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Documents Category for Persistent, Bioaccumulative, and Toxic New Chemical Substances 

Category for Persistent, Bioaccumulative, and 

Toxic New Chemical Substances 

 [Federal Register: November 4, 1999 (Volume 64, Number 213)] 

[Notices] 

[Page 60194-60204] 

From the Federal Register Online via GPO Access [wais.access.gpo.gov] 

[DOCID:fr04no99-64] 

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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-Hotline@epa.gov. 

Federal Register Environmental Documents

Last updated on Wednesday, January 2nd, 2008.

http://www.epa.gov/fedrgstr/EPA-TOX/1999/November/Day-04/t28888.htm

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 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: moss.kenneth@epa.gov. 

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: 

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 Category NAICS Code SIC Cod

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Chemical manufacturers or importers 325, 32411 28, 2911 

 

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 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 

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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 

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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<INF>-</INF>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. 

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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 

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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) 

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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 

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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. 

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 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 

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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 riskbased 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 exposurebased 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, 

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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 

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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 longterm 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 

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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 

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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 

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``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 

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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 

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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 

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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 Testing<SUP>2</S

 Use Rule (SNUR)<SUP>1</SUP> 

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

Persistence (transformation half- > 2 months........ > 6 months 

 life). 

Bioaccumulation (Fish BCF or <gr-thn-eq> 1,000. <gr-thn-eq> 5,000 

 BAF)<SUP>3</SUP>. 

Toxicity........................ Develop toxicity Develop toxicity 

 data where data where 

 necessary<SUP>4</SUP>. necessary

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

<SUP>1</SUP>Exposure/release controls included in order; testing required.

<SUP>2</SUP>Deny commercialization; testing results may justify removing ch

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 from ``high risk concern''. 

<SUP>3</SUP>Chemicals must also meet criteria for MW (< 1000) and cross-sec

 diameter (< 20A , or < 20 x 10<SUP>-8</SUP> cm). 

<SUP>4</SUP>Based 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 TRItype 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 

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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, CO<INF>2</INF> Evolution, Modified MITI 

(I), Closed Bottle, Modified OECD Screening, Manometric Respirometry. 

 2. Sealed-vessel CO<INF>2</INF> 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 

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specific analytical method, and allows for the development of a firstorder 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 

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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<INF>-</INF>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 

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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 

Notices

For 

2008 2007 2006 2005 2004 2003 2002 2001

2000 1999 1998 1997 1996 1995 1994

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