Major changes to the hazard communication standard explained

Last updated 2026-07-09

What is the hazard communication standard and why did OSHA change it?

The Hazard Communication Standard, codified at 29 CFR 1910.1200, is OSHA's rule that requires chemical manufacturers, importers, and employers to tell workers about chemical hazards through labels, Safety Data Sheets (SDS), and training. It covers nearly every general industry workplace that uses or handles hazardous chemicals. Parallel versions cover construction (29 CFR 1926.59) and maritime work.

The U.S. first adopted a GHS-aligned HazCom rule in 2012, locking it to the United Nations' Globally Harmonized System of Classification and Labelling of Chemicals (GHS) Revision 3. GHS kept evolving. U.S. rules didn't.

By the time OSHA started its revision, most of the world had moved to GHS Revision 7 or Revision 8, while American labels were still anchored to a version that was more than a decade old. That gap caused real friction for companies that import or export chemicals, and for workers trying to reconcile a label that used one hazard category with an SDS that described another.

OSHA published the final rule on May 20, 2024, in the Federal Register ^[1]. The agency said its goal was to "improve the quality and consistency of hazard information" while reducing the burden on the chemical industry created by that misalignment with international standards. Those two goals sometimes pull against each other, which is why the compliance timeline runs in phases instead of a single cutover date.

What are the major changes OSHA made to HazCom in 2024?

Five areas changed in real ways. Each carries practical consequences for employers, not only for chemical manufacturers.

1. New and updated hazard classes

The 2024 rule adds hazard classes that didn't exist in HazCom 2012. The biggest ones ^[1][2]:

• Flammable gases, now split into Category 1A and 1B, with new designations for chemically unstable gases and pyrophoric gases inside the flammable gas class.
• Desensitized explosives, a new class covering chemicals that are wetted or diluted to suppress explosive properties (think certain organic peroxide solutions shipped in water).
• Non-flammable aerosols, which used to be grouped only as flammable or non-flammable and now get their own hazard category.

Some existing categories were revised too. Acute toxicity estimates now allow conversion factors when a mixture's data are incomplete, which can change how a product is classified and labeled.

2. Updated label requirements

The 2012 rule already required GHS-style labels with pictograms, signal words, hazard statements, precautionary statements, and supplier identification. The 2024 revision keeps that structure and adds a few practical fixes:

• Small container labeling: OSHA now allows abbreviated label formats for containers too small to hold a full label, with pull-out or fold-back labels explicitly permitted.
• Bulk shipment labels: chemicals shipped in bulk (tank trucks, rail cars, vessels) now carry explicit labeling requirements that used to be ambiguous.
• Label updates: labels must be updated within six months of a manufacturer learning of new significant hazard information, closing a gap in the 2012 rule.

3. Safety Data Sheet changes

The 16-section SDS format stays. The required content in a few sections changes. Section 2 (Hazard Identification) must now reflect the new hazard classes and categories. Section 9 (Physical and Chemical Properties) gets an expanded list of required properties, including particle size where that matters for exposure.

OSHA also set a firm clock: SDSs must be reviewed and updated within three months of a manufacturer learning of significant new hazard information. That deadline wasn't explicit before.

4. Alignment with GHS Revision 7

The 2024 rule formally anchors U.S. HazCom to GHS Revision 7, with certain provisions pulled from Revision 8 ^[1]. This matters for anyone using the Purple Book (the UN's GHS document) to classify chemicals. An SDS preparer already working from Rev 7 or Rev 8 is mostly fine. One still working from Rev 3 has real work ahead.

5. Definitions and scope clarifications

OSHA updated the definitions of several terms, including "hazardous chemical," "physical hazard," and "health hazard," to match GHS Revision 7 language. The definition of "exposure" was refined too. These aren't cosmetic. Classification decisions often turn on how the underlying terms are defined.

What are the compliance deadlines for the 2024 HazCom changes?

OSHA set a phased timeline instead of one date. The logic is straightforward: manufacturers and importers update their classifications, SDSs, and labels first; distributors get time to clear inventory; then employers update training and workplace processes ^[1][3].

Affected party	Compliance deadline
Chemical manufacturers and importers (classification, SDS, labels)	January 19, 2026
Distributors (shipping updated labels)	July 19, 2026
Employers (workplace labeling, updated SDSs, employee training)	January 19, 2027
Employers (new hazard classes: flammable gases, desensitized explosives)	July 19, 2027
Small manufacturers and importers (fewer than 20 employees)	January 19, 2028

Those are OSHA's official dates from the final rule. The employer training deadline of January 19, 2027, is the one most small businesses should watch.

One nuance worth knowing: you can keep complying with the 2012 version until the relevant deadline for your category arrives. You don't have to train workers on new hazard classes before the SDSs and labels reflecting those classes actually exist. OSHA said as much in the preamble to the final rule.

How do the new flammable gas categories affect workplace chemical management?

The expanded flammable gas classification is probably the change that touches the most small businesses. Under HazCom 2012, a flammable gas was either Category 1 (flammable) or Category 2 (less flammable). The 2024 rule breaks Category 1 into 1A and 1B and adds designations for chemically unstable gases and pyrophoric gases ^[1][2].

Category 1A covers gases with a flammability range wider than 12 percentage points or a lower flammability limit below 5 percent. Hydrogen, acetylene, and many fuel gases land here. Category 1B covers gases that miss the 1A criteria but are still flammable. The practical difference: 1A gases get more severe precautionary statements and tighter handling requirements.

For most employers, the impact shows up sideways. The SDSs for gases you already use may carry a new category designation, and your written hazard communication program and training materials have to reflect it. If you store or handle hydrogen, acetylene, propane, or similar gases, review the updated SDSs from your supplier as they arrive.

When you update your hazard communication written program to cover the new categories, make sure your training spells out what 1A versus 1B means for emergency response and storage. Those precautionary statements differ, and that difference is the whole point.

What do employers need to do right now to prepare for the changes?

The employer deadline is January 19, 2027. That sounds far off. It isn't, if you have dozens of chemicals on site. Here's the honest sequence.

First, take stock of every chemical in your workplace. This is your chemical inventory. Keep it simple: a spreadsheet with product name, manufacturer, and current SDS version does the job. If you've never built one, you're already behind on the 2012 requirements, so this is overdue no matter what.

Second, watch your suppliers. Starting January 2026, manufacturers and importers must update SDSs and labels to the new format. Request updated SDSs from your suppliers around mid-2026. Don't wait for them to arrive on their own. Some suppliers move slowly.

Third, update your written hazard communication program. The 2024 rule doesn't change the requirement to have a written program under 29 CFR 1910.1200(e) ^[7], but the program has to reflect the new hazard classes and updated procedures. If your program names HazCom 2012 or GHS Revision 3 by version, fix that language.

Fourth, retrain employees. This is the step most employers underestimate. Workers need to understand what the new categories mean, how to read updated labels, and how to find information in the expanded SDS content. OSHA requires training on any new physical or health hazard when it's introduced into the workplace ^[4].

If building that updated written program sounds like a heavy lift, SafetyFolio's safety program generator can produce a compliant HazCom written program in about 15 minutes, with fields for your chemical inventory and the updated hazard categories.

Fifth, update your SDS management system. Binders, a digital tool, a third-party service, whatever you use, make sure you have a process to swap old SDSs for updated versions as they come in from manufacturers.

How do the new label requirements change what workers see on chemical containers?

For most containers in most workplaces, labels will look about the same as they do under HazCom 2012: GHS pictograms, a signal word (Danger or Warning), hazard statements, precautionary statements, and supplier contact information. The visual format isn't being torn up.

The meaningful changes hit three specific situations.

Small containers are the biggest practical issue. If you use a product that ships in small vials, ampules, or similarly tiny containers, the 2024 rule explicitly allows a pull-out, fold-back, or tag format to carry the required information. Before this, OSHA's small container provisions were thin, and there was genuine confusion about how to comply when a container was too small for a full label ^[10]. The new rule settles it.

For bulk shipments, the rule now requires manufacturers and importers to make sure bulk containers shipped by tank truck, rail car, or vessel carry specific hazard information. Employers receiving bulk deliveries should expect updated documentation with those shipments.

On pictograms, the new hazard classes come with GHS pictograms already assigned under GHS Rev 7. Desensitized explosives, for instance, use the exploding bomb pictogram, the same one used for unstable explosives. Workers already familiar with the current pictograms won't face a foreign system, but training should explain the new categories those pictograms now cover.

What changed with Safety Data Sheets under the 2024 revision?

The 16-section SDS format is unchanged. Worth saying plainly, because safety forums have floated the idea that employers need to scrap their current SDS systems. You don't.

What changes is the content required in certain sections.

Section 2 (Hazard Identification) must include any new hazard classes and categories that apply under the 2024 criteria. A chemical that picks up a desensitized explosive classification under the new rules has to show it in Section 2.

Section 9 (Physical and Chemical Properties) now has an expanded required property list. OSHA added several properties that used to be optional, including particle characteristics where they matter for health exposure. If an SDS looks thin in Section 9 compared to what the new rules expect, that's a flag to raise with your supplier.

Section 3 (Composition/Information on Ingredients) has clarifications about when concentration ranges are acceptable versus when exact percentages are required. Trade secret claims still apply, but the rule tightens the conditions for invoking them.

OSHA also made the update clock explicit: manufacturers and importers must update SDSs within three months of receiving significant new hazard information ^[1]. That window was implied before, not stated. For employers, this means your SDS process needs a way to receive and file updated SDSs, more than the original version you got when you first ordered a chemical.

For a worked example of what an SDS looks like in the wild, see our hcl safety data sheet breakdown, which walks all 16 sections using a real chemical.

Does the 2024 HazCom revision change training requirements for employees?

Yes, and this is where many employers hit real work. The base requirement under 29 CFR 1910.1200(h) hasn't changed structurally: train workers on the hazardous chemicals in their workplace, how to read labels and SDSs, and how to protect themselves. The content that training must cover is what shifts.

Employees need to understand the new hazard categories. If a gas they work with is now classified 1A instead of plain "Category 1 flammable," they need to know what that means for storage, handling, and emergency response. If a product they use is now a desensitized explosive, that's a significant new piece of information.

Get the timing rule right. The standard requires training "at the time of their initial assignment" and "whenever a new chemical hazard the employees have not previously been trained about is introduced into their work area" ^[4]. Under that language, you don't have to retrain every worker on every new hazard class by January 2027. You train them when the updated SDSs and labels actually introduce new hazard information into their specific work area.

Still, the practical move is to run a general HazCom refresher for all employees by mid-2027 that covers what changed, why, and how to read the updated labels. Chemical-by-chemical training as each new SDS trickles in is administratively painful and easy to fall behind on.

For how OSHA structures training across standards, see our overview of osha training.

How does HazCom 2024 compare to the 2012 version?

Here's the side-by-side on the differences that matter.

Feature	HazCom 2012	HazCom 2024
GHS version	Revision 3	Revision 7 (with some Rev 8 provisions)
Flammable gas categories	Category 1, Category 2	Category 1A, 1B, 2; plus pyrophoric and chemically unstable gas designations
Desensitized explosives	Not classified separately	New hazard class
Non-flammable aerosols	Not a distinct category	New hazard category
Small container labels	Limited flexibility	Explicit fold-out/pull-out label permission
Bulk shipment labels	Ambiguous	Explicit requirements
SDS Section 9 properties	Shorter required list	Expanded required properties
SDS update timeline	Unclear	Three months from new significant information
Label update timeline	Not specified	Six months from new significant information

The 2012 rule was a full overhaul. The 2024 revision is a targeted update. If your HazCom program was solid under the 2012 rules, you have a manageable list of changes, not a teardown.

What are the penalties for not complying with the updated HazCom standard?

HazCom violations carry the same penalty structure as any serious or other-than-serious violation under the OSH Act. OSHA adjusts these civil penalties every year for inflation ^[5]. As of 2024, the maximums are:

• Serious violations: up to $16,131 per violation
• Willful or repeated violations: up to $161,323 per violation
• Other-than-serious violations: up to $16,131 per violation

Hazard communication is one of OSHA's most-cited standards, year after year. It has landed in the top ten most-cited standards for general industry every year since the 2012 revision took effect ^[6]. The usual citation items: missing or incomplete SDSs, incomplete written programs, and inadequate employee training.

Once the 2027 employer deadline passes, inspectors will start checking whether written programs and training reflect the updated standard. The common citations aren't dramatic failures. They're SDSs nobody updated, written programs that still name the old categories, and training records that don't document the new content.

The most cost-effective thing a small business can do before 2027: audit your existing HazCom program against the new requirements, update the written program, pull new SDSs from suppliers, and document retraining. Done before an inspection, that sequence is your real protection.

Does the HazCom update affect small businesses differently than large ones?

OSHA gave small manufacturers and importers (fewer than 20 employees) an extra year, with their deadline running to January 19, 2028. That break applies to the SDS and label production side of the obligation. It does not apply to employers who simply use chemicals in their workplaces.

If you're a small business that uses chemicals but doesn't manufacture or import them, your employer compliance deadline is still January 19, 2027. The extra time for small manufacturers doesn't flow down to you as the end user.

The hard part for small businesses is tracking when updated SDSs land, without a dedicated safety staff to chase them. A workable approach: set a calendar reminder for July 2026 to request updated SDSs from your main suppliers, then run a training update in the third or fourth quarter of 2026, well ahead of the January 2027 deadline.

Not sure whether your current program covers what the 2024 rule requires? That's exactly the gap-check to do now, not during an inspection. Our overview of the broader hazard communication standard covers what the written program must include under the baseline 2012 requirements, which are still the foundation.

Where can I find OSHA's official guidance and the actual text of the 2024 rule?

OSHA published the final rule in the Federal Register on May 20, 2024 ^[1]. The full regulatory text, including the preamble, is available through the Federal Register's website and through OSHA's HazCom page at osha.gov.

OSHA maintains a Hazard Communication page that hosts the current regulatory text, compliance guides, and frequently asked questions ^[3]. It's been updated to reflect the 2024 changes and is the most reliable single source for employers.

For classification details, the authoritative reference is the UN's GHS Revision 7 document (the Purple Book), free from the UN Economic Commission for Europe ^[2]. If you're trying to work out exactly how a chemical should be classified under the new criteria, that's the primary source.

OSHA's own HazCom training resources and outreach materials are useful starting points for training, though not all of them had been updated to the 2024 rule as of this article's publication date ^[4].

For how standards like HazCom fit into OSHA's overall structure, our article on what does osha stand for covers the agency's mandate and enforcement framework.

Frequently asked questions

When does my business have to comply with the 2024 HazCom changes?

Most employers must comply by January 19, 2027. That's the deadline for updating workplace labeling, obtaining new SDSs, updating your written hazard communication program, and retraining employees. Small manufacturers and importers with fewer than 20 employees get until January 19, 2028, but that extra year applies to manufacturing and importing obligations, not to employer obligations for using chemicals.

Do I have to replace all my current SDSs right now?

No. Chemical manufacturers and importers have until January 19, 2026, to issue updated SDSs under the new classification criteria. Start requesting updated SDSs from your suppliers around mid-2026 and file them into your management system before the January 2027 employer deadline. Tossing your current SDSs before updated ones exist would leave you without required information.

What new hazard classes were added in the 2024 HazCom revision?

The 2024 rule added desensitized explosives as a new hazard class and created a non-flammable aerosol category. It also expanded the flammable gases class by splitting Category 1 into 1A and 1B and adding designations for chemically unstable gases and pyrophoric gases. These additions align U.S. rules with GHS Revision 7, which most of the world adopted years earlier.

Is the 16-section SDS format changing under the 2024 rule?

No. The 16-section format stays. What changes is the required content within certain sections, particularly Section 2 (Hazard Identification) and Section 9 (Physical and Chemical Properties), which now has an expanded required property list. If you already manage SDSs using a 16-section system, your format is still correct. You just need the content to reflect the updated classification criteria.

What does the 2024 HazCom rule say about small container labeling?

The 2024 rule explicitly allows pull-out, fold-back, or tag label formats for containers too small to carry a full GHS label. This was a long-standing gray area under the 2012 rule. The abbreviated format still has to contain all required label elements. It just lets you present them in a folded or attached format rather than a flat label on the container surface.

Does HazCom 2024 change what information must be in a written hazard communication program?

The structural requirements under 29 CFR 1910.1200(e) haven't changed: the program must describe how your workplace handles labels, SDSs, and training. What needs updating is any language that names the 2012 classification categories or GHS Revision 3. Your written program should reflect the new hazard classes and updated SDS content requirements before the January 2027 employer deadline.

How is the 2024 HazCom update different from the 2012 revision?

The 2012 revision was a fundamental overhaul that introduced GHS-style labels, the 16-section SDS, and standardized hazard categories for the first time. The 2024 revision is a targeted update that adds new hazard classes, expands SDS content, clarifies labeling options for small and bulk containers, and aligns the standard with GHS Revision 7. A solid 2012-era program needs updates, not a full rebuild.

What are the OSHA penalties for violating the hazard communication standard?

Serious violations can reach $16,131 per violation, and willful or repeated violations can reach $161,323 per violation under current OSHA penalty levels adjusted for inflation through 2024. HazCom is consistently among OSHA's most-cited standards, with common violations including missing SDSs, incomplete written programs, and inadequate training records.

Do workers need to be retrained immediately under the 2024 changes?

Retraining must happen by the employer deadline of January 19, 2027, or sooner if a new chemical hazard covered by the updated standard shows up in an employee's work area before that date. The practical advice is to schedule a HazCom refresher for all workers in the second half of 2026, after updated SDSs start arriving, so the training reflects the actual labels and categories employees will see.

Does the 2024 HazCom revision apply to construction and maritime workplaces?

Yes. OSHA's general industry HazCom standard at 29 CFR 1910.1200 is adopted by reference in the construction standard at 29 CFR 1926.59 and in maritime standards. The 2024 changes flow through to those sectors. Employers in construction and maritime follow the same compliance timeline as general industry employers.

What is a desensitized explosive and why does it now have its own hazard class?

Desensitized explosives are substances or mixtures that would classify as explosives in pure form but are wetted, diluted, or otherwise treated to suppress explosive properties for safer transport and handling. Certain organic peroxide solutions and phlegmatized powders fall here. The 2024 rule gives them a distinct classification because their hazard profile differs from both pure explosives and non-explosive chemicals, requiring specific precautionary labeling.

How does the 2024 HazCom rule handle trade secrets on SDSs?

Trade secret protections for SDS ingredient information still exist under the 2024 rule, but the conditions for invoking them were tightened. Manufacturers must still provide the actual chemical identity to health professionals, emergency responders, and employees experiencing adverse health effects, on request. The updated rule clarifies when concentration ranges are acceptable in place of exact percentages and when trade secret claims are and aren't valid.

Where can I find the official text of the 2024 HazCom final rule?

OSHA published the final rule in the Federal Register on May 20, 2024. The full text is available through the Federal Register online. OSHA's HazCom page at osha.gov also hosts the updated regulatory text and compliance guidance. The UN's GHS Revision 7 Purple Book, free from the UN Economic Commission for Europe, is the primary reference for classification criteria.

Sources

1. OSHA, Hazard Communication Standard Final Rule (Federal Register, May 20, 2024): OSHA finalized revisions to 29 CFR 1910.1200 on May 20, 2024, adding new hazard classes, updating SDS and label requirements, and setting phased compliance deadlines from 2026 through 2028
2. United Nations Economic Commission for Europe, GHS Revision 7 (Purple Book): GHS Revision 7 is the international classification framework to which OSHA's 2024 HazCom revision is aligned, including definitions for flammable gas sub-categories and desensitized explosives
3. OSHA, Hazard Communication Standard overview page: OSHA's HazCom page provides the current regulatory text of 29 CFR 1910.1200, compliance guides, and frequently asked questions updated to reflect the 2024 revision
4. OSHA, 29 CFR 1910.1200(h) - Employee Information and Training: Employers must train employees at initial assignment and whenever a new physical or health hazard is introduced into the work area; the 2024 rule extends this to new hazard classes
5. OSHA, Civil Penalties Inflation Adjustments: As of 2024, OSHA maximum penalties are $16,131 per serious violation and $161,323 per willful or repeated violation, adjusted annually for inflation
6. OSHA, Top 10 Most Frequently Cited Standards (FY2023): Hazard Communication Standard (29 CFR 1910.1200) has appeared in OSHA's top ten most-cited standards list for general industry every year since the 2012 revision took effect
7. OSHA, 29 CFR 1910.1200(e) - Written Hazard Communication Program: Employers must maintain a written hazard communication program describing how labels, SDSs, and training are managed in their workplace
8. OSHA, 29 CFR 1926.59 - Hazard Communication (Construction): The construction industry HazCom standard adopts 29 CFR 1910.1200 by reference, meaning the 2024 revisions apply to construction workplaces under the same timeline
9. OSHA, Hazard Communication 2012 Final Rule (GHS alignment): OSHA's 2012 HazCom revision aligned the standard with GHS Revision 3, introducing GHS-style labels and the 16-section SDS format
10. OSHA, Letters of Interpretation - Small Container Labeling: OSHA has issued letters of interpretation addressing small container labeling flexibility under HazCom, a gap the 2024 rule explicitly addresses by permitting fold-out and pull-out label formats