SDS Section 3

Composition: the ingredients, their CAS numbers, and concentration ranges.

Section 3 lists the substances in the product with their CAS numbers and concentration, either as an exact figure or a range.

This is the section that identifies whether a mixture contains an Extremely Hazardous Substance or a TRI-listed chemical, which is what determines reporting obligations for the product as a whole.

Concentrations may be withheld as trade secret under defined conditions, in which case the sheet states so rather than giving the figure.

Related terms

• CAS numberA unique numeric identifier for a chemical substance, used to match inventories against regulatory lists.
• Extremely Hazardous SubstanceA substance on EPA's Section 302 list, subject to lower reporting thresholds and emergency planning notification.
• Safety Data SheetThe 16-section document a manufacturer must supply describing a hazardous chemical's hazards, handling and properties.
• Trade secret claimA withheld chemical identity or concentration on a safety data sheet, permitted under defined conditions.

A plain-English explanation, not legal advice. Figures are the federal baseline; your state may differ, so see the state-by-state requirements.