TSCA Update: 5 Chemicals Get Final High Priority Designations

On December 18, 2024, EPA designated five chemicals as High Priority Substances for risk evaluation under the Toxic Substances Control Act (TSCA), as amended in 2016: 

• Acetaldehyde 
• Acrylonitrile 
• Benzenamine
• Vinyl Chloride 
• 4,4’Methylene bis (2-chloroaniline) (MBOCA)

EPA also named five other chemicals as new candidates for future prioritization

What Happens Next?
Designation as s High Priority Substance does not, by itself, result in new regulations or restrictions on these chemicals. As part of the TSCA risk evaluation process, EPA must prioritize chemicals for evaluation based on factors like volume of the chemical in use, the level of risk, etc.

As EPA says in the rule, “A designation of a substance as a High Priority Substance is not a finding of unreasonable risk. Rather, the designation of these chemical substances as high priority constitutes the initiation of evaluation of associated risk.” 

TSCA directs EPA to conduct risk evaluations for chemicals on the TSCA Inventory List in order to determine whether each chemical poses an “unreasonable risk” to human health, the environment, or both. When EPA determines that a chemical does pose an unreasonable risk, the agency must create regulations to address the risk by prohibiting or restricting activities involving the chemical. 

Next Step: Scoping Out the Risk Evaluation 

Once a chemical is designated as a High Priority Substance, EPA produces a "scope" for a risk evaluation. The scope document comes from an in-depth study of the chemical and available information from stakeholders, medical professionals, and others. 

The scope describes the hazards, exposures, and uses of the chemical EPA will evaluate. TSCA risk evaluation scopes also identify potentially exposed or susceptible subpopulations. Once a scope has been subjected to the public comment process, a final scope is created and published. At that point, the risk evaluation begins. 

The five newest High Priority Substances are now on a list with several other chemicals, most of which received the priority designation in 2019 and already have an approved final scope.

For more details, click the "High Priority" tab of the TSCA Activity Tracker. 

5 Chemicals Down, 5 More Up  

To keep the risk evaluation process moving forward, each time EPA designates a chemical as a High Priority Substance, another chemical must be placed up for consideration. With five chemicals getting final designations from EPA ls at week, the law requires EPA to name 5 more they will consider as possible priorities.

The five chemicals now being considered for prioritization are: 

• 4-teat-Ocylphenol 
• Benzene
• Ethylbenzene
• Naphthalene 
• Styrene 

Online TSCA Training

Be confident you can meet your EPA chemical reporting, recordkeeping, and management requirements under the newest TSCA rules.

The TSCA Regulations Online Course guides EHS managers through these complex rules—including how to use the TSCA Chemical Inventory; inventory, IUR, or “Form U” reporting responsibilities; Pre Manufacture Notifications (PMN); Significant New Use Rules (SNUR); and management standards for PCBs.