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Now Final: 20 High-Priority Chemicals for TSCA Risk Evals

Posted on January 07, 2020 by Roger Marks

On December 20, US EPA finalized the first twenty High-Priority chemical substances scheduled for risk evaluations under the Toxic Substances Control Act (TSCA).

Under TSCA section 6(b), EPA is required to evaluate the risks associated with the conditions of use of all the chemicals on the TSCA inventory. Of the more than 80,000 listed on the TSCA inventory, 40,655 are active in commerce (meaning they are currently manufactured, imported, or processed in the US).

In August 2019, EPA proposed these first 20 high-priority chemicals to undergo risk evaluations under the reformed chemical law. Under the Frank R. Lautenberg Chemical Safety for the 21st Century Act (LCSA), which amended TSCA, EPA is required to be working on twenty risk evaluations at any one time. 

Here’s EPA’s final list of the first 20 High-Priority chemicals:




1,3-Butadiene 106-99-0
Butyl benzyl phthalate (BBP) 85-68-7
Dibutyl phthalate (DBP) 84-74-2
o-Dichlorobenzene 95-50-1
p-Dichlorobenzene 106-46-7
1,1-Dichloroethane 75-34-3
1,2-Dichloroethane 107-06-2
1,2-Dichloropropane 78-87-5
Dicyclohexyl phthalate 84-61-7
Di-ethylhexyl phthalate (DEHP) 117-81-7
Di-isobutyl phthalate (DIBP) 84-69-5
Ethylene dibromide 106-93-4
Formaldehyde 50-00-0
HHCB* 1222-05-5
4,4′-(1-Methylethylidene)bis[2, 6-dibromophenol] (TBBPA) 79-94-7
Phosphoric acid, triphenyl ester (TPP) 115-86-6
Phthalic anhydride 85-44-9
1,1,2-Trichloroethane 79-00-5
Tris(2-chloroethyl) phosphate (TCEP) 115-96-8

*  1,3,4,6,7,8-Hexahydro-4,6,6,7,8,8-hexamethylcyclopenta [g]-2-benzopyran

Details about each high-priority chemical substance is available at EPA's website. 

(See EPA's Notice in the Federal Register) 

What’s Next for TSCA Risk Evaluations?

Proposing a chemical as a “high-priority” chemical does not mean that the chemical necessarily poses an unreasonable risk to human health or the environment. It means that EPA has determined that the chemical may pose such a risk—and initiates the official risk evaluation process.

Now that final designations have been made for the first twenty high-priority chemicals, EPA will begin the process of evaluation the risks posed by these chemical substances.

To evaluate each chemical, EPA will consider: 
  • Hazard and exposure potential
  • Persistence and bioaccumulation 
  • Potentiallly exposed or susceptible subpopulations
  • Storage of the chemical near drinking wate sources 
  • Conditions of use or significant changes in conditions of use 
  • Product volume or significant changes in production volume 
  • Other risk-based criteria EPA believes is relevant   
If EPA’s risk evaluation process determines that a chemical substance does in fact present an unreasonable risk, EPA must create new management standards or restrictions for the chemical under TSCA within one year.

Master TSCA Compliance

The Toxic Substances Control Act (TSCA) is complex and enforcement is stringent, making a comprehensive understanding of the rules critical for compliance.  The law has broad applicability, subjecting all companies that “manufacture, use, process, distribute, import, or export chemical products” to complex reporting and management requirements.
Be confident you’re meeting your TSCA chemical management and reporting responsibilities! Sign up now for the interactive TSCA Regulations Online Course or call 888-546-6511 to speak with a Lion regulatory expert.