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Below is an unedited answer from the PlainReg AI RegWiki, generated on this site against a knowledge base compiled from nine official government documents — the laws themselves, not summaries of them — current to July 30, 2026.
United States (OSHA HCS)
For mixtures, the key deadlines under the amended HCS (aligning primarily with GHS Rev. 7) are:
- Manufacturers/importers/distributors must comply with all modified provisions for mixtures by November 19, 2027 — extended by four months from the original July 19, 2027 date by the January 2026 extension rule US-186OSHA HCS — Extension of Compliance Dates
- Employers must update alternative workplace labeling, the hazard communication program, and employee training for newly identified mixture hazards by May 19, 2028 — also extended by four months from the original January 19, 2028 date US-187
Two important 2026 changes affecting the US
- Extension rule (effective Jan 15, 2026) — 91 FR 1695 pushed all four HCS compliance dates back by four months. This replaced the original dates in the May 2024 final rule. This extension is flagged as an unresolved contradiction in the wiki (C-001) because it supersedes the older obligations US-052 US-053 Contradictions Log
- Corrections and technical amendment (effective Jan 8, 2026) — 91 FR 562 corrected typographical and definitional errors in the regulatory text and appendices. These corrections do not create new obligations or change compliance dates US-195
Transition flexibility: between May 20, 2024 and the applicable compliance date, you may comply with the 2012 HCS, the 2024 HCS, or both US-188
Canada (WHMIS / HPR)
Canada aligned its Hazardous Products Regulations with GHS Rev. 7 (and select Rev. 8 provisions) via the WHMIS 2023 amendments Amendments to the HPR (WHMIS 2023)
- The 3-year general transition period ended December 14, 2025 — this deadline has PASSED, meaning you are already expected to be compliant with the amended HPR for your mixture CA-692
- Until July 19, 2027, Health Canada is following a compliance promotion approach rather than strict enforcement CA-693; from that date it transitions to risk-based enforcement CA-694
Summary
| Milestone | US date | Canada date | Status |
|---|---|---|---|
| Transition period ended | — | Dec 14, 2025 | PASSED |
| Mfr/importer/distributor mixture compliance | Nov 19, 2027 (extended) | Compliant since Dec 14, 2025 | Upcoming (US) |
| Employer mixture updates | May 19, 2028 (extended) | — | Upcoming (US) |
| End of compliance promotion / start enforcement | — | Jul 19, 2027 | Upcoming |
Bottom line: in Canada you should already be compliant (transition ended Dec 2025), with enforcement tightening July 19, 2027. In the US, your mixture obligations run to November 19, 2027 (manufacturer/importer) and May 19, 2028 (employer), reflecting the four-month extension issued in January 2026.
Sources cited by this answer
Every source chip is a wiki page compiled from an official text — eCFR, Federal Register, Justice Laws Canada, Health Canada, UNECE — with provenance recorded at ingestion. If a question falls outside the corpus, the system says so instead of guessing.
What's in the knowledge base behind this answer
- The current US HazCom rulebook (29 CFR 1910.1200) with all technical appendices, as enforced today
- The 2024 Federal Register rule that rewrote it — and the January 2026 notices that moved its deadlines and corrected its text
- The UN GHS "Purple Book" (Rev 7) that both countries build on
- Canada's Hazardous Products Regulations, Health Canada's supplier guidance, and the WHMIS 2023 amendment record
- Canada's Transportation of Dangerous Goods classification rules
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