In April 2026, the US Environmental Protection Agency advanced its evaluations of four high-priority chemicals under Section 6 of the Toxic Substances Control Act: the fragrance ingredient HHCB, phthalic anhydride, o-dichlorobenzene, and p-dichlorobenzene. EPA released draft risk evaluations for HHCB and phthalic anhydride, while the two dichlorobenzenes remain at the draft hazard-assessment stage. The Science Advisory Committee on Chemicals reviewed the documents during a public meeting held from 8–12 June 2026.

EPA preliminarily concluded that HHCB does not present an unreasonable risk under its evaluated conditions of use. The outcome is more significant for phthalic anhydride: EPA identified preliminary unreasonable risks in 38 of 44 evaluated uses, mainly involving workers, with additional concerns for certain occupational non-users and consumers using adhesives, sealants, paints, and coatings. Respiratory and skin sensitization were central to the findings, although EPA noted that engineering controls and suitable personal protective equipment may reduce workplace exposures.

For the industry, the review creates a clear need to verify exposure assumptions, document existing controls, and assess whether safer formulations or process changes are feasible. Manufacturers and downstream users of phthalic anhydride face the greatest near-term pressure, as a final unreasonable-risk determination would require EPA to develop risk-management measures. The dichlorobenzene assessments also warrant close monitoring because they cover uses in chemical production, deodorizing products, automotive applications, and insulation materials.