposed Rule?

Title III of SARA (EPCRA) establishes authorities for emergency planning and 

preparedness, emergency release notification reporting, community right-to-know reporting, and 

toxic chemical release reporting. It is intended to encourage State and local planning for, and 

response to releases of, hazardous substances and to provide the public, local governments, fire 

departments, and other emergency officials with information concerning potential chemical 

hazards present in their communities. The implementing regulations for emergency planning, 

emergency release notification and the chemicals subject to these regulations (Extremely 

Hazardous Substances) are codified in 40 CFR part 355. The implementing regulations for 

community right-to-know reporting (or hazardous chemical reporting) are codified in 40 CFR 

part 370. 
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Subtitle A of EPCRA establishes the framework for local emergency planning. The 

statute requires that EPA publish a list of ―extremely hazardous substances‖ (EHSs). The EHS 

list was established by EPA to identify chemical substances which could cause serious 

irreversible health effects from accidental releases (52 FR 13378). The Agency was also 

directed to establish ―threshold planning quantities‖ (TPQs) for each extremely hazardous 

substance. 

Under EPCRA section 302, a facility which has an EHS in excess of its TPQ on-site must 

notify the State Emergency Response Commission (SERC) and Local Emergency Planning 

Committee (LEPC), as well as participate in local emergency planning activities. Under EPCRA 

section 304, the facility owner or operator must report accidental releases of EHSs and hazardous 

substances listed under Comprehensive Environmental Response, Compensation, and Liability 

Act (CERCLA) listed in 40 CFR 302.4 in excess of the Reportable Quantity (RQ) to the LEPC 

and SERC. Under EPCRA section 311 and 312, facilities which have a hazardous chemical 

defined under the Hazard Communication Standards (HCS) of the Occupational Safety and 

Health Act (OSHA) at or above 10,000 pounds or an EHS at or above its TPQ or 500 pounds, 

whichever is lower, are required to submit an Emergency and Hazardous Chemical Inventory 

form and Material Safety Data Sheet (MSDS) for that chemical to their SERC, LEPC and local 

fire department. 

The purpose of the EHS list is to focus initial efforts in the development of State and 

local contingency plans. Inclusion of a chemical on the EHS list does not mean state or local 

communities should ban or otherwise restrict use of a listed chemical. Rather, such identification 
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indicates a need for the community to undertake a program to investigate and evaluate the 

potential for accidental exposure associated with the production, storage or handling of the 

chemical at a particular site and develop a chemical emergency response plan around those risks.

1. Regulatory Background

The list of EHSs and their TPQs are codified in 40 CFR part 355, Appendices A & B. 

EPA first published the EHS list and TPQs along with the methodology for determining TPQs as 

an interim final rule on November 17, 1986 (51 FR 41570 and 41580). In the final rule of April 

22, 1987 (52 FR 13378), EPA made a number of revisions. Among other things, the final rule 

republished the EHS list, added four new chemicals and revised the methodology for some 

TPQs. The final rule also defined TPQs for EHS solids in solution, based on comments on the 

interim final rule. Details of the methodology used in determining whether to list a substance as 

an EHS and deriving the TPQs are found in the November 1986 and April 1987 Federal Register 

notices and in the technical support documents in the rulemaking record. These documents are 

found in the docket for this rulemaking. 

EPA has since amended the EHS list and deleted 51 chemicals. Ten chemicals were 

deleted based on the request of petitioners and the remaining 41 chemicals were deleted as a 

result of Agency review. The chemicals were deleted because they did not meet the toxicity 

criteria for the list and/or were originally listed in error. Petitions requesting deletion of two 

chemicals, Paraquat Dichloride (which is discussed below) and Isophorone Diisocyante have 

been denied. Isophorone Diisocyanate was not deleted from the EHS list because its inhalation 
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toxicity met the EHS listing criteria. 

EPA has also changed the TPQs for some of the EHS substances. In the April 22, 1987 

final rule, EPA reduced the TPQs for 36 substances, while it raised the TPQs for 12 substances 

based on updated acute toxicity data. Since then, EPA has lowered the TPQ for Muscimol 

because of a typographical error in a prior rulemaking; EPA has raised the TPQ for Isophorone 

Diisocyanate because it was mistakenly based on a physical state of reactive solid, when it is 

actually a liquid; and EPA has denied a petition to raise the TPQs for Azinphos Methyl and 

Fenamiphos.

2. Petition for Paraquat Dichloride 

Paraquat dichloride was originally listed as Paraquat with a CAS No. 1910-42-5 on the 

final EHS list. The lower TPQ was set at 10 pounds for Paraquat Dichloride with a particle size 

less than 100 microns in diameter, in molten form or as a solid in solution. The higher TPQ was 

set at 10,000 pounds for a particle size equal to or greater than 100 microns in diameter. ICI 

Americas submitted a petition in October 1989 that requested the Agency to remove Paraquat 

from the EHS list or alternatively, revise the TPQ. The TPQ for Paraquat was based on an

Immediately Dangerous to Life and Health (IDLH) value of 1.5 milligrams per cubic meter 

(mg/m3). The petitioner requested that EPA base the TPQ on the LD50 or LC50 test results rather 

than the IDLH level. (LD50 is the median lethal dose via dermal exposure or ingestion, defined 

as the dose at which 50 percent of the test animals died during exposure. LC50 is the median 

lethal concentration, defined as the concentration level at which 50 percent of the test animals 
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died when exposed by inhalation within the stated study time.) ICI Americas also noted that the 

CAS No. 1910-42-5 represented the chemical Paraquat Dichloride, not the Paraquat cation, 

which can form many different salts. 

On October 12, 1994 (59 FR 51816), EPA denied the petition to delete Paraquat or 

modify the TPQ, but changed the listed chemical name from Paraquat to Paraquat Dichloride. 

The oral toxicity for Paraquat Dichloride met the listing criteria based on the Paraquat ion only, 

but did not meet the listing criteria based on total Paraquat Dichloride weight. Therefore, EPA 

changed the basis of the listing from an oral LD50 of 22 milligrams Paraquat ion per kg of body 

weight (mg/kg) to an inhalation LC50 of 0.00138 milligrams Paraquat Dichloride per liter of air 

(mg/L). Because this inhalation toxicity met the EHS listing criteria, Paraquat Dichloride was 

not deleted from the EHS list. Further explanation of EPA‘s rationale for denying the petition 

can be found in the October 12, 1994 final rule (59 FR 51816).

3. Zeneca‘s Request to Reconsider the Paraquat Dichloride Petition

In November 1999, Zeneca (formerly ICI Americas) requested that EPA reconsider either 

removing Paraquat Dichloride from the EHS list or raising its TPQ. Zeneca claimed that the 

form of the chemical used in inhalation toxicity tests (temporarily atomized powder under 

laboratory conditions) is not relevant data to use for listing Paraquat Dichloride. Zeneca 

believed that it was highly unlikely that inhalable particles or vapors of Paraquat Dichloride 

could become airborne during an accidental release. Zeneca did not agree with the rationale 

EPA used to assign a TPQ of 10 pounds to Paraquat Dichloride, which is only manufactured, 
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processed and used in solution form. Zeneca claimed that EPA did not explain why a greater 

potential for airborne dispersion for solids in solution exists as opposed to liquid chemicals. 

On October 11, 2000, Syngenta (formerly Zeneca) filed an action in US District Court for 

the District of Columbia under the Administrative Procedures Act seeking judicial review of 

EPA‘s decisions regarding Paraquat Dichloride. In this complaint, Syngenta requested EPA to 

either delete Paraquat Dichloride from the EHS list or raise its TPQ. On January 23, 2003, EPA 

filed a Motion for Voluntary Remand in order to reconsider the petition. The court granted 

EPA‘s motion and dismissed Syngenta‘s complaint on January 31, 2003. By order of February 

24, 2003, the court denied Syngenta‘s Motion to Amend Judgment. EPA again reviewed the 

request to delete Paraquat Dichloride and/or to raise its TPQ. In a November 21, 2003 letter to 

the petitioner, EPA reaffirmed its denial to delete Paraquat Dichloride from the EHS list. EPA 

concluded that the acute toxicity of Paraquat Dichloride meets the criteria for listing it as an EHS 

chemical. In the same letter to the petitioner, however, EPA agreed to consider a revision to the 

TPQ for Paraquat Dichloride in the context of a proposed rule to amend the TPQ for all EHS 

chemicals handled as solids in solution. 

II. Summary of This Action

A. What is the Scope of This Proposed Rule?

The scope of this proposed rule is to revise the manner by which the regulated 

community would apply the TPQ for EHS chemicals that are handled as solids in solution. 
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There are 157 EHS chemicals that are non-reactive solids at ambient temperature, which could 

potentially be affected by this change, if they are handled by facilities in a solution form. The 

affected chemicals are identified in Appendix C in the Technical Support Document, which is in 

the Docket to this rulemaking. However, this change will not apply to the 12 solid EHS 

chemicals that are reactive solids (noted by footnote ―b‖ in Appendix A and B of 40 CFR part 

355). Reactive solids are highly reactive with air or water or are explosive. Because of this, they 

are more likely than other solids to be dispersed into the air due to the energy or heat created 

when they react. 

Additionally, the proposed methodology of applying TPQs for solids in solution does not 

affect the reporting requirements for Sections 311 and 312 of EPCRA (40 CFR 370). 

Specifically, emergency planning notification under Section 302 helps LEPCs identify those 

facilities whose accidental releases pose risks to the surrounding community so they can develop 

emergency plans that identify the location and number of affected populations, evacuation or 

shelter-in-place procedures etc. On the other hand, Sections 311 and 312 require submission of 

MSDSs and an on-site inventory of hazardous chemicals to help emergency responders assess 

how to respond to an emergency release or fire. Responders need the amounts, manner of 

storage and locations of the chemical on-site, not only the amount released off-site. They need 

information on the chemical and physical properties, hazard ratings, toxicity information and 

incompatibilities of the chemical, as well as measures needed to contain the spill or fire at the 

facility. They need to know what type of protective equipment is needed to protect them from 

exposure, not only airborne, but dermal. 
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Solid EHSs (except reactive solids) have a 10,000 pound TPQ or a specified lower TPQ 

for certain forms. For purposes of complying with the emergency planning notification 

requirements of Section 302 of EPCRA, EPA is proposing that facilities multiply the amount of 

EHS chemical handled as a solid in solution on-site by 0.2 and then determine if this amount 

equals or exceeds the established lower TPQ. If the amount of the solid EHS in solution on-site 

multiplied by 0.2 does not equal or exceed the lower TPQ for that solid EHS, then the facility is 

not subject to the EPCRA Section 302 emergency planning notification requirements for that 

substance. This amount includes only the weight of the chemical and not the solvent or other 

chemicals in solution. The amount of solid in solution may be determined by multiplying the 

weight percent of the solid in solution in a particular container by the weight of the solution. 

Solutions include aqueous or organic solutions, slurries, viscous solutions, suspensions, 

emulsions, and pastes. The revised TPQ methodology for solids in solution is similar to the use 

of the TPQ for EHS chemicals that are molten solids.

1

 

The emergency release notification requirements under EPCRA Section 304 are not 

affected by this proposal. Section 304 requires facilities to notify the community emergency 

coordinator for the LEPC of any area likely to be affected by the release and the SERC of any 

area likely to be affected by the release (defined in 40 CFR 355.42) at or above the Reportable 

Quantity (RQ) of any EHS or CERCLA hazardous substance. The RQ is not the same as the 

TPQ. TPQs are based on acute mammalian toxicity and potential for airborne dispersion. RQs 

are developed using several criteria, including aquatic toxicity, mammalian toxicity, ignitability, 

reactivity, chronic toxicity, biodegradation, hydrolysis, and photolysis (50 FR 13468, April 4, 

 

1 The TPQ for EHSs that are in a molten form on-site is calculated by multiplying the weight of the chemical by 0.3 

to determine if the lower TPQ is met or exceeded. 
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1985). 

As an example, a facility has 4,000 pounds of a solution of 37% by weight Paraquat 

Dichloride on-site. Therefore, this solution contains 1,480 pounds of Paraquat Dichloride (0.37 

x 4,000 pounds). The facility would multiply 1,480 pounds by 0.2 which equals 296 pounds. 

This amount is then compared to the TPQ for Paraquat Dichloride, which is 10 pounds. Because 

this amount exceeds the 10 pound TPQ, the facility is required to comply with the emergency 

notification requirements of Section 302 of EPCRA.

Facilities that handle both the powdered and solution forms of a particular solid EHS will 

have to consider the quantities of each form and the particle size to determine whether they 

exceed a TPQ. For example, a facility may handle both powder and solution forms of a solid 

which has a lower TPQ of 500 pounds. The powder has a particle size greater than 100 microns, 

which means it has a TPQ of 10,000 pounds. The amount of powder form on-site is 5,000 

pounds, which is less than the 10,000 pound TPQ. However, they have 1,000 gallons of a 35% 

by weight EHS solid in solution with a density of 9 pounds per gallon. The amount of solids in 

solution is 3,150 pounds (1000 gallons x 9 pounds per gallon x 0.35). Multiplying the 3,150 

pounds of solids in solution by a factor of 0.2 equates to 630 pounds, which exceeds the lower 

TPQ of 500 pounds. Thus, the facility must report under Section 302 of EPCRA based on 

exceeding the lower TPQ for the solid in solution form.

EPA is proposing this change based on data in the literature that shows the original 

assumption of 100% potential airborne release for solids in solution is inappropriate because it 
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appears to overestimate the amount of chemical that would remain airborne after release. 

Review of the literature for accidental releases of liquid aerosols suggests a new methodology for 

applying the TPQs for solids in solution is warranted. The data shows that no more than 20% of 

the release is expected to remain airborne. More detailed discussion can be found in Section 

B.4.a of this preamble and in the Technical Support Document in the docket to this proposed 

rule. 

EPA‘s revised TPQ methodology for EHS solids in solution and supporting data was peer 

reviewed and the Technical Support Document was revised based on peer review comments. 

The results of the peer review and response to peer review comments are found in a separate 

document, Peer Review of Technical Support Document for Revised TPQ Method for EHS 

Solids in Solution, which is available in the docket to this rulemaking. A summary of the peer 

reviewer‘s comments and EPA responses to them are presented in Section II.D of this preamble. 

. 

B. What is EPA’s Rationale for the TPQ Changes?

1. Development of Existing TPQs 

The TPQs were initially assigned based on a ranking scheme using a Level of Concern 

(LOC) based on acute toxicity and the potential for airborne dispersion. The TPQ methodology 

is described in detail in the Threshold Planning Quantities Technical Support Document dated 

April 7, 1987, which can be found in the docket for this rulemaking. For each chemical, a 
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ranking index was calculated which equaled the LOC divided by an air dispersion factor (―V‖). 

For gases, ―V‖ = 1, while for liquids, ―V‖ was based on a volatilization model using the 

molecular weight and boiling point of the chemical. 

Solid EHS chemicals with a particle size less than 100 microns in diameter, molten 

solids, solids in solution, and solids with a National Fire Protection Association (NFPA) 

reactivity rating of 2, 3, or 4 were assigned a ―V‖ equal to 1. If the EHS solid does not have a 

particle size less than 100 microns, is not molten or handled in solution form, and does not have 

an NFPA reactivity rating of 2, 3, or 4, then the EHS chemical was assigned a TPQ of 10,000 

pounds, which corresponds to the highest index value. Solids with a NFPA reactivity rating of 2, 

3, or 4 are noted with footnote ―b‖ in the EHS list. 

 Between one and 10,000 pounds, chemicals were assigned to the intermediate TPQ 

categories of 100, 500 or 1,000 pounds based on the order of magnitude ranges of the index 

values. Also, for solids in molten form, before applying the TPQ, the amount of chemical on-site 

at any time is multiplied by an adjustment factor of 0.3 to conservatively account for the 

maximum volatilization of the spilled molten substance that is likely to take place. 

2. Petitioner‘s Arguments for Changing Paraquat Dichloride‘s TPQ

In their complaint, Syngenta did not agree with EPA‘s rationale to assign a lower TPQ of 

10 pounds to Paraquat Dichloride, which is only manufactured, processed and used in solution 

form. Syngenta claimed that EPA did not explain why it assumed a greater potential for airborne 
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dispersion for solids in solution as opposed to liquid chemicals. In addition, Syngenta argued 

that Paraquat Dichloride solution is basically a non-volatile salt dissolved in water, and that the 

physical and chemical characteristics of many solids like Paraquat Dichloride limit their capacity 

to become airborne. Pure Paraquat Dichloride has a very low vapor pressure and decomposes at 

about 340 °Celsius (C) before it reaches a boiling point. Syngenta further argued that using a 

liquid volatilization model to set a TPQ for Paraquat Dichloride is inappropriate.2 Moreover, 

Syngenta stated that ―the laws of physics preclude the possibility of a release of Paraquat 

Dichloride becoming completely airborne. Regardless of the emergency release scenario

(extreme temperature, explosion, etc.), the amount to become airborne would not only be less 

than 100%, it would be virtually zero.‖ Syngenta also stated that although Paraquat Dichloride 

can be temporarily atomized under laboratory conditions for testing animals, they do not believe 

that inhalable particles or vapors of Paraquat Dichloride can become airborne during an 

accidental release. 

In discussions with EPA, Syngenta also raised the issue of aerosol size as a factor to be

considered in developing the TPQ methodology for EHS solids in solution. 

3. Basis for Existing Solids in Solution TPQs

In the April 7, 1987 Threshold Planning Quantities Technical Support Document (page 

27), EPA noted that ―solids may also be handled in solution and molten form and could 

 

2 EPA agrees with the petitioner that using the liquid volatilization model to set a TPQ for Paraquat Dichloride, 

whether handled as a pure chemical or in solution, is inappropriate. However, the TPQ for Paraquat Dichloride was 

not set using the volatilization method. 
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potentially follow a liquid release scenario. However, even at molten temperatures, significant 

amounts of vapor are not likely to be generated.‖ On page 24 of the same Technical Support 

Document, when discussing liquid releases, EPA assumed that a spill of a liquid could occur as a 

result of an accidental situation that involves heat (e.g. fire, exothermic runaway reaction, or 

reactions with air or water). 

More specifically, when a solid chemical is in solution form, the solution can behave like 

a liquid during an accidental release and be dispersed into the air due to overheating, 

overpressure or anything that can cause a loss of containment from a vessel or piece of 

equipment. An accident involving a release of energy could create a liquid aerosol type of release 

into the air. Such liquid aerosol droplets, if small enough, can be dispersed into the air and 

remain airborne beyond the facility boundary, resulting in EHS exposure to the surrounding 

community. Environmental conditions and the properties of the specific chemical will dictate the 

behavior and dispersion of the chemical after a release or spill has occurred. For example, the 

solvent can evaporate from solution (especially at higher temperature) and small particulates of 

solid remaining after evaporation of the solvent can potentially be carried off-site. EPA 

recognized that the solid EHS (dissolved or suspended in a liquid solution) will not be dispersed 

into the air based on volatilization of the solid, but because of the energy released from the 

accident, or by wind.

At the time of the April 1987 rulemaking, EPA did not have sufficient information to 

determine how much of the solid EHS in solution could be dispersed airborne off-site and 

conservatively used V=1 for this release scenario. Furthermore, although Paraquat Dichloride 
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decomposes at a temperature of 340 °C (644 °Fahrenheit, F), EPA believed that accidents 

involving aerosol releases of Paraquat Dichloride solution could potentially occur at 

temperatures less than 340 °C. Boiling solutions containing non-volatile solids result in 

vaporization of the solvent, but not the solid. However, the turbulence of boiling the solution 

can entrain liquid aerosol droplets containing the solid into the air.

4. Airborne Dispersion of Solids in Solution.

Based on more recent information, EPA has re-evaluated the assumption of 100% 

airborne releases when setting the TPQ for solids in solution, not just for Paraquat Dichloride 

solution, but for all EHS solids in solution, except for the 12 solid EHS chemicals that are 

reactive solids. 

a.. Liquid Aerosol Release Data

EPA reviewed data in the literature on releases of aerosols to evaluate their potential use 

for revising the application of the TPQs for EHS solids in solution. EPA was specifically 

looking for data on how much of a solution containing a dissolved or suspended solid would 

remain airborne after an accidental release. One problem encountered in reviewing the literature 

was some studies only involved chemicals that are pure liquids and which have vapor pressures 

much higher than solid chemicals. That data would likely not represent the release and 

dispersion of a solid chemical that normally has a very low vapor pressure. However, the US 

Department of Energy (USDOE) used experimental liquid aerosol release data involving metal 
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salt solutions to estimate the Airborne Release Fraction (ARF) of metal salt solutions for a wide 

variety of release scenarios. This information was collected in a 1994 report, which is available 

in the docket to this rulemaking.3 Many of the DOE scenarios had very low ARFs; EPA 

considered the scenarios with higher release potential to best serve the purposes of emergency 

planning. Also, scenarios which required hypothetical input data to compute the ARF were not 

used. When median and bounding (maximum) values of ARFs were provided for a scenario, 

EPA used the maximum ARF in order to be conservative and cover the worst case scenario. 

EPA summarized the data from those DOE aerosol release scenarios with the highest (ARFs) in 

the table below. (The ARF values, release scenarios from the USDOE report and other data are 

discussed in greater detail in the Technical Support Document for this rulemaking, which is 

available in the docket to this rulemaking.) From this data, EPA determined that a worst case 

estimate of the ARF for a solution containing non-volatile solids would be 0.2 This particular 

ARF is based on the scenarios of an aqueous solution or air dried salts under gasoline fire on a 

metal surface. The airborne fractions from the DOE report generally contained aerosol sizes less 

than or equal to 100 microns. Droplets larger than 100 microns in diameter are expected to fall 

out before they reach a community outside a facility. 

Aerosol Release Scenario Maximum Airborne Release Fraction (ARF)

 

3 USDOE. 1994. DOE Handbook, Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor 

Nuclear Facilities. December 1994. US Department of Energy, Washington, DC 20585 DOE-HDBK-3010-94. 

Volume 1- Analysis of Experimental Data and Volume II- Appendices. 
Page 22 of 50

Thermal Stress from Boiling 0.002

High Pressure Venting Below Liquid Level 0.12

Pressure Venting Above the Liquid Level 0.002

Superheated Liquid 

 Temp. ≥50 oC and ≤ 100 oC

0.1

Superheated Liquid Temp ≤50 oC 0.01

Burning Organic Layer Over Aqueous Solution 0.1

Aqueous Solution or Dry Salt Under Gasoline 

Fire on Metal

0.2

Aerodynamic Entrainment and Re-Suspension 0.1

Using the highest airborne release fraction rather than an average result of the scenarios is 

consistent with the intent of the emergency planning program to plan for a reasonable worst case 

scenario. This data is a good surrogate to use to predict the maximum potential aerosol release 

fraction of EHS solids in solution in the event of an accidental release. Water is probably the 

most common solvent that would be used with most of the EHS solids, whether they are 

dissolved, suspended or emulsified in water. Many of the EHS solids are pesticides and 

pesticides are commonly applied as water solutions or emulsions. 

EPA also looked at experimental data collected by the Center for Chemical Process 

Safety (CCPS) for aerosol releases of water and cyclohexane. EPA did not use the aerosol 
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release fraction from the CCPS data because these liquids did not contain any solid material in 

solution. However, the CCPS data supports EPA‘s belief that assuming a 100% airborne liquid 

aerosol release is inappropriate. 

USDOE was interested in applying the experimental aerosol release data to estimate 

airborne fractions of liquid aerosol releases that were below respirable size, which they defined 

as particles of 10 micron Aerodynamic Equivalent Diameter (AED) or less. By USDOE‘s 

definition, respirable size particles are those that can be transported through the air and inhaled 

into the human respiratory system. 

For purposes of establishing TPQs, EPA chose a distance of 100 meters (330 feet) to 

represent the distance from a source inside a chemical facility to the point where the community 

might be exposed. This decision was based on data indicating that a particle size greater than 

100 microns is not likely to be deposited more than 100 meters from the source. The 100 

micron cutoff is also consistent with CERCLA regulations (for reportable quantities) which also 

uses a 100 micron particle size level for powdered materials. 

Most of the DOE experimental aerosol release data had median aerosol diameters of less 

than 100 microns. This size is consistent with what EPA believes is the size of aerosols to 

which the community could be exposed. On the other hand, the water and cyclohexane aerosol 

release data compiled by CCPS had much larger mean aerosol diameter sizes, generally over 100 

microns. For the reasons already discussed and because it is likely that aerosol releases with 

diameters larger than 100 microns will fall out of the air before they reach a community, the 
Page 24 of 50

water and cylcohexane aerosol release fractions were not used in determining the TPQs for solids 

in solution. 

b. Liquid and Solution TPQ Comparison

Pure EHS liquids could also be released accidentally as aerosols via the same 

catastrophic scenarios (overpressure, superheating). It could be argued that perhaps the TPQ 

method for solids in solution could also apply to liquids. However, this goes against the ranking 

used for setting TPQs based on the extent of airborne releases by physical state as being high for 

gases, less for liquids and even less for solids in solution. Currently, the release scenario used 

for developing the liquid TPQs considers a spill of the liquid due to a loss of containment. The 

liquid then escapes into the air by volatilization. An airborne release of solids in solution will 

require more than a failure of containment to have appreciable airborne dispersion. An energy 

source, such as overpressure or high temperature would be required to disperse the solution into 

the air and create aerosol droplets. Not all of the droplets will stay airborne (unlike volatilized 

vapors) and affect the community, whose exposure depends on droplet size and distance from the 

facility fence line. 

If one assumes that there is an equal potential for airborne releases for gases, liquids, 

small particulate solids and solids in solution, then the TPQ ranking scheme would change 

radically and rely almost entirely on the toxicity of the chemical. However, EPA believes that 

airborne dispersibility is a critical factor in determining TPQs. Limited State and local resources 

should be focused on those EHS chemicals that can potentially cause the greatest harm and less 
Page 25 of 50

on those that might be toxic, but less likely to be released to the air and carried beyond the 

facility boundary.

As a hypothetical scenario, EPA determined if the current TPQ method for liquids gives 

more conservative (or at least as conservative) TPQs (lower thresholds) as compared to the 

proposed TPQ methodology for solids in solution. To do this, EPA estimated the TPQs for 

liquids by assuming that ―V‖ = 1, and then divided it by 0.2 (based on an expected 20% 

maximum airborne dispersion) to determine the amount of EHS on-site that would trigger 

emergency planning notification. These amounts or ―effective TPQs‖ were then compared to the 

current listed TPQs for liquids. For 116 of the 163 EHS liquids, the current TPQs for liquids 

based on volatilization were equal to or lower than the new effective TPQs based on 

aerosolization. Most of the other 47 liquids had current TPQs that were about twice the effective 

TPQ. This comparison with a table of results for the EHS liquids is discussed in the Technical 

Support Document for this rulemaking. Based on this analysis, EPA believes that using the 

volatilization model to establish V for liquid TPQs is still appropriate. The spilled liquid using a 

boiling point scenario is probably the most prevalent worst-case scenario that is reasonable to use 

for establishing TPQs for liquids. 

Further examination of the 47 liquid chemicals was undertaken to see why these had 

TPQs greater than the effective TPQs—that is, about twice the effective TPQ. Many of these 

liquids had effective TPQ values of 5, 50 and 5,000 pounds. However, there are no TPQs of 5, 

50 or 5,000 pounds. Rather, the use of order of magnitude index ranges assigned to various TPQ 

levels resulted in assigned TPQ values of 1, 10, 100, 500, 1,000 and 10,000 pounds. Thus, 
Page 26 of 50

where the effective TPQs are either 5, 50, or 5,000 pounds, the comparison of a current TPQ 

versus an effective TPQ may not be valid. More discussion on this can be found in the Technical 

Support Document. 

C. What Alternative Approaches Were Considered?

Given the data in the literature available on aerosol releases of solids in solution, EPA 

considered various alternative approaches. One alternative was using an index ranking method 

with an assigned ―V‖ similar to the original method of assigning TPQs. Another alternative was 

to apply the ARF to the existing lower TPQ for solids to develop a new TPQ for solids in 

solution for each solid EHS. A third alternative was similar to the approach of multiplying the 

maximum ARF by the amount on-- site, except that the ARF would only represent aerosol sizes 

less than respirable size. Below we discuss these alternatives, as well as the basis for not 

selecting them.

1. Index Ranking Method with ―V‖ less than 1.

This alternative would establish TPQs using a ranking approach based on each 

chemical‘s physical state, acute toxicity and, the potential for the chemical to become airborne

(―V‖). For this alternative, ―V‖ would be set to 0.2 for EHS solids in solution. 

For the original development of the TPQs, the ranking index was defined as the LOC 

divided by ―V,‖ where ―V‖ was set equal to 1 for gases and solids in powder form with a particle 
Page 27 of 50

size less than 100 microns, molten solids and solids in solution. For liquid EHS, ―V‖ (the 

potential to become airborne) depended upon the property of volatility (evaporation of liquid into 

the gas phase). In the development of ―V‖ for use in setting TPQs for liquids, ―V‖ represented 

the mass per time evolved to the air per mass of the spill. This is explained in further detail in 

the April 1987 Threshold Planning Quantities Technical Support Document available in the 

docket.

Most of the values for ―V‖ for liquids are approximately 0.1 (see Appendix B in the 

Technical Support Document). Using a higher ―V‖ equal to 0.2 for solids in solution implies that 

in the event of an accidental release, more of the solution would become airborne than if it were 

volatilized from a liquid spill. Even if a liquid were accidentally released via aerosol form, the 

volatility of the liquid chemical will increase the fraction that remains dispersed in the air. 

Therefore, it would not be a fair representation to have a solid in solution with a ―V‖ higher than 

that used for a volatile liquid. Also, because there are different mechanisms involved in the two 

types of releases, it may not be comparable to use the 0.2 as a substitute for ―V‖ for solids in 

solution. 

2. Existing TPQ and Aerosol Release Fraction.

Another alternative is to apply the ARF to the existing lower TPQ for solids to develop a 

new TPQ. For example, the lower TPQ for Paraquat Dichloride is 10 pounds. Dividing 10 

pounds by 0.2, the maximum expected aerosol release fraction for a solution, would result in a 

new TPQ of 50 pounds for Paraquat Dichloride in solution form. For each of the 157 nonreactive solids on the EHS list, a new TPQ for the solution form of the EHS solid could be 
Page 28 of 50

determined and listed. However, for each solid non-reactive chemical, there are already two 

TPQs, one developed based on the ranking index methodology of (Index = Level of Concern/V) 

and one based on the default TPQ of 10,000 pounds for non-molten, non-reactive, non-solution 

solids with a particle size equal to or greater than 100 microns. Including a third set of TPQs for 

EHS solids in solution could be confusing to the regulated community. Thus, EPA believes that 

using the existing lower TPQ for solids and comparing that to the product of the amount on-site 

multiplied by 0.2 is a better approach, and similar to the approach used for the molten solids 

form.

3. Using ARF Limited to Smaller Aerosol Sizes

Another approach considered is similar to the proposed approach of multiplying the 

maximum ARF by the amount on-site, except that the ARF would only represent the fraction of 

aerosols with particles less than respirable size. Through discussions with the petitioner and 

EPA ̳s November 2003 response to the petition, EPA has considered whether ―aerosol size‖ 

should be used as a factor in developing new TPQs for solids in solution. A consultant for 

Syngenta believes that EPA should only consider the dispersion of aerosols with particle sizes 

less than or equal to 4 microns because these smaller aerosols are the size that can enter the lung 

and because the inhalation toxicity tests used for the basis of the EHS listing only used very 

small particles.

This approach would require sufficient data on the aerosol size distribution for each 

release scenario to develop a new ARF that would include only aerosols of size 4 microns and 
Page 29 of 50

lower. The ARFs currently cited for the scenarios used for the preferred approach include 

aerosol sizes of 100 microns and lower. For some of the USDOE accident scenarios, it is 

possible to recalculate the airborne aerosol fractions using the raw experimental data to include 

only aerosols sizes less than or equal to 4 microns in diameter. This results in smaller airborne 

release fractions. 

EPA does not believe this approach should be used for a number of reasons, including: 

Inhalation toxicity tests are designed to use small particles to ensure that the lung is 

exposed. However, EPA is not using the inhalation toxicity for risk assessment, but only 

as a screening tool. 

Although the EHS listing for paraquat dichloride is based on inhalation toxicity, EPA 

also has concerns regarding dermal and ingestion exposure via swallowing for the larger 

aerosols. 

Solvent evaporation from larger aerosols can also create smaller aerosols which can enter 

the lung. 

Each of these is discussed below.

a. Aerosol Size in Toxicity Tests

Aerosols may be defined as a suspension of solid or liquid particles in air. Inhalation 

acute toxicity tests are purposely designed with very small diameter particles in order to ensure 

that particles are small enough to enter the rodent‘s lungs and test the toxicity in the lungs. 

Larger particles may not enter deep areas of the lungs and thus, test results may be 
Page 30 of 50

misinterpreted if little inhalation toxicity is shown. EPA is not attempting to use the airborne 

aerosol fraction for purposes of risk assessment, but only as a tool to set screening levels for the 

amount of chemicals on-site which may potentially cause harm if accidentally released. Also, 

the size of the aerosols used in an animal laboratory test cannot be assumed to be the same as 

those that people may be exposed to during an accidental release.

b. Particle Size and Exposure

Inhalable size particles enter the respiratory tract, including the head airways and are 

generally equal to or less than 100 microns. Thoracic size particles (generally equal to or less 

than 10 microns) travel past the larynx and reach the lung airways and the gas-exchange regions 

of the lung. Respirable size particles (generally less than or equal to 4 microns) are a subset of 

thoracic particles that are more likely to reach the gas-exchange region of the lung.4 

Most particles that enter the upper airways are trapped in mucous that moves to the throat 

and is swallowed within a few hours. Thus, instead of inhalation exposure deep in the lungs, 

exposure to larger particles of chemicals may occur through dermal exposure to mucous 

membranes or ingestion exposure through swallowing. Emergency planning for EHS chemicals 

is not limited to inhalation exposure only, although many of the EHS chemical listings are based 

on studies which meet the EHS listing criteria for inhalation toxicity. Although airborne 

exposure is the most likely route of exposure, it is not the only route of exposure. In the event of 

 

4 USEPA. October 2004. Air Quality Criteria for Particulate Matter. Vol I, Chapter 2 and Volume II, Chapter 6. 

U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental 

Assessment. Research Triangle Park, NC. EPA/600/P-00/002aF and EPA/600/P-00/002bF
Page 31 of 50

an accidental release, EPA is concerned about all routes of exposure (inhalation, dermal and 

ingestion) to the community. Thus, exposure to larger size aerosols (e.g. those above 4 or 10 

microns) by any route, such as through the skin or mucous membranes) should not be ignored 

when setting TPQs. 

c. Solvent Evaporation from Aerosols

Even after liquid aerosol droplets are released, some of the solvent may evaporate in the 

air. This would result in even smaller size aerosols or solid EHS particulates in the air to which a 

community would be exposed. One concern is that droplets of size greater than 100 microns

could settle quickly, dry into a smaller particle size and then become airborne again (resuspension). In the event of an accidental release, the responsible party should clean up 

chemicals deposited on the facility grounds before additional exposure to the community would 

take place. The USDOE report did include data on re-suspension of particulates from soil after 

an aerosol release. However, the amount re-suspended did not add much to the reasonable worst 

case aerosol release fraction of 0.2 This is explained further in the Technical Support 

Document.

D. What are the Peer Review Results?

EPA‘s revised TPQ methodology for EHS solids in solution and supporting data was peer 

reviewed and the Technical Support Document was revised based on the peer review comments. 

The description of the peer review process, the results of the peer review and EPA‘s response to 
Page 32 of 50

the peer review comments are found in a separate document, Peer Review of Technical Support 

Document for Revised TPQ Method for EHS Solids in Solution, which is available in the docket

to this rulemaking. Below are the questions posed to the peer reviewers, a summary of the peer 

reviewer‘s comments and EPA‘s response.

1. Based on your reading and analysis of the information provided, do you find the revised TPQ 

method to be logical with a sound scientific basis?

Two of the three reviewers agreed that the revised TPQ method was logical with a sound 

scientific basis using the DOE experimental aerosol release data. However, one reviewer 

thought the revised TPQ method may not be based on the most sound science because the LOC 

is based on Immediately Dangerous to Health and Life values (IDLH) and animal lethality data 

that he believes may not be appropriate. Nonetheless, this reviewer did think that a cursory 

review of the effective TPQ list (Appendix B in Technical Support Document) appears to have 

appropriately listed the ranking of chemicals by potential hazard to the public. 

EPA recognizes that use of the IDLH was an imperfect measure for determining the 

LOC, but believes the approach provides a consistent relative ranking of the EHS. Where animal 

lethality data were substituted, safety factors were applied to the data to estimate the LOC. 

Human data were taken into account for some chemicals, such as chemical warfare agents, and 

adjustments were made to the TPQ initially based on index values. EPA realizes that better data 

are being developed that could be used for the LOC (such as AEGLs- Acute Exposure Guideline 

Levels). However, a re-evaluation of the LOC for all EHS chemicals would best be undertaken 
Page 33 of 50

by a separate rulemaking effort, given the extent and complexity of this issue. 

2. Is the writing clear and concise? Has EPA provided the right level of detail? Is the method 

understandable? Are the results clearly presented?

Two of the three reviewers thought that the revised method was not clear and 

understandable and suggested improvements. For example, it was recommended that EPA clarify 

the definition of a solution, as well as include a flow-chart of the method or a graph to help 

describe the approach.

EPA agrees that improvements were needed in order to present the information in a better 

way for the regulated community to understand and apply, and the revised technical support 

document addresses those concerns. Thus, additional supporting background information, 

discussion about the development of TPQs, and examples and calculations of how to apply the 

TPQs for EHS solids in solution have been added to the technical support document and has 

been further explained in the preamble to the proposed rule. The proposed rule, which was not 

provided to the peer reviewers, is written more clearly and is less technical than the materials 

given to the peer reviewers to review.

One reviewer thought that EPA had provided the right amount of detail, and thought the 

method is understandable, and the text is for the most part readable. However, he had several 

clarifications and corrections he thought EPA should make. These clarifications have been made 

to the Technical Support Document, including improving a description of background on TPQ 
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development, clarifying some terms used in the document, and adding some references and other 

editorial comments. 

This same reviewer thought the argument against the alternative approach of using V=0.2 

for developing TPQ for solids in solutions was not that convincing. EPA has revised the 

discussion on this alternative approach by stating that EPA believes that this approach would 

result in TPQs that would be too low as compared to TPQs for liquids of similar toxicity because 

most of the liquids have approximately V= 0.1. EPA believes that liquids have a higher potential 

for airborne dispersion because of their inherently higher volatility. Also, the mechanism for 

airborne dispersion for liquids using the spill model is volatilization, whereas solids in solution 

will be dispersed via aerosolization, so using V=0.2 for solutions may be not comparable. 

3. Is the revised method consistent with the overall approach used for setting TPQs for other 

EHS chemicals?

All three reviewers thought that the revised method was fairly consistent with the

approach used for setting other TPQs. However, one reviewer thought that EPA should consider 

lowering the TPQs for 46 of 163 EHS liquids based on the comparison of using the revised TPQ 

method versus the current method. EPA believes that using a V of 0.2 to recalculate the TPQ 

indexes would result in conservatively low TPQs for solids in solution as compared to liquids of 

the same toxicity. Given that volatilization requires only the loss of containment of a chemical, 

whereas aerosolization requires the loss of containment and usually an energy release, EPA 

believes the higher potential for airborne dispersion should be assigned to liquids as compared to 

a non-volatile solid in solution. Because there are different mechanisms (volatilization versus 
Page 35 of 50

aerosolization) involved in the two types of releases, it may not be comparable to use 0.2 as a 

substitute for ―V‖ for solids in solution. Based on the comments, EPA has revised the discussion 

in the preamble to the rule of Section VI.A Use Original Ranking Method to Develop New 

TPQs. EPA has also provided a more logical and clearer explanation for TPQs for different 

forms in Appendix A: Assigning Threshold Planning Quantities (TPQs) for Extremely 

Hazardous Substances.

4. Is the revised method sufficiently protective for fulfilling accident prevention purposes of 

section 302 of EPCRA?

The reviewers all agreed that the method was sufficiently conservative to fulfill the 

accident prevention purposes of section 302 of EPCRA. 

5. Is the revised method presented in a straightforward and uncomplicated way for the regulated 

community to understand and apply? 

One reviewer thought that the revised method is not particularly straightforward and 

uncomplicated and that the regulated community will have difficulty understanding and applying 

it. Another reviewer suggested that examples be provided of how to apply the method when 

both powdered and solution form of a solid EHS is on-site. One reviewer thought a flow chart 

might be helpful to summarize the TPQ approach for the full spectrum of chemical forms. 

To address these concerns, EPA has provided in the Technical Support Document and the 
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preamble to the proposed rule, a number of examples of how to apply the new TPQ method for 

solids in solution. 

6. Are you aware of any other approaches or significant data/studies that are relevant and should 

be included or referenced in this document? Please explain.

The reviewers were not able to provide any other approaches or data that should be used 

to revise the TPQ method for solids in solution, although one did provide other recommendations 

regarding the EHS chemical listing process and the toxicity values used for TPQs. Some of 

these comments address issues that are outside the scope of the current effort, which focuses only 

on TPQs for solids in solution. 

7. Please provide any other suggestions you may have about how to strengthen the document.

To address other comments and concerns of the reviewers, EPA has clarified that the 12 

reactive EHS solids are not subject to the revised TPQ method for solids in solution. EPA has 

also added several technical references as suggested into the Technical Support Document.

E. What Are the Economic Impacts of The TPQ Changes?

Currently, facilities, who have an EHS present in an amount equal to or greater than the EHS‘s

TPQ, are required to:
Page 37 of 50

Notify the SERC and LEPC that the facility is subject to emergency planning notification.

Notify the SERC and LEPC of a facility representative to participate in the local emergency 

planning process.

Notify the LEPC of any relevant facility changes that affect emergency planning.

Provide the LEPC with the necessary information for developing a local emergency plan, as 

requested.

For facilities with an EHS that exists as solids in solution, emergency planning 

notification is required if the amount of solids by weight meets or exceeds the lower published 

TPQ for that chemical. Solid EHSs have another higher TPQ of 10,000 pounds that applies only 

if the EHS is not in solution, has a particle size equal to or greater than 100 microns, is not 

molten and does not have an NFPA reactivity rating of 2, 3, or 4. 

The proposed rule would subject facilities with an EHS solid in solution to the emergency 

planning requirements if the amount of solid chemical on-site, when multiplied by 0.2, equals or 

exceeds the lower published TPQ. The effect would be to allow facilities to have up to five 

times larger amounts of EHS solids in solution on-site than before without being subject to the 

above emergency planning requirements. 

Facilities who already had EHS solids in solution on-site above the TPQ and who have 

already (or should have already) completed emergency planning notification should notify their 

LEPC if they no longer exceed the TPQ as a result of this rulemaking. Section 303 (d)(2) of 

EPCRA requires facilities to promptly provide to their LEPC any changes relevant to emergency 
Page 38 of 50

planning. Regulations at 40 CFR 355.21 clarify that relevant changes to emergency planning 

should be reported within 30 days. EPA expects that this notification will be a minimal burden. 

The emergency planning notification requirement is not required annually. Facilities, who are 

handling an EHS solid in solution for the first time, may benefit from the changes. However, if 

they have other EHSs on-site which trigger the reporting requirements, they would still have to 

make the necessary notifications. 

EPA believes that the changes proposed by this rule can benefit SERCs and LEPCs to 

better focus their limited resources on those amounts of EHS chemicals that will potentially 

cause the greatest harm and to spend fewer resources on those that pose less harm, when 

released. The EHS list has a total of 355 chemicals, of which 157 are non-reactive solids. This 

proposed rule applies only to those 157 non-reactive solids and only when they exist in solution 

form. While the Agency does not collect information to quantify the number of facilities that 

may be impacted by this rule, we suspect it will likely be a minimal number of facilities that are 

impacted since we believe that many of these facilities handle other EHS chemicals that will 

trigger the emergency planning requirements. However, the Agency solicits comment and data 

on the number of facilities that may be impacted, and the extent of the impact. 

III. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is a 
Page 39 of 50

"significant regulatory action‖ because it raises novel policy issues arising out of litigation on the 

listing of Paraquat Dichloride as an EHS. Specifically, as a result of a legal complaint seeking

judicial review of a 1994 EPA decision of a petition requesting the deletion of Paraquat 

Dichloride from the EHS list or raising its TPQ, EPA agreed to reconsider the petition. EPA has 

decided to modify the manner by which the TPQ is applied for Paraquat Dichloride, as well as

any other EHS that exists as a non-reactive solid in solution. Specifically, facilities with a nonreactive solid EHS in solution would be subject to the Emergency Planning requirements of 40 

CFR 355 Subpart B-Emergency Planning only if the amount of non-reactive EHS solids in 

solution on-site multiplied by 0.2 equals or exceeds the lower published TPQ. This means that 

affected facilities could have up to five times larger amounts of EHS solids in solution on-site 

than before without having to report its presence to local and state emergency planning 

organizations. Accordingly, EPA submitted this action to the Office of Management Budget for 

review under EO 12866 and any changes made in response to OMB recommendations have been 

documented in the docket for this action.

The proposed regulation will not 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. Facilities that already had EHS solids in solution on-site above 

the TPQ and who have already (or should have already) completed emergency planning 

notification should notify their LEPC if the facility finds they have an EHS solid in solution onsite that no longer equals or exceeds the TPQ as a result of this rulemaking. Facilities are 

required to provide to their LEPC any changes relevant to emergency planning within 30 days 
Page 40 of 50

(40 CFR 355.21). EPA expects that this notification will be a minimal burden. The emergency 

planning notification requirement is not required annually. There may be a slight burden 

reduction for facilities who are reporting EHS non-reactive solids in solution for the first time 

under the Section 302 requirements. 

B. Paperwork Reduction Act 

 

This proposed rule does not impose any new information collection burden. Rather, this 

proposed rule, in effect, raises the amount of chemical on-site required before triggering 

emergency planning reporting under 40 CFR part 355 for EHS non-reactive solids in solution. 

Facilities with this form of EHS chemical would have already (or should have already) reported 

their presence to their SERC and LEPC and identified a Facility Emergency Coordinator and 

necessary information for development of a local emergency plan to their LEPC. If as a result of 

this rulemaking, facilities find that they have an EHS solid in solution on-site which no longer 

equals or exceeds the TPQ, the facility should notify their LEPC. Section 303 (d)(2) of EPCRA 

requires facilities to promptly provide to their LEPC any changes relevant to emergency 

planning. Regulations at 40 CFR 355.21 clarify that relevant changes to emergency planning 

should be reported within 30 days. EPA expects that this notification will be a minimal burden. 

The emergency planning notification requirement is not required annually. There may be a 

slight burden reduction for facilities who are reporting EHS non-reactive solids in solution for 

the first time under the Section 302 requirements. 

The Office of Management and Budget (OMB) has previously approved the information 
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collection requirements contained in the existing regulations at 40 CFR part 355 under the 

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

control number 2050-0092, EPA ICR number 1395.07. The OMB control numbers for EPA's 

regulations in 40 CFR are listed in 40 CFR part 9. 

C. Regulatory Flexibility Act 

The Regulatory Flexibility Act (RFA) generally requires an agency to prepare a 

regulatory flexibility analysis of any rule subject to notice and comment rulemaking 

requirements under the Administrative Procedure Act or any other statute unless the agency 

certifies that the rule will not have a significant economic impact on a substantial number of 

small entities. Small entities include small businesses, small organizations, and small 

governmental jurisdictions.

For purposes of assessing the impacts of today's proposed rule on small entities, small 

entity is defined as: (1) a small business as defined by the Small Business Administration‘s 

(SBA) regulations at 13 CFR 121.201; (2) a small governmental jurisdiction that is a government 

of a city, county, town, school district or special district with a population of less than 50,000; 

and (3) a small organization that is any "not-for-profit enterprise which is independently owned 

and operated and is not dominant in its field." 

After considering the economic impacts of today‘s proposed rule on small entities, I 

certify that this action will not have a significant economic impact on a substantial number of 
Page 42 of 50

small entities. In determining whether a rule has a significant economic impact on a substantial 

number of small entities, the impact of concern is any significant adverse economic impact on 

small entities, since the primary purpose of the regulatory flexibility analyses is to identify and 

address regulatory alternatives ―which minimize any significant economic impact of the rule on 

small entities‖ 5 USC 603 and 604. Thus, an agency may certify that a rule will not have a 

significant economic impact on a substantial number of small entities if the rule relieves 

regulatory burden, or otherwise has a positive economic effect on all of the small entities subject 

to the rule. 

This proposed rule changes the manner by which facilities apply the TPQs for those 

EHSs that are solid chemicals in solution form. Specifically, facilities with a non-reactive solid 

EHS in solution would be subject to the Emergency Planning requirements of 40 CFR 355 

Subpart B- Emergency Planning only if the amount of non-reactive EHS solids in solution onsite, multiplied by 0.2 equals or exceeds the lower published TPQ. This will allow affected 

facilities to have up to five times larger amounts of EHS solids in solution on-site than before 

without having to report its presence to local and state emergency planning organizations if they 

have not already done so. This proposed rule would only affect non-reactive EHS solid 

chemicals and then only if the solid exists in solution form. This proposed rule would reduce 

burden on any facilities who would have a non-reactive EHS solid in solution on-site for the first 

time and could be subject to the emergency planning requirements for that chemical under 40 

CFR 355 Subpart B. 

Facilities that have non-reactive EHS solids in solution on-site have already (or should 
Page 43 of 50

have already) reported these chemicals to their SERC and LEPC and identified a Facility 

Emergency Coordinator and necessary information for developing an emergency plan to their 

LEPC. If a facility with an EHS solid in solution is no longer subject to the emergency planning 

notification because it no longer equals or exceeds the TPQ as a result of this rulemaking, they 

should notify their LEPC. Facilities are required to provide to their LEPC any changes relevant 

to emergency planning within 30 days (40 CFR 355.21). EPA expects that this will be a minimal 

burden. The emergency planning notification requirement is not required annually. We have 

therefore concluded that today's proposed rule will relieve regulatory burden for some affected 

small entities and minimally increase the reporting burden for some affected small entities. We 

continue to be interested in the potential impacts of the proposed rule on small entities and 

welcome comments on issues related to such impacts.

D. Unfunded Mandates Reform Act 

This action contains no Federal mandates under the provisions of Title II of the Unfunded 

Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 1532-1538 for State, local, or tribal 

governments or the private sector. This proposed rule does not impose any new requirements on 

State, local or tribal governments. This action will reduce the reporting burden on any facility who 

would have an EHS non-reactive solid in solution on-site for the first time and could be subject to 

the emergency planning requirements for that chemical under 40 CFR 355 Subpart B- Emergency 

Planning. Facilities currently with EHS non-reactive solids in solution on-site have already (or 

should have already) reported these chemicals to their SERC and LEPC and identified a Facility 

Emergency Coordinator and the necessary information for developing an emergency plan to their 
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LEPC. We expect that this proposed action will neither increase nor decrease the requirements for 

SERCs or LEPCs. Therefore, this action is not subject to the requirements of sections 202 or 205 

of the UMRA.

This action is also not subject to the requirements of section 203 of UMRA because it contains 

no regulatory requirements that might significantly or uniquely affect small governments. This 

proposed action does not impose any new requirements on State, local or tribal governments. It 

may reduce the number of additional emergency planning notification reports received by SERCs 

and LEPCs because reporting thresholds for EHS non-reactive solids in solution will be applied in 

a manner which would allow a larger amount of EHS to be exempt from the reporting

requirements. 

E. Executive Order 13132 (Federalism)

This action does not have federalism implications. It will not have substantial direct 

effects on the States, on the relationship between the national government and the States, or on 

the distribution of power and responsibilities among the various levels of government, as 

specified in Executive Order 13132. 

This proposed rule would reduce the reporting burden on any facilities who would have a 

EHS non-reactive solid in solution on-site for the first time and could be subject to the 

emergency planning requirements for that chemical under 40 CFR 355 Subpart B- Emergency 
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Planning. The proposed rule may increase reporting for some facilities who already have 

reported non-reactive EHS solids in solution to their SERC and LEPC. If a facility finds that it 

has an EHS non-reactive solid in solution on-site that no longer exceeds the TPQ as a result of 

this rulemaking, then the facility should notify their LEPC. Facilities are required to provide to 

their LEPC any changes relevant to emergency planning within 30 days (40 CFR 355.21). EPA 

expects that this will be a minimal burden. We also expect that this proposed action will neither 

increase nor decrease the requirements for SERCs or LEPCs. This rule does not impose any 

requirements on State or local governments. Thus, Executive Order 13132 does not apply to this 

action. 

In the spirit of Executive Order 13132, and consistent with EPA policy to promote 

communications between EPA and State and local governments, EPA specifically solicits 

comment on this proposed action from State and local officials. 

F. Executive Order 13175 (Consultation and Coordination with Indian Tribal Governments)

This action does not have tribal implications, as specified in Executive Order 13175, (65 

FR 67249, November 9, 2000). This proposed rule would reduce reporting burden on any 

facilities who would have an EHS non-reactive solid in solution on-site for the first time and 

could be subject to the emergency planning requirements for that chemical under 40 CFR 355 

Subpart B- Emergency Planning. The proposed rule may increase reporting for some facilities 

who already have reported non-reactive EHS solids in solution to their SERC and LEPC. If a 

facility finds that it has an EHS non-reactive solid in solution on-site that no longer exceeds the 
Page 46 of 50

TPQ as a result of this rulemaking, then the facility should notify their LEPC. Facilities are 

required to provide to their LEPC any changes relevant to emergency planning within 30 days 

(40 CFR 355.21). EPA expects that this will be a minimal burden. This action also does not 

impose any new requirements on tribal governments. Thus, Executive Order 13175 does not 

apply to this action. 

G. Executive Order 13045 (Protection of Children From Environmental Health Risks and Safety 

Risks)

This action is not subject to EO 13045 (62 FR 19885, April 23, 1997) because it is not 

economically significant as defined in Executive Order 12866 and because the Agency does not 

believe the environmental health or safety risks addressed by this action present a 

disproportionate risk to children. This proposed rule would reduce reporting burden on any 

facilities who would have an EHS non-reactive solid in solution on-site for the first time and 

could be subject to the emergency planning requirements for that chemical under 40 CFR 355 

Subpart B- Emergency Planning. The proposed rule may increase reporting for some facilities 

who already have reported non-reactive EHS solids in solution to their SERC and LEPC. If a 

facility finds that it has an EHS solid in solution on-site that no longer exceeds the TPQ as a 

result of this rulemaking, then the facility should notify their LEPC. Facilities are required to 

provide to their LEPC any changes relevant to emergency planning within 30 days (40 CFR 

355.21). EPA expects that this will be a minimal burden.

H. Executive Order 13211 (Energy Effects)
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This action is not a ―significant energy action‖ as defined in Executive Order 13211 (66 

FR 28355 (May 22, 2001)), because it is not likely to have a significant adverse effect on the 

supply, distribution, or use of energy. Rather, this proposed rule would reduce reporting burden 

on any facilities who would have a EHS non-reactive solid in solution on-site for the first time 

and could be subject to the emergency planning requirements for that chemical under 40 CFR 

355 Subpart B- Emergency Planning. The proposed rule may increase reporting for some 

facilities who already have reported non-reactive EHS solids in solution to their SERC and 

LEPC. If a facility finds that it has an EHS solid in solution on-site that no longer exceeds the 

TPQ as a result of this rulemaking, then the facility should notify their LEPC. Facilities are 

required to provide to their LEPC any changes relevant to emergency planning within 30 days 

(40 CFR 355.21). EPA expects that this will be a minimal burden. 

I. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement Act of 1995 

(―NTTAA‖), Public Law No. 104-113, 12(d) (15 U.S.C. 272 note) directs EPA to use voluntary 

consensus standards in its regulatory activities unless doing so would be inconsistent with 

applicable law or would otherwise be impractical. Voluntary consensus standards are technical 

standards (e.g., materials specifications, test methods, sampling procedures, and business 

practices) that are developed or adopted by voluntary consensus standards bodies. NTTAA 

directs EPA to provide Congress, through OMB, explanations of when the Agency decides not to 

use available and applicable voluntary consensus standards. 
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This proposed rule does not involve technical standards. Therefore, EPA does not 

consider the use of any voluntary consensus standards.

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations

Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes federal executive 

policy on environmental justice. Its main provision directs federal agencies, to the greatest 

extent practicable and permitted by law, to make environmental justice part of their mission by 

identifying and addressing, as appropriate, disproportionately high and adverse human health or 

environmental effects of their programs, policies, and activities on minority populations and lowincome populations in the United States. 

EPA has determined that this proposed rule does not have disproportionately high and 

adverse human health or environmental effects on minority or low-income populations because it 

does not affect the level of protection provided to human health or the environment. That is, 

based on new information and data, the Agency believes that amounts of EHS non-reactive 

solids in solution that would remain airborne from a potential release into the environment from 

an accident would be lower than previously considered, and thus, would have less impact on the 

local community. This in turn will allow SERCs and LEPCs to better focus their limited 

resources on the amounts of EHS chemicals that will potentially cause the greatest harm, 
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including those affecting minority or low-income populations and to spend fewer resources on 

those that pose less harm, when released.

List of Subjects

40 CFR Part 355

Air pollution control, Chemicals, Disaster assistance, Hazardous substances, Hazardous waste, 

Intergovernmental relations, Natural resources, Penalties, Reporting and recordkeeping 

requirements, Superfund, Water pollution control, Water supply 

Dated: 

Lisa P. Jackson,

Administrator

PART 355--EMERGENCY PLANNING AND NOTIFICATION

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

Regulations is proposed to be amended as follows:

1. The authority citation for part 355 continues to read as follows:

 Authority: Sections 302, 303, 304,325, 327,328, and 329 of the Emergency Planning and 

Community Right-to-Know Act of 1986 (EPCRA) (42 U.S.C. 11002, 11003, 11004, 11045, 

11047, 11048, and 11049).
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2. Section 355.16 is amended by revising paragraph (b) to read as follows: 

Sec. 355.16 How do I determine the quantity of extremely hazardous substances present 

for certain forms of solids?

 For the three forms of solids that are listed in §355.15(a) (1) through (3), use these 

instructions to determine the quantity of extremely hazardous substance present:

(a) * * *

(b) Solids in solution. Multiply the weight percent of non-reactive solids in solution in a 

particular container by the total weight of solution in the container. Then multiply by 0.2.

* * * * * 

3. Section 355.61 is amended by adding in alphabetical order the definition of ―Solution‖ to read

as follows:

Sec. 355.61 How are key words in this part defined?

*****

Solution means any aqueous or organic solutions, slurries, viscous solutions, suspensions, 

emulsions, or pastes.

*****