Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act

Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act

Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act

In June 2017, the Environmental Protection Agency (EPA) issued the final rule for Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (TSCA). This rule establishes the process by which EPA will conduct risk evaluations – a TSCA requirement used to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment.


TSCA section 6(b)(4) requires EPA to establish a process to conduct risk evaluations. The final rule identifies the steps of a risk evaluation, including:

  • Scope
  • Hazard Assessment
  • Risk Characterization
  • Risk Determination

All chemicals designated as high-priority substances during the prioritization process and those chemicals for which EPA has initiated a risk evaluation in response to a manufacturer request will always be subject to this process.

Scoping Document

The scope of each risk evaluation will include: the conditions of use, potentially exposed or susceptible subpopulations EPA expects to consider, and a description of the reasonably available information and science approaches the agency plans to use. The scope will also include an analysis plan which will identify the approaches and methods EPA plans to use to assess exposure, hazards, and risk.

EPA will publish a notice in the Federal Register announcing the availability of the final scope within six months of the initiation of the risk evaluation. Although not required, EPA will also publish a draft scope and provide at least a 45-calendar day public comment period during this six-month period.

Conditions of Use

“Conditions of use” is defined as “the circumstances, as determined by the Administrator, under which a chemical substance is intended, known, or reasonable foreseen to be manufactured, processed, distributed in commerce, used, or disposed of.”

EPA will identify the circumstances that constitute the conditions of use for each chemical substance on a case-by-case basis. EPA is not required to consider all conditions of use in a risk evaluation, and may exclude certain conditions of use from a risk evaluation. Any exclusions will generally be identified in the scoping document.

Hazard Assessment

EPA will conduct a hazard assessment on each chemical substance or category, under the conditions of use as identified in the scope. This hazard assessment will identify the types of hazards to human health or the environment. The hazard assessment may include, but is not limited to, evaluation of the potential toxicity of the chemical substance with respect to cancer, mutation, reproductive, developmental, respiratory, immune, and cardiovascular impacts. This will also consider the likelyhood and severity of adverse health effects in relation to the extent of exposure.

Risk Characterization and Determination

A risk characterization will be made for both human health risk assessments and ecological risk assessments. These characterizations will include information on the type of risk a chemical presents, populations that are expected to be affected, and supporting information. In some cases, EPA may present alternative interpretations in the risk characterizations.

EPA will then make a determination on each use for a chemical as identified in the scoping document. A determination that a condition of use does not present an unreasonable risk is considered to be a final EPA action. If EPA determines that the chemical substance, under one or more condition of use, does present an unreasonable risk, EPA must initiate a rulemaking to impose requirements to the extent necessary so that the substance no longer presents such risk.

Timing of Risk Evaluations

At the completion of the prioritization process, chemicals will be designated as either high- or low- priority. A risk evaluation is initiated upon designation of a chemical as high-priority and is complete upon the publication of the final risk evaluation, which includes the final risk determination for all the conditions of use identified in the scoping document.

Manufacturer-Requested Risk Evaluations

TSCA allows a manufacturer or group of manufacturers to request that the Agency conduct a risk evaluation of a chemical substance that they manufacture. The final rule allows manufacturers to submit requests for risk evaluation on only the conditions of use of the chemical substances that are of interest to the manufacturer. However, in these cases EPA will conduct a full risk evaluation that encompasses both the conditions of use that formed the basis for the manufacturer request, and any additional conditions of use that EPA identifies.

As part of a manufacturer’s submission, a request must include:

  • The chemical identity – all known names, CAS number, and molecular structure
  • All necessary information on the chemical’s hazard and exposure potential
  • The chemical substances persistence and bioaccumulation
  • Any relevant potentially exposed or susceptible subpopulation
  • Whether there is any storage of the chemical substance near significant sources of drinking water
  • The chemical substance’s production volume
  • Any other information relevant to the risks potentially presented by the chemical substance