• EPA must make an unreasonable risk finding or determination before requiring information on, or regulating, a chemical.
• Even if EPA concludes under TSCA that a chemical presents an unreasonable risk, TSCA provides that other federal laws supersede EPA’s authority under TSCA to address unreasonable risks.

In addition to excluding groups of chemicals from the scope of chemicals covered under the Toxic Substances Control Act (TSCA), Congress generally limited the extent to which the Environmental Protection Agency (EPA) may regulate a chemical.

Unreasonable risk threshold

EPA cannot simply regulate a chemical at will. The agency must make an unreasonable risk finding or determination before requiring information on, or regulating, a chemical. The trouble is TSCA does not explicitly define what constitutes an unreasonable risk. In 1991, the U.S. Court of Appeals for the Fifth Circuit held that the “unreasonable risk” standard as originally set forth in TSCA meant that “[i]n evaluating what is ‘unreasonable,’ the EPA is required to consider the costs of any proposed actions and to ‘carry out this chapter in a reasonable and prudent manner [after considering] the environmental, economic, and social impact of any action.’” This interpretation led the court to vacate parts of the 1989 EPA rule that regulated various asbestos uses.

Though the Frank R. Lautenberg Chemical Safety for the 21st Century Act (LCSA) did not amend TSCA to explicitly define unreasonable risk, it prohibited EPA from considering cost or nonrisk factors when evaluating risks. However, EPA must consider “reasonably ascertainable economic consequences” and other nonrisk factors when restricting uses of a chemical. Additionally, the LCSA codified existing agency practice to consider risks for “potentially exposed or susceptible subpopulations” when evaluating the risks of a chemical.

Relationship with other federal laws

Even if EPA concludes under TSCA that a chemical presents an unreasonable risk, TSCA provides that other federal laws supersede EPA’s authority under TSCA to address unreasonable risks. If EPA determines that a risk associated with a chemical may be sufficiently eliminated or reduced by actions taken under other federal laws that the agency administers, section 9(b) of the Act requires the agency to use those authorities to protect against the risk unless the agency determines that it is in the public interest to take action under TSCA.

If EPA determines that a chemical presents an unreasonable risk that may be sufficiently prevented or reduced by action taken under a federal law a different federal agency administers, section 9(a) directs EPA to submit to that other agency a report describing the risk and a request for a response. A federal agency that receives such a report from EPA must respond within 90 days (or a shorter period if specified by EPA). If that federal agency issues an order disagreeing with EPA about the unreasonable risk or initiates action to protect against such risk, then EPA may not regulate the chemical under TSCA.