Section 3: Composition/information on ingredients

This section names each hazardous ingredient (or ingredient range, for mixtures) and its CAS number, subject to a trade-secret carve-out.

Section number: 3
Heading: Composition/information on ingredients
Content status: Mandatory content
Required information: (trade-secret carve-out per (i)).
For substances: (a) chemical name; (b) common name and synonyms; (c) CAS number and other unique identifiers; (d) classified impurities/stabilizing additives contributing to classification.
For mixtures, additionally: (a) chemical name, CAS number or other unique identifier, and exact percentage or ranges of all health-hazard-classified ingredients above cut-offs or presenting risk below cut-offs (note: when CAS unavailable/trade-secret, indicate the source of the unique identifier); (b) exact percentage unless trade secret, batch variability, or substantially-similar mixture group — then ranges (prescribed ranges of (i)(1)(iv)-(vi) when concentration withheld as trade secret).
Trade-secret statement required where claimed.

Reference only. Not legal or regulatory advice. Verify against the primary source before you act.

Adjacent sections

See the whole sheet

SDS Section Guide lays out all sixteen sections in order with what each one must carry.

Sources

29 CFR 1910.1200 Appendix D (Table D.1), post-2024-HazCom-update text — as of 2026-07-13

Sections 1 to 11 and 16 carry mandatory content. Sections 12 to 15 must appear as headings, but OSHA does not enforce their content.

open the source

Data vintage

Data: Safety data sheet 16-section structure, U.S. Occupational Safety and Health Administration current revision (77 FR 17884, Mar 26 2012; 89 FR 44459, May 20 2024; 91 FR 594-598, Jan 8 2026), retrieved 2026-07-13, 16 sections.