[Federal Register Volume 63, Number 192 (Monday, October 5, 1998)]
[Notices]
[Pages 53417-53423]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26630]


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ENVIRONMENTAL PROTECTION AGENCY

[OPPTS-53171; FRL-5771-6]


Proposed Category for Persistent, Bioaccumulative, and Toxic 
Chemical Substances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: EPA has grouped new chemical substances with similar 
structural and toxicological properties into working categories. These 
groupings enable the Toxic Substances Control Act (TSCA) section 
5(a)(1), Premanufacture Notice (PMN) submitters, and EPA reviewers to 
benefit from accumulated data and decisional precedents. The 
establishment of over 45 of these chemical categories has streamlined 
the process for Agency review of and regulatory follow-up on new 
chemical substances. Consistent with TSCA section 26(c), which allows 
EPA action under TSCA with respect to categories of chemical substances 
or mixtures, EPA is developing a category of persistent, 
bioaccumulative, and toxic (PBT) chemical substances. This notice 
solicits comments on proposed criteria for identifying PBT chemical 
substances and their supporting scientific rationale.


[[Page 53418]]


DATES: Written comments should be received on or before December 4, 
1998.
ADDRESSES: Comments may be submitted by regular mail, electronically, 
or in person. Please follow the detailed instructions for each method 
as provided in Unit I. of this document.

FOR FURTHER INFORMATION CONTACT: Susan B. Hazen, Director, 
Environmental Assistance Division (7408), Rm. E-531, Office of 
Pollution Prevention and Toxics, Environmental Protection Agency, 401 M 
St., SW., Washington, DC 20460, telephone: (202) 554-1404, TDD: (202) 
554-0551; e-mail: TSCA-H[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this notice apply to me?

    You may be potentially affected by this notice if you are or may in 
the future be a submitter of a Premanufacture Notice (PMN) under TSCA. 
Potentially affected categories and entities may include, but are not 
limited to:

------------------------------------------------------------------------
                                               Examples of Potentially
                 Category                         Affected Entities
------------------------------------------------------------------------
Chemical manufacturers or importers         Anyone who plans to
                                             manufacture or import a new
                                             chemical substance for a
                                             non-exempt commercial
                                             purpose is required to
                                             provide the EPA with a PMN
                                             at least 90 days prior to
                                             the activity. Any substance
                                             that is not on the TSCA
                                             Inventory is classified as
                                             a new chemical.
------------------------------------------------------------------------

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this table could also be 
affected. To determine whether you or your business is affected by this 
action, you should carefully examine the applicability provisions in 40 
CFR 720.22. If you have any questions regarding the applicability of 
this action to a particular entity, consult the technical person listed 
in the ``FOR FURTHER INFORMATION CONTACT'' section.

B. How can I get additional information or copies of support documents?

    1. Electronically. Electronic copies of this document are available 
from the EPA Home page at the Federal Register-Environmental Documents 
entry for this document under ``Laws and Regulations'' (http://
www.epa.gov/fedrgstr/).
    2. In person. The official record for this notice, as well as the 
public version, has been established under docket control number OPPTS-
53171 (including comments and data submitted electronically as 
described in Unit I.C.3. of this preamble). A public version of this 
record, including printed, paper versions of any electronic comments, 
which does not include any information claimed as Confidential Business 
Information (CBI), is available for inspection from 12 noon to 4 p.m., 
Monday through Friday, excluding legal holidays. The official record is 
located in the TSCA Nonconfidential Information Center, Rm. NE-B607, 
401 M St., SW., Washington, DC.

C. How and to whom do I submit comments?

    All comments must be identified by the docket control number OPPTS-
53171. You may submit comments through the mail, in person, or 
electronically:
    1. By mail. Submit written comments to: Document Control Office 
(7407), Office of Pollution Prevention and Toxics (OPPT), Environmental 
Protection Agency, 401 M St., SW., Rm. G-099, East Tower, Washington, 
DC 20460. The Document Control Office telephone number is (202) 260-
7093.
    2. In person. Deliver written comments to: Document Control Office 
in Rm. G-099, East Tower, Waterside Mall, 401 M St., SW., Washington, 
DC.
    3. Electronically. Submit your comments and/or data electronically 
to: [email protected]. Please note that you should not submit any 
information electronically that you consider to be CBI. Electronic 
comments must be submitted as an ASCII file avoiding the use of special 
characters and any form of encryption. Comment and data will also be 
accepted on disks in Wordperfect 5.1/6.1 or ASCII file format. 
Electronic comments on this notice may also be filed online at many 
Federal Depository Libraries.

D. How should I handle information that I believe is confidential?

    You may claim information that you submit in response to this 
document as confidential by marking any part or all of that information 
as CBI. Information so marked will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2. A copy of the 
comment that does not contain CBI must be submitted for inclusion in 
the public record. Information not marked confidential will be included 
in the public docket by EPA without prior notice.

II. New Chemicals Program

A. Overview of the PMN Process

    Under section 5(a) of TSCA, persons must notify EPA at least 90 
days before manufacturing or importing a new chemical substance for 
non-exempt purposes. A new chemical substance, as defined in section 
3(9) of TSCA, is any chemical that is not included on the Inventory 
compiled under section 8(b) of TSCA.
    Section 5 of TSCA gives EPA 90 days to review a PMN. However, the 
review period can be extended under TSCA section 5(c) for ``good 
cause''; it may also be suspended voluntarily by the mutual consent of 
EPA and the PMN submitter. During the review period, EPA may take 
action under TSCA section 5(e) or (f) to prohibit or limit the 
production, processing, distribution in commerce, use, and disposal of 
new chemical substances that raise health or environmental concerns. If 
EPA has not taken action under TSCA section 5(e) or (f), the PMN 
submitter may manufacture or import the new chemical substance when the 
review period expires.
    No later than 30 days after the PMN submitter initiates 
manufacturing or importing, it must provide EPA with a notice of 
commencement of manufacture or import. Section 8(b) of TSCA provides 
that, upon receipt of such a notice, EPA must add the substance to the 
TSCA Inventory. Thereafter, other manufacturers and importers may 
engage in activities involving the new substance without submitting a 
PMN.

B. Actions under TSCA Sections 5(e) and (f)

    Section 5(e) of TSCA authorizes EPA to control commercial 
activities involving a new chemical substance for which available 
information is insufficient to permit a reasoned evaluation of 
potential health and environmental effects if EPA determines either 
that:
    1. The manufacture (including import), processing, distribution in 
commerce, use, or disposal of the substance may present an unreasonable 
risk of injury to health or the environment (``risk-based'' finding, 
under TSCA section 5(e)(1)(A)(ii)(I)).
    2. The substance is or will be produced in substantial quantities, 
and such substance either enters or may reasonably be anticipated to 
enter the environment in substantial quantities or there is or may be 
significant or substantial human exposure to the

[[Page 53419]]

substance (``exposure-based'' finding, under TSCA section 
5(e)(1)(A)(ii)(II)).
    The restrictions under TSCA section 5(e) are imposed pending the 
development of the test data or other information needed to evaluate 
the new substance's health or environmental effects.
    Section 5(f) of TSCA authorizes EPA to take action where it finds 
that there is a reasonable basis to conclude that the activities 
involving a new chemical substance will present an unreasonable risk of 
injury to health or the environment. If EPA makes such a determination, 
it may prohibit or limit manufacture (including import), distribution 
in commerce, processing, use, and disposal of the new substance to 
protect against the unreasonable risk.

C. EPA's Strategy under TSCA Section 5(e)

    On occasion, EPA may have concerns about a new chemical substance 
based on test data included in the PMN or obtained from other sources. 
However, because test data on PMN chemical substances are not required, 
EPA typically receives few PMNs that contain sufficient data on health 
or environmental effects, or on the potential to persist or 
bioaccumulate in the environment. As a result, the Agency often relies 
on computer models and structural or functional analogues as indicators 
of the potential toxicity and environmental fate of a PMN chemical 
substance.
    Due to the generally limited test data that are submitted or are 
otherwise available on a new chemical substance, EPA often identifies 
the substance for TSCA section 5(e) action because it is similar in 
molecular structure or function to other chemical substances known or 
suspected to have adverse health or environmental effects. These 
predictive methods, which estimate the properties of a chemical, e.g., 
melting point, vapor pressure, toxicity and ecotoxicity, on the basis 
of its structure, are referred to as Structure-Activity Relationships 
(SAR). A joint US/European Union (EU) study evaluated the predictive 
power of the SAR by applying SAR methods to chemical substances for 
which ``base set'' test data were already available and then comparing 
the properties predicted by SAR with the properties observed in 
laboratory testing. The available test data were part of a minimum pre-
market data set (MPD) submitted on chemical substances in the context 
of the notification scheme established in the EU. Analysis of the 
results of this study showed that while this SAR approach was largely 
successful in identifying chemical substances of concern, the process 
could be improved by selectively incorporating specific testing schemes 
into the process (USEPA, 1994, see Unit IV.1. of this preamble).
    As indicated in Unit II.B., during PMN review, EPA may determine 
that the available information is insufficient to permit a reasoned 
evaluation of the new chemical substance that is the subject of the 
PMN. At the same time, EPA may determine, under TSCA section 
5(e)(1)(A)(ii)(I), based on SAR analysis that activities involving the 
new substance ``may present an unreasonable risk of injury to health or 
the environment.'' When EPA makes both of these two findings, it acts 
under TSCA section 5(e) to regulate the activities involving the new 
substance which contribute to the potential risk. The new chemicals 
program determines the effectiveness of environmental release controls, 
consistency with existing chemical regulatory activity in the Agency, 
and the affordability of certain testing, etc. in formulating the 
appropriate regulatory response for each new chemical. In cases where a 
potential hazard is identified, EPA believes that it is appropriate to 
negotiate an order (known as a ``consent order'') under TSCA section 
5(e) with the PMN submitter to control human exposure and/or 
environmental releases until test data or other information sufficient 
to assess adequately the potential risk become available. Section 5(e) 
of TSCA ``risk-based'' consent orders have specified a variety of 
control measures, including protective equipment, use limitations, 
process restrictions, labeling requirements, and limits on 
environmental release. Some recent consent orders have included testing 
requirements that are triggered when specified levels of production 
volume or other indices of increased exposure are reached; under these 
orders, the submitter may not exceed the production volume limitation 
or any other restriction imposed by EPA until test data specified by 
EPA have been submitted to and reviewed by EPA.
    In other instances, during PMN review EPA may determine under TSCA 
section 5(e)(1)(A) (ii)(II) that a new substance will be produced in 
substantial quantities and ``may reasonably be anticipated to enter the 
environment in substantial quantities or there is or may be significant 
or substantial human exposure to the substance,'' and that the 
available information is insufficient to determine the effects of the 
substance. Since 1988, EPA has used internally developed guidelines to 
assist in identifying new chemical substances received as PMNs which 
would meet the TSCA section 5(e)(1)(A)(ii)(II) exposure-based finding 
(USEPA, 1988 and 1989, see Unit IV.2. and 3. of this preamble). Data 
received as a result of EPA's implementation of this exposure-based 
policy via TSCA section 5(e) consent orders have been used by EPA to 
better characterize the fate and effects of the new chemical, confirm 
or refute a prediction of low risk, and supplement and validate the use 
of SAR in the review of PMNs. These exposure-based guidelines capture 
all PMN chemical substances with estimated production volumes greater 
than or equal to 100,000 kilograms (kg) per year and exceeding specific 
exposure/release criteria. In some cases, however, where these 
thresholds are not met, it may be more appropriate to use a case-by-
case approach for making findings by applying other considerations 
(i.e., toxicity or physical/chemical properties). For reasons that have 
been articulated in the proposed statement of policy for TSCA section 
4(a)(1)(B) (July 15, 1991, 56 FR 32294), where persistence and 
bioaccumulation were used as examples, EPA may consider additional 
factors for making findings for substances which do not meet the 
numerical thresholds for evaluating new chemical substances under TSCA 
section 5(e)(1)(A)(ii)(II). Conversely, EPA may not take action under 
this TSCA section 5(e)(1)(A)(ii)(II) policy when the chemical substance 
meets the proposed criteria if EPA finds that existing data are 
sufficient to evaluate health or environmental effects of the new 
chemical substance, or that regulation and the development of 
information is not otherwise necessary.
    Exposure-based consent orders issued to address concerns under TSCA 
section 5(e)(1)(A)(ii)(II) include testing requirements, record keeping 
provisions, and production volume limits. The proposed PBT category 
criteria would impact EPA's development of both risk-based and 
exposure-based TSCA section 5(e) consent orders for new PBT chemical 
substances.

D. EPA's Use of Chemical Substance Categories in PMN Review and in 
Regulatory Decision Making under TSCA Section 5(e)

    In 1987, EPA grouped chemical substances with similar 
physicochemical, structural, and toxicological properties into working 
categories. Candidate categories for the new chemicals review process, 
such as the category being proposed today for PBT chemical substances, 
are proposed by new chemicals program staff based

[[Page 53420]]

on available data and experience reviewing PMNs on related substances. 
These groupings enable both PMN submitters and EPA reviewers to benefit 
from the accumulated data and decisional precedents. The first category 
defined by SAR was ``acrylates and methacrylates.'' Currently, there 
are over 45 categories, the detailed summaries of which can be found on 
the Internet at http://www.epa.gov/opptintr/newchms/chemcat.htm.
    The establishment of these categories has streamlined the process 
for Agency review of new chemical substances. As it gained experience 
with reviews of chemical substances in categories, EPA moved certain 
decisions for the category chemical substances to points much earlier 
in the 90-day PMN review period. One such point is the Focus Meeting, 
where exposure and hazard information about a PMN substance is first 
brought together for a risk management decision. If, for example, a new 
substance is identified as being a member of the proposed PBT chemical 
substances category, the chemical would be evaluated in the context of 
the potential health or environmental concerns associated with that 
category.
    The Agency recommends that regulatory action be taken under TSCA 
section 5(e) to control potential risks to health or the environment on 
about 10 percent of the approximately 2,000 PMNs submitted yearly. Only 
2-3 percent of the total number of PMNs submitted (20-30 percent of the 
above 10 percent) now undergo a detailed review that takes most of the 
standard 90-day PMN period, while the remaining 7-8 percent are 
identified for expedited review by virtue of them being members of the 
new chemicals program chemical categories. In response to pending 
regulatory action by the Agency, half of this 10 percent total are 
voluntarily withdrawn by PMN submitters.

E. New Chemical Significant New Use Rules (SNURs)

    TSCA section 5(e) consent orders (as described in Unit II.C.) apply 
only to PMN submitters. When a PMN submitter commences commercial 
manufacture of the substance and submits a Notice of Commencement of 
Manufacture to EPA, EPA adds the substance to the TSCA Chemical 
Substance Inventory maintained pursuant to section 8(b) of TSCA. When a 
substance is listed on the Inventory, it is no longer a ``new chemical 
substance'' for which a PMN would be required. Thus, other persons 
would be able to manufacture, import, or process the substance without 
EPA review and without the restrictions imposed on the PMN submitter by 
the TSCA section 5(e) consent order.
    In addition to consent orders issued under section 5(e) of TSCA 
regulating the PMN submitter, EPA uses its Significant New Use Rule 
(SNUR) authority under TSCA section 5(a)(2) to extend limitations in 
TSCA section 5(e) consent orders to other manufacturers, importers, and 
processors of the PMN substance. Section 5(a)(2) of TSCA (15 U.S.C. 
2604(a)(2)) authorizes EPA to determine that a use of a chemical 
substance is a ``significant new use.'' EPA must make this 
determination in a SNUR after considering relevant information about 
the toxicity of the substance and the 4 factors listed in section 
5(a)(2) of TSCA (projected production volume, the extent to which a use 
changes the type or form of exposure to the chemical substance, the 
extent to which a use changes the magnitude and duration of exposure to 
the chemical substance, and the reasonably anticipated manner and 
methods of manufacturing, processing, distribution in commerce, and 
disposal of the chemical substance). EPA designates the significant new 
uses of each chemical substance based on these considerations. Once EPA 
determines that a use of a chemical substance is a significant new use, 
section 5(a)(1)(B) of TSCA requires persons to submit a notice to EPA 
at least 90 days before they manufacture, import, or process the 
substance for that use. The required notice provides EPA with the 
opportunity to evaluate the intended use, and if necessary, to prohibit 
or limit that activity before it occurs.
    EPA's use of its SNUR authority ensures that the original PMN 
submitters and subsequent manufacturers, importers, and processors are 
treated in an equivalent manner. These SNURs are framed so that non-
compliance with the control measures or other restrictions in the TSCA 
section 5(e) consent orders is defined as a ``significant new use.'' 
Thus, other manufacturers, importers, and processors of the substances 
must either observe the SNUR restrictions or submit a significant new 
use notice to EPA at least 90 days before initiating activities that 
deviate from these restrictions. After receiving and reviewing such a 
notice, EPA has the option of either permitting the new use or acting 
to regulate the new submitter's activities.
    EPA also reviews some new chemical substances that do not warrant 
direct regulation of the PMN submitter under TSCA section 5(e) but 
merit other follow-up monitoring and evaluation. On the basis of test 
data or SAR analysis, EPA may identify potential health or 
environmental effects that could create a basis for concern if the 
substances exposure or release potential later changes or increases 
beyond that described in the PMN. In most of these cases, EPA believes 
it is appropriate to use SNUR authority to monitor the commercial 
development of these substances so that EPA can be apprised of 
significant increases in exposure potential, which may warrant control 
measures or testing.
    In addition to ensuring that all manufacturers, importers, and 
processors are subject to similar reporting requirements and 
restrictions, SNURs have the following additional objectives:
    1. EPA will receive notice of any company's intent to manufacture, 
import, or process a chemical substance listed on the TSCA Inventory 
for a significant new use before that activity begins.
    2. EPA will have an opportunity to review and evaluate data 
submitted in a SNUR notice before the notice submitter begins 
manufacturing, importing, or processing a listed chemical substance for 
a significant new use.
    3. When necessary, EPA will be able to take regulatory action under 
TSCA section 5(e), 5(f), 6, or 7 to control the activities for which it 
received a SNUR notice before a significant new use of that substance 
occurs.

III. EPA's PBT Chemical Substances Initiative

A. Background

    PBT chemical substances possess characteristics of persistence (P) 
in the environment, accumulation in biological organisms 
(bioaccumulation (B)), and toxicity (T) that make them priority 
pollutants and potential risks to humans and ecosystems. Prominent 
examples of PBT chemical substances include DDT and polychlorinated 
biphenyls (PCBs). Consistent with TSCA section 26(c), which allows EPA 
action under TSCA with respect to categories of chemical substances or 
mixtures, EPA is developing a category of persistent, bioaccumulative, 
and toxic (PBT) chemical substances. The category being proposed is for 
the purposes of facilitating the assessment of new chemical substances 
under TSCA section 5(e) prior to their entry into the marketplace.
    The proposed category description draws upon ongoing international 
efforts (e.g., the U.S.-Canada Binational Strategy for virtual 
elimination of PBTs; the North American Free Trade

[[Page 53421]]

Agreement (NAFTA) Commission for Environmental Cooperation negotiations 
on Persistent Organic Pollutants (POPs); the United Nations Economic 
Commission for Europe (UNECE) convention on Long-Range Transboundary 
Air Pollution (LRTAP); and the POPs Initiative under the United Nations 
Environment Programme (UNEP)) as well as Agency efforts (e.g., the 
Waste Minimization Prioritization Tool (WMPT)) to craft a coordinated 
and scientifically supportable approach to identifying PBT chemical 
substances. In particular, the proposed category is viewed by the 
Agency as furthering the objectives of UNECE's convention on LRTAP, 
Article 7, paragraphs 2 (b) and (c), which state that ``Each Party 
shall....encourage the implementation of other management programmes to 
reduce emissions of persistent organic pollutants'' and ``consider the 
adoption of additional policies and measures as appropriate in its 
particular circumstances'' (UNECE-LTRAP, 1998, see Unit IV.4. of this 
preamble).
    The proposed PBT category reflects the exchange of information 
across offices within EPA and results, in part, from the opportunity 
for programs to collaborate and complement each other's work. The 
category statement includes the boundary conditions, such as fish 
bioconcentration/bioaccumulation factors and environmental persistence 
values, that would determine inclusion in (or exclusion from) the 
category, and standard hazard and fate tests to address P, B, and T 
concerns for the chemical substances fitting the category description.
    It should be noted that the Agency is separately considering lower 
manufacture, processing, and ``otherwise use'' reporting thresholds for 
PBT chemical substances subject to reporting under the Emergency 
Planning and Community Right-To-Know Act (42 U.S.C. 11023), section 313 
or Toxic Chemical Release Inventory (TRI) program. Rather than rely 
exclusively on statutorily separate, single-medium approaches to 
address these pollutants, an Agency-wide PBT Strategy is presently 
being developed and implemented. The PBT Strategy coordinates the 
efforts being made by various EPA offices on PBT chemical substances 
and directs them in a targeted fashion to chemical substances that may 
present the greatest health and environmental risks. Establishment of 
this category would thus provide a vehicle by which the Agency may 
gauge the flow of PBT chemical substances through the TSCA new 
chemicals program and measure the results of its risk screening and 
risk management activities for new chemical members of this category of 
chemical substances as one component in the Agency's overall PBT 
initiative.

B. Proposed Evaluation Criteria and Process for PBT Chemical Substances

    Generally, persistent bioaccumulators are chemical substances that 
partition to water, sediment, or soil and are not removed at rates 
adequate to prevent their bioaccumulation in aquatic or terrestrial 
species (Veith et al., 1979, see Unit IV.5. of this preamble). EPA is 
proposing the following specific identification criteria and associated 
process for use in evaluating new chemical substances.

         New Chemicals Program PBT Category Criteria and Process
------------------------------------------------------------------------
                                           TSCA Section 5 Action
                                 ---------------------------------------
                                      5(e) Order/
                                    Significant New       Ban Pending
                                   Use Rule (SNUR)1        Testing2
------------------------------------------------------------------------
Persistence (transformation half- > 2 months........  > 6 months
 life).
Bioaccumulation (Fish BCF or       1000..   5000
 BAF)3.
Toxicity........................  Develop toxicity    Develop toxicity
                                   data where          data where
                                   necessary4.         necessary4
------------------------------------------------------------------------
1Exposure/release controls included in order; testing required.
2Deny commercialization; testing results may justify removing chemical
  from ``high risk concern''.
3Chemicals must also meet criteria for MW (< 1000) and cross-sectional
  diameter (< 20A , or < 20  x  10-8 cm).
4Based upon various factors, including concerns for P, B, other physical/
  chemical factors, and predicted toxicity.

    The half-life/persistence criterion for aquatic environments of > 2 
months is the same as that proposed under the UNECE-LRTAP negotiations 
(UNECE-LRTAP, 1997, see Unit IV.6. of this preamble). It represents a 
chronic exposure to aquatic organisms, as well as approximating the 
duration of some standard bioconcentration (28-56 days) and chronic 
toxicity (14-90 days) tests, and is therefore thought to be adequate 
for detecting many long-term toxic effects as well as any tendency for 
a substance to accumulate in fatty tissue of aquatic organisms. The 
bioconcentration or bioaccumulation factor (BCF/BAF) measures the 
potential for a chemical to accumulate in living organisms relative to 
its concentration in the surrounding environment. BCF/BAF is estimated 
using calculations based on octanol-water partition coefficients (Kow), 
although data can also be provided from field or laboratory 
measurements (Spacie et al., 1995, see Unit IV.7. of this preamble). 
Chemical substances having a BCF or BAF > 1000 are characterized by a 
tendency to accumulate in organisms (Smrchek et al., 1998, Zeeman, 
1995, Smrchek et al., 1993, see Unit IV.8., 9., and 10. of this 
preamble). The relationship between BCF/BAF and log Kow, which is a 
complex one above log Kow = 7, is discussed by several authors (Fisk et 
al., 1998, Bintein et al., 1993, Gobas et al., 1989, Mackay et al., 
1996, see Unit IV.11., 12., 13., and 14. of this preamble).
    Chemical substances meeting the persistence criterion of > 6 months 
and the bioaccumulation criterion of  5000 have properties 
consistent with substances widely acknowledged to be persistent, 
bioaccumulative, and toxic (e.g., DDT, PCBs, and other chemical 
substances identified as persistent organic pollutants during 
negotiations on LRTAP) and, as such, are accorded an appropriate level 
of concern. Other support for this higher tier can be found in the 
Chemical Manufacturers Association's (CMA's) product risk management 
guidance for PBT chemical substances (Chemical Manufacturers 
Association, 1996, see Unit IV.15. of this preamble). This guidance, 
which underscores CMA's commitment to the principles of the industry's 
Responsible Care initiative, cites these P and B criteria as 
benchmarks in the screening process for PBT chemical substances.
    Releases to all environmental media, such as air emissions from 
stacks, wastes disposed of in landfills or on land, and waste 
discharged into water, will be factored into the Agency's determination 
of potential risk posed by a given PMN chemical substance's total 
environmental load. In making this determination of potential risk the 
Agency may employ multimedia fate models, such as the Environmental 
Quality Criteria (EQC) model (Mackay, 1982, see Unit IV.16. of this 
preamble), in order to account for all potential sources and loadings, 
environmental transformation processes, and intermedia partitioning, in 
an integrated fashion. EPA solicits comments on this approach.
    Chemical substances characterized as suspected persistent 
bioaccumulators may need to undergo testing on ``P'' and ``B'' 
endpoints which, if confirmed, would be followed by appropriate

[[Page 53422]]

toxicity testing to identify ``PBT chemical substances.'' Control 
action under TSCA section 5(e) may be needed in varying degrees, based 
upon level of risk concern. The ``ban'' criteria are equivalent to 
those that have been used internationally to identify PBT substances. 
Agency control actions taken under TSCA section 5(e) for chemical 
substances meeting these criteria would be based upon the level of 
certainty for the PBT properties of a PMN substance (e.g., measured vs. 
estimated values), the magnitude of Agency concerns, and conditions of 
expected use and release of the chemical. For example, new chemical 
substances meeting the PBT criteria listed under ``TSCA Section 5(e) 
Consent Order/Significant New Use Rule (SNUR)'' could be addressed via 
a negotiated consent agreement under which necessary testing is 
``triggered'' by specific production limits. While the PMN submitter 
would be allowed to commercialize the substance, certain controls could 
be stipulated, including annual TRI-type reporting on environmental 
releases of the PMN substance and specific limits on exposures, 
releases, or uses. For the chemical substances meeting the criteria 
listed under ``Ban Pending Testing,'' the concern level is higher and 
the Agency would look carefully at any and all environmental releases. 
Because of the increased concern, more stringent control action would 
be a likely outcome, up to a ban on commercial production until data 
are submitted which allow the Agency to determine that the level of 
risk can be appropriately addressed by less restrictive measures. The 
described control actions represent just one body of possible decisions 
and should not be considered as exclusive of other risk management 
options.

C. Testing Strategy for PBT Chemical Substances

    Where EPA is unable to adequately determine the potential for 
bioaccumulation, persistence in the environment, and toxicity which may 
result from exposure of humans and environmental organisms to a 
possible PBT chemical substance, the Agency may conclude pursuant to 
sections 5(e)(1)(A)(I) and 5(e)(1)(A)(ii)(I) and (II) of TSCA that the 
information available to the Agency is insufficient to permit a 
reasoned evaluation of the human health and environmental effects of 
that PMN substance. The manufacturing, processing, distribution in 
commerce, use, or disposal of the substance may present an unreasonable 
risk of injury to human health or the environment and/or that the PMN 
substance will be produced in substantial quantities and there may be 
significant or substantial human exposure to the substance, or the PMN 
substance may reasonably be anticipated to enter the environment in 
substantial quantities. Accordingly, the Agency may find it appropriate 
to prohibit a company from manufacturing, importing, processing, 
distributing in commerce, using, or disposing of the PMN substance in 
the United States pending the development of information necessary for 
a reasoned evaluation of these effects. The following testing strategy 
describes test data which, if not otherwise available, EPA believes are 
needed to evaluate the potential persistence, bioaccumulation, and 
toxicity of a PBT chemical substance for which EPA has made the 
described risk and/or exposure-based findings under section 
5(e)(1)(A)(I) and (ii) of TSCA. The tests are tiered; depending upon 
the circumstances, such as magnitude of environmental releases, results 
of testing, or SAR, testing could begin above Tier 1 or additional, 
higher levels of testing may be required.
    Tier 1. If, based upon SAR and professional judgment, the Agency 
identifies a new chemical substance as a possible PBT chemical 
substance, Log Kow should be determined experimentally, using either 
the liquid chromatography (OPPTS 830.7570 test guideline) or generator 
column (OPPTS 830.7560 test guideline) method. Ready biodegradability 
should be determined according to either one of the following test 
guidelines:
    1. Ready biodegradability (OPPTS 835.3110 test guideline) 6 methods 
(choose one): DOC Die-Away, CO2 Evolution, Modified MITI 
(I), Closed Bottle, Modified OECD Screening, Manometric Respirometry.
    2. Sealed-vessel CO2 production test (OPPTS 835.3120 
test guideline).
    3. Hydrolysis in water (OPPTS 835.2110 test guideline) should be 
determined if, based upon SAR, susceptibility to hydrolysis is 
suspected.
    If the measured log Kow is < 3.5 or if the test chemical passes 
(pass criteria are described in the test guidelines) the ready 
biodegradability test (i.e., not persistent in the environment), no 
further PBT-related testing is required. If the measured log Kow is 
 3.5, the chemical does not pass the ready biodegradability 
test, and no further testing is deemed necessary in tier 1; the 
chemical would require tier 2 testing. If hydrolysis testing is 
conducted and results in a half-life of < 60 days, further testing may 
not be needed, but the need for testing must be determined after 
consideration of factors specific to the case, such as physical/
chemical properties, persistence and bioaccumulative qualities of 
hydrolysis products, and the nature of the expected releases.
    Tier 2. Biodegradability should be determined according to the 
Shake-flask die-away test (OPPTS 835.3170 test guideline) or an 
equivalent test. This test is based on the principle of aerobic 
incubation of the test chemical in natural water with and without 
suspended sediment, requires a chemical-specific analytical method, and 
allows for the development of a first-order rate constant and half-
life. It provides information on persistence that is relevant to the 
natural environment and is intermediate in cost between ready 
biodegradability tests (tier 1) and aquatic microcosms (tier 3).
    Bioaccumulation potential should be determined by experimental 
measurement of the bioconcentration factor (BCF), using the Fish 
bioconcentration test (OPPTS 850.1730 test guideline (public draft)). 
Measured BCF should be based on 100 percent active ingredient and 
measured concentration(s).
    If the measured biodegradation half-life is > 60 days and measured 
BCF is > 1000, tier 3 testing will be required. If only one condition 
is met, releases and exposure are further considered to determine if 
additional testing is required.
    Tier 3. Toxicity/advanced environmental fate testing. Human health 
hazards should be determined in the combined repeated dose oral 
toxicity with the reproductive/developmental toxicity screening test 
(Organization for Economic Cooperation and Development (OECD) guideline 
no. 422) in rats. Other health testing will be considered where 
appropriate.
    Environmental fate testing should be conducted according to the 
Sediment/water microcosm biodegradation test (OPPTS 835.3180 test 
guideline). The principle of this method is the determination of the 
test chemical's fate, including transport and transformation, in core 
chambers containing intact benthic sediment and overlying site water. 
The method permits more accurate and reliable extrapolation to natural 
aquatic environments than is possible with lower tier test methods.
    Chronic toxicity to fish (rainbow trout) and daphnids should be 
determined according to 40 CFR 797.1600 and 40 CFR 797.1330, 
respectively. Additional testing to evaluate other biota (e.g., avian, 
sediment dwelling organisms) or other effects (e.g., endocrine 
disrupting

[[Page 53423]]

potential) will be considered where appropriate.

IV. References

    The OPPTS harmonized test guidelines referenced in this document 
are available on EPA's World Wide Web site (http://www.epa.gov/epahome/
research.htm) under the heading ``Test Methods and Guidelines/OPPTS 
Harmonized Test Guidelines.''
    1. USEPA. March, 1994. U.S. EPA/EC Joint Project on the Evaluation 
of (Quantitative) Structure Activity Relationships. EPA 743-R-94-001.
    2. USEPA. 1988. Implementation Proposal; ``New Chemicals Exposure-
Based Finding,'' letter from Charles L. Elkins to Geraldine V. Cox 
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA 
(September 22, 1988).
    3. USEPA. 1989. ``EPA's Exposure-Based Policies under Section 5 of 
TSCA,'' letter from Charles L. Elkins to Geraldine V. Cox (Chemical 
Manufacturers Association). Office of Toxic Substances, USEPA (August 
31, 1989).
    4. UNECE-LRTAP. 1998. Draft protocol to the convention on long-
range transboundary air pollution on persistent organic pollutants. 
United Nations Economic Commission for Europe. EB.AIR/1998/2; 31 March 
1998.
    5. Veith, G.D., DeFoe, D.L. and Bergstedt, B.V. 1979. Measuring and 
estimating the bioconcentration factor of chemicals in fish. J. Fish. 
Res. Board Can. 36:1040-1048.
    6. UNECE-LRTAP. 1997. Draft composite negotiating text for a 
protocol on persistent organic pollutants. United Nations Economic 
Commission for Europe. EB.AIR/WG.5/R.72/Rev.1; 22 July 1997.
    7. Spacie, A., McCarty, L.S. and G.M. Rand. 1995. Bioaccumulation 
and bioavailability in multiphase systems, pp. 493-521. In, G.M. Rand 
(ed.), Fundamentals of Aquatic Toxicology, 2nd. ed. Taylor Francis 
Publishers, Washington, DC.
    8. Smrchek, J.C. and M.G. Zeeman. 1998. Assessing Risks to 
Ecological Systems from Chemicals, pp. 24-90. In, P. Calow (ed.), 
Handbook of Environmental Risk Assessment and Management, Blackwell 
Science Ltd., Oxford, UK.
    9. Zeeman, M.G. 1995. Ecotoxicity Testing and Estimated Methods 
Developed Under Section 5 of the Toxic Substances Control Act (TSCA), 
pp. 703-715. In, Rand (ed.), Fundamentals of Aquatic Toxicology, 2nd. 
ed. Taylor Francis Publishers, Washington, DC.
    10. Smrchek, J.C., Clements, R., Morcock, R., and W. Rabert. 1993. 
Assessing Ecological Hazard Under TSCA: Methods and Evaluation of Data, 
pp. 22-39. In, W.G. Landis, J.S. Hughes, and M.L. Lewis (eds.), 
Environmental Toxicology and Risk Assessment, ASTM STP 1179, American 
Society for Testing and Materials, Philadelphia, PA.
    11. Fisk, A.T., Norstrom, R.J., Cymbalisty, C.D., Muir, D.C.G. 
1998. Dietary accumulation and depuration of hydrophobic 
organochlorines: bioaccumulation parameters and their relationship with 
the octanol/water partition coefficient. Environ. Toxicol. Chem. 
17:951-961.
    12. Bintein, S., Devillers, J. and Karcher, W. 1993. Nonlinear 
dependence of fish bioconcentration on n-octanol/water partition 
coefficient. SAR and QSAR in Environ. Research 1:29-39.
    13. Gobas, F.A.P.C., Clark, K.E., Shiu, W.Y., Mackay, D. 1989. 
Bioconcentration of polybrominated benzenes and biphenyls and related 
superhydrophobic chemicals in fish: role of bioavailability and 
elimination into the feces. Environ. Toxicol. Chem. 8:231-245.
    14. Mackay, D., Di Guardo, A., Paterson, S., Cowan, C.E. 1996. 
Evaluating the environmental fate of a variety of types of chemicals 
using the EQC model. Environ. Toxicol. Chem. 15:1627-1637.
    15. Chemical Manufacturers Association. 1996. PTB Policy 
Implementation Guide. Product Risk Management Guidance for PTBs. 
Arlington, VA.
    16. Mackay, D. 1982. Correlation of bioconcentration factors. 
Environ. Sci. Technol. 16:274-278.

List of Subjects

    Environmental protection, Chemical, Hazardous substances, Reporting 
and recordkeeping requirements

Dated: September 24, 1998.

Lynn R. Goldman,

Assistant Administrator, Office of Prevention, Pesticides and Toxic 
Substances.

[FR Doc. 98-26630 Filed 10-5-98; 8:45 am]
BILLING CODE 6560-50-F