Hazard communication meaning: what it is and why it matters

Last updated 2026-07-10

What does hazard communication actually mean?

Hazard communication means telling workers about chemical hazards before they get hurt. That sounds simple. The details are where employers trip.

The formal definition comes straight from OSHA's standard at 29 CFR 1910.1200: the rule requires chemical manufacturers and importers to evaluate the hazards of their chemicals, and then pass that information downstream to employers and workers through labels, safety data sheets, and training. ^[1] The whole system is sometimes called HazCom, or the "Right-to-Know" law, though that second name is more common in state-plan states.

Picture a worker who opens a drum at your facility with no idea what's inside or what to do if it splashes on skin. That's a hazard communication failure. OSHA's standard exists to prevent exactly that.

The standard has been around since 1983, but the version most workplaces follow today came from a major 2012 revision that aligned U.S. rules with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). ^[2] That update is why you now see standardized pictograms on chemical containers instead of the wildly inconsistent label designs that existed before. Learn more about the broader OSHA framework in our OSHA overview.

HazCom is also OSHA's most-cited standard year after year. In fiscal year 2023, it ranked as the second most frequently cited standard across all industries, with over 2,600 violations issued. ^[3] That frequency tells you two things: the rule genuinely matters to OSHA inspectors, and a lot of workplaces are still getting it wrong.

Who does hazard communication apply to?

Almost every employer in the United States with any hazardous chemicals on site. That's the short answer.

OSHA's general industry standard (29 CFR 1910.1200) covers about 43 million workers in nearly 5 million workplaces. ^[1] Parallel standards apply to the construction industry (29 CFR 1926.59) and maritime (29 CFR 1915.99), and they incorporate essentially the same requirements by reference. One hazardous chemical is enough to pull you in.

A "hazardous chemical" under HazCom is any chemical that poses a physical hazard (like flammability or reactivity) or a health hazard (like carcinogenicity or skin corrosion). The definition is broad on purpose. Common household cleaners, automotive fluids, welding gases, and industrial solvents all qualify. Even some materials people don't think of as chemicals, like wood dust in high concentrations, can fall under the rule depending on how they're processed.

There are a few limited exemptions. Consumer products used in the workplace the same way and at the same exposure level as a consumer would use them at home are generally exempt. So is tobacco, wood (the article, not wood dust generated by processing), food, drugs under certain conditions, and a handful of other specific categories listed in 1910.1200(b). ^[1] If you're not sure whether something is exempt, assume it isn't and check with OSHA or a safety professional.

State-plan states, which run their own OSHA-approved programs, must maintain standards at least as effective as the federal rule. Some, like California, have additional requirements. ^[4]

What are the three main components of hazard communication?

HazCom has three pillars: labels, safety data sheets, and training. The written hazard communication program ties them together. Miss any one and you're out of compliance.

Labels. Every hazardous chemical container must have a label with six specific elements: the product identifier, signal word ("Danger" or "Warning"), hazard statements, precautionary statements, pictograms, and supplier contact information. ^[1] These aren't suggestions. OSHA inspectors check containers during walkthroughs, and an unlabeled or improperly labeled container is a citable violation.

Safety Data Sheets (SDS). SDSs replaced Material Safety Data Sheets (MSDS) with the 2012 revision. Every hazardous chemical must have an SDS in a standardized 16-section format covering everything from physical properties to first aid measures to disposal information. You must keep SDSs accessible to workers at all times during their shifts. "Accessible" means they can get the information immediately, not after filing a request and waiting. ^[1] Electronic SDS systems are fine as long as workers can reach them without barriers and there's a backup plan for power outages.

Training. Workers must receive training on HazCom before they start working with hazardous chemicals and when new hazards are introduced. The training has to cover how to read labels and SDSs, what the pictograms and signal words mean, and how to protect themselves from the specific hazards in your workplace. ^[1] Generic online videos don't fully satisfy this requirement if they never address the actual chemicals in your facility.

The written program. You need a written hazard communication program that describes how your workplace does all of the above, including your chemical inventory list. The written program must be available to workers and to OSHA inspectors on request. See our detailed guide on hazard communication programs for a walkthrough of what a compliant written program includes.

If pulling together a written program feels like too much, SafetyFolio's safety program generator can build you an OSHA-aligned written HazCom program in about 15 minutes, a lot faster than starting from a blank document.

What do the hazard communication pictograms mean?

Pictograms are the red-bordered diamond icons on chemical labels and SDSs. OSHA uses nine GHS pictograms, and each one signals a specific category of hazard. ^[2] Workers need to recognize these on sight because in an emergency there's no time to read fine print.

Here's what each one means:

Pictogram name	Symbol description	Hazard category covered
Flame	A flame	Flammables, self-reactives, pyrophorics, self-heating, water-reactive, organic peroxides
Flame over circle	Flame above a circle	Oxidizers
Exploding bomb	Bomb with explosion	Explosives, self-reactives, organic peroxides
Skull and crossbones	Skull with crossed bones	Acute toxicity (severe), fatal doses
Exclamation mark	Exclamation point	Irritants, skin/eye sensitizers, harmful if swallowed, acute toxicity (moderate)
Health hazard	Torso with starburst	Carcinogens, mutagens, reproductive toxicity, respiratory sensitizers, organ toxicity
Corrosion	Material dripping onto hand and surface	Skin/eye corrosion, metal corrosion
Gas cylinder	Pressurized cylinder	Gases under pressure
Environment	Tree and fish	Aquatic environmental hazard (not always required in the U.S.)

The signal words ("Danger" vs. "Warning") layer on top of the pictograms to indicate severity. "Danger" means a more severe hazard category. "Warning" means a less severe one. A product labeled "Danger" with the skull pictogram is a whole different risk level than one labeled "Warning" with the exclamation mark, even if workers sometimes treat them the same.

Training on pictogram meanings is required under 1910.1200(h). ^[1] In practice, that means hanging a pictogram reference chart near chemical storage areas and making sure workers can correctly identify each symbol before working with chemicals. A quick quiz during onboarding works well for this. See our OSHA training guide for how to structure and document that training.

What goes in a Safety Data Sheet, and what do all 16 sections mean?

The 16-section SDS format is one of the most practical changes from the 2012 HazCom revision. Before GHS alignment, safety data sheets looked completely different from one manufacturer to the next. Now the layout is standardized, so once workers learn to read one SDS, they can read all of them.

Section 1: Identification. Product name, manufacturer contact, recommended use, and emergency phone number.

Section 2: Hazard identification. This is where pictograms, signal words, and hazard statements live. Read this section first in an emergency.

Section 3: Composition/information on ingredients. Lists chemical components, including mixtures and trade secret disclosures.

Section 4: First aid measures. What to do immediately if someone is exposed by skin contact, eye contact, inhalation, or ingestion. This section should inform your emergency response procedures.

Section 5: Firefighting measures. Suitable extinguishing methods, what not to use, and hazards from combustion.

Section 6: Accidental release measures. Spill containment, cleanup procedures, and personal protective equipment needed.

Section 7: Handling and storage. Safe use conditions, storage temperature requirements, incompatible materials.

Section 8: Exposure controls and personal protective equipment. OSHA permissible exposure limits (PELs), recommended engineering controls, and specific PPE requirements. This section connects directly to your PPE decisions.

Section 9: Physical and chemical properties. Appearance, odor, pH, boiling point, vapor pressure, and similar technical data.

Section 10: Stability and reactivity. Conditions to avoid, incompatible materials, hazardous decomposition products.

Section 11: Toxicological information. Health effects from short and long-term exposure, routes of exposure, and known or suspected carcinogenicity.

Section 12: Ecological information. Environmental fate and toxicity (required by GHS but the U.S. does not currently enforce this section).

Sections 13-15: Disposal, transport, and regulatory information. Useful for compliance but less relevant to day-to-day operations.

Section 16: Other information. Revision date and any additional notes from the manufacturer.

For a real-world example of what a completed SDS looks like, our HCl safety data sheet walkthrough breaks down every section using hydrochloric acid as the example chemical.

What must a written hazard communication program include?

OSHA requires every employer covered by HazCom to have a written program. ^[1] It doesn't have to be elaborate, but it has to be real: a document that describes how your specific workplace handles labels, SDSs, and training.

At minimum, the written program must include:

1. A list of all hazardous chemicals in each work area (your chemical inventory). 2. How you ensure containers are labeled, including how you handle portable containers and pipes. 3. How SDSs are obtained, maintained, and made accessible to workers. 4. How you train workers, including what the training covers and when it happens. 5. How you handle non-routine tasks involving hazardous chemicals. 6. What you tell contractors whose employees may be exposed to hazardous chemicals at your site.

The program must be available to employees and their designated representatives. It must also be available to OSHA inspectors without delay. ^[1] Keeping it in a binder in a locked office that only one person can open is a compliance problem waiting to happen.

Many small businesses write their HazCom program once and never touch it again. That's a mistake. Every time you bring in a new chemical, you need to update your inventory, get the SDS, and verify your training covers the new hazard. OSHA doesn't specify how often you must review the program, but any competent inspector will ask about your update process.

How does hazard communication training work, and what does it have to cover?

Training is where a lot of employers fall short, not because they skip it entirely but because they do it in a way that doesn't actually meet the standard.

Under 29 CFR 1910.1200(h), training must happen at the time of initial assignment and whenever a new physical or health hazard is introduced into the work area. ^[1] The training must cover:

• The requirements of the HazCom standard itself and where workers can find the written program.
• Any operations in their work area where hazardous chemicals are present.
• Where to find and how to use SDS information.
• How to detect the presence or release of hazardous chemicals (visual clues, odor, monitoring equipment).
• Physical and health hazards of the specific chemicals in their area.
• Protective measures they can take, including PPE, engineering controls, and safe work practices.
• An explanation of the label elements and SDS sections.

Generic online training can satisfy parts of this, but it can't satisfy the requirement to cover the specific chemicals in your workplace. You have to add that workplace-specific component yourself. The safest approach is a hybrid: a general HazCom module (online or in person) followed by a walkthrough of your actual chemical inventory, storage areas, and SDSs.

Document everything. Record the date, who was trained, what was covered, and how you verified comprehension. OSHA does not specify a required format for training records, but if an inspector asks and you have nothing, you have a problem. A sign-in sheet plus a brief quiz or acknowledgment form is enough for most small businesses.

For broader context on how OSHA training requirements work across standards, our OSHA training guide covers the documentation piece in detail. And if your team needs formal safety certification, OSHA 30 includes a HazCom module in its curriculum.

What are the penalties for violating hazard communication requirements?

OSHA penalty amounts adjust every year for inflation. As of 2024, serious violations carry a maximum penalty of $16,131 per violation, and willful or repeated violations can reach $161,323 per violation. ^[5] HazCom citations often come in clusters, because an inspector who finds one unlabeled container is going to look at all of them.

HazCom has stayed among OSHA's top 10 most-cited standards for over a decade. In fiscal year 2023, it ranked second, behind only fall protection in construction. ^[3] The most common specific violations are missing or incomplete labels, no written program, and SDSs that aren't accessible to workers.

The good news for small businesses: OSHA inspectors have discretion to reduce penalties for good faith efforts, smaller employer size, and prior history of compliance. A business with fewer than 25 employees may qualify for a 60% penalty reduction, and one with 26 to 100 employees may get 40% off. ^[5] That's not a reason to stay out of compliance, but it does mean a first-time violation at a small business won't necessarily land at the maximum.

The number that's harder to pin down is the liability exposure when a worker gets hurt because they weren't properly trained on a chemical hazard. Workers' compensation costs, potential third-party litigation, and the human cost of a preventable chemical injury all dwarf most HazCom fines.

How is hazard communication different from process safety management?

People sometimes confuse HazCom with Process Safety Management (PSM), and the difference is worth spelling out.

Hazard communication (29 CFR 1910.1200) covers essentially all hazardous chemicals in a workplace and focuses on informing workers about those hazards through labels, SDSs, and training. It's broad and applies to nearly every employer.

Process safety management (29 CFR 1910.119) is a completely different standard that applies only to facilities with highly hazardous chemicals in quantities above specific thresholds. PSM requires formal process hazard analyses, written operating procedures, mechanical integrity programs, and pre-startup safety reviews. ^[6] Think large chemical plants, refineries, or facilities with large quantities of flammable liquids. Most small businesses will never trigger PSM coverage.

Here's how they relate: PSM facilities still have to comply with HazCom. The two standards overlap but don't replace each other. At a PSM-covered facility, HazCom is the floor, not the ceiling.

A simpler way to hold the distinction: HazCom tells workers what the hazards are. PSM requires facilities to systematically prevent catastrophic releases of those hazards.

How does GHS alignment change what hazard communication means in practice?

The 2012 update that aligned U.S. HazCom with the Globally Harmonized System (GHS) mattered a lot for multinational supply chains and for worker comprehension.

Before GHS alignment, a chemical label's appearance depended entirely on the manufacturer. Some used the National Fire Protection Association's diamond system, some used the Hazardous Materials Identification System (HMIS), and some invented their own formats. Workers who changed jobs or dealt with multiple suppliers faced a new labeling system every time.

After GHS alignment, the pictograms, signal words, and SDS format are standardized globally (with some country-level variations). ^[2] A worker trained on GHS pictograms in the U.S. can recognize those same symbols on a drum shipped from Germany or South Korea.

For employers, GHS alignment meant updating SDSs from the 8-section MSDS format to the 16-section SDS format by June 1, 2016. It also meant retraining workers on the new label elements and pictograms by December 1, 2013. Those deadlines are long gone, so if you're still running on old MSDS documents, you're out of compliance.

OSHA published a detailed account of the GHS transition in its Hazard Communication Standard Final Rule, available on OSHA's website. ^[2] The agency's own FAQ on HazCom is also a useful reference when a specific labeling question comes up. ^[1]

One thing GHS didn't fix: hazard classification quality still depends on the manufacturer. GHS standardized the communication format, but chemical manufacturers still run their own hazard evaluations. Different manufacturers can classify the same chemical differently, and that inconsistency is real and documented.

What's the fastest way for a small business to get HazCom compliance right?

Most small businesses are not starting from zero. They already have chemicals, they probably have some labels, and they may even have some SDSs. The job is to audit what you have and close the gaps in order.

Start with your chemical inventory. Walk every work area and list every hazardous chemical present. If you don't have an SDS for something on that list, get one from the manufacturer or distributor. Chemical suppliers are required to provide SDSs at the time of first shipment and upon request. ^[1]

Then audit your containers. Every container of a hazardous chemical must have a label with all six required elements. Portable containers used immediately and only by the person who filled them have a limited exemption, but anything stored, passed to another worker, or used over time needs a proper label.

Then write or update your written program. If you don't have one, write it from scratch. If you have one that predates 2016, it needs updating for GHS-aligned requirements. SafetyFolio's safety program generator is built for exactly this: you answer questions about your workplace and chemicals, and it produces a written HazCom program formatted to match 1910.1200's requirements.

Finally, train your workers and document it. Even a one-hour session covering your chemical inventory, the SDS binder, and what the pictograms mean is a real training you can defend to an inspector.

The whole effort doesn't have to eat weeks. A focused half-day can close most gaps for a small business with a manageable chemical inventory. See our incident report guide for how to connect your HazCom program to your incident documentation process, which closes another common compliance gap at the same time.

Frequently asked questions

What is hazard communication in simple terms?

Hazard communication means making sure workers know what chemicals they're working with and how those chemicals can hurt them. Under OSHA's standard (29 CFR 1910.1200), that happens through three tools: chemical labels with standardized pictograms and signal words, safety data sheets with detailed hazard information, and workplace training. The goal is that no worker opens a chemical container without knowing the risks.

What are the 9 GHS hazard communication pictograms?

The nine GHS pictograms used in U.S. hazard communication are: Flame (flammable materials), Flame over circle (oxidizers), Exploding bomb (explosives), Skull and crossbones (acute severe toxicity), Exclamation mark (moderate hazards and irritants), Health hazard torso (carcinogens and organ toxins), Corrosion (corrosive to skin or metals), Gas cylinder (pressurized gases), and Environment (aquatic hazard, not currently enforced in the U.S.).

Is a written hazard communication program required by OSHA?

Yes. 29 CFR 1910.1200(e) requires every covered employer to prepare and implement a written hazard communication program. It must include your chemical inventory, describe how you handle labels and safety data sheets, and explain your training process. It must be available to workers and OSHA inspectors on request. Having chemicals on site without a written program is a citable violation.

What is the difference between an MSDS and an SDS?

MSDS (Material Safety Data Sheet) was the old format used before OSHA aligned with the Globally Harmonized System in 2012. SDS (Safety Data Sheet) is the standardized 16-section replacement. The content is similar, but the SDS format is consistent across all manufacturers and countries that use GHS. OSHA required chemical manufacturers to update to the SDS format by June 1, 2016. Old MSDS documents are no longer compliant.

What does 'Danger' vs 'Warning' mean on a chemical label?

Both are signal words required under HazCom's GHS-aligned labeling system. 'Danger' indicates the more severe hazard categories within a given hazard class. 'Warning' indicates a less severe category. For example, a chemical with acute oral toxicity in Category 1 gets 'Danger,' while one in Category 4 gets 'Warning.' A single label uses only one signal word, the stronger one if multiple hazards are present.

Does hazard communication apply to small businesses?

Yes. There is no small business exemption in 29 CFR 1910.1200. Any employer with hazardous chemicals on site is covered, regardless of size. The only relevant difference is that OSHA can reduce penalties for employers with fewer than 25 workers (up to 60% reduction) or 26 to 100 workers (up to 40% reduction), but the compliance requirements themselves are identical for businesses of any size.

How often does hazard communication training need to happen?

OSHA requires initial HazCom training before workers are assigned to work with hazardous chemicals, and additional training whenever a new physical or health hazard is introduced into the work area. The standard does not require annual refresher training, though many employers do it anyway. Retraining is also a good idea after an incident involving a chemical exposure or after bringing in a new chemical category your workers haven't encountered before.

What chemicals are exempt from hazard communication requirements?

Limited exemptions exist for: consumer products used in the workplace the same way consumers use them at home, hazardous waste regulated under RCRA, tobacco products, wood (the article itself, not dust from processing), food and beverages under FDA jurisdiction, drugs in solid final form, and certain other categories listed in 29 CFR 1910.1200(b)(6). When in doubt, treat a chemical as covered and verify the exemption before removing HazCom protections.

Can safety data sheets be stored electronically?

Yes. OSHA allows electronic SDS systems, but with conditions. Workers must be able to access the SDS immediately during their shifts, without barriers like passwords that only supervisors know or a system that requires a manager's approval. There must also be a backup plan for computer downtime or power failures. A printed backup binder for frequently used chemicals is a simple and defensible solution.

What is the most commonly cited hazard communication violation?

The most frequent HazCom violations involve missing or incomplete labels on chemical containers, failure to maintain or make accessible safety data sheets, and inadequate or undocumented training. Missing written programs are also commonly cited. HazCom ranked as OSHA's second most-cited standard in fiscal year 2023, with violations found in workplaces ranging from warehouses to healthcare facilities to small manufacturing shops.

Does hazard communication cover physical hazards as well as health hazards?

Yes. OSHA's HazCom standard covers both physical hazards (flammability, explosivity, reactivity, oxidizers, compressed gases, and others) and health hazards (carcinogens, acute toxicity, skin and eye irritants, reproductive toxicants, and more). A chemical can have both types of hazards, and the label and SDS must reflect all of them. Physical hazard classification follows criteria in Appendix B of 29 CFR 1910.1200.

What do contractors need to know about hazard communication on my site?

Under 29 CFR 1910.1200(e)(2), if contractors' employees may be exposed to hazardous chemicals at your workplace, you must provide them with information about those hazards, the labeling system you use, the SDS for relevant chemicals, and protective measures. You and the contractor also need to coordinate if the contractor is bringing their own chemicals onto your site. This is often handled through a pre-work meeting and site-specific safety briefing.

Sources

1. OSHA, Hazard Communication Standard (29 CFR 1910.1200): HazCom covers approximately 43 million workers in nearly 5 million workplaces; requires labels, SDS, training, and written program; lists exemptions; specifies training content and SDS accessibility requirements
2. OSHA, Hazard Communication Standard Final Rule (GHS alignment, 2012): 2012 revision aligned U.S. HazCom with the Globally Harmonized System (GHS), standardizing pictograms, signal words, and the 16-section SDS format
3. OSHA, Top 10 Most Frequently Cited Standards, FY2023: Hazard communication ranked as the second most frequently cited OSHA standard in fiscal year 2023
4. OSHA, State Plans: State-plan states must maintain safety standards at least as effective as federal OSHA; some states have additional HazCom requirements
5. OSHA, Penalties: As of 2024, serious violations carry a maximum of $16,131 per violation; willful or repeated violations up to $161,323; small employer penalty reductions of 40-60% available
6. OSHA, Process Safety Management Standard (29 CFR 1910.119): PSM applies only to facilities with highly hazardous chemicals above specific threshold quantities and requires formal hazard analyses, operating procedures, and mechanical integrity programs
7. United Nations Economic Commission for Europe, Globally Harmonized System of Classification and Labelling of Chemicals (GHS): GHS is the international standard for chemical hazard classification and communication; the U.S. adopted GHS-aligned requirements via the 2012 HazCom revision
8. Bureau of Labor Statistics, Injuries, Illnesses, and Fatalities: BLS injury and illness data tracks chemical exposure incidents across industry sectors, providing context for why hazard communication standards address chemical hazards