40 C.F.R. §§ 702.37–702.43

EPA will use applicable EPA guidance when conducting risk evaluations, as appropriate and where it represents the best available science.

EPA will document that the risk evaluation is consistent with the best available science and based on the weight of the scientific evidence. In determining best available science, EPA shall consider as applicable:

EPA will ensure that all supporting analyses and components of the risk evaluation are suitable for their intended purpose, and tailored to the problems and decision at hand, in order to inform the development of a technically sound determination as to whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use, based on the weight of the scientific evidence.

EPA will not exclude conditions of use from the scope of the risk evaluation, but a fit-for-purpose approach may result in varying types and levels of analysis and supporting information for certain conditions of use, consistent with paragraph (b) of this section. The extent to which EPA will refine its evaluations for one or more condition of use in any risk evaluation will vary as necessary to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment.

EPA will evaluate chemical substances that are metals or metal compounds in accordance with 15 U.S.C. 2605(b)(2)(E).

EPA will base each risk evaluation on reasonably available information.

EPA will apply systematic review methods to assess reasonably available information, as needed to carry out risk evaluations that meet the requirements in TSCA section 26(h) and (i), in a manner that is objective, unbiased, and transparent.

EPA may determine that certain information gaps can be addressed through application of assumptions, uncertainty factors, models, and/or screening to conduct its analysis with respect to the chemical substance, consistent with 15 U.S.C. 2625. The approaches used will be determined by the quality of reasonably available information, the deadlines specified in TSCA section 6(b)(4)(G) for completing the risk evaluation, and the extent to which the information reduces uncertainty.

EPA expects to use its authorities under the Act, and other information gathering authorities, when necessary to obtain the information needed to perform a risk evaluation for a chemical substance before initiating the risk evaluation for such substance. EPA will also use such authorities during the performance of a risk evaluation to obtain information as needed and on a case-by-case basis to ensure that EPA has adequate, reasonably available information to perform the evaluation. Where appropriate, to the extent practicable, and scientifically justified, EPA will require the development of information generated without the use of new testing on vertebrates.

Among other sources of information, EPA will also consider information and advice provided by the Science Advisory Committee on Chemicals established pursuant to 15 U.S.C. 2625(o).

The hazard assessment process includes the identification, evaluation, and synthesis of information to describe the potential health and environmental hazards of the chemical substance under the conditions of use.

Hazard information related to potential health and environmental hazards of the chemical substance will be reviewed in a manner consistent with best available science based on the weight of scientific evidence and all assessment methods will be documented.

Consistent with § 702.37(b), information evaluated may include, but would not be limited to: Human epidemiological studies, in vivo and/or in vitro laboratory studies, biomonitoring and/or human clinical studies, ecological field data, read across, mechanistic and/or kinetic studies in a variety of test systems. These may include but are not limited to: toxicokinetics and toxicodynamics (e.g., physiological-based pharmacokinetic modeling), and computational toxicology (e.g., high-throughput assays, genomic response assays, data from structure-activity relationships, in silico approaches, and other health effects modeling).

The hazard information relevant to the chemical substance will be evaluated for identified human and environmental receptors, including all identified potentially exposed or susceptible subpopulation(s) determined to be relevant, for the exposure scenarios relating to the conditions of use.

The relationship between the dose of the chemical substance and the occurrence of health and environmental effects or outcomes will be evaluated.

Hazard identification will include an evaluation of the strengths, limitations, and uncertainties associated with the reasonably available information.

Where relevant, the likely duration, intensity, frequency, and number of exposures under the conditions of use will be considered.

Exposure information related to potential human health or ecological hazards of the chemical substance will be reviewed in a manner consistent with best available science based on the weight of scientific evidence and all assessment methods will be documented.

Consistent with § 702.37(b), information evaluated may include, but would not be limited to: chemical release reports, release or emission scenarios, data and information collected from monitoring or reporting, release estimation approaches and assumptions, biological monitoring data, workplace monitoring data, chemical exposure health data, industry practices with respect to occupational exposure control measures, and exposure modeling.

Chemical-specific factors, including, but not limited to physical-chemical properties and environmental fate and transport parameters, will be examined.

The human health exposure assessment will consider all potentially exposed or susceptible subpopulation(s) determined to be relevant.

Environmental health exposure assessment will characterize and evaluate the interaction of the chemical substance with the ecological receptors and the exposures considered, including populations and communities, depending on the chemical substance and the ecological characteristic involved.

EPA will describe whether sentinel exposures under the conditions of use were considered and the basis for their consideration.

EPA will consider aggregate exposures to the chemical substance, and, when supported by reasonably available information, consistent with the best available science and based on the weight of scientific evidence, include an aggregate exposure assessment in the risk evaluation, or will otherwise explain in the risk evaluation the basis for not including such an assessment.

EPA will assess all exposure routes and pathways relevant to the chemical substance under the conditions of use, including those that are regulated under other federal statutes.

Requirements. To characterize the risks from the chemical substance, EPA will:

Summary of considerations. EPA will summarize, as applicable, the considerations addressed throughout the evaluation components, in carrying out the obligations under 15 U.S.C. 2625(h). This summary will include, as appropriate, a discussion of:

As part of the risk evaluation, EPA will make a single determination as to whether the chemical substance presents an unreasonable risk of injury to health or the environment, without consideration of costs or other non-risk factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation, under the conditions of use.

In determining whether unreasonable risk is presented, EPA's consideration of occupational exposure scenarios will take into account reasonably available information, including known and reasonably foreseen circumstances where subpopulations of workers are exposed due to the absence or ineffective use of personal protective equipment. EPA will not consider exposure reduction based on assumed use of personal protective equipment as part of the risk determination.

EPA will determine whether a chemical substance does or does not present an unreasonable risk after considering the risks posed under the conditions of use and, where EPA makes a determination of unreasonable risk, EPA will identify the conditions of use that significantly contribute to such determination.

For each risk evaluation to be conducted, EPA will publish a document that specifies the draft scope of the risk evaluation EPA plans to conduct and publish a notice of availability in the Federal Register. The document will address the elements in § 702.39(b).

EPA generally expects to publish the draft scope during the prioritization process concurrent with publication of a proposed designation as a High-Priority Substance pursuant to § 702.9(g), but no later than 3 months after the initiation of the risk evaluation process for the chemical substance.

EPA will allow a public comment period of no less than 45 calendar days during which interested persons may submit comment on EPA's draft scope. EPA will open a docket to facilitate receipt of public comments.

EPA will, no later than 6 months after the initiation of a risk evaluation, publish a document that specifies the final scope of the risk evaluation EPA plans to conduct, and publish a notice of availability in the Federal Register. The document shall address the elements in § 702.39(b).

For a chemical substance designated as a High-Priority Substance under subpart A of this part, EPA will not publish the final scope of the risk evaluation until at least 12 months have elapsed from the initiation of the prioritization process for the chemical substance.

EPA will complete and publish a final risk evaluation for the chemical substance under the conditions of use as soon as practicable, but not later than 3 years after the date on which EPA initiates the risk evaluation. The document shall include the elements in § 702.39(c) through (f) and EPA will publish a notice of availability in the Federal Register.

EPA may extend the deadline for a risk evaluation for not more than 6 months. The total time elapsed between initiation of the risk evaluation and completion of the risk evaluation may not exceed 3- and one-half years.