HCS 2024 compliance checklist for chemical manufacturers

OSHA updated the Hazard Communication Standard in 2024 and then extended the compliance dates by four months in January 2026. Here is what changed, the current dates, and a checklist of what a chemical manufacturer needs to update.

The 2024 final rule (29 CFR 1910.1200) aligns the Hazard Communication Standard with a newer edition of the GHS. It revised hazard classification criteria, changed what goes on labels and safety data sheets, and added a few physical hazard classes. The work falls on chemical manufacturers, importers, and distributors first, and on employers a little later.

One thing to get right before anything else: the deadlines moved. The original dates were extended by four months, effective January 2026. The dates below are the current ones from the regulation.

The dates

Source: 29 CFR 1910.1200(j). Until your applicable date, you may comply with the updated standard, the prior version (revised as of July 1, 2023), or both.
Who	What	Deadline
Manufacturers, importers, distributors	Comply with the updated standard for substances	May 19, 2026
Employers	Update workplace labeling, the written program, and training for substances	Nov 20, 2026
Manufacturers, importers, distributors	Comply with the updated standard for mixtures	Nov 19, 2027
Employers	Update workplace labeling, the written program, and training for mixtures	May 19, 2028

If you make mixtures, which most formulators do, the date that matters is November 19, 2027. The substance date has already passed. If you ship pure substances and have not updated those SDSs and labels yet, you are past due.

What changed

The update is not a full rewrite, but the changes touch real parts of an SDS and a label:

Classification criteria. The hazard classes and category cut-offs were revised to match the newer GHS edition. A product that was correctly classified under the old rules can land in a different category under the new ones.
New and clarified physical hazards. Aerosols, chemicals under pressure, desensitized explosives, and a definition for combustible dust were added or revised. If you make any of these, re-check them specifically.
Concentration ranges on the SDS. When you withhold an exact concentration as a trade secret, Section 3 now uses a set of prescribed concentration ranges, and you must use the narrowest one that fits.
Small container labels. Containers of 100 mL or less can carry a reduced label, and containers of 3 mL or less where a label interferes with use can carry just the product identifier, as long as the outer package has the full label.
Released for shipment. When you learn of significant new hazard information, you revise the label within six months. Stock already packaged and waiting to ship does not have to be relabeled, but you must supply the updated label with each shipment.
Bulk shipment labels. For bulk shipments the label can be on the immediate container, sent with the shipping papers or bill of lading, or, by agreement with the receiver, transmitted electronically so it is available in print on their end.

The checklist

Work product by product. For each hazardous chemical you make or import:

Classification

Re-evaluate the classification against the updated criteria, not just carry forward the old result.
Check the added and revised physical hazards (aerosols, chemical under pressure, desensitized explosives, combustible dust) for any product they could apply to.
Record which rule and which regulatory revision produced each classification, so the result can be defended later.

Safety data sheets

Update Section 2 (hazards) to reflect the re-evaluated classification, signal word, and statements.
Update Section 3 (composition). Where a concentration is a trade secret, switch to the prescribed ranges and use the narrowest range that fits. 1910.1200(i)(1)(iv)
Reconcile the rest of the sixteen sections with the new classification (first aid, handling, disposal, transport, and so on).
Reissue updated SDSs to the customers who received the affected products.

Labels

Update pictograms, signal word, hazard statements, and precautionary statements to match the new classification.
Apply the small-container rules where they help (100 mL and 3 mL provisions), keeping the full label on the outer package. 1910.1200(f)(12)
Confirm how bulk-shipment labels are conveyed (on container, with shipping papers, or electronically by agreement). 1910.1200(f)
Set the rule for stock already released for shipment: relabel it, or supply the updated label with each shipment. 1910.1200(f)(11)

Program and training (if you are also an employer)

Update the written hazard communication program and any workplace (alternative) labeling.
Train affected employees on any newly identified hazards before the employer deadline (Nov 20, 2026 for substances, May 19, 2028 for mixtures).
Confirm you have received updated SDSs and labels from your own suppliers for the products you buy in.

This is a working summary, not legal advice. The controlling text is 29 CFR 1910.1200, including appendices A through F. Dates and details here reflect the regulation as of April 2026; confirm against the current text before you rely on it.