Priority setting for carcinogen regulation

No — OSHA does not use a fixed scoring formula when setting priorities for potential occupational carcinogens. The rule explicitly states that "it is not appropriate to establish a rigid formula or to assign predetermined weight to each factor," and that the listed elements are guidance only (1990.132(a)).

• Practical point: Expect OSHA to weigh factors case-by-case rather than apply a mechanical points system.
• Compliance tip: Prepare evidence across multiple factors (exposure numbers, exposure levels, health studies, alternatives) because OSHA will consider the whole picture rather than a single score.

Under 1990.132(b)(1), employers should estimate the number of workers exposed by using available workplace data and reasonable methods to count or sample potentially exposed employees (1990.132(b)(1)).

• Practical steps: review work processes, job titles, shift patterns, production volumes, and historical monitoring records; use job-exposure matrices or walk-through surveys when direct measurements are limited.
• Document your approach and assumptions so OSHA or others can understand how you arrived at exposure population estimates.

Under 1990.132(b)(2), OSHA considers estimates of actual human exposure levels, meaning measured or reasonably estimated concentrations or doses that workers encounter (1990.132(b)(2)).

• Practical examples: personal air sampling results, area air samples, biological monitoring, and modeled exposure estimates when measurements are not available.
• Tip: Provide context (task, duration, controls in use) with exposure numbers so OSHA can compare them to health-effect data and decide priority.

Under 1990.132(b)(3), OSHA uses reported exposure levels that have been associated with increased neoplasms in humans or animals as a key factor in deciding how urgently to regulate a substance (1990.132(b)(3)).

• Practical interpretation: If studies show cancer at exposure levels close to workplace levels, the substance will likely receive higher priority.
• What to provide: peer-reviewed studies, dose–response data, and comparisons between reported harmful levels and measured workplace exposures.

Yes — under 1990.132(b)(4), OSHA will consider whether regulatory action could reduce other occupational or environmental health hazards in addition to cancer risk (1990.132(b)(4)).

• Practical implication: A substance that also causes respiratory, reproductive, or acute toxic effects may be prioritized higher because regulation could yield multiple health benefits.
• Strategy: When submitting data or comments, highlight non-cancer hazards and potential co-benefits of regulation to strengthen the priority case.

Under 1990.132(b)(5), a substance whose molecular structure is similar to a confirmed or suspected carcinogen can be given higher priority because structural similarity suggests shared biological risks (1990.132(b)(5)).

• What this means in practice: Structural analogs may prompt OSHA to review mechanistic data, toxicology studies, and read-across evidence.
• What to supply: chemical structure comparisons, mechanistic or toxicological data, and any read-across analyses that show biological plausibility.

Under 1990.132(b)(6), OSHA considers whether there are substitutes that pose lower cancer or health risks and whether regulation would impose only small social or economic costs, which can raise a substance’s priority for regulation (1990.132(b)(6)).

• Practical use: If low-risk substitutes exist and are feasible, OSHA may prioritize regulation because the burden of change is smaller.
• What to document: availability, performance, cost comparisons, and barriers to substitution for alternative materials or processes.

Yes — under 1990.132(b)(7), OSHA will consider actions being taken or planned by other governmental agencies and balance its responsibilities with other health and safety hazards when setting priorities (1990.132(b)(7)).

• Practical effect: OSHA may give weight to scientific reviews, regulatory decisions, or ongoing rulemakings from agencies like EPA, NIOSH, or FDA.
• How to use this: Provide cross-agency reports or relevant regulatory findings to show alignment and avoid duplicated effort.

Under 1990.132, OSHA recognizes that some factors may be unavailable and allows consideration of whatever reliable data are available rather than requiring complete datasets (1990.132(b)).

• Practical steps: supply the best available evidence (exposure estimates, case reports, animal studies, analog chemical data) and clearly state data gaps and uncertainties.
• Tip: Explain how missing data affect conclusions and, if possible, propose reasonable assumptions or monitoring plans to fill gaps.

No — under 1990.132(a), the priority-setting elements are guidance for OSHA staff and the public and are not intended to create any legal rights regarding priority decisions (1990.132(a)).

• Practical interpretation: Priority-setting is an internal and policy tool, not a source of enforceable obligations by itself.
• Note: While priority lists do not create rights, subsequent rulemaking or standards based on those priorities can create enforceable requirements.

Under 1990.132(b), regulators consider both the number of workers exposed and the exposure levels together rather than applying a fixed formula, weighing each case qualitatively based on available data (1990.132(b)).

• Practical guidance: A substance with low exposure but millions exposed may get high priority, as might a substance with high exposures affecting few workers; provide clear data on both dimensions.
• Recommendation: Present scenarios showing how many workers are exposed at low, medium, and high levels and include task-specific exposure information.

Under 1990.132(b)(3), employers should present both human and animal evidence, emphasizing human epidemiology but including animal data to fill gaps and support biological plausibility (1990.132(b)(3)).

• Practical ordering: Lead with well-conducted human studies, then add corroborating animal studies, dose–response details, and mechanistic information.
• Tip: Explain differences in exposure routes, doses, and relevance to workplace conditions to help OSHA evaluate comparability.

Under 1990.132(b)(4), a company should document specific health outcomes and exposure pathways showing how one regulatory action would mitigate multiple hazards, using monitoring data, incident reports, and toxicology evidence (1990.132(b)(4)).

• What to include: quantitative exposure reductions expected, descriptions of other health endpoints affected, and any co-benefits such as reduced environmental contamination.
• Practical tip: Provide before-and-after scenarios or modeling that estimate reductions in cancer risk and other health effects.

Under 1990.132(b)(5), OSHA benefits from clear chemical structural information, such as molecular formulas, structural diagrams, functional groups, and mechanistic toxicology that show similarity to known carcinogens (1990.132(b)(5)).

• Useful materials: structure–activity relationship (SAR) analyses, in vitro bioassays, metabolic pathway data, and read-across justifications.
• How to present it: include diagrams and concise explanations of how structural features link to genotoxic or carcinogenic mechanisms.

Under 1990.132(b)(6), employers should provide cost and feasibility information showing that substitutes or control measures are available and affordable, demonstrating small social and economic impacts (1990.132(b)(6)).

• What to include: cost comparisons of current practice vs. alternatives, supply-chain availability, productivity impacts, and case studies where substitutions were successfully implemented.
• Presentation tip: Quantify costs per facility or per worker where possible and include sensitivity ranges to account for uncertainty.

Under 1990.132(b)(7), stakeholders should submit relevant documents from other agencies (for example, regulatory decisions, scientific assessments, or risk evaluations) to show existing or planned actions that OSHA can consider when setting priorities (1990.132(b)(7)).

• Examples to provide: EPA risk assessments, NIOSH recommendations, FDA safety findings, or international agency classifications.
• Why this helps: Cross-agency information can streamline OSHA’s review and help harmonize regulatory approaches.

Under 1990.132, workers and unions can provide data and comments that address any of the listed factors (exposure numbers, exposure levels, health studies, substitutes, etc.) to inform OSHA’s priority decisions (1990.132(b)).

• Practical advice: Submit concise, evidence-based comments with supporting documents (monitoring data, incident logs, medical surveillance results) and identify which factor(s) the submission addresses.
• Tip: Highlight workplace examples and provide contact information for follow-up or clarifying questions.