16 CFR § 1500.5 - Hazardous mixtures.

---
identifier: "/us/cfr/t16/s1500.5"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "16 CFR § 1500.5 - Hazardous mixtures."
title_number: 16
title_name: "Commercial Practices"
section_number: "1500.5"
section_name: "Hazardous mixtures."
chapter_name: "CONSUMER PRODUCT SAFETY COMMISSION"
subchapter_number: "C"
subchapter_name: "FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS"
part_number: "1500"
part_name: "HAZARDOUS SUBSTANCES AND ARTICLES: ADMINISTRATION AND ENFORCEMENT REGULATIONS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "15 U.S.C. 1261-1278."
regulatory_source: "38 FR 27012, Sept. 27, 1973, unless otherwise noted."
cfr_part: "1500"
---


# 1500.5 Hazardous mixtures.

For a mixture of substances, the determination of whether the mixture is a “hazardous substance” as defined by section 2(f) of the act (repeated in § 1500.3(b)(4)) should be based on the physical, chemical, and pharmacological characteristics of the mixture. A mixture of substances may therefore be less hazardous or more hazardous than its components because of synergistic or antagonistic reactions. It may not be possible to reach a fully satisfactory decision concerning the toxic, irritant, corrosive, flammable, sensitizing, or pressure-generating properties of a substance from what is known about its components or ingredients. The mixture itself should be tested.