448 U.S. 607 (1980)
Often called the "Benzene Case," Industrial Union Department, AFL-CIO v. American Petroleum Institute is a landmark in administrative law and workplace safety regulation.
Under the OSH Act, may OSHA set a permanent health standard for a carcinogen by reducing exposure to the lowest technologically and economically feasible level without first determining on the record that a significant risk of material health impairment exists at current exposure levels and that the new standard will materially reduce that risk?
Before promulgating a permanent health standard under the OSH Act, OSHA must determine, based on substantial evidence and the best available information, that (1) a significant risk of material health impairment exists at then-current exposure levels and (2) the proposed standard is reasonably necessary or appropriate to reduce that risk to a significant degree and is feasible. The Act does not authorize OSHA to set exposure limits at the lowest technologically feasible level solely because a substance is a carcinogen; a reasoned, evidence-based significant-risk finding is required. See 29 U.S.C. §§ 652(8) (standards must be "reasonably necessary or appropriate") and 655(b)(5) (toxic materials standards must protect employees "to the extent feasible" on the basis of the best available evidence).
Affirmed. OSHA's benzene standard reducing the PEL from 10 ppm to 1 ppm was invalid because the agency failed to make a threshold finding, supported by substantial evidence, that a significant risk of material health impairment existed at 10 ppm and that the 1 ppm limit would significantly reduce that risk. The case was remanded for further proceedings consistent with this requirement.
Industrial Union is foundational for administrative law and regulatory practice. It establishes the "significant risk" threshold for OSHA health standards, demanding evidence-based, reasoned decision making and rejecting a purely feasibility-driven zero-threshold approach. The case shaped modern risk assessment in health and safety regulation and is frequently cited for the proposition that agencies must tether rules to demonstrable risks and articulate how their actions will materially reduce those risks. For law students, the case illustrates key tools of statutory interpretation, the substantial evidence standard on review of rulemaking records, the use of constitutional avoidance to limit agency discretion, and the boundary between feasibility and precaution. It foreshadows later debates about major questions and nondelegation by insisting that Congress must supply and courts must enforce meaningful limits on agency power, especially when rules carry major economic and policy consequences.