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Hazards not otherwise classified under HCS

Summary A petroleum trade group asked what counts as a “hazard not otherwise classified” under the 2012 hazard-communication rule. OSHA said the effect must be a material impairment from a chemical’s intrinsic hazard under normal use or a foreseeable emergency. Burns from hot water, slips on spilled liquids and similar situational hazards alone do not make a chemical an HNOC. Later rule amendments leave the current reach of this interpretation unconfirmed.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
2014-03-04-1
Date issued
March 4, 2014
Status
Unknown
This letter interprets the 2012 Hazard Communication Standard. OSHA amended 29 CFR 1910.1200 in 2024 and 2026 and has not confirmed whether this interpretation remains unchanged.
Status last verified October 8, 2026

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The current status of this document is unclear
This letter interprets the 2012 Hazard Communication Standard. OSHA amended 29 CFR 1910.1200 in 2024 and 2026 and has not confirmed whether this interpretation remains unchanged. It may no longer reflect the agency's current position. Treat this page as historical context, not current guidance, and verify current law before relying on anything here.
About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

March 4, 2014

Erik C. Baptist

Counsel

American Petroleum Institute

[Recipient address omitted]

Re: Request for Interpretation of OSHA's Amended Hazard Communication Standard (HCS 2012) about Hazards Not Otherwise Classified

Dear Mr. Baptist:

This letter is being issued to API to provide additional guidance on how to apply the requirements for Hazards Not Otherwise Classified (HNOC) under the March 26, 2012, revisions to OSHA's Hazard Communication Standard (HCS 2012).

Under OSHA's Hazard Communication Standard, an HNOC is defined as follows:

an adverse physical or health effect identified through evaluation of scientific evidence during the classification process that does not meet the specified criteria for the physical and health hazard classes addressed in this section. This does not extend coverage to adverse physical and health effects for which there is a hazard class addressed in this section, but the effect either falls below the cut-off value/concentration limit of the hazard class or is under a GHS hazard category that has not been adopted by OSHA (e.g., acute toxicity Category 5).

29 C.F.R. § 1910.1200(c).

Classifiers may rely on the following guidance in applying the definition of an HNOC under HCS 2012:

  • An adverse physical or health effect is a material impairment of health or functional capacity, as that phrase is used in section 6(b)(5) of the OSH Act, 29 U.S.C. § 655(b)(5), resulting from workplace exposure to a chemical.

  • A health effect is determined in accordance with the weight of evidence criteria in A.0.3.

  • The term physical effect generally refers to a material impairment of health or functional capacity caused by the intrinsic hazard(s) of a particular chemical in normal conditions of use or foreseeable emergencies. Scalds caused by exposure to chemicals at high temperatures, and slips and falls caused by treading on a solid chemical shaped in a rounded form or spilled liquids are not covered physical effects under the HNOC definition. By way of example, water is not classified as an HNOC merely because an employee might be scalded by contact with boiling water or because an employee might contract hypothermia by being immersed in cold water for a long period of time. Similarly, water is not classified as an HNOC by virtue of the fact that an employee might be injured when slipping and falling on a wet surface or when sprayed by water at high pressure. The foregoing examples of adverse physical effects that are outside the scope of HNOCs are designed to assist in better understanding the concept of HNOCs. They are not intended to be exhaustive or limited to chemicals, such as water, which are not hazardous chemicals.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules.

Sincerely,

David Michaels, Ph.D, MPH

cc: Lawrence P. Halprin, Esq.

Keller and Heckman LLP

Attorney for API

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