Issues in carcinogen rulemaking

OSHA decides whether substances should be grouped by evaluating if they are appropriately considered in a single proceeding under 1990.146(a).

• OSHA will look at scientific similarity (mechanism of action, exposure routes), common uses or workplace settings, and whether combining them improves regulatory clarity or efficiency.
• If grouping would obscure important differences in hazard or exposure, OSHA may keep proceedings separate.

See also the general scope of issues listed in 1990.146 for how this question fits into the broader rulemaking process.

You must show reliable scientific evidence that links the substance to carcinogenic potential in workers to meet the definition under 1990.146(b) and the criteria set in 1990.103.

• Evidence can include animal bioassays, well-conducted epidemiological studies, or mechanistic data that are judged reliable and relevant to occupational exposure.
• OSHA evaluates study quality, reproducibility, and relevance to workplace exposures when deciding whether the substance meets the definition.

Refer to 1990.103 for the detailed definition and factors used to judge scientific reliability.

OSHA evaluates whether the studies and data are relevant and directly applicable to the specific substance, group, or combination being reviewed under 1990.146(c).

• OSHA checks if the tested chemical form, exposure route, dose levels, and workplace contexts match the use being regulated.
• If data are from close chemical analogs, OSHA assesses whether those analogs reliably predict effects for the substance in question.

This assessment helps determine whether the data can support regulatory decisions for that specific rulemaking (see 1990.146).

New information submitted under 1990.144 can warrant an exception to the part if it shows the substance or situation falls outside the scope or assumptions of the rulemaking according to 1990.146(d).

• For example, evidence that worker exposures are non-existent for a particular use, or that a substance is already regulated adequately under another standard, may justify an exception.
• Submissions should be timely, factual, and include supporting data to be considered sufficient.

See 1990.144 for how to submit information for consideration.

OSHA will evaluate whether the data and arguments submitted under 1990.145 are sufficient to warrant amending the part, as described in 1990.146(e).

• OSHA looks for credible scientific studies, exposure data, or legal/policy arguments that demonstrate the need for amendment.
• Submissions should be specific about how the current regulatory approach is inadequate or how new information changes the risk or feasibility calculus.

Refer to 1990.145 for the type of petitions and information OSHA expects to consider.

A Category I Potential Carcinogen is one for which evidence meets the stronger criteria of probable occupational carcinogenicity, while a Category II Potential Carcinogen meets lesser but still concerning criteria; OSHA evaluates these using the standards in 1990.146(f) together with the definition in 1990.103.

• Category I typically requires more consistent, high-quality human or animal evidence indicating a real risk in occupational settings.
• Category II may be used when evidence suggests carcinogenic potential but is less definitive or directly applicable to workplace exposures.

See 1990.103 for the scientific factors OSHA uses to categorize potential carcinogens.

OSHA considers environmental impacts arising from regulation of the substance as one of the issues to evaluate under 1990.146(g).

• This can include assessing how controlling workplace exposures may shift emissions, waste, or other impacts to the environment, and whether such impacts need mitigation.
• OSHA will weigh environmental consequences alongside worker protection goals when crafting regulatory options.

For the broader list of issues considered in a proceeding, see 1990.146.

OSHA must address any issues required by statute or executive order, such as economic analyses, information collection, or environmental reviews, as identified in 1990.146(h).

• Common examples include compliance with the Regulatory Flexibility Act, Executive Orders on regulatory review, and requirements under the National Environmental Policy Act.
• OSHA will identify these requirements early and incorporate them into the rulemaking record and analyses.

See 1990.146 for context on how these statutory/EO issues fit into the proceeding.

OSHA determines the control level for Category I Potential Carcinogens by evaluating engineering and work practice controls along with technological and economic feasibility per 1990.146(i).

• OSHA aims to set exposure levels achievable primarily through engineering and work practice controls and considers whether those controls are technologically and economically feasible.
• The agency analyzes exposure-response data, available control technologies, costs, and impacts on affected workplaces.

See 1990.146(i) and the general issues in 1990.146 for how this fits into the rulemaking.

For Category II Potential Carcinogens, OSHA determines an appropriate employee exposure level consistent with the Act's requirements as stated in 1990.146(j).

• OSHA considers the best available scientific evidence on dose-response, feasibility, and the statutory mandate to protect worker health when setting these levels.
• Because Category II substances may have less definitive evidence, OSHA balances uncertainty, practicability, and the need for protection in choosing an exposure limit.

Refer to 1990.146(j) and the general 1990.146 issues for context.

OSHA evaluates whether suitable substitutes are available for uses of Category I Potential Carcinogens and, if so, whether a no occupational exposure level can be achieved using engineering and work practice controls, as required by 1990.146(k).

• The agency looks at the availability, safety, performance, and economic feasibility of substitutes for specific uses.
• If substitution is feasible, OSHA may set a regulatory target of no occupational exposure achievable through controls and substitution-related measures.

See 1990.146(k) for requirements related to substitution evaluations.

OSHA assesses appropriateness by reviewing whether the proposal and the model standards in 1990.151 and 1990.152 are suitable for the substance, except where limited by 1990.142, according to 1990.146(l).

• OSHA examines whether model provisions (monitoring, medical surveillance, controls) are effective and feasible for the specific carcinogen.
• The agency also considers if additional regulatory requirements are needed beyond the models.

See 1990.151 and 1990.152 for the model standards referenced.

Section 1990.144 covers submitting information, data, and views to ask for an exception to the part, while 1990.145 covers petitions to amend the part; both are considered under the issues in 1990.146(d)–(e).

• Use 1990.144 to provide factual data or arguments that a particular substance or circumstance should be excepted from the rulemaking scope.
• Use 1990.145 to petition formally for amendments to the regulatory part based on new evidence or policy reasons.

Both kinds of submissions must be timely and supported by data to influence OSHA’s consideration under 1990.146.

You should submit information under 1990.144 because that section provides the mechanism for submitting data, information, and views that could support an exception, which OSHA will evaluate under 1990.146(d).

• Provide clear factual evidence showing why the specific use falls outside the rulemaking assumptions (e.g., no exposure in workplaces, existing adequate regulation).
• Timely, well-documented submissions have the best chance of being considered.

See 1990.144 for submission details and how OSHA uses those materials in the proceeding.

Yes, while 1990.146(a) focuses on whether substances should be in a single proceeding, OSHA also considers technological and economic implications of regulatory approaches under related provisions such as 1990.146(i) when determining appropriate controls across grouped substances.

• Grouping decisions weigh scientific similarity and whether a combined rule would allow effective, feasible control strategies.
• If grouping masks important differences in feasible controls or costs, OSHA may choose separate proceedings.

See 1990.146 for the full list of issues considered during proceedings.