In 1971, OSHA initially adopted a permissible exposure limit (PEL) for benzene of 10 parts per million (ppm), reflecting existing consensus standards. After accumulating evidence linking benzene to leukemia and other hematological disorders, OSHA in 1978 promulgated a new permanent health standard lowering the PEL from 10 ppm to 1 ppm, with ancillary requirements (monitoring, protective equipment, medical surveillance). OSHA emphasized that benzene is a carcinogen for which no safe threshold could be definitively established, and it elected to reduce exposure to the lowest level it considered technologically and economically feasible. OSHA declined to quantify the degree of risk at 10 ppm or the risk reduction achieved by 1 ppm, reasoning that the best available evidence did not allow precise quantification and that § 6(b)(5) of the OSH Act directs the agency to protect workers "to the extent feasible." The American Petroleum Institute and other industry groups petitioned for review, arguing that OSHA lacked substantial evidence of a significant risk at 10 ppm and that the statute required more than a feasibility-driven, zero-threshold policy. The Fifth Circuit vacated the 1 ppm standard and remanded. The Industrial Union Department (representing labor) sought Supreme Court review, contending that the OSH Act allowed OSHA to act on carcinogens without establishing a particular risk level at the prior standard.
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.
The plurality began with the OSH Act's text and structure. Section 3(8) limits standards to those "reasonably necessary or appropriate," while § 6(b)(5) directs OSHA to protect workers from toxic materials "to the extent feasible" using the best available evidence. Reading these provisions together, the Court concluded Congress did not grant OSHA unbounded discretion to push exposures to the lowest feasible level without a reasoned finding that a standard addresses a significant workplace risk. The significant-risk requirement ensures that OSHA's standards are tethered to demonstrable hazards rather than driven by generalized precaution. Applying this framework, the Court emphasized that OSHA must do more than invoke the possibility that carcinogens have no safe threshold. While the agency may rely on conservative assumptions and need not prove risk with mathematical precision, it must make a rational, record-based determination that current exposure levels present a significant risk of material health impairment and that the chosen standard will materially reduce that risk. Here, OSHA expressly declined to quantify or otherwise reasonably assess the magnitude of risk at 10 ppm or to explain how much risk reduction the 1 ppm standard would achieve. Instead, it relied on a policy judgment—reduce benzene exposure to the lowest feasible level because benzene is carcinogenic—without the necessary threshold risk findings. The plurality also invoked the canon of constitutional avoidance. Interpreting § 6(b)(5) to authorize OSHA to regulate to zero risk whenever technically feasible, without any limiting principle, would raise serious nondelegation concerns by conferring virtually standardless power. By requiring a significant-risk finding, the Court cabined OSHA's discretion and avoided those constitutional difficulties. Although a concurring opinion would have gone further and questioned the statute under the nondelegation doctrine, the plurality resolved the case on statutory grounds. The Court did not impose a cost-benefit mandate, but it insisted on a reasoned risk assessment showing both the existence of significant risk at the baseline and a meaningful risk reduction under the new standard.
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.
Industrial Union Department v. American Petroleum Institute anchors the principle that agency health standards must be grounded in demonstrable, significant risks and reasoned explanations of risk reduction, not merely in precautionary policies or feasibility. By vacating OSHA's 1 ppm benzene standard, the Court reinforced the requirement that agencies build robust records and make explicit threshold findings before imposing far-reaching rules.