Proposed Test Rule for Certain Chemicals on the ATSDR/EPA CERCLA Priority List of Hazardous Substances, 61926-61944 [E6-17569]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 71, Number 203 (Friday, October 20, 2006)]
[Proposed Rules]
[Pages 61926-61944]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E6-17569]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 799

[EPA-HQ-OPPT-2002-0073; FRL-8081-3]
RIN 2070-AB79


Proposed Test Rule for Certain Chemicals on the ATSDR/EPA CERCLA 
Priority List of Hazardous Substances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: In this action, EPA is proposing to require testing for 
certain chemicals on the Agency for Toxic Substances and Disease 
Registry (ATSDR)/EPA Priority List of Hazardous Substances which is 
compiled under the Comprehensive Environmental Response Compensation 
and Liability Act (CERCLA), and is soliciting proposals for enforceable 
consent agreements (ECAs). EPA is proposing a test rule under section 
4(a) of the Toxic Substances Control Act (TSCA) that would require 
manufacturers (including importers) and processors of four chemical 
substances (chloroethane, hydrogen cyanide, methylene chloride, and 
sodium cyanide) to conduct testing for certain health effects relating 
to the manufacture, distribution in commerce, processing, use, or 
disposal of these substances. The data that would be obtained under the 
testing program will be used to address health effects data needs 
identified by ATSDR and EPA for these substances, which are among the 
hazardous substances most commonly found at sites listed on the CERCLA 
National Priorities List (NPL) and which are also hazardous air 
pollutants (HAPs) under section 112 of the Clean Air Act (CAA). EPA is 
soliciting proposals for ECAs involving the conduct of physiologically 
based pharmacokinetics (PBPK) studies as an alternative to the testing 
proposed in this rule, as appropriate. Alternatively, if ECA proposals 
involving the conduct of PBPK studies are not received, or if received, 
are not considered by the Agency to be adequate, EPA may consider ECA 
proposals which cover some or all of the testing identified for a given 
chemical in this proposed rule.

DATES: Comments must be received on or before December 19, 2006. Your 
request to present oral comments must be in writing and must be 
received by EPA on or before December 19, 2006.

 ADDRESSES: Submit your comments, identified by docket (ID) number EPA-
HQ-OPPT-2002-0073, by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the on-line instructions for submitting comments.
     Mail: Document Control Office (7407M), Office of Pollution 
Prevention and Toxics (OPPT), Environmental Protection Agency, 1200 
Pennsylvania Ave., NW., Washington, DC 20460-0001.
     Hand Delivery: OPPT Document Control Office (DCO), EPA 
East, Rm. 6428, 1201 Constitution Ave., NW., Washington, DC. Attention: 
Docket ID Number EPA-HQ-OPPT-2002-0073. The DCO is open from 8 a.m. to 
4 p.m., Monday through Friday, excluding legal holidays. The telephone 
number for the DCO is (202) 564-8930. Such deliveries are only accepted 
during the DCO's normal hours of operation, and special arrangements 
should be made for deliveries of boxed information.
    Instructions: Direct your comments to docket ID number EPA-HQ-OPPT-
2002-0073. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available on-line 
at https://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 regulations.gov or e-
mail. The regulations.gov website 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 regulations.gov, 
your e-mail address will be automatically captured and included as part 
of the comment that is placed in the 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

[[Page 61927]]

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.
    Docket: All documents in the docket are listed in the 
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 electronically at 
https://www.regulations.gov, or, if only available in hard copy, at the 
OPPT Docket, EPA Docket Center (EPA/DC). The EPA/DC suffered structural 
damage due to flooding in June 2006. Although the EPA/DC is continuing 
operations, there will be temporary changes to the EPA/DC during the 
clean-up. The EPA/DC Public Reading Room, which was temporarily closed 
due to flooding, has been relocated in the EPA Headquarters Library, 
Infoterra Room (Room Number 3334) in EPA West, located at 1301 
Constitution Ave., NW., Washington, DC. The EPA/DC Public Reading Room 
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding 
legal holidays. The telephone number of the EPA/DC Public Reading Room 
is (202) 566-1744, and the telephone number for the OPPT Docket is 
(202) 566-0280. EPA visitors are required to show photographic 
identification and sign the EPA visitor log. Visitors to the EPA/DC 
Public Reading Room will be provided with an EPA/DC badge that must be 
visible at all times while in the EPA Building and returned to the 
guard upon departure. In addition, security personnel will escort 
visitors to and from the new EPA/DC Public Reading Room location. Up-
to-date information about the EPA/DC is on the EPA website at https://
www.epa.gov/epahome/dockets.htm.

FOR FURTHER INFORMATION CONTACT:  For general information contact: 
Colby Lintner, Regulatory Coordinator, Environmental Assistance 
Division (7408M), Office of Pollution Prevention and Toxics, 
Environmental Protection Agency, 1200 Pennsylvania Ave., N.W., 
Washington, DC 20460-0001; telephone number: (202) 554-1404; e-mail 
address:  TSCA-Hotline@epa.gov.
     For technical information contact: Robert Jones, Chemical Control 
Division (7405M), Office of Pollution Prevention and Toxics, 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (202) 564-8161; e-mail 
address: jones.robert@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may potentially be affected by this action if you manufacture 
(defined by the statute to include import) or process, or intend to 
manufacture or process, any of the chemical substances that are listed 
in Sec.  799.5100(j) of the regulatory text. Any use of the term 
``manufacture'' in this document will encompass ``import,'' unless 
otherwise stated. In addition, as described in Unit V., any person who 
exports or intends to export, any of the chemical substances in the 
final rule is subject to the export notification requirements in 40 CFR 
part 707, subpart D. Persons that could be subject to the requirements 
in this proposed rule may include, but are not limited to:
     Manufacturers (defined by statute to include importers) of 
one or more of the four subject chemical sustances (NAICS code 325 and 
324110), e.g., chemical manufacturing and petroleum refineries.
     Processors of one or more of the four subject chemical 
substances (NAICS code 325, 32411), e.g., chemical manufacturing and 
petroleum refineries.
    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding persons likely to be affected by this 
action. Other types of persons not listed in this Unit could also be 
affected. The North American Industry Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain types of businesses. To 
determine whether you or your business may be affected by this action, 
you should carefully examine the applicability provisions in Unit IV.F. 
entitled Would I Be Required to Test Under This Rule? and consult the 
regulatory text at 40 CFR 799.5100(b). If you have any questions 
regarding the applicability of this action to a particular person, 
consult the technical person listed under FOR FURTHER INFORMATION 
CONTACT.
    If you are a person identified in this unit, you would be subject 
to the requirements contained in the final rule only if you manufacture 
(including import) or process, or intend to manufacture or process, any 
of the four chemical substances that are listed in Sec.  799.5100(b) of 
the regulatory text.

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

    1. Submitting CBI. Do not submit this information to EPA through 
regulations.gov or e-mail. Clearly mark the part or all of the 
information that you claim to be CBI. For CBI information in a disk or 
CD ROM that you mail to EPA, mark the outside of the disk or CD ROM as 
CBI that you mail to EPA as CBI and then identify electronically within 
the disk or CD ROM the specific information that is claimed as CBI. In 
addition to one complete version of the comment that includes 
information claimed as CBI, a copy of the comment that does not contain 
the information claimed as CBI must be submitted for inclusion in the 
public docket. Information so marked will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2.
    2. Tips for preparing your comments. When submitting comments, 
remember to:
    i. Identify the rulemaking by docket ID number and other 
identifying information (subject heading, Federal Register date and 
page number).
    ii. 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.
    iii. Explain why you agree or disagree; suggest alternatives and 
substitute language for your requested changes.
    iv. Describe any assumptions and provide any technical information 
and/or data that you used.
    v. If you estimate potential costs or burdens, explain how you 
arrived at your estimate in sufficient detail to allow for it to be 
reproduced.
    vi. Provide specific examples to illustrate your concerns, and 
suggest alternatives.
    vii. Explain your views as clearly as possible, avoiding the use of 
profanity or personal threats.
    viii. Make sure to submit your comments by the comment period 
deadline identified.

C. Can I Request an Opportunity to Present Oral Comments to the Agency?

    You may submit a request for an opportunity to present oral 
comments. This request must be in writing. If such a request is 
received on or before December 19, 2006, EPA will hold a public meeting 
on this proposed rule in Washington, DC. This written request must be 
submitted to the mailing or hand delivery addresses provided under 
ADDRESSES. If such a request is received, EPA will announce the 
scheduling of

[[Page 61928]]

the public meeting in a subsequent Federal Register document. If a 
public meeting is announced, and if you are interested in attending or 
presenting oral and/or written comments at the public meeting, you 
should follow the instructions provided in the subsequent Federal 
Register document announcing the public meeting.

II. Background

A. What Action is the Agency Taking?

    EPA is proposing to issue a rule that would require manufacturers 
and processors to test certain chemical substances on the ATSDR/EPA 
CERCLA Priority List of Hazardous Substances. EPA is proposing this 
test rule to address data needs identified by ATSDR to enable ATSDR to 
conduct comprehensive health assessments for populations living near 
sites identified on the CERCLA NPL that may be exposed to any of the 
four chemical substances. The four chemicals included in this proposed 
rule were selected and the respective data needs were identified after 
a lengthy review process. As detailed in this unit, the process began 
with the listing of contaminated sites on the NPL, and the 
identification of hazardous substances most commonly found at sites on 
the NPL. Toxicological profiles and priority data needs were developed 
for a number of these chemicals according to the ATSDR ``Decision Guide 
for Identifying Substance-Specific Data Needs Related to Toxicological 
Profiles'' (54 FR 37618, September 11, 1989) (Decision Guide), and the 
priority data needs were reviewed by a number of Federal agencies 
(e.g., ATSDR, EPA (Office of Air and Radiation (OAR), OPPT, Office of 
Solid Waste and Emergency Response (OSWER), Office of Water (OW), and 
Office of Research and Development (ORD)), Occupational Safety and 
Health Administration (OSHA), National Institute for Occupational 
Safety and Health (NIOSH), and the National Toxicology Program (NTP) at 
the National Institute for Environmental Health and Science (NIEHS)), 
as well as the public.
    ATSDR is required under CERCLA section 104(i)(3) to perform 
extensive reviews of the scientific literature in order to develop and 
update toxicological profiles for the hazardous substances which are 
most commonly found at sites on the NPL. The toxicological profiles are 
developed by ATSDR in collaboration with EPA and NTP, independent peer 
reviewers, and the public. When developing the toxicological profiles, 
ATSDR identifies any available data that would be necessary for a 
complete understanding of the chemicals. See CERCLA section 104(i)(3). 
ATSDR then determines, by applying certain criteria, whether an 
existing ``data gap'' constitutes a ``data need'' that is critical to 
its ability to meet its statutory mandates under CERCLA section 104(i), 
such as the performance of health assessments for NPL and certain other 
facilities, or whether the missing data would only be useful to ATSDR 
in conducting a thorough review of a chemical. The criteria used in 
making this distinction are described in ATSDR's Decision Guide.
    Chemical-specific Priority Data Needs (PDN) documents are then 
compiled by ATSDR to describe the data needs identified for each 
hazardous substance commonly found at sites on the NPL. PDN documents 
undergo several reviews, including public review, peer review by an 
external peer review panel, and review by scientists at the NTP and the 
Centers for Disease Control (CDC). ATSDR also coordinates its 
identification of PDNs with EPA and NIEHS through the Tri-Agency 
Superfund Applied Research Committee (TASARC). On October 17, 1991, 
ATSDR announced PDNs for 38 chemical substances commonly found at NPL 
sites, and allowed the public to comment on the needs identified (56 FR 
52178, October 17, 1991). ATSDR received comments from academic 
institutions, industry groups, law firms, health groups, environmental 
groups, and government agencies. Manufacturers and processors were 
encouraged to volunteer to conduct research to fill specific priority 
data needs. ATSDR proposed procedures for conducting the needed 
research voluntarily as part of the ATSDR Substance-Specific Applied 
Research Program (SSARP) (57 FR 4758, February 7, 1992). A public 
meeting was held on April 29, 1992, to discuss voluntary testing 
agreements associated with any of the chemical substances. ATSDR 
announced final priority data needs for the 38 chemical substances and 
offered the public an opportunity to participate in a voluntary testing 
program to fill these data needs (57 FR 54160, November 16, 1992).
    On October 27, 1992, ATSDR referred 60 data needs for the 38 
chemical substances to EPA, and requested that EPA use its authority 
under TSCA and the Federal Insecticide, Fungicide and Rodenticide Act 
(FIFRA), 7 U.S.C. 136 to 136y, to obtain the needed data (Ref. 3). 
ATSDR's request was evaluated within EPA by OPPT, OAR, OW, OSWER, and 
ORD. Other Federal agencies, including OSHA, NIOSH, CPSC, and the Mine 
Safety and Health Administration (MSHA) also reviewed the referral. In 
addition, ATSDR's request was discussed at a TASARC meeting held in 
1993.
    EPA responded in part in December, 1992 (Ref. 4) and in April, 1993 
(Ref. 5). These responses noted that, for a variety of reasons, 18 of 
the 38 chemical substances were more suitable for consideration by EPA 
for inclusion in potential future testing actions under TSCA and/or 
FIFRA, and that these substances and information needs would be 
prioritized based on various factors including, but not limited to, the 
appropriateness of using TSCA authority to require testing and the 
needs of other EPA offices and agencies for the test data.
    On November 9, 1993, EPA agreed to consider the development of 
testing actions for most of the PDNs for 12 of the chemical substances 
referred by ATSDR (Ref. 6). The 12 chemicals included mercury, vinyl 
chloride, benzene, trichloroethylene, chromium, tetrachloroethylene, 
cyanide, beryllium, toluene, methylene chloride, di(2-ethylhexyl) 
phthalate (DEHP), and chloroethane. Arsenic, chloroform, carbon 
tetrachloride, nickel, zinc, and selenium were determined to be lower 
priority candidates for testing under TSCA section 4 authority at that 
time.
    For testing purposes, sodium cyanide was deemed most relevant for 
testing by ATSDR. Sodium cyanide is prevalent at hazardous waste sites 
and is suitable for testing by the oral route, the major route of 
concern identified by ATSDR. Hydrogen cyanide is the most prevalent 
form of cyanide found in air, and is suitable for testing by 
inhalation, the major route of concern identified by EPA's OAR (Ref. 
12). Simple cyanides, such as sodium cyanide and hydrogen cyanide 
dissociate completely yielding the cyanide ion that is the object of 
concern. Complex cyanides are less bioavailable and therefore less 
toxic. Complex cyanides are not good cyanide species for testing free 
cyanide toxicity (Ref. 13).
    On September 30, 1994 (59 FR 49934) (FRL-4756-5), EPA invited 
manufacturers and processors to voluntarily develop and submit testing 
program proposals to EPA for consideration in the development of ECAs. 
The notice described testing needs for vinyl chloride, benzene, 
trichloroethylene, tetrachloroethylene, hydrogen cyanide, sodium 
cyanide, toluene, methylene chloride, chloroethane, mercury, chromium, 
and beryllium. The metals (mercury, chromium, and beryllium) were 
included, but the specific tests for these

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substances were not described in the solicitation.
    EPA received no proposals for testing through the solicitation, but 
the American Chemistry Council, rather than entering into an ECA with 
EPA, agreed to test vinyl chloride under a voluntary agreement with 
ATSDR (Ref. 11). That testing has been completed and accepted by ATSDR.
    EPA, at this point, has determined that it would propose testing 
for the following substances under a TSCA section 4 test rule: 
Chloroethane (Chemical Abstract Service Registry Number (CAS No.) 75-
00-3), hydrogen and sodium cyanide (CAS Nos. 74-90-8 and 143-33-9, 
respectively), and methylene chloride (CAS No. 75-09-2). Testing on 
DEHP is being deferred until EPA further defines its testing objectives 
and approach. At ATSDR's recommendation, and with TASARC's concurrence, 
testing for the metals will be considered for inclusion under separate 
TSCA section 4 testing actions, to the extent that the TSCA section 4 
findings can be made, because these metals present unique issues 
related to fate, transport, speciation, bioavailability, and metabolism 
under different environmental conditions, and other issues specific to 
metals (Ref. 8).
    Benzene, tetrachloroethylene, toluene, and trichloroethylene are 
among the 20 chemicals sponsored under Tier 1 of the pilot phase of 
EPA's Voluntary Children's Chemical Evaluation Program (VCCEP). The 
VCCEP is intended to provide data to help the public understand the 
potential health risks to children associated with certain chemicals. 
As explained in the December 26, 2000 Federal Register notice that 
announced the VCCEP (65 FR 81699) (FRL-6758-5), companies that 
manufacture or import certain chemicals may volunteer to sponsor an 
evaluation of these chemical substances in Tier 1 of the VCCEP pilot. 
As part of their sponsorship, companies collect and/or develop health 
effects and exposure information on their chemical(s). The VCCEP 
consists of three tiers to which a sponsor can commit to separately. 
Tier 1 includes an assessment of acute toxicity, repeated dose toxicity 
with reproductive and developmental toxicity screens, and genotoxicity, 
as well as an assessment of readily available exposure information. As 
part of the VCCEP Tier 1 sponsorship commitment, sponsors also assess 
the need for additional toxicity and exposure data, which could be 
provided by the next tier, to more fully characterize the risks the 
chemical may pose to children. After the submission of Tier 1 
information and its evaluation by a Peer Consultation Group, EPA will 
review the sponsor's submission and the Peer Consultation report and 
then announce the Agency's decision as to whether additional 
information (i.e., toxicity testing and/or exposure information) is 
needed to adequately characterize the chemical's risk to children. If 
additional information is needed, companies may sponsor chemicals at a 
higher Tier under VCCEP. Additional information about the VCCEP, 
including the framework document and archives of public meetings, is 
available at the website https://www.epa.gov/chemrtk/vccep/childhlt.htm.
    EPA has decided not to include benzene, tetrachloroethylene, 
toluene, and trichloroethylene in this proposed TSCA section 4 test 
rule. Instead, EPA has decided to continue evaluation and review of the 
data needs for these four substances within the context of previous 
commitments made by the sponsors of these substances under VCCEP. EPA 
expects that one of the outcomes of this evaluation will be an Agency 
decision on whether to pursue one or more TSCA section 4 testing 
action(s) for these chemicals.
    ATSDR has developed criteria for evaluating the status of the PDNs 
as new information becomes available (67 FR 4836, January 31, 2002) and 
ATSDR provides updates on the status of the PDNs in the SSARP 
approximately every 3 years. Based on these criteria and the review of 
the current literature, ATSDR determines whether a PDN has been filled 
or is unchanged. A PDN is considered by ATSDR to be filled if 
information (i.e., new peer-reviewed and publicly available studies) to 
address the PDN has been identified and accepted by ATSDR. In addition, 
ATSDR considers a PDN to be filled if a study to generate the needed 
information has been initiated. In this latter case, even though the 
study has not yet been completed, ATSDR no longer considers it a 
priority to initiate additional studies at this time. During the 
literature review by ATSDR, new studies may be identified suggesting 
other effects of concern which were not included in the original list 
of PDNs. In such cases, additional PDNs may be added to the SSARP. This 
proposed TSCA section 4 test rule incorporates the PDNs listed in the 
latest update of the SSARP (70 FR 73749, December 13, 2005).
    In addition to its proposal to require the testing of four chemical 
substances, EPA is soliciting proposals for ECAs as an alternative to 
the testing proposed in this document, as appropriate (see Unit IV.E.).

B. How Would the Data Developed Under this Test Rule Be Used?

    ATSDR and EPA's OAR have asked that OPPT obtain specific data for 
these chemicals through its authority under TSCA to assist ATSDR and 
EPA in fulfilling their responsibilities under various statutes. For 
example, EPA is proposing to use its TSCA section 4 authority to obtain 
data supporting ATSDR's Substance-Specific Applied Research Program, a 
program for collecting the data and other information needed for 
developing health assessments for populations located near ``Superfund 
sites,'' i.e., sites that are included on the NPL under CERCLA, 42 
U.S.C. 9601 et seq. ATSDR referred the chemicals subject to this action 
to EPA under the authority of section 104(i) of CERCLA, 42 U.S.C. 
9604(i).
    Section 104(i)(2) of CERCLA requires ATSDR and EPA to prepare and 
revise a list of hazardous substances which are most commonly found at 
sites listed on the CERCLA NPL and which ATSDR and EPA, in their sole 
discretion, determine are posing the most significant potential threat 
to human health.
    Section 104(i)(3) of CERCLA directs ATSDR to prepare toxicological 
profiles for each substance included on the ATSDR/EPA list of chemicals 
most commonly found at NPL sites and it prescribes the profiles' 
contents. Each profile includes an examination, summary, and 
interpretation of available toxicological information and 
epidemiological evaluations on a hazardous substance to ascertain 
levels of human exposure and the associated human health effects. The 
adequacy of data currently available and under development are also 
evaluated in the toxicological profiles. ATSDR will update the 
toxicological profiles with the data obtained under the testing program 
proposed in this rule. If ATSDR determines that adequate information on 
a chemical substance is not available or is under development, ATSDR is 
required to assure the initiation of a program of research on the 
substance to determine its health effects including using toxicological 
testing. See CERCLA section 104(i)(5)(A) and (C).
    Section 104(i)(5)(C) of CERCLA requires ATSDR to coordinate with 
EPA and NTP to avoid duplicative research being conducted in other 
programs and under other authorities. Section 104(i)(5)(D) of CERCLA 
states ``it is the sense of Congress that the costs of research 
programs'' initiated by ATSDR ``be borne by the manufacturers and 
processors of the hazardous substance

[[Page 61930]]

in question as required in programs of toxicological testing under the 
Toxic Substances Control Act.''
    For purposes of the chemicals included in this proposed rule, ATSDR 
has determined that adequate information on the health effects of these 
chemical substances for certain endpoints is not available (70 FR 
73749, December 13, 2005) (Ref. 3). Testing under TSCA would ensure 
that these substances are tested at the earliest practicable date.
    EPA is often in a position of making decisions in the face of 
uncertainty. Requiring these additional data will allow EPA to refine 
risk assessments and reduce uncertainty. Nevertheless, EPA will 
continue to make decisions as the state-of-the-science evolves and data 
are being generated. The data that would be developed under the rule, 
as proposed, would provide a stronger scientific basis for risk 
assessments developed by EPA, other Federal agencies, State, and local 
governments, and the general public. Assessments affect decisions for 
listing/delisting the chemicals from regulatory lists of chemicals 
including, for example, the CERCLA section 104(i)(2)(A) list of 
hazardous substances most commonly found at sites on the NPL, and the 
list of HAPs under section 112 of CAA. The data would also be expected 
to influence other regulatory decisions such as how much of the 
chemical should be removed from Superfund sites, and what 
concentrations can safely be allowed in the air and water. The data 
would improve decisions setting protective standards and guidelines, 
and they could affect decisions for regulating the manufacturing, 
processing, distribution in commerce, use, and disposal of these 
chemical substances.
    EPA would also use the data provided by this proposed TSCA test 
rule in various chemical evaluations EPA performs to meet the 
requirements under CAA, 42 U.S.C. 7401 et seq. For example, section 
112(f) of CAA, 42 U.S.C. 7412(f), requires EPA to assess risks of HAPs 
remaining (i.e., residual risks) after maximum achievable control 
technology (MACT) standards have been imposed. MACT standards are 
technology-based air emission standards required under section 112(d) 
of CAA, 42 U.S.C. 7412(d). Studies included in this proposed rule would 
generate data useful for determining the nature and magnitude of 
residual risks. Based on these and other available data, EPA must 
decide whether additional standards (post-MACT standards) will be 
necessary for protecting the public health with an ample margin of 
safety.
    In addition, the chemical substances identified in this proposed 
test rule are all included on the list of HAPs in section 112(b)(1) of 
CAA, 42 U.S.C. 7412(b)(1). Pursuant to section 112(b)(4) of CAA, 42 
U.S.C. 7412(b)(4), ``if the Administrator determines that information 
on health or environmental effects of a substance is not sufficient to 
make a determination [that the list of HAPs should be modified], the 
[Agency] may use any authority available to the Administrator to 
acquire such information.'' If the data collected under the final TSCA 
test rule show that a chemical substance is not a concern to human 
health, this information may be helpful in making decisions concerning 
the potential delisting of any substance from the CAA HAPs list.
    The data that would be developed under the final TSCA test rule may 
also be used to support assessments and other Agency actions, such as 
those related to the accidental release prevention program under 
section 112(r) of CAA, 42 U.S.C. 7412(r). The development of data under 
the final rule may also be used in conjunction with EPA's efforts to 
fulfill the Agency's statutory obligation under section 103(d) of CAA, 
42 U.S.C. 7403(d), to conduct a research program on the health effects 
of air pollutants. For a more detailed discussion about how testing 
generally relates to requirements under the CAA, refer to the proposed 
TSCA section 4 test rule for HAPs at 61 FR 33178, June 26, 1996 (FRL-
4869-1) and amended at 62 FR 67466, December 24, 1997 (FRL-5742-2) and 
at 63 FR 19694, April 21, 1998 (FRL-5780-6).
    In developing this proposed rule, EPA and ATSDR have made maximum 
use of scientifically adequate existing test data to avoid unnecessary, 
duplicative testing, thereby avoiding the excessive use of animal 
testing. If at any time, including after this rule is finalized, the 
Agency receives adequate existing data that fulfill a specific data 
need for one of these chemicals, EPA will ensure that unnecessary 
testing is not required. In addition, EPA is particularly interested in 
receiving ECA proposals for PBPK studies as an alternative to the 
testing specified in this proposed rule, as appropriate (see Unit 
IV.E.).
    All of the chemicals included in this proposed rule are of broad 
programmatic interest, and are included in the Agency's Integrated Risk 
Information System (IRIS). The health effects data that would be 
generated by the final rule may result in improvement of the health 
effects database and increased confidence in the reference doses (RfDs) 
and reference concentrations (RfCs) developed by EPA that are contained 
in IRIS. Improvements to the quality of IRIS data can result in 
considerable benefits to the public, because IRIS is publicly available 
and is used by a wide variety of governmental and non-governmental 
entities for assessing the safety of chemicals.

C. What is the Agency's Authority for Taking this Action?

    EPA is proposing a test rule under TSCA section 4(a), 15 U.S.C. 
2603(a), that would require certain health effects testing for four 
chemical substances for which the ATSDR has PDNs. In addition, EPA's 
OAR may use the submitted data to implement section 112 of CAA. With 
this data, OAR will be able to characterize risks associated with both 
acute and longer term exposures.
    Section 2(b)(1) of TSCA, 15 U.S.C. 2601(b)(1), states that it is 
the policy of the United States that ``adequate data should be 
developed with respect to the effect of chemical substances and 
mixtures on health and the environment and that the development of such 
data should be the responsibility of those who manufacture [which is 
defined by statute to include import] and those who process such 
chemical substances and mixtures[.]'' To implement this policy, TSCA 
section 4(a) mandates that EPA require by rule that manufacturers and 
processors of chemical substances and mixtures conduct testing if the 
Administrator finds that:
    (1)(A)(i) the manufacture, distribution in commerce, processing, 
use, or disposal of a chemical substance or mixture, or that any 
combination of such activities, may present an unreasonable risk of 
injury to health or the environment,
    (ii) there are insufficient data and experience upon which the 
effects of such manufacture, distribution in commerce, processing, 
use, or disposal of such substance or mixture or of any combination 
of such activities on health or the environment can reasonably be 
determined or predicted, and
    (iii) testing of such substance or mixture with respect to such 
effects is necessary to develop such data; or
    (B)(i) a chemical substance or mixture is or will be produced in 
substantial quantities, and (I) it enters or may reasonably be 
anticipated to enter the environment in substantial quantities or 
(II) there is or may be significant or substantial human exposure to 
such substance or mixture,
    (ii) there are insufficient data and experience upon which the 
effects of the manufacture, distribution in commerce, processing, 
use, or disposal of such substance or mixture or of any combination 
of such activities on health or the environment can reasonably be 
determined or predicted, and
    (iii) testing of such substance or mixture with respect to such 
effects is necessary to develop such data[.]


[[Page 61931]]


    If EPA makes these findings for a chemical substance or mixture, 
the Administrator must require that testing be conducted on that 
chemical substance or mixture. The purpose of the testing would be to 
develop data about the substance's or mixture's health and 
environmental effects for which there is an insufficiency of data and 
experience, and which are relevant to a determination that the 
manufacture, distribution in commerce, processing, use, or disposal of 
the substance or mixture, or any combination of such activities, does 
or does not present an unreasonable risk of injury to health or the 
environment.
    Once the Administrator has made a finding under TSCA section 
4(a)(1)(A)(i) (i.e., a finding that a chemical substance may present an 
unreasonable risk of injury to health or the environment) or a finding 
under TSCA section 4(a)(1)(B)(i) (i.e., a finding that a chemical 
substance is or will be produced in substantial quantities and it may 
either enter the environment in substantial quantities or there may be 
significant or substantial human exposure to the chemical substance), 
EPA may require any type of health or environmental effects testing 
necessary to address unanswered questions about the effects of the 
chemical substance. EPA need not limit the scope of testing required to 
the factual basis for TSCA section 4(a)(1)(A)(i) or (B)(i) findings as 
long as EPA also finds that there are insufficient data and experience 
upon which the effects of the manufacture, distribution in commerce, 
processing, use, or disposal of such substance or mixture or of any 
combination of such activities on health or the environment can 
reasonably be determined or predicted, and that testing is necessary to 
develop such data. This approach is explained in more detail in EPA's 
TSCA section 4(a)(1)(B) Final Statement of Policy published in the 
Federal Register issue of May 14, 1993 (58 FR 28736, 28738-28739) 
(``B'' Policy).

III. Findings

A. What is the Basis for EPA's Proposal to Test These Chemical 
Substances?

    As indicated in Unit II.C., in order to issue a rule under TSCA 
section 4(a) requiring the testing of chemical substances or mixtures, 
EPA must make certain findings for those chemicals regarding:
    1. Risk (TSCA section 4(a)(1)(A)(i)); or
    2. Production and either substantial release or significant or 
substantial human exposure (TSCA section 4(a)(1)(B)(i)); and
    3. That the available data and experience are insufficient for EPA 
to determine or predict the health or environmental effects of the 
manufacture, distribution in commerce, processing, use, or disposal of 
the chemicals or mixtures subject to the rule or of any combination of 
such activities; and
    4. That testing is necessary to develop the data.

B. What are EPA's Preliminary Findings Regarding the Chemical 
Substances in This Proposed Rule?

    EPA is proposing to require the testing of the chemical substances 
included in this test rule based on its preliminary findings under both 
TSCA section 4(a)(1)(A)(i) relating to risk to health or the 
environment and TSCA section 4(a)(1)(B)(i) relating to ``substantial'' 
production, and ``substantial'' release into the environment, and/or 
``significant'' and/or ``substantial'' human exposure, as well as 
findings under TSCA sections 4(a)(1)(A)(ii) and (iii) and TSCA sections 
4(a)(1)(B)(ii) and (iii), regarding the insufficiency of the available 
data and experience and whether testing is necessary to develop the 
data.
    EPA has made preliminary findings under TSCA section 4(a)(1)(A)(i) 
that the chemical substances identified in this proposal may present an 
unreasonable risk of injury to health or the environment. Consistent 
with criteria discussed in its ``B'' Policy, EPA has also made 
preliminary findings under TSCA section 4(a)(1)(B)(i) that the chemical 
substances are produced in substantial quantities, and that they enter 
or may reasonably be anticipated to enter the environment in 
substantial quantities, and/or that there is or may be significant and/
or substantial human exposure to these chemicals. EPA is making 
preliminary findings that the available data and experience are 
inadequate for determining or predicting the effects of manufacture, 
distribution in commerce, processing, use, or disposal of each of these 
substances on health or the environment or of any combination of such 
activities, (TSCA sections 4(a)(1)(A)(ii) and 4(a)(1)(B)(ii)), and EPA 
is making preliminary findings that testing is necessary to develop the 
needed data (TSCA sections 4(a)(1)(A)(iii) and 4(a)(1)(B)(iii)).
    In EPA's ``B'' Policy, discussed in Unit II.C., EPA explained that 
it generally considers ``substantial'' production of a chemical 
substance or mixture to be aggregate production (including import) 
volume equaling or exceeding one million pounds (lbs) per year (58 FR 
28736, 28746, May 14, 1993). The ``B'' Policy also provides guidelines 
that are generally considered in evaluating whether there is 
``substantial release,'' and/or ``substantial human exposure'' of 
workers, consumers, and the general population to a chemical substance 
or mixture. Refer to EPA's ``B'' Policy for further discussion on how 
EPA generally evaluates chemicals or mixtures under TSCA section 
4(a)(1)(B)(i). For the reasons set out in the ``B'' Policy, EPA 
believes that the guidance included in the ``B'' Policy is appropriate 
for consideration in this proposed rule and EPA sees no reason not to 
act consistently with the guidelines with respect to the chemicals 
included in this proposed rule.
    A detailed discussion of EPA's preliminary findings for each 
chemical substance included in this proposed rule is contained in a 
separate document entitled TSCA Section 4(a) Preliminary Findings: 
Supporting Document for the Proposed Test Rule for Certain Chemical 
Substances on the ATSDR/EPA CERCLA Priority List of Hazardous 
Substances that is available in the docket (Ref. 1). Table 1 of this 
unit (Summary, TSCA Section 4(a) Preliminary Statutory Findings) 
provides a summary of the preliminary findings EPA has made for the 
four chemicals that are the subject of this proposed rule.

[[Page 61932]]



                      Table 1.-- Summary, TSCA Section 4(a) Preliminary Statutory Findings
----------------------------------------------------------------------------------------------------------------
                                        Health effects used in     Basis for the TSCA     Testing endpoints \1\
     Chemical substance  CAS No.       making the TSCA section   section 4(a)(1)(B)(i)   (reference to TSCA test
                                        4(a)(1)(A)(i) findings          findings               guidelines)
----------------------------------------------------------------------------------------------------------------
Chloroethane                           Lung, liver, and heart   Substantial production:  Sec.   799.9110 acute
CAS No. 75-00-3......................   toxicity                 >=1,000,000 lbs/year     oral toxicity
                                       Neurological effects...  Substantial human        Sec.   799.9310 90-day
                                       Gastrointestinal          exposure: >=1,000        oral toxicity in
                                        effects.                 workers.                 rodents
                                                                                         Sec.   799.9370
                                                                                          prenatal developmental
                                                                                          Toxicity--inhalation
                                                                                         Sec.   799.9380
                                                                                          reproduction and
                                                                                          fertility effects--
                                                                                          oral and inhalation
                                                                                         Sec.   799.9430
                                                                                          combined chronic
                                                                                          toxicity/
                                                                                          carcinogenicity--inhal
                                                                                          ation
                                                                                         Sec.   799.9620
                                                                                          neurotoxicity
                                                                                          screening battery--
                                                                                          oral and inhalation
                                                                                         Sec.   799.9630
                                                                                          developmental
                                                                                          neurotoxicity--inhalat
                                                                                          ion
                                                                                         Sec.   799.9780
                                                                                          immunotoxicity--oral
                                                                                          and inhalation
----------------------------------------------------------------------------------------------------------------
Hydrogen cyanide                       Acute toxicity           Substantial production:  Sec.   799.9135 acute
CAS No. 74-90-8......................  Neurotoxicity..........   >=1,000,000 lbs/year     inhalation toxicity
                                       Thyroid toxicity.......  Substantial               with histopathology
                                                                 environmental release:  Sec.   799.9346 90-day
                                                                 >=1,000,000 lbs/year.    inhalation toxicity
                                                                Substantial human        Sec.   799.9370
                                                                 exposure: >=1,000        prenatal developmental
                                                                 workers.                 Toxicity--inhalation
                                                                                         Sec.   799.9380
                                                                                          reproduction and
                                                                                          fertility effects--
                                                                                          inhalation
                                                                                         Sec.   799.9620
                                                                                          neurotoxicity
                                                                                          screening battery--
                                                                                          inhalation
                                                                                         Sec.   798.6500
                                                                                          schedule-controlled
                                                                                          operant behavior--
                                                                                          inhalation
----------------------------------------------------------------------------------------------------------------
Sodium cyanide                         Acute toxicity           Substantial production:  Sec.   799.9370
CAS No. 143-33-9.....................  Neurotoxicity..........   >=1,000,000 lbs/year     Prenatal Developmental
                                       Thyroid toxicity.......  Substantial human         Toxicity--oral
                                                                 exposure: >=1,000
                                                                 workers.
----------------------------------------------------------------------------------------------------------------
Methylene chloride                     Neurotoxicity            Substantial production:  Sec.   799.9370
CAS No. 75-09-2......................  Liver toxicity.........   >=1,000,000 lbs/year     prenatal developmental
                                       Developmental toxicity.  Substantial               toxicity--inhalation
                                       Oncogenicity...........   environmental release:  Sec.   798.6500
                                       Teratogenicity.........   >=1,000,000 lbs/year.    schedule-controlled
                                                                Substantial human         operant behavior--oral
                                                                 exposure: >=1,000       Sec.   799.9630
                                                                 workers, >=10,000        developmental
                                                                 consumers, >=100,000     neurotoxicity--inhalat
                                                                 general population.      ion
----------------------------------------------------------------------------------------------------------------
\1\ Support for the preliminary finding that the available data are insufficient to determine or predict the
  human health effects of a chemical substance for these particular endpoints and for the finding that testing
  is necessary to develop the necessary data can be found in ``TSCA Section 4(a) Preliminary Findings:
  Supporting Document for the Proposed Test Rule for Certain Chemical Substances on the ATSDR/EPA CERCLA
  Priority List of Hazardous Substances'' (Ref. 1).

IV. Proposed Testing

A. How Would the Studies Proposed Under This Test Rule Be Conducted?

    EPA is proposing specific testing and reporting requirements for 
each of the chemical substances specified in Table 2 of Sec.  
799.5100(j) of the proposed regulatory text, according to the test 
standards set forth at Sec.  799.5100(j) of the proposed regulatory 
text. Testing under this proposed rule would be conducted in accordance 
with TSCA Good Laboratory Practice Standards (GLPS) (40 CFR part 792).

B. What Substances Would Be Tested Under This Rule?

    EPA is proposing that, with the exception of hydrogen cyanide and 
sodium cyanide, the chemical substances listed in Table 2 of Sec.  
799.5100(j) of the proposed regulatory text be tested at a purity of at 
least 99%. EPA is proposing that hydrogen cyanide and sodium cyanide be 
tested at a purity of at least 95%. Using data on relatively pure 
chemicals, EPA avoids the possible confounding effects of impurities 
that might be found in technical grade substances. EPA believes that 
the specified purities of 95% and 99% are available or readily 
achievable for all substances covered by this rule based on a search of 
on-line information from catalogs of chemical suppliers (https://
chemacx.cambridgesoft.com/chemacx/index.asp) and chemical safety 
information provided on-line by the International Programme on Chemical 
Safety (IPCS) (https://www.inchem.org).

C. When Would Any Testing Imposed by This Rule Begin?

    The proposed testing requirements contained in this proposed rule 
are not effective until and unless the Agency issues a subsequent final 
rule. Based on the effective date of the final rule, which is typically 
30 days after the publication of a final rule in the Federal Register, 
the test sponsor would need to plan the initiation of the required 
testing at a time sufficient to allow the final report to be submitted 
by the deadline indicated in Sec.  799.5100(j) of the proposed 
regulatory text.

D . May I Submit Data From Studies in Which the Test Substance was 
Administered by a Route of Administration Other Than the Route 
Specified for Testing Under This Proposed Rule?

    EPA may accept data from studies in which the test substance was 
administered by a route of administration other than the route 
specified in the test under this proposed rule. Such data could result 
in a decision by EPA not to include the related testing under the 
proposed rule

[[Page 61933]]

in the final rule or in EPA's withdrawal of the related testing 
following promulgation of the final rule. These data, however, must be 
accompanied by an appropriate analysis that includes a scientifically 
sound route-to-route extrapolation of the quantitative dose-response 
relationship to meet the testing requirements from this rulemaking. 
Route-to-route extrapolations are generally conducted with the use of a 
PBPK model. A PBPK model simulates the kinetics (i.e., absorption, 
distribution, metabolism, and elimination) of a chemical substance, and 
can be used to derive an internal dose at a target site (or an internal 
dose that can be used as a surrogate for the dose at a target site) 
that would result from a given exposure scenario. The internal dose can 
then be related to the response to develop a more robust and 
biologically relevant characterization of the dose-response 
relationship. For example, a PBPK model would first be used to estimate 
an internal dose (e.g., average blood level) that would occur in a test 
species from an exposure at a given level to the chemical in drinking 
water. The model can then be used to estimate what the level of 
chemical in air would need to be to yield a comparable average blood 
level for the test species assuming a continuous inhalation exposure. 
This prediction then forms the basis for the route-to-route 
extrapolation.
    There is no prescriptive formula or generic PBPK model that can be 
used to conduct a route-to-route extrapolation. EPA realizes that PBPK 
modeling expertise is often required, and that the approach and 
supporting arguments must be developed and evaluated on a case-by-case 
basis. Increasingly, however, route-to-route extrapolation using a PBPK 
model has been shown to be a useful and less expensive alternative to 
conducting studies via different routes of exposure. By potentially 
reducing the number of toxicity tests that are performed to fill the 
data needs, use of PBPK approaches can also reduce the number of test 
animals that otherwise would have been required.
    Some of the main factors to consider in presenting a scientifically 
supportable route-to-route extrapolation include:
    1. The nature of the adverse effect,
    2. The adequacy of the kinetic and physiology data used to develop 
the PBPK model for the test species of interest, and
    3. Sufficient understanding of the chemical-specific toxicokinetic 
processes that might result in a difference in the internal dose 
depending upon the route of exposure.
The nature of the adverse effect is a key determinant of whether a 
route-to-route extrapolation is feasible. If an adverse effect is 
observed at a target site following delivery of the chemical or a 
metabolite via the systemic circulation, then, regardless of the route 
of exposure, a given internal concentration in the blood should 
reproducibly yield a comparable response. If, however, the adverse 
effect of interest occurs from direct action with barrier tissues at 
the portal-of-entry (e.g., epithelial damage in the nasal region or the 
gastrointestinal (GI) tract), then one would not expect similar 
toxicity to occur from a different route of exposure. Secondly, the 
PBPK model must be calibrated and tested with sufficient data in the 
test species of interest to support a credible estimate of the internal 
dose. Third, the kinetics of the chemical must be sufficiently 
understood with respect to differences in internal disposition that may 
occur following different routes of exposure. For example, if the 
chemical is extensively metabolized in the liver, then the initial 
level of parent compound in the systemic circulation will depend upon 
whether the chemical is orally absorbed, and immediately enters the 
liver from the portal circulation where some portion will be 
metabolized before being systemically distributed, or is absorbed 
through the lungs and is immediately available for systemic 
distribution.

E. May I Submit Proposals for Enforceable Consent Agreements (ECAs)?

    Yes. EPA encourages the submission of such proposals, which could 
lead to the development of ECAs. EPA is particularly interested in 
receiving proposals for ECAs involving the conduct of PBPK studies as 
an alternative to the testing specified in this proposed rule, as 
appropriate. Route-to-route extrapolation using a PBPK model is a 
potentially useful and less expensive alternative to conducting studies 
via different routes of exposure. PBPK approaches can additionally 
reduce the number of test animals that would otherwise have been needed 
in order to conduct the toxicity tests specified in the rule. 
Alternatively, if ECA proposals involving the conduct of PBPK studies 
are not received, or if received, are not considered by the Agency to 
be adequate, EPA may consider ECA proposals received which cover some 
or all of the testing identified for a given chemical in this proposed 
rule.
    Each ECA proposal submitted to EPA in response to this proposed 
rule should include the name of the chemical(s), a detailed description 
of the proposed study(ies), and, in the case of ECAs involving the 
conduct of PBPK studies, a discussion of how the proposed studies would 
support the application of the pharmacokinetics data in performing 
route-to-route extrapolations. Such discussions should reflect an 
understanding of the factors involved in developing a scientifically 
supportable route-to-route extrapolation (see Unit IV.D.), the existing 
database on the chemical, and the testing specified in this proposed 
test rule.
    Each study proposal should be labeled: ``Proposal for Study of 
(name of chemical),'' identified by docket ID number EPA-HQ-OPPT-2002-
0073, and sent according to the instructions under ADDRESSES.
    EPA would review the proposals and decide whether to proceed with 
the ECA process under the procedures in 40 CFR 790.22. To initiate the 
ECA procedures, EPA would publish a notice in the Federal Register 
soliciting persons interested in participating in or monitoring 
negotiations for the development of an ECA to send EPA a written notice 
of their interest.

F. Would I Be Required to Test Under This Rule?

    Under TSCA sections 4(a)(1)(A)(ii) and 4(a)(1)(B)(ii), EPA has made 
preliminary findings that there are insufficient data and experience to 
reasonably determine or predict health effects resulting from the 
manufacturing, processing, distribution in commerce, use, or disposal 
of the chemical substances listed in this proposed rule or of any 
combination of such activities. As a result, under TSCA section 
4(b)(3)(B), manufacturers and processors of these substances, and those 
who intend to manufacture or process them, would be subject to the rule 
with regard to those listed chemicals which they manufacture or 
process.
    1. Would I be subject to this rule? You would be subject to the 
final rule and may be required to test if you manufacture (which is 
defined by statute to include import) or process, or intend to 
manufacture or process, one or more of the chemical substances listed 
in Table 2 of Sec.  799.5100(j) in the proposed regulatory text during 
the time period discussed in Unit IV.F.2. However, if you do not know 
or cannot reasonably ascertain that you manufacture or process a listed 
test rule substance (based on all information in your possession or 
control, as well as all

[[Page 61934]]

information that a reasonable person similarly situated might be 
expected to possess, control, or know, or could obtain without 
unreasonable burden), you would not be subject to the final rule for 
that listed substance.
    2. When would my manufacture or processing (or my intent to do so) 
cause me to be subject to this rule? You would be subject to the final 
rule if you manufacture or process, or intend to manufacture or 
process, a substance listed in Table 2 of Sec.  799.5100(j) of the 
proposed regulatory text at any time from the effective date of the 
final test rule to the end of the test cost reimbursement period. The 
term ``reimbursement period'' is defined at 40 CFR 791.3(h) and may 
vary in length for each substance to be tested under a final TSCA 
section 4(a) test rule, depending on when testing is completed. See 
Unit IV.F.4.
    3. Would I be required to test if I were subject to the rule? It 
depends on the nature of your activities. All persons who would be 
subject to the final TSCA section 4(a) test rule, which unless 
otherwise noted in the regulatory text would incorporate EPA's generic 
procedures applicable to TSCA section 4(a) test rules (contained within 
40 CFR part 790), would fall into one of two groups, designated here as 
Tier 1 and Tier 2. Persons in Tier 1 (those who would have to initially 
comply with the final rule) would either: Submit to EPA letters of 
intent to conduct testing, conduct this testing, and submit the test 
data to EPA; or apply to and obtain from EPA exemptions from testing.
    Persons in Tier 2 (those who would not have to initially comply 
with the final rule) would not need to take any action unless they are 
notified by EPA that they are required to do so, as described in Unit 
IV.F.3.b. Note that persons in Tier 1 who obtain exemptions and persons 
in Tier 2 would nonetheless be subject to providing reimbursement to 
persons who do actually conduct the testing, as described in Unit 
IV.F.4.
    a. Who would be in Tier 1 and Tier 2? All persons subject to the 
final rule would be considered to be in Tier 1 unless they fall within 
Tier 2. The table in this unit describes who is in Tier 1 and Tier 2.

   Table 2.--Persons Subject to the Rule: Persons in Tier 1 and Tier 2
------------------------------------------------------------------------
  Tier 1 (Persons initially required to    Tier 2 (Persons not initially
                 comply)                        required to comply)
------------------------------------------------------------------------
Persons who manufacture (as defined at     A. Persons who manufacture
 TSCA section 3(7)), or intend to           (as defined at TSCA section
 manufacture, a test rule subtance, and     3(7)) or intend to
 who are not listed under Tier 2            manufacture a test rule
                                            substance solely as one or
                                            more of the following:
                                           -As a byproduct (as defined
                                            at 40 CFR 791.3(c));
                                           -As an impurity (as defined
                                            at 40 CFR 790.3);
                                           -As a naturally occurring
                                            substance (as defined at 40
                                            CFR 710.4(b));
                                           -As a non-isolated
                                            intermediate (as defined at
                                            40 CFR 704.3);
                                           -As a component of a Class 2
                                            substance (as described at
                                            40 CFR 720.45(a)(1)(i));
                                           -In amounts of less than 500
                                            kilogram (kg) (1,100 lbs)
                                            annually (as described at 40
                                            CFR 790.42(a)(4)); or
                                           -In small quantities solely
                                            for research and development
                                            (as described at 40 CFR
                                            790.42(a)(5)).
                                           B. Persons who process (as
                                            defined at TSCA section
                                            3(10)) or intend to process
                                            a test rule substance (see
                                            40 CFR 790.42(a)(2)).
------------------------------------------------------------------------


    Under 40 CFR 790.2, EPA may establish procedures applying to 
specific test rules that differ from the generic procedures governing 
TSCA section 4(a) test rules in 40 CFR part 790. For purposes of this 
proposed rule, EPA is proposing to establish certain requirements that 
differ from those under 40 CFR part 790.
    In this proposed test rule, EPA has reconfigured the tiers in 40 
CFR 790.42. In addition to processors, manufacturers of less than 500 
kg (1,100 lbs) per year (``small-volume manufacturers''), and 
manufacturers of small quantities for research and development (``R&D 
manufacturers''), EPA has added the following persons to Tier 2: 
Byproduct manufacturers, impurity manufacturers, manufacturers of 
naturally occurring substances, manufacturers of non-isolated 
intermediates, and manufacturers of components