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. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

January 20, 1987

Mr. D. S. Richardson
2655 Harland Drive
Hudson, Ohio 44236

Dear Mr. Richardson:

This is in response to your letter of December 13, 1986, requesting clarification of the terms "appropriate hazard warning" and "mandatory" as used in the Occupational Safety and Health Administration's (OSHA) Hazard Communication Standard.

Concerning "appropriate hazard warning," OSHA's guidelines to its compliance staff on the Hazard Communication Standard OSHA Instruction CPL 2-2.38A Change 1, page A-11, enclosed states that the specific hazards indicated in the standards definition for "physical" and "health" hazards must be used in evaluating the appropriateness of specific warnings. In the example you presented, if the only scientific information available is the LC(50) of 5 milligrams per kilogram administered orally to rats, "highly toxic if ingested" may be the appropriate warning. If the chemical causes specific target organ effects when ingested, then the specific target organ effects would be appropriate.

As stated in Appendix B of the Hazard Communication Standard, the hazard determination is performance-oriented and relies heavily on the professional judgment of the evaluator. Nevertheless, the hazard determination must examine all relevant data and produce a scientifically defensible evaluation. The results of any studies which are designed and conducted according to established scientific principles must be reported if statistically significant health effects are found. If these statistically significant health effects are known to the target organ level, then these health effects would be "appropriate."

If only general health effects are known, then it would be "appropriate" to list these on the label.

The Hazard Communication Standard at 29 CFR 1910.1200(d)(2) states, "Appendix A shall be consulted for the scope of health hazards covered." The term "mandatory" refers to the requirement to consult Appendix A for the scope of health hazards.

Please feel free to contact us, if further assistance is needed.


John A. Pendergrass
Assistant Secretary