EPA Opens Consultation on Draft TSCA Risk Assessments for HHCB and Phthalic Anhydride

In April 2026, the U.S. Environmental Protection Agency (EPA) published draft TSCA risk assessments for two substances: HHCB, a synthetic fragrance ingredient, and phthalic anhydride, a chemical intermediate widely used in industrial applications. The publication initiates a public consultation phase under the Toxic Substances Control Act.
EPA’s draft findings indicate divergent preliminary outcomes for the two substances. 

• For HHCB, which is commonly used in detergents, cleaners, and air fresheners, EPA does not preliminarily identify unreasonable risks under the evaluated conditions of use. 
• For phthalic anhydride, however, EPA’s draft assessment points to potential unreasonable risks to human health, primarily linked to specific occupational and consumer exposure scenarios.

The consultation is intended to gather technical and scientific input on exposure assumptions, hazard characterization, and methodological approaches used in the assessments. Stakeholders with manufacturing, import, or downstream use interests are encouraged to review the draft evaluations and provide comments, particularly where use patterns, exposure data, or risk assumptions may not reflect current practices.
The consultation period is open until 15 June 2026. Following review of submitted comments and scientific peer input, EPA will finalise the risk evaluations. Where unreasonable risk is confirmed in a final assessment, TSCA requires EPA to proceed to risk management measures in a subsequent regulatory step.
Source: WTO TBT Notification – US EPA Notice on Draft TSCA Risk Evaluations for HHCB and Phthalic Anhydride, Federal Register, April 2026.