EPA publishes TSCA New Chemicals Program risk assessment default values used in new chemical reviews

EPA published the key default values used in its risk assessments for new chemicals (TSCA section 5 reviews). This transparency update can affect how submitters and compliance teams prepare PMNs, exemption submissions, and supporting exposure/hazard arguments because EPA’s default assumptions influence risk determinations and potential TSCA orders/SNUR conditions. Companies should align dossiers and internal modeling with EPA’s published defaults and document any proposed alternative values with supporting rationale.