EPA Announces Availability of Final Scope Documents for TSCA Risk Evaluations

The U.S. Environmental Protection Agency (EPA) published a notice on September 4, 2020 announcing final scope document availability for 20 chemicals. These represent the first group of substances deemed, in December 2019, as being high priority for risk evaluation under the Toxic Substances Control Act (TSCA). In this blog post, we review these chemicals and look at the makeup of the corresponding documents.

Risk Evaluation

During the process of risk evaluation, the EPA uses information aligning with TSCA requirements. The Agency is required to meet TSCA’s criteria for best available science and uses a “weight-of-scientific-evidence” methodology. The ultimate goal of the process is to ascertain whether a chemical poses an unreasonable risk to health or to the environment under its use conditions.

20 High Priority Chemicals

The 20 chemicals previously designated by the EPA as high-priority substances for the purpose of risk evaluation under TSCA are listed in the table below.

Substance NameCAS Registry NumberChemical Group
o-Dichlorobenzene (Benzene, 1,2-dichloro-)95-50-1N/A
p-Dichlorobenzene (Benzene, 1,4-dichloro-)106-46-7N/A
trans-1,2-Dichloroethylene (Ethene, 1,2-dichloro-, (1E)-)156-60-5Solvent
Ethylene dibromide (Ethane, 1,2-dibromo-)106-93-4N/A
1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta [g]-2-benzopyran (HHCB)1222-05-5Fragrance Additive
4,4′-(1-Methylethylidene)bis[2, 6-dibromophenol] (TBBPA)79-94-7Flame Retardant
Phosphoric acid, triphenyl ester (TPP)115-86-6Flame Retardant
Tris(2-chloroethyl) phosphate (TCEP) (Ethanol, 2-chloro-, 1,1′,1″-phosphate)115-96-8Flame Retardant
Butyl benzyl phthalate (1,2-Benzenedicarboxylic acid, 1- butyl 2-(phenylmethyl) ester)85-68-7Phthalate
Dibutyl phthalate (1,2-Benzenedicarboxylic acid, 1,2- dibutyl ester)84-74-2Phthalate
Dicyclohexyl phthalate84-61-7Phthalate
Phthalic anhydride (1,3-Isobenzofurandione)85-44-97N/A
Di-ethylhexyl phthalate (1,2-Benzenedicarboxylic acid, 1,2- bis(2-ethylhexyl) ester)117-81-7Phthalate
Di-isobutyl phthalate (1,2-Benzenedicarboxylic acid, 1,2-bis(2-methylpropyl) ester)84-69-5Phthalate

Source: U.S. Environmental Protection Agency

Key Scope Document Components

The final scope documents for the prioritized chemical substances each contain several key components:

  • A description of the use conditions the EPA intends review in its risk evaluations.
  • A review of the potentially exposed groups, and the environmental and health hazards, that the EPA intends to consider.
  • A description of the approaches and information the EPA intends to use.
  • A conceptual model focused on the relationships between chemical substance, conditions of use, and more.
  • A plan for analysis identifying the EPA’s intended methods for evaluating hazards, exposure, risks, etc.
  • A peer review plan.

Finalization of the documents was shaped by public feedback and comments received on the previous corresponding draft scope documents.

To Learn More

To learn more about the availability of the EPA’s final scope documents regarding the 20 high-priority chemical substances, read the notice published in the Federal Register.

To access additional, detailed information on any of these prioritized chemicals (as well as countless others), contact ToxPlanet and register for a Free Trial.