[Federal Register Volume 64, Number 213 (Thursday, November 4, 1999)]
[Notices]
[Pages 60194-60204]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-28888]


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ENVIRONMENTAL PROTECTION AGENCY

[OPPTS-53171A; FRL-6097-7]


Category for Persistent, Bioaccumulative, and Toxic New Chemical 
Substances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Policy statement.

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SUMMARY: EPA groups new chemical substances with similar structural and 
toxicological properties into categories to facilitate premanufacture 
assessment and regulation. These groupings enable both Toxic Substances 
Control Act (TSCA) section 5(a)(1) Premanufacture Notice (PMN) 
submitters and EPA reviewers to benefit from accumulated data and 
decisional precedents and have 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 
issuing this policy statement regarding a category of persistent, 
bioaccumulative, and toxic (PBT) new chemical substances.

DATES: This document will become effective January 3, 2000.

FOR FURTHER INFORMATION CONTACT: For general information contact: 
Christine Augustyniak, Associate Director, Environmental Assistance 
Division (7408), Office of Pollution Prevention and Toxics, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460; 
telephone numbers: 202-554-1404 and TDD: 202-554-0551; e-mail address: 
TSCA-H[email protected].
    For technical information contact: Kenneth Moss, Chemical Control 
Division (7405), Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460; telephone number: 202-260-3395; fax number: 202-
260-0118; e-mail address: [email protected].

SUPPLEMENTARY INFORMATION: On October 5, 1998 (63 FR 53417) (FRL-5571-
6), EPA published a Federal Register notice soliciting comments on 
proposed criteria for identifying PBT chemical substances and their 
supporting scientific rationale. This policy statement responds to 
comments on the proposed criteria for identifying PBT new chemical 
substances and their supporting scientific rationale. Please consult 
the October 5, 1998 (63 FR 53417) Federal Register notice for further 
information on the TSCA new chemicals program. The docket control

[[Page 60195]]

number for this document is OPPTS-53171A.

I. General Information

A. Does This Document Apply to Me?

    You may be potentially affected by this document if you are or may 
in the future be a submitter of a PMN under TSCA. Potentially affected 
entities may include, but are not limited to the following:


----------------------------------------------------------------------------------------------------------------
                                                                                       Examples of Potentially
              Category                     NAICS Code               SIC Codes             Affected Entities
----------------------------------------------------------------------------------------------------------------
Chemical manufacturers or importers  325, 32411              28, 2911                Anyone who plans to
                                                                                      manufacture or import a
                                                                                      new chemical substance (as
                                                                                      defined in TSCA Section 3)
                                                                                      for a non-exempt
                                                                                      commercial purpose is
                                                                                      required to provide the
                                                                                      EPA with a PMN at least 90
                                                                                      days prior to the
                                                                                      activity. Any TSCA
                                                                                      chemical substance that is
                                                                                      not on the TSCA Inventory
                                                                                      is classified as a new
                                                                                      chemical. New chemical
                                                                                      substances submitted by
                                                                                      chemical manufacturers or
                                                                                      importers as PMNs and
                                                                                      which are determined by
                                                                                      EPA to meet the PBT
                                                                                      criteria described here
                                                                                      may be subject to
                                                                                      regulatory controls under
                                                                                      TSCA section 5(e).
----------------------------------------------------------------------------------------------------------------

    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
document. Other types of entities not listed above could also be 
affected. The four-digit Standard Industrial Classification (SIC) codes 
or the six-digit North American Industrial Classification System 
(NAICS) codes have been provided to assist you and others in 
determining whether or not this document might apply to certain 
entities. To determine whether you or your business is affected by this 
document, you should carefully examine the applicability provisions in 
40 CFR 720.22. If you have any questions regarding the applicability of 
this document to a particular entity, consult the technical person 
listed in the ``FOR FURTHER INFORMATION CONTACT'' section.

B. How Can I Get Additional Information, Including Copies of This 
Document and Other Related Documents?

    1. Electronically. You may obtain copies of this document from the 
EPA Internet Home Page at http://www.epa.gov/. On the Home Page select 
``Laws and Regulations'' and then look up the entry for this document 
under the ``Federal Register - Environmental Documents.'' You can also 
go directly to the ``Federal Register'' listings at http://www.epa.gov/
fedrgstr/. To access information about the TSCA New Chemicals Program, 
go directly to the Home Page for the New Chemicals Program, within the 
Office of Pollution Prevention and Toxics, at http://www.epa.gov/
opptintr/newchms/.
    2. In person. The Agency has established an official record for 
this document under docket control number OPPTS-53171A. The official 
record consists of the documents specifically referenced in this 
document, any public comments received during an applicable comment 
period, and other information related to this document, including any 
information claimed as Confidential Business Information (CBI). This 
official record includes the documents that are physically located in 
the docket, as well as the documents that are referenced in those 
documents. The public version of the official record does not include 
any information claimed as CBI. The public version of the official 
record, which includes printed, paper versions of any electronic 
comments submitted during an applicable comment period, is available 
for inspection in the TSCA Nonconfidential Information Center, Rm. NE 
B-607, Waterside Mall, 401 M St., SW., Washington, DC. The Center is 
open from 12 noon to 4 p.m., Monday through Friday, excluding legal 
holidays. The telephone number of the Center is 202-260-7099.
    3. By phone. If you need additional information about this 
document, you may also contact the person identified in the ``FOR 
FURTHER INFORMATION CONTACT'' section.

II. Background

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 substance (as defined by section 3(2)) 
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 (also referred 
to as a ``section 5 notice''). 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, unless the Agency has used its Significant New Use Rule (SNUR) 
authority under TSCA section 5(a)(2) to designate a use of a chemical 
substance as a ``significant new use.'' Section 5(a)(1)(B) of TSCA 
would then require persons to submit a Significant New Use Notice 
(SNUN) to EPA at least 90 days before they manufacture, import, or 
process the substance for the use designated as significant. The 
required SNUN provides EPA with the opportunity to evaluate the 
intended use, and if necessary, to prohibit or limit that activity 
before it occurs.

B. History

    Since 1979, EPA has reviewed over 30,000 TSCA section 5 submissions 
for new chemical substances. During the intervening years, EPA has 
implemented various initiatives which have enabled the Agency to review 
a greater number of new chemicals more

[[Page 60196]]

efficiently. In 1988, for example, EPA's Office of Toxic Substances 
(now the Office of Pollution Prevention and Toxics) first used its 
accumulated experience to group chemical substances with similar 
physicochemical, structural, and toxicological properties into working 
categories (USEPA, 1988, see Unit VI.8.). These categories, including 
the subject one for PBT chemical substances, are developed by EPA based 
on available data and experience reviewing PMNs on similar substances. 
Such groupings enable both PMN submitters and EPA reviewers to benefit 
from the accumulated data and decisional precedents and facilitates the 
assessment of new chemical substances.
    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 the insecticide DDT and 
polychlorinated biphenyls (PCBs).
    Establishment of a PBT category alerts potential PMN submitters to 
possible assessment or regulatory issues associated with PBT new 
chemicals review. It also provides 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 PBT new chemical substances; as such, it 
is a major element in the Agency's overall strategy to further reduce 
risks from PBT pollutants.
    As described in the Federal Register notice of October 5, 1998 (63 
FR 53417), development of the TSCA new PBT chemicals policy has 
occurred in coordination with U.S. national, U.S./Canada binational, 
and international efforts to identify and control the environmental 
release of persistent organic pollutants (POPs). The proposed TSCA PBT 
category has been provided to the Criteria Expert Group (CEG) 
established at the first session of the Intergovernmental Negotiating 
Committee (INC) for an International Legally Binding Instrument for 
Implementing International Action on Certain Persistent Organic 
Pollutants, in accordance with the mandate given by the Governing 
Council of the United Nations Environment Programme (UNEP) in paragraph 
9 of its decision 19/13 C (http://irptc.unep.ch/pops/
gcpops-e.html). The CEG is an open-ended technical working 
group with a mandate to present to the INC proposals for science-based 
criteria and a procedure for identifying additional POPs as candidates 
for future international action. The CEG is to incorporate criteria 
pertaining to persistence, bioaccumulation, toxicity and exposure in 
different global regions and should take into account the potential for 
regional and global transport, including dispersion mechanisms for the 
atmosphere and the hydrosphere, migratory species, and the need to 
reflect possible influences of marine transport and tropical climates. 
At its first meeting, October 26-30, 1998 in Bangkok, the CEG 
recommended that the INC consider developing a provision encouraging 
countries and regions to include in their new chemicals schemes 
elements relating to development and introduction of new chemical POPs. 
The U.S. described its proposed TSCA new chemicals program policy for 
the category of PBT new chemicals, and the full text of the October 5, 
1998 Federal Register notice was distributed to all delegations as a 
Conference Room Paper. The CEG's recommendation was accepted at the 
second meeting of the INC (January 25-29, 1999 in Nairobi) and the INC 
will consider it further in its deliberations.
    This policy statement is important in our new chemical assessment 
and TSCA regulatory programs, and represents the first formal statement 
of national policy regarding new chemical ``persistent organic 
pollutants.'' Under our domestic program, the policy statement provides 
guidance criteria for persistence, bioaccumulation, and toxicity for 
new chemicals and advises the industry about our regulatory approach 
for chemicals meeting the criteria. Internationally, the Federal 
Register notice of October 5, 1998 (63 FR 53417) alerted the parties 
involved in negotiation of the POPs Convention to the need for 
inclusion of a new chemicals provision in the Convention. The issuance 
of the final policy statement will reaffirm US leadership on this issue 
and serve as a model for other countries in taking steps to discourage 
the introduction of POPs as new chemicals and pesticides.

III. Discussion of Final Policy Statement and Response to Comments

    Today's policy statement adopts the criteria and testing strategy 
of the Federal Register notice of October 5, 1998 (63 FR 53417), with 
minor revisions. The Agency reviewed and considered all comments 
received on the October 5, 1998 (63 FR 53417) notice. A complete copy 
of all comments received is available in the public docket for this 
document. A discussion of the policy statement, including a summary of 
significant comments and the Agency's response follows:

A. Pigments

    Comment 1-Pigments. Commenters suggested that EPA not identify 
pigments as bioaccumulators and were concerned that testing could end 
up being expensive for pigments, which are persistent by design.
    Response. EPA assesses PMN chemical substances for PBT attributes 
on a chemical-by-chemical basis, regardless of whether or not they fall 
into a chemical use category such as pigments. Not all pigments are the 
same and a precise definition of the term ``pigment'' is not available. 
As a result, EPA does not have general ``pigments'' or ``dyes'' 
assessment categories; there are, however, more specifically described 
categories of dyes or pigments that have been described by EPA (e.g., 
acid or amphoteric dyes, dichlorobenzidine-based pigments, and others; 
see categories document at http://www.epa.gov/opptintr/newchms/
chemcat.htm). Moreover, the fact that a substance is ``persistent by 
design'' by itself is not a sufficient basis for identifying a PBT new 
chemical substance. Persistence is only one of three criteria used to 
identify a chemical as PBT. When combined with a potential to 
bioaccumulate, toxicity concern, and sufficient release to the 
environment to result in potential risk or significant exposure, 
pigments may be of concern, whether or not they are persistent by 
design. If a PMN chemical is persistent by design, and becomes subject 
to testing requirements by EPA, it would be counterproductive to test 
initially for persistence, but rather to address the ``B'' and ``T'' 
criteria instead.

B. Ready Biodegradability Testing

    Comment 2-Ready biodegradability testing. Commenters suggested that 
EPA avoid the use of strict pass/fail criteria for ready 
biodegradability of poorly water-soluble substances.
    Response. Poor water solubility does not necessarily lead to 
inability to pass a ready biodegradability test, as amply demonstrated 
by the fact that many fats, oil, petroleum hydrocarbons, etc. easily 
pass ready biodegradability tests. While strict OECD (Organization for 
Economic Co-operation and Development) pass/fail criteria are given in 
the OPPTS Ready Biodegradability test guidelines (see http://
www.oecd.org//ehs/test/degrad.htm and Testing Strategy for PBT Chemical 
Substances, Unit IV.B. of this document), the Agency recognizes the 
limitations in applying such criteria

[[Page 60197]]

rigidly given that many substances of concern as potential PBTs are 
unlikely to pass ready biodegradability tests. A variety of critical 
aspects beyond the pass/fail result will be considered when evaluating 
potential new chemical PBTs or when testing decisions are made about 
specific PMN substances. These more critical aspects include those 
related to chemical structure (e.g., degree of branching) and 
bioavailability (e.g., uptake of a substance by fish or 
microorganisms), and their influence on both biodegradation and 
bioaccumulation.

C. Bioconcentration Factor and Kow

    Comment 3-Bioconcentration factor. Commenters requested 
clarification on how bioconcentration factor (BCF) will be estimated 
using calculations based on octanol-water partition coefficient.
    Response. The octanol-water partition coefficient (Kow) is 
correlated with the potential for a chemical to bioaccumulate in 
organisms; the BCF can be predicted from log Kow, via computer programs 
based on structure activity relationship (SAR). The Agency process for 
predicting bioaccumulation factors (BAFs) and BCFs, along with 
literature references, is described in some detail in the proposed rule 
for lowering of reporting thresholds for certain PBT toxic chemicals 
subject to reporting under section 313 (Toxic Release Inventory, or 
TRI) of the Emergency Planning and Community Right-to-Know Act (EPCRA) 
of 1986 (January 5, 1999 (64 FR 688) (FRL-6032-3), see page 704).
    Comment 4-Log Kow and low solubility chemicals. Commenters 
suggested that the October 5, 1998 (63 FR 53417) Federal Register 
notice identified methods for calculating log Kow that are not 
appropriate for organic pigments, which are insoluble in octanol. They 
wanted to know how EPA handles low octanol or water soluble chemicals.
    Response. EPA believes that the methods cited in the October 5, 
1998 (63 FR 53417) Federal Register notice for experimental measurement 
of the octanol/water partition coefficient (Kow), or SAR to predict 
Kow, are appropriate, and the results of either can then be used to 
predict the Fish BCF. Chemicals are unlikely to be accorded special 
treatment in the new chemicals review process solely because of low 
solubility in octanol or water alone. The test guidelines (OPPTS 
830.7570 or 830.7560) cited in the October 5, 1998 (63 FR 53417) 
Federal Register notice are viewed as the most appropriate for 
measuring Kow, and alternatively, the shake-flask method (OPPTS 
830.7550 test guideline) or the new ``slow-stir'' method currently 
under development by the OECD, can be used. However, if the chemical 
manufacturer still views these methods as inappropriate for a given 
chemical, it would be advisable to proceed to more definitive testing 
to address bioaccumulation potential (i.e., the Fish BCF study). This 
approach can be applied to other testing endpoints as well; for 
example, based on physicochemical properties of a particular PMN 
chemical substance, a company might forgo a lower tier acute Daphnia 
toxicity study in favor of the chronic study because it would yield the 
best information for the screening level risk assessment.
    Comment 5-Use of octanol solubility data alone. Commenters wanted 
to know if octanol or fat solubility data can be used before 
determining which chemical substances have the potential for 
bioaccumulation.
    Response. By itself, solubility in octanol (as a surrogate for fat) 
is not a good predictor of potential bioaccumulation in fish. Kow is 
correlated with the potential for a chemical to bioaccumulate in 
organisms; the bioconcentration factor (BCF) can be predicted from log 
Kow, via SAR. Kow is a coefficient which serves as a surrogate for the 
partitioning of chemicals between water and fat, and cannot be 
accurately estimated via separate determinations of solubility in pure 
octanol and water (i.e., by calculating the ratio of the pure-solvent 
solubilities) (Sijm et al., 1999, see Unit VI.1.). The Agency uses and 
recommends the use of computer models to predict Kow where there are no 
measured data.

D. Environmental Half-Life

    Comment 6-Calculation of half-life. Commenters wanted to know how 
half-life is calculated in the review of PBT new chemicals.
    Response. Multimedia fate models like the Environmental Quality 
Criteria (EQC) model (Mackay et al., 1996, see Unit VI.2.) require 
compartmental half-lives for air, water, soil and sediment, which 
cannot necessarily be interpreted as half-lives for any specific 
process such as biodegradation. Data on air half-lives for input to 
models would be either measured or derived from the Atmospheric 
Oxidation Program (AOP or AOPWIN) or similar methodology. Studies by 
Boethling et al. (1995, see Unit VI.3.) and Federle et al. (1997, see 
Unit VI.4.) suggest that half-lives in bulk soil may be assumed for 
screening purposes to be about the same as for surface water, and that 
sediment half-lives may be assumed to be 3-4 times longer. EPA's 
current suggested approach to finding water half-life is to use the 
Ultimate Survey Model (USM) in the EPI BIOWIN program (Boethling et 
al., 1994, see Unit VI.5.). Estimation of bulk compartment half-lives 
from USM model data requires several assumptions, including that (1) 
biodegradation is the only significant fate process in water, soil, 
sediment; (2) water and soil half-lives are the same; and (3) sediment 
is dominated by anaerobic conditions and therefore sediment half-life 
is four times longer than water half-life.

E. Computer Models and the Use of Models vs. Actual Data

    Comment 7-Use of models vs. actual data. Commenters support the use 
of the Mackay/EQC model, but stressed the importance of having a 
process for using actual data in place of the model.
    Response. This is a reasonable suggestion. The EQC model is based 
on the fugacity approach and subsequently applied to numerous 
environmental processes. It uses an ``evaluative environment'' in which 
environmental parameters such as bulk compartment dimensions and 
volumes (e.g., total area, volume of soil and sediment, etc.) are 
standardized, so that overall persistence for chemicals with different 
properties and rates of transformation may be compared on an equal 
basis. In general, measured values of toxicity, chemical properties, 
compartmental transformation half-lives, etc., provided the data are of 
acceptable quality, are preferred over those that are predicted or 
estimated via a model or computer program.
    Comment 8-Modeling of air releases. Commenters noted that the 
October 5, 1998 (63 FR 53417) Federal Register notice considered only 
biodegradation and aqueous hydrolysis and asked about fate of a 
chemical upon release to air. They suggested that EPA estimate 
atmospheric oxidation using AOPWIN.
    Response. Although the testing strategy for this policy statement 
focuses on biodegradability, all relevant transport and transformation 
processes will be considered in evaluating the potential for a PMN 
substance to behave as a PBT. Transformation processes not mentioned in 
the Federal Register notice but which may be important for specific PMN 
substances include atmospheric oxidation and photolysis, photolysis in 
water, and redox transformations (of which there are various types) in 
water, soil, and sediment. Although EPA believes that for most organic 
chemicals, biodegradation in water, soil, and sediment will be the most 
important

[[Page 60198]]

transformation process, each suspected PBT chemical substance will be 
evaluated on its use and disposal patterns.
    Clearly the atmosphere is an important environmental medium, and is 
especially relevant where a substance is emitted directly to the 
atmosphere or transported there via volatilization or aerosolization. 
We know by deduction that it is only, or at least chiefly, through the 
atmosphere that POPs like dioxins and Polychlorinated biphenyls (PCBs) 
reach remote locations, and it will be an important factor in 
determining the ultimate fate of many PMN substances as well. It is 
through multimedia fate models such as EQC that atmospheric fate will 
be considered in developing an overall prediction of environmental 
persistence for suspected PBT substances. Where measured data are not 
available, appropriate estimation methods such as that in the AOPWIN 
program will be used to generate screening-level estimates of 
atmospheric half-lives.

F. Use of ``Weight of Evidence'' and Professional Judgment

    Comment 9-Laboratory vs. field behavior of chemicals. Commenters 
indicated that EPA needs to incorporate any differences between lab and 
field behavior of chemicals into its analysis of new chemical 
substances, acknowledge the limitations of screening-level 
biodegradation tests, and acknowledge the value of using professional 
judgment when interpreting data from extended (> 60 day) degradation 
studies.
    Response. EPA recognizes that laboratory tests at best provide a 
snapshot of expected environmental behavior, which ideally is studied 
in the field. But since field testing is nearly always impractical for 
PMN chemical substances, it is necessary to conduct laboratory tests 
and to apply scientific judgment in extrapolating from lab to field. 
EPA similarly acknowledges the limitations of ready biodegradability 
and other screening tests as indicators of ultimate environmental 
behavior. Finally, it is well known that even this policy statement's 
higher tier (Testing Tiers 2 and 3) environmental fate guidelines, 
despite being designed to provide test conditions closer to those 
expected in the field, become less reliable when tests are run for 
longer than the maximum duration specified in the guidelines. EPA will 
give appropriate weight to these and other complexities in its 
assessments.
    Comment 10-``Check the box'' vs. ``weight of evidence.'' Commenters 
noted that the TSCA PMN requirements for PBT chemicals look more like 
``check-the-box'' than ``weight of evidence'' and wanted to know how 
EPA will make professional judgment and use SAR and assessment methods 
to identify PBT new chemicals.
    Response. These tools (professional judgment, SAR, computer models, 
assessment methods, etc.) would be applied to potential PBT chemical 
substances in the same way they are applied to any other chemical 
substance in the PMN review process. Using predictive tools (in the 
absence of test data) and professional judgment, EPA leans towards a 
``reasonable worst case'' when there is lack of chemical-specific data. 
Industry always has the option of assisting and enhancing the Agency's 
determinations by submitting scientifically valid test data. There are 
a number of existing documents describing the PMN process and the 
critical role played by SAR and professional judgment in that process, 
including the Chemistry Assistance Manual for Premanufacture 
Notification Submitters (USEPA, 1997, see Unit VI.6.) and parts of the 
report on the joint U.S./European Union study that evaluated the 
predictive power of the SAR (USEPA, 1994, see Unit VI.7.). EPA believes 
that, where no or insufficient actual toxicity data exist upon which to 
base a decision, toxicity estimates generated by SARs and other 
predictive techniques may constitute sufficient evidence to be used in 
human health and environmental hazard and environmental fate assessment 
as components in certain risk determinations under TSCA (see also the 
Federal Register of December 1, 1993 (58 FR 63507) for a similar 
statement related to meeting section 313 listing criteria under EPCRA 
of 1986).
    Comment 11-Implement PBT policy within risk assessment framework. 
Commenters suggested that EPA risk management decisions should not be 
made solely on hazard information; these PBT criteria should be 
implemented within a risk assessment framework. They indicated that 
toxicity has been largely overlooked in the PBT scheme and no criteria 
have been provided for toxicity. Commenters suggested that EPA needs to 
take into account P and B and T before requiring further testing or 
identifying a chemical as a ``true'' PBT, and asked whether persistence 
and log Kow would be sufficient to determine that a PBT PMN chemical 
substance may pose a significant risk. Commenters also suggest that EPA 
should except non-toxic and low exposure/release substances from 
consideration under this category and were concerned that the current 
proposed criteria do not consider any health and safety benefits of a 
PBT chemical substance.
    Response. New chemicals identified as potential PBT chemicals are 
assessed on a case-by-case basis. 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 (1) that 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), or (2) that 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 substance (``exposure-based'' finding). 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. EPA draws on 
information and data submitted with the PMN form, other information 
available to the Agency, and modeling (e.g., exposure, release, SAR, 
etc.).
    The Agency will consider P and B and T, individually and together, 
and exposure in making risk-based judgments. Risk, specific to the PMN 
substance as well as its risk relative to substitutes currently on the 
market, is predicted as a function of the potential hazard of the 
substance and the expected exposure. In other instances, as discussed 
in the October 5, 1998 (63 FR 53417) Federal Register notice, during 
PMN review EPA may determine 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. For such exposure-based determinations on suspected PBT new 
chemicals, EPA will use a case-by-case approach for making findings by 
applying considerations beyond P and B (i.e., toxicity or physical/
chemical properties), and consider P and B aspects as factors which 
might argue for regulatory action under TSCA section 5(e) at lower 
levels of production or exposure/release than are described in the 
general guidelines for the new chemicals program's

[[Page 60199]]

exposure-based policy (USEPA, 1988, USEPA, 1989, see Unit VI.8. and 
9.). Overall, companies are not being prevented from developing and 
using new substances that are judged to be potential PBT chemicals, but 
EPA may require certain controls (e.g., limiting the release of the PMN 
chemical to the environment) or testing as a result of its assessments.
    In order to be so identified as a PBT new chemical based on a risk-
based finding, all three criteria must be satisfied. The Agency has 
adopted a 1 to 3 rating system for each of P, B, and T. If chemical has 
a low Kow (i.e., ``B1,'' with BCF estimated as less than 1,000), the B1 
rating does not support the new chemical's identification as a 
potential ``PBT chemical.'' For example, some surfactants could be 
P3B1T3; they are highly persistent in the environment and chronically 
toxic to organisms, but with low bioaccumulation potential. However, 
Agency action may still be taken under TSCA on chemicals not meeting 
all of the PBT criteria, if they otherwise meet the risk or exposure-
based elements of TSCA section 5(e). Similarly, calcium would also not 
be considered a PBT chemical, as it would be ranked P3B3T1; it is 
persistent in the environment, it bioaccumulates, but it is not 
considered toxic. Although the Agency does not promote the 
environmental discharge of more persistent materials, the environmental 
``desirability'' of a given chemical often depends on a balance of 
various factors, including toxicity and ability of the chemical to 
bioaccumulate. Like the previous surfactant example, the Agency may 
nonetheless take action on a P3B3T1 chemical (not calcium per se), most 
likely under its exposure-based authority.
    The toxicity rating for a PBT chemical applies to repeated 
exposures which result in human or environmental toxicity, including, 
for example, systemic toxicity, mutagenic damage, reproductive 
toxicity, or developmental toxicity. An example of this is chronic 
toxicity towards aquatic organisms of organotins from contaminated 
marine environments, which ultimately resulted in the regulation of use 
of tributyl tin in marine anti-fouling paints. Repeated exposures 
result from a PBT chemical after it has been released into the 
environment, usually via contaminated water, sediments, or food. The 
classic PBT problems (i.e., PCBs and Dichloro diphenyl trichloroethane 
(DDT)) have been associated with food chain contamination.

G. Scientific Justification for PBT Technical Criteria

    Comment 12-Support for lower threshold criteria for ``P'' and 
``B.'' Commenters believed that there is little precedent, scientific 
justification, evidence or data to support the lower regulatory 
threshold of bioaccumulation factor of 1,000 and environmental 
persistence of 2 months. They suggested that EPA needs a rationale for 
these criteria beyond ``...are characterized by a tendency to 
accumulate in organisms.''
    Response. There is no ``bright line'' that clearly identifies a 
bioaccumulation factor of 1,000 or a half-life of 2 months as the best 
bioaccumulation or persistence criterion from a scientific perspective. 
However, it is not accurate to state that there is no precedent or 
basis for using these values. As outlined in EPA's recent proposal to 
lower the reporting thresholds for PBT chemicals that are subject to 
reporting under section 313 of EPCRA (64 FR 688; January 5, 1999), 
similar values have been proposed by several authorities, including the 
Ontario, Canada Ministry of Environment and Energy (MOEE) for its 
Candidate Substances List for Bans or Phaseouts (MOEE, 1992, see Unit 
VI.10.); the Canadian initiative for Accelerated Reduction/Elimination 
of Toxics (ARET) (ARET, 1995 and ARET, 1994, see Unit VI.11. and 12.); 
the International Joint Commission (IJC)'s Great Lakes Water Quality 
Agreement (GLWQA) (IJC, 1993, see Unit VI.13.); and the United Nations 
Economic Commission for Europe Convention on Long-Range Transboundary 
Air Pollution (UNECE-LRTAP), which did adopt 2 months as the 
persistence criterion of record for water (UNECE-LRTAP, 1998, see Unit 
VI.14.).
    In determining the thresholds for this policy statement, EPA 
concluded that it would be appropriate to reflect the levels of concern 
that the various PBT chemicals presented, based on the differing 
degrees to which the chemicals persist and bioaccumulate. The Agency 
ultimately chose to adopt a two-tier approach, and to establish two 
separate thresholds to reflect the chemicals' varying potentials to 
persist and bioaccumulate, as well as to reflect the Agency's belief 
that the different levels of regulatory action under TSCA are warranted 
for the two tiers. As discussed in detail in the preamble to the 
mentioned EPCRA proposed rule, EPA found that generally the criteria 
selected by various U.S. and international regulatory bodies for either 
persistence or bioaccumulation clustered around two values. For 
persistence in water, soil, and sediment, the criteria were grouped 
around half-lives of 1 to 2 months and 6 months, and for persistence in 
air, either 2 or 5 days. Bioaccumulation criteria were grouped around 
BAF/BCF values of 1,000 and 5,000. The preamble to the EPCRA proposed 
rule states ``Bearing in mind that one of Congress' articulated 
purposes for EPCRA section 313 was to provide local communities with 
relevant information on the release and other waste management 
activities of chemicals in their community that may present a hazard, 
EPA determined that the criteria that were most consistent with these 
purposes were, for persistence, half-lives of 2 months for water, 
sediment, and soil, and 2 days in air, and for bioaccumulation, 
bioaccumulation/bioconcentration factor values of 1,000 or greater'' 
(64 FR 692; January 5, 1999). EPA is making a similar determination for 
the PBT new chemicals policy under TSCA. The PMN process is one of 
EPA's cornerstone Pollution Prevention programs and plays a critical 
gatekeeper role in making sure that all new chemical substances do not 
present unreasonable risks when they are commercialized. Given this, 
and the uncertainty which often accompanies Agency review of a PMN 
chemical substance due to lack of data, the TSCA new chemicals program 
is and must be conservative by nature, which suggests that a half-life 
shorter than 6 months and a BCF criterion lower than 5,000--values that 
were selected solely or primarily to isolate substances already widely 
acknowledged to be POPs are appropriate for regulatory scrutiny of new 
chemicals under TSCA. Note that the CEG, at the October 26-30, 1998 
Bangkok meeting described in Unit II.B. of this document, developed 
indicative numerical values as bracketed criteria text which included 
persistence of 2 vs. 6 months in water and log Kow of 4 vs. 5 
(equivalent to a BCF of approximately 1,000 vs. 5,000, respectively).
    A series of PMNs submitted to EPA in 1990 (Zeeman et al., 1999, see 
Unit VI.15.) illustrates (1) why EPA believes that the persistence 
criterion for bioaccumulating substances in soil, water, or sediment 
should be set substantially lower than 6 months; and (2) that concern 
for potential exposures to persistent and bioaccumulative toxics must 
extend beyond the UNEP's 12 widely acknowledged POPs. The substances in 
question were alkylated diphenyls, for which EPA expected discharge to 
receiving streams and rivers. The submitter supplied data on use and 
disposal, aquatic toxicity, and

[[Page 60200]]

biodegradability. The submitted environmental fate data and EPA 
estimates of biodegradability based on structural analogs suggested 
that half-lives in water would be well below 6 months, but not 
necessarily lower than 2 months. As a result of concerns expressed by 
EPA, use was limited to sites where resulting water concentrations 
could be limited to 1 microgram per liter or less; concomitantly, the 
submitter was also informed of EPA's belief that a potential for long-
term risk existed, but that EPA could not quantify this risk since 
assessments typically evaluated releases over a period of only 1 year. 
In 1998, results of monitoring revealed that the PMN substances had 
been found in fish fillets and sediment samples from the receiving 
stream. If, for these 1990 PMNs, EPA were to have had in place the 2 
month persistence criterion described in today's policy statement, 
further scrutiny under the new chemicals program would have been 
warranted, and beyond simply informing the PMN submitter of the 
potential for long-term risk, the Agency would likely have required 
further testing to obtain an experimental value for environmental 
persistence of the chemicals. This in turn would have given the Agency 
a better picture of the behavior of the chemicals in the environment 
and the environmental half-life relative to the 2 month value.
    Comment 13-Deny commercialization to lower threshold PBT chemicals. 
Some commenters supported exercising the ``Precautionary Principle'' by 
not allowing commercialization under a TSCA 5(e) consent order or SNUR 
pending testing of the PMN chemicals which meet the P=2 month and 
BCF=1,000 criteria. They suggested that these chemicals should be 
banned instead, pending the necessary testing.
    Response. Whereas a half-life of 2 months and BCF of 1,000 can be 
justified as lower-tier cutoffs in a deliberately conservative TSCA new 
chemicals program that is designed to prevent commercialization of 
potentially risky substances, it would not be appropriate to 
automatically trigger a ``ban pending testing'' at these cutoffs given 
the uncertainties about substance properties, release, and 
environmental behavior that normally characterize PMN review. The 
Agency believes that the available predictive tools and current 
knowledge of POPs lend support for this two-phased approach to 
screening of PBT chemicals and collection of information ``sufficient 
to permit a reasoned evaluation of potential health and environmental 
effects'' if EPA makes the requisite risk- or exposure-based findings 
under TSCA section 5(e).
    Comment 14-Relationship of P, B, and T criteria. Commenters 
suggested that the October 5, 1998 (63 FR 53417) notice is inaccurate 
when it states that 2 months is adequate for detecting many long-term 
toxic effects as well as any tendency for a substance to bioaccumulate 
in aquatic organisms. Commenters pointed out that the persistence 
criterion is not related to detection of long-term toxicity.
    Response. The statement in question was intended simply to note 
that the 2 months half-life in water persistence criterion closely 
tracks the duration of long-term environmental toxicity or 
bioaccumulation tests. If a new chemical substance is predicted to or 
measurably demonstrates chronic toxicity, potential to bioaccumulate, 
and environmental persistence over that same time period (2 months), it 
would meet the minimum TSCA PBT criteria. It is true that, in general, 
half-life cutoffs for identifying POPs warranting international action 
(e.g., in programs like UNECE-LRTAP and UNEP Global Negotiations on 
POPs) have not been selected based on the duration of toxicity or 
bioaccumulation tests. There are no cutoffs or ``fence lines'' for 
environmental persistence criteria that emerge as immutable quantities 
solely from scientific analysis; the choice of screening criteria is a 
policy decision guided by the anticipated scope of a negotiation or 
regulatory activity. In the case of the PMN program, 2 months 
represents a reasonable screening level value for ``persistence'' which 
is more than the 1-month period in a ready biodegradation study and 
less than the 6 month value widely agreed to internationally (U.S.-
Canada binational agreement to control the discharge or release of POPs 
in the Great Lakes Basin, UNECE-LRTAP, North American Free Trade 
Agreement Commission for Environmental Cooperation (NAFTA-CEC), etc.) 
as reflecting the persistence of known POPs chemicals (e.g., DDT, 
hexachlorobenzene). As mentioned in the previous response, there is 
international support, through the CEG, for persistence values of 2 or 
6 months in water.
    Comment 15-Relationship of P and B. Commenters suggested that the 
October 5, 1998 (63 FR 53417) notice's statement, ``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,'' 
should be revised to reflect that persistence alone is not sufficient 
to cause a substance to bioaccumulate.
    Response. EPA did not intend that the sentence be read to mean that 
persistence alone is sufficient to result in bioaccumulation. The point 
that was intended to be conveyed was that a certain level of 
persistence is a necessary condition for bioaccumulation to occur. 
There are other conditions that affect bioaccumulation, such as 
bioavailability and the metabolic transformation rate in the target 
species. These and other factors will be evaluated by EPA in the 
determination of the PBT concern level for PMN chemical substances.

H. Relationship of TSCA PBT Policy to Other Agency and International 
PBT Initiatives

    Comment 16-Finalize overall Agency multimedia strategy first. 
Commenters suggested that the PBT classification criteria being 
proposed for TSCA section 5(e) may have broader application, e.g., 
international or other Agency PBT initiatives, and may be used to 
establish precedent in other programs. In addition to the TSCA October 
5, 1998 (63 FR 53417) Federal Register notice, there have been three 
other notices published in Federal Register dealing with (1) the 
promotion of voluntary waste minimization efforts to reduce the 
generation of those PBT chemicals which are found in hazardous waste 
regulated under the Resource Conservation and Recovery Act (RCRA) (63 
FR 60332; November 9, 1998 (FRL-6186-7)), (2) the Agency draft 
Multimedia PBT Strategy (63 FR 63926; November 17, 1998 (FRL-6045-2)), 
and (3) the lowering of reporting thresholds for certain PBT toxic 
chemicals subject to reporting under section 313 (Toxic Release 
Inventory, or TRI) of EPCRA of 1986 (64 FR 688; January 5, 1999). These 
commenters stated that the TSCA notice is premature, occurring before 
adoption of the overall Agency strategy, and is inconsistent with other 
initiatives, domestic and international, which have lists of chemicals 
and more selective criteria (i.e., specific to environmental media, 
fate and transformation processes). Commenters recommended that EPA 
finalize the Agency strategy first, before proceeding with the TSCA, 
RCRA, and TRI actions, and that there should be coordination among them 
all with uniform PBT criteria as part of the Agency strategy.
    Response. The PBT Multimedia Strategy formalizes an Agency process 
for integration of program activities involving these types of 
substances. While the strategy intends to coordinate Agency PBT-related 
activities under its

[[Page 60201]]

framework, the strategy does not establish rigid criteria with respect 
to PBTs. Program offices must operate within the parameters of their 
legislative mandates and established regulatory and policy frameworks. 
For some programs such as the Toxics Release Inventory, the TSCA New 
Chemicals Program and the RCRA National Waste Minimization Plan, 
actions involving PBTs are a historical reality and their experience 
has, in fact, largely shaped the strategy. Therefore, EPA does not 
intend to halt all ongoing work involving PBTs until the strategy is 
``finalized.'' With respect to the PMN process, it is important to 
understand and acknowledge its fundamental purpose, which is to allow 
EPA to evaluate the hazards, exposures, and risks of new chemicals, and 
the opportunity to protect against unreasonable risks, if any. The 
structure of that process and the tools used to implement it flow 
logically from its statutory purpose and suggest that the category 
approach outlined in this policy statement is the most appropriate 
means of addressing potential concerns for substances possessing PBT 
characteristics. It is EPA's intention that the strategy be a living 
document. Therefore, the strategy will be updated based upon public 
comment; it will not be ``finalized'' in the more traditional sense of 
a rulemaking. EPA does agree that consistency is a laudable goal where 
the criteria are meant to be used for similar purposes and is seriously 
considering comments within the context of the strategy regarding 
establishment of consistent criteria for priority PBTs.
    Comment 17-Carefully communicate lower thresholds. Commenters 
suggested that EPA should use only the environmental persistence of 6 
months/BCF of 5,000 screening levels for consistency among EPA and 
U.S./international programs and should carefully communicate proposed 
lower criteria internationally.
    Response. As discussed in the response to Comment 12, EPA believes 
that a lower tier of 2 month/BCF of 1,000 is appropriate for risk 
screening activities under TSCA. Communication is occurring in the 
international forum. Unit II.B. of this document discusses the CEG for 
POPs, established under UNEP mandate. At its first meeting, on October 
30, 1998 in Bangkok, the CEG recommended that the INC consider 
developing a provision encouraging countries and regions to include in 
their new chemicals schemes elements relating to development and 
introduction of new chemical POPs. The U.S. described its proposed TSCA 
new chemicals program policy for the category of PBT new chemicals, and 
the full text of the October 5, 1998 (63 FR 53417) Federal Register 
notice was distributed to all delegations as a Conference Room Paper. 
The CEG's recommendation was accepted at the second meeting of the INC 
(January 25-29, 1999 in Nairobi) and the INC will consider it further 
in its deliberations.

I. Testing Strategy

    Comment 18-Toxicity testing. Commenters asked whether toxicity was 
considered at each testing tier or only in tier 3. It was not clear to 
them when toxicity testing would be requested, nor what results will be 
considered acceptable by the Agency.
    Response. Each of P and B and T are weighed in the Agency's 
assessment. The testing strategy outlined in this policy statement is 
intended to build the case, starting with testing to establish 
persistence and bioaccumulation, and then determining toxicity and 
confirming a chemical's status as a PBT chemical in tier 3. Once a 
chemical becomes distributed in the environment at low concentrations, 
the combination of persistence and bioconcentration in organisms can 
result in residues high enough to approach a toxic dose. The first two 
tiers focus on P and B because of the critical role these aspects play 
in PBT determinations and because of their relatively lower cost to 
determine P and B. Thus, chronic toxicity testing, which is expected to 
be the most expensive testing, is reserved until tier 3 where it serves 
to establish PBT status. Although the early tier P and B testing may 
either obviate the need for toxicity testing or result in more directed 
and cost-effective toxicity testing, the need for toxicity testing is 
considered in each testing tier and will be obtained in lower tiers 
where needed on a case-specific basis. As with all new chemicals 
reviewed by the Agency under TSCA, the potential toxicity of the 
chemical is determined from test data, if any, or by analogy to 
structurally similar chemicals. If a company knows or suspects prior to 
testing that their chemical is likely to be persistent and 
bioaccumulative, consideration should be given to conducting chronic 
toxicity testing in the first tier. For any suspected PBT chemicals for 
which a risk finding has not been made, but which meet production, 
release, and exposure thresholds under the Agency's exposure-based 
policy (USEPA, 1988, USEPA, 1989, see Unit VI.8. and 9.), the standard 
screening level battery of testing (or an appropriate subset thereof) 
currently utilized for exposure-based cases in the new chemicals 
program could be required in addition to PBT testing.
    Comment 19-Equivalent tests. Commenters suggested that all tests 
referenced in the testing strategy should also state ``or an equivalent 
test.''
    Response. EPA realizes that often there are a number of different 
but acceptable means to providing testing information. However, EPA's 
acceptance of a guideline not specified in this policy statement and/or 
use of data generated under such guidelines depends on multiple factors 
including the specifics of the test substance, purpose of the testing, 
familiarity with specific procedures and equipment, validation of the 
method, etc. Typical TSCA 5(e) consent orders require that testing 
performed pursuant to the order must be conducted according to TSCA 
Good Laboratory Practice Standards at 40 CFR part 792 and using 
methodologies generally accepted at the time the study is initiated. 
Before starting to conduct any such study, the PMN submitter must 
obtain approval of test protocols from EPA by submitting written 
protocols. Published test guidelines specified in the Test Strategy 
section (see Unit IV. B. of this document) provide general guidance for 
development of test protocols, but are not themselves acceptable 
protocols.

J. Applicability of PBT Criteria to Metals

    Comment 20-PBT criteria are not appropriate for metals. Commenters 
suggested that the application of Persistence and Bioaccumulation 
criteria appropriate for organic chemicals does not make sense for 
metals and metal compounds. They also suggested that EPA needs criteria 
to identify potential problems generated by organometals.
    Response. The approach and the criteria are sufficiently flexible 
to apply to organic chemicals, inorganic metals and organometallics. It 
is important to distinguish between criteria for identifying potential 
PBTs, on the one hand, and on the other: (1) the means of generating 
information on the P, B, and T endpoints for comparison to the 
criteria, and (2) the applicability of existing test guidelines for 
generating such information experimentally.
    EPA understands that metals are intrinsically not degradable in the 
sense of ultimate degradation of organics (although they may undergo 
biologically as well as chemically induced changes in, e.g., oxidation 
state), and therefore are persistent by definition, but nevertheless 
may not be bioaccumulative. It is widely accepted that elemental metals 
are persistent by definition, since they may take different

[[Page 60202]]

forms that can be interconverted, but the elemental metal itself cannot 
be destroyed. All elemental metals therefore meet the 6 month half-life 
criterion. Given this, it is not correct that EPA's proposed 
persistence criteria cannot be applied to metals. It may be more 
accurate to state that the persistence criteria are not themselves very 
helpful in screening or assessing metals and metal compounds with 
respect to the potential for risk, whether from direct exposure or 
through bioaccumulation. Relative to applicability of test guidelines, 
the same level of judgment will be brought to bear such that, for 
example, EPA would not require ready biodegradability testing for a 
metal or metal salt. (EPA may, however, request such testing for 
organometallics, which, depending on chemical structure, could still 
show significant degradation in such tests.)
    EPA understands that bioavailability is important in determining 
the potential for risk, and notes that the same generalization applies 
to any substance whether metallic or not. Metals and organometallic 
compounds are no different from other organic chemicals with respect to 
the applicability of the proposed criteria for identifying persistent, 
bioaccumulative, and toxic substances, except that Kow determination 
may not be relevant for metals (although the fish BCF study is 
relevant). Similarly, it is not necessary to develop different criteria 
or assessment strategies for pigments (see first comments/responses in 
this policy statement) or any other specific classes of organics. What 
is necessary is to consider what is known about the behavior of 
substances like metals during the TSCA PMN review process, both in the 
assessment of whether a given chemical substance meets the established 
criteria and in subsequent testing decisions. For any untested PMN 
chemical substance, if there are no close analogs with data and no 
clear evidence that available estimation methods are unreliable for 
this or closely related substances, then the estimation methods can be 
assumed to apply and the resulting data compared to PBT criteria. Put 
another way, a metal or organometallic (or, similarly, a pigment) that 
is judged sufficiently persistent and meets the criteria for 
bioaccumulation potential and toxicity is of concern for ``PBTness'' 
regardless of theoretical arguments or generalizations.
    The key is how persistence and bioaccumulation potential are 
determined in the PMN process, and by implication, how bioavailability 
is determined. This policy statement leaves unspecified how EPA intends 
to do this, but the Agency will consider all available and relevant 
data, and will use its professional judgment in considering issues like 
bioavailability of metals. Using lead as an example, many processes 
commonly observed in the environment can result in the presence of 
bioavailable (ionic) lead where it can be bioaccumulated by organisms. 
These processes may occur in soil and aquatic environments with low pH 
and low levels of organic matter. Under these conditions, the 
solubility of lead is enhanced and, in the absence of sorbing surfaces 
and colloids, lead ion can remain in solution for a sufficient period 
to be taken up by biota. Lead sorption to soil organic matter has been 
shown to be pH dependent. Decreasing pH can lead to increasing 
concentrations of lead in soil and water. Microbial transformations in 
soil, water, and sediment are also important in determining the overall 
fate of metals and metal compounds, and therefore the potential for 
formation of bioavailable forms. Metals are generally taken into cells 
by nutrient metal transport systems, and these are not sufficiently 
specific to completely exclude nonessential metals, some of which may 
be toxic and/or bioaccumulative. In this situation, nutrient metals can 
be displaced from their binding sites by undesirable, toxic metals, 
which then gain access to the cell interior with concomitant exclusion 
of the essential metal (Stumm and Morgan, 1996 see Unit VI.16.). Toxic 
metal ions are then free to react with critical enzymes or otherwise 
disrupt cellular functions if they reach certain levels. EPA concludes 
that under many environmental conditions, metals and metal compounds 
may be available to express toxicity and to bioaccumulate, and that 
these effects are not necessarily limited to metals that are not 
essential nutrients. It is appropriate, therefore, to be concerned 
about the potential for risk from these effects. It is the policy of 
the TSCA New Chemicals Program that if the metal in a metal compound 
cannot become available as a result of biotic or abiotic processes then 
the metal will not be available to express its toxicity, and by 
extension, to bioaccumulate. If the intact metal compound is not toxic 
and the metal is not available from the metal compound, then such a 
chemical would not be a strong candidate for regulation under TSCA 
section 5(e).

IV. Final TSCA New Chemicals Program Policy for PBT Chemical 
Substances

A. Evaluation Criteria and Process for New PBT Chemical Substances

    EPA is adopting 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(e) Action
                                 ---------------------------------------
                                  5(e) Order Pending
                                       Testing/        5(e) Ban Pending
                                    Significant New        Testing2
                                   Use Rule (SNUR)1
------------------------------------------------------------------------
Persistence (transformation half- > 2 months........  > 6 months
 life).
Bioaccumulation (Fish BCF or       1,000.   5,000
 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 persistence,
  bioaccumulation, other physical/chemical factors, and toxicity based
  on existing data.

    Chemical substances suspected as persistent bioaccumulators under 
the criteria listed in the table in Unit IV.A. of this document may 
need to undergo testing on ``P'' and ``B'' endpoints which, if 
confirmed, would be followed by appropriate toxicity testing to 
identify ``PBT chemical substances.'' Control action under TSCA section 
5(e) may be needed in varying degrees, based upon the level of risk 
concern. 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 ``5(e) 
Order Pending Testing/Significant New Use Rule (SNUR)'' could be 
addressed via a negotiated consent agreement under

[[Page 60203]]

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. The ``ban pending 
testing'' criteria are equivalent to those that have been used 
internationally to identify POPs. For the chemical substances meeting 
these criteria, 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 control 
actions described in the table in Unit IV.A. of this document represent 
just one body of possible decisions and should not be considered as 
exclusive of other risk management options.

B. 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, that 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 that 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 or otherwise limit the manufacture, import, processing, 
distribution in commerce, use, or disposal 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 EPA believes are needed to evaluate the 
persistence, bioaccumulation, and toxicity of a PBT chemical substance 
for which EPA has made the above 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. 
As discussed in the response to Comment 19 in Unit III.I. of this 
document, testing must be conducted according to TSCA Good Laboratory 
Practice Standards at 40 CFR part 792 and using methodologies generally 
accepted at the time the study is initiated. Before starting to conduct 
any such study under the terms of a Consent Order under TSCA section 
5(e), the PMN submitter must obtain approval of test protocols from EPA 
by submitting written protocols. Published test guidelines specified in 
Unit IV.B. of this document provide general guidance for development of 
test protocols, but are not themselves acceptable protocols.
    Tier 1. If, based upon available test data, 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. Hydrolysis 
in water (OPPTS 835.2110 test guideline) should be determined if, based 
upon SAR, susceptibility to hydrolysis is suspected. 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).
    If the measured log Kow is < 4.2 (equivalent to an estimated BCF of 
1,000) 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 greater than or equal to 4.2, and 
the chemical does not pass the ready biodegradability test, no further 
testing will normally be deemed necessary in tier 1; the Agency would 
likely 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). 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 
sediment/water microcosm biodegradation test (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 > 1,000, tier 3 testing will normally 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 
(OECD No. 422 test guideline) 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 (same as OPPTS test guideline 
850.1400 (public draft)) and 40 CFR 797.1330 (same as OPPTS test 
guideline 850.1300 (public draft)), respectively. Additional testing to 
evaluate other biota (e.g., avian, sediment dwelling organisms) or 
other effects (e.g.,

[[Page 60204]]

endocrine disrupting potential) will be considered where appropriate.

V. Intended Legal Affect of this Policy Statement

    The policy discussed in this document provides general guidance on 
the Agency's use of a category grouping for PBT new chemical substances 
to facilitate the PMN assessment process for PMN submitters and EPA 
reviewers. EPA uses groupings of new chemical substances with similar 
structural and toxicological properties to allow PMN submitters and EPA 
reviewers to benefit from accumulated data and decisional precedents, 
as well as streamlined procedural requirements related to the review of 
and follow-up for new chemical substances.
    As guidance, the policy presented in this document is not binding 
on either EPA or any outside parties, and this document is not 
intended, nor can it be relied upon, to create any rights enforceable 
by any party in litigation with the United States. Although this 
guidance provides a starting point for assessing PBT new chemical 
substances, EPA will depart from its policy where the facts or 
circumstances warrant. In such cases, EPA will explain why a different 
course was taken. Similarly, outside parties remain free to assert that 
this policy is not appropriate for a specific PMN or that the 
circumstances surrounding a specific PMN demonstrate that this policy 
should not be applied. Although the Agency has provided an opportunity 
for public comment on the guidance provided in this policy statement 
and is likely to request additional feedback if changes are necessary 
at some point in the future, the Agency may revise, clarify, or update 
the text of this guidance without public notice.

VI. References

    The OPPTS harmonized test guidelines referenced in this document 
are available on EPA's World Wide Web site (http://www.epa.gov/
OPPTS-Harmonized/).
    1. Sijm, D.T.H.M., Schuurmann, G., de Vries, P.J., Opperhuizen, A. 
Aqueous Solubility, Octanol Solubility, and Octanol/Water Partition 
Coefficient of Nine Hydrophobic Dyes. Environ. Toxicol. and Chem. 
18:1109-1117.
    2. 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.
    3. Boethling RS, PH Howard, JA Beauman and ME Larosche. 1995. 
Factors for intermedia extrapolation in biodegradability assessment. 
Chemosphere 30: 741-752.
    4. Federle TW, SD Gasior and BA Nuck. 1997. Extrapolating 
mineralization rates from the ready CO2 screening test to activated 
sludge, river water, and soil. Environ. Toxicol. Chem. 16: 127-134.
    5. Boethling RS, Howard PH, Meylan W, Stiteler W, Beauman J, Tirado 
N. 1994. Group contribution method for predicting probability and rate 
of aerobic biodegradation. Environ. Sci. Technol. 28: 459-465.
    6. USEPA. March, 1997. Chemistry Assistance Manual for 
Premanufacture Notification Submitters. EPA 744-R-97-003. Also 
available as Premanufacture Notification: Chemistry Assistance for 
Submitters, by Steven C. DeVito and Carol A. Farris (ISBN: 0-471-19151-
5) through the publisher, John Wiley and Sons, at 1-800-225-5945 or the 
TSCA Hot Line, at 202-554-1404.
    7. USEPA. March, 1994. U.S. EPA/EC Joint Project on the Evaluation 
of (Quantitative) Structure Activity Relationships. EPA 743-R-94-001.
    8. USEPA. 1988. Letter from Charles L. Elkins to Geraldine V. Cox 
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA 
(September 22, 1988).
    9. USEPA. 1989. Letter from Charles L. Elkins to Geraldine V. Cox 
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA 
(August 31, 1989).
    10. Ministry of Environment and Energy for Ontario (MOEE). 1992. 
Candidate substances list for bans or phase-outs. Report perpared by 
the Hazardous Contaminants Branch and the Water Resources Branch, MOEE. 
Ontario, Canada, ISBN 0-7729-9764-0.
    11. Accelerated Reduction/Elimination of Toxics (ARET) Secretariat. 
1995. Environment leaders 1. Voluntary commitments to action on toxics 
through ARET. March 95.
    12. Accelerated Reduction/Elimination of Toxics (ARET) Secretariat. 
1994. The ARET substance selection process and guidelines. January 94.
    13. International Joint Commission (IJC). 1993. A strategy for the 
virtual elimination of persistent toxic substances. Vol. 1, report of 
the Virtual Elimination Task Force to the IJC. Windsor, Ontario, 
Canada, 72 pp.
    14. United Nations Economic Commission for Europe, Convention on 
Long-Range Transboundary Air Pollution (UNECE-LRTAP). 1998. Draft 
composite negotiating text for a protocol on persistent organic 
pollutants. UNECE, EB.AIR/1998/2, 31 March 1998.
    15. Zeeman, M., D Rodier, and JV Nabholz. 1999. Chapter 2. 
Ecological Risks of a New Industrial Chemical. Under TSCA. In 
Ecological Risk Assessment in the Federal Government (Executive Office 
of the President, National Science and Technology Council, Committee on 
Environment and Natural Resources, Ed.). CENR/5-99/001, May, 1999, pp 
2-1 to 2-30.
    16. Stumm, W. and JJ Morgan. 1996. Aquatic Chemistry, 3rd ed. New 
York: Wiley.

List of Subjects

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

    Dated: October 22, 1999.

Susan H. Wayland,

Deputy Assistant Administrator for Prevention, Pesticides and Toxic 
Substances.

[FR Doc. 99-28888 Filed 11-3-99; 8:45 am]
BILLING CODE 6560-50-F