EPA Begins Prioritization Process for Five Chemicals for Risk Evaluation Under Toxic Substances Control Act (TSCA)


On Thursday, 12/14, EPA announced the beginning of the process to prioritize five additional toxic chemicals for risk evaluation under the Toxic Substances Control Act (TSCA). If, during the 12-month process, EPA designates these five chemicals as High Priority Substances, the EPA will begin risk evaluations for these chemicals, which would take a few years. EPA plans to prioritize the following chemicals for risk evaluation under TSCA:

  • Acetaldehyde (CASRN 75-07-0),
  • Acrylonitrile (CASRN 107-13-1),
  • Benzenamine (CASRN 62-53-3),
  • 4,4’-Methylene bis(2-chloroaniline) (MBOCA) (CASRN 101-14-4), and
  • Vinyl Chloride (CASRN 75-01-4).

Only one of the five, vinyl chloride, is potentially significant for drinking water. Vinyl chloride is used in the production of polyvinyl chloride (PVC) pipe, which is one of the most commonly used materials distribution system pipes. The current MCL for vinyl chloride is 0.002 mg/L, established in 1987 as part of the Phase I regulation. It should be noted that any potential revision to that MCL is several years down the road, as EPA would have to complete its risk assessment process (few/several years), and then decide to revise the MCL, and finally propose and finalize the revised MCL (also few/several years).