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.

May 20, 2016

Ms. Nicole Shoshenskiy
Authoring Services Team Lead
MSDSonline
350 N. Orleans St., Suite 950
Chicago, Illinois 60654

Dear Ms. Shoshenskiy:

Thank you for your letter to the Occupational Safety and Health Administration’s (OSHA) Directorate of Enforcement Programs. Your letter requested clarification on the hazard information that must be included in the safety data sheet (SDS) as required by the Hazard Communication Standard (HCS 2012), 29 CFR 1910.1200. This letter constitutes OSHA’s interpretation only of the requirements herein, and may not be applicable to any questions not delineated within your original correspondence. Your questions have been paraphrased below, followed by our responses.

Background: The HCS 2012 compliance directive, CPL 02-02-079,1 includes guidance for by-products that are covered under the HCS. It provides that “a manufacturer's or importer's hazard determination or hazard classification must anticipate the full range of downstream uses of their products and account for any hazardous by-products which may be formed.”

Question 1: Are chemical by-products required to be included in SDS Section 2, in Hazards Not Otherwise Classified (HNOC), or merely as warning language throughout the SDS? Should information on by-products be included in SDS Section 3?

Response: A manufacturer’s or importer’s hazard classification must account for the hazards of by-products, including HNOCs. This information must be included in SDS Section 2, as well as in SDS Section 10 (Stability and reactivity). If a by-product poses an HNOC, that information must be included in SDS Section 2(c) (which requires information on HNOCs). A manufacturer's or importer's hazard determination or hazard classification must anticipate the full range of downstream uses of their products and account for any hazardous by-products which may be formed. There is no requirement to include chemical by-product(s) information in SDS Section 3 (Composition/information on ingredients).

Question 2: Do manufacturers have the obligation to track down their products to all downstream users in the supply chain to obtain information on the uses of their products that may form hazardous by-products?

Response: Manufacturers and importers covered by the HCS 2012 must make a reasonable effort to obtain reliable information to determine how their product(s) or by-product(s) may expose workers under normal conditions of use or in foreseeable emergencies. A manufacturer's or importer's hazard classification must anticipate the full range of downstream uses of its products and account for any hazardous by-products that are known to be present and may be formed. However, there is no requirement that each and every downstream work environment be contacted to obtain the hazard information.

Question 3: Is polymerization considered an HNOC because of the chemical reaction, or because of the quantity of heat that is released?

Response: Polymerization of monomers is a chemical reaction that is often exothermic (evolves heat). Loss of control of polymerization reactions can result in fires, explosions, or toxic releases. Polymerization is considered an HNOC because of these hazards.

Question 4: What are the criteria for determining if something is or is not an HNOC?

Response: CPL 02-02-079 clarifies that an HNOC means 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 the standard. OSHA’s definition for HNOC ensures that hazards previously covered under HCS 1994 remain covered under HCS 2012 by including hazards that currently fall outside the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (GHS) hazard classes. It is OSHA’s intent that the HNOC classification would be an interim measure, used until harmonized criteria for a hazard can be adopted at the UN Sub-committee level, and subsequently incorporated into the HCS through rulemaking.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA’s requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA’s interpretation of the requirements discussed. From time to time, letters are affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To ensure that you are using the correct information and guidance, please consult OSHA’s website at https://www.osha.gov. If you have further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs

1. CPL 02-02-079, Inspection Procedures for the Hazard Communication Standard (HCS 2012), /OshDoc/Directive_pdf/CPL_02-02-079.pdf.