Hazard communication symbols: every GHS pictogram explained

Last updated 2026-07-09

What are hazard communication symbols and where do they come from?

Hazard communication symbols are standardized pictograms, each a black symbol inside a red-bordered diamond, that tell workers at a glance what kind of danger a chemical poses. They come from the Globally Harmonized System of Classification and Labelling of Chemicals, a United Nations framework the United States adopted when OSHA revised its Hazard Communication Standard in 2012. ^[1]

Before that alignment, the U.S. leaned on orange-and-black NFPA diamonds and HMIS bar ratings. Different countries used different symbols entirely. A worker moving between employers, or a shop importing a chemical from a European supplier, could face labels that meant nothing to them. The GHS fixed that.

OSHA's current rule, 29 CFR 1910.1200, phased in the new pictograms over several years, with full compliance due by June 1, 2016 for most employers. ^[2] The rule covers any workplace where hazardous chemicals are used, stored, or produced, which in practice means nearly every manufacturing, construction, agriculture, and service business in the country.

The standard governs more than what appears on a container. It governs the whole communication chain: the label on the product, the Safety Data Sheet (SDS) that ships with it, and the training your workers get before they ever touch the stuff. The symbols are the visible tip of that system. Compliance training almost always starts here.

What are the 9 GHS pictograms and what does each one mean?

There are exactly nine GHS pictograms recognized under OSHA's Hazard Communication Standard. Each maps to one or more hazard classes. Here's what each one means in plain language, plus the hazard categories it covers.

Pictogram name	Symbol description	Hazard classes covered
Flame	Flame over a horizontal line	Flammable gases, liquids, solids, aerosols, self-reactives, pyrophorics, self-heating substances, substances that emit flammable gas on contact with water
Flame over circle	Flame above a circle	Oxidizing gases, liquids, and solids
Exploding bomb	Bomb mid-explosion	Explosives, self-reactives, organic peroxides
Skull and crossbones	Classic skull	Acute toxicity (fatal or toxic), categories 1-3
Exclamation mark	Plain exclamation point	Acute toxicity category 4, skin/eye irritants, skin sensitizers, harmful if inhaled, hazardous to ozone layer
Health hazard	Silhouette with starburst on chest	Carcinogens, respiratory sensitizers, reproductive toxins, target organ toxins, mutagens, aspiration hazards
Corrosion	Liquid eating through a surface and a hand	Skin corrosives, eye damage, corrosive to metals
Gas cylinder	Pressurized tank	Gases under pressure: compressed, liquefied, refrigerated liquefied, dissolved
Environment	Dead tree with dead fish	Aquatic toxicity (hazardous to the aquatic environment)

A few things to know about this table. The environment pictogram is not mandatory under the federal OSHA standard, though OSHA states it "may" be used and some states require it. ^[3] A single product can carry multiple pictograms if it has multiple hazard classes, which is common. A paint thinner, for example, might show the flame, exclamation mark, and health hazard symbols all at once.

The exclamation mark trips people up. It looks mild next to a skull, but it can flag serious harm, including skin sensitization (which can become a permanent allergy) and STOT (specific target organ toxicity) for single exposures. Never treat it as the "minor" symbol.

The health hazard silhouette gets underestimated most often in small shops. That starburst means the chemical has a documented link to cancer, reproductive harm, or organ damage from repeated exposure. Long-term risk is easy to ignore when the drum doesn't smell bad and nobody's visibly sick. This is the symbol employers most often neglect in training, because workers usually get no instruction on what chronic exposure means. ^[4]

What do the other required label elements mean besides the symbols?

Pictograms don't work alone. Under 29 CFR 1910.1200(f), every shipped container of a hazardous chemical must carry six label elements from the manufacturer or importer. ^[2] Workers need to understand all of them, not only the pictures.

Product identifier. The chemical name or number that matches the Safety Data Sheet. This lets you pull the right SDS fast in an emergency.

Signal word. Either "Danger" or "Warning." Danger is the higher severity. If a product has both a Danger-level hazard and a Warning-level hazard, only "Danger" appears, because using both would be redundant and confusing. OSHA's labeling hierarchy codifies this. ^[2]

Hazard statements. Short standardized phrases that describe the nature and degree of the hazard, such as "Causes serious eye damage" or "May cause cancer." They're assigned by hazard category, not left to the manufacturer's discretion.

Precautionary statements. These tell workers what to do, covering prevention, response, storage, and disposal. A product might say "Wear protective gloves" or "If in eyes: rinse cautiously with water for several minutes."

Supplier information. The name, address, and phone number of the manufacturer or importer.

Supplemental information. Optional space where the supplier can add anything the standardized elements don't capture, like a batch number or handling notes.

For workplace containers (ones you've transferred chemicals into, not the original shipping containers), the rules bend a little. OSHA lets employers use an alternate labeling system as long as it conveys equivalent hazard information and workers are trained to understand it. ^[2] Most small businesses come out ahead by keeping chemicals in their original containers and skipping the extra burden of a secondary labeling system entirely.

What is the Safety Data Sheet and how do the symbols connect to it?

The Safety Data Sheet is the 16-section document that travels with every hazardous chemical. The pictograms on the label and the information in the SDS are two sides of the same coin. Section 2 of every SDS holds the hazard identification, and it must list the same GHS pictograms that appear on the label, using the same hazard classifications. ^[2]

If a label shows the health hazard silhouette, Section 2 of the SDS explains whether the concern is carcinogenicity, reproductive toxicity, or something else. Section 11 (Toxicological Information) goes deeper, with exposure limits, symptoms of overexposure, and relevant study data.

OSHA requires employers to keep SDSs for all hazardous chemicals in the workplace and make them accessible to workers on every shift, including nights. ^[2] Accessible means immediately accessible, not locked in a manager's office. Most small operations use a binder at a central spot; some use a tablet or a shared drive. Either works, as long as every worker on every shift can reach the SDS without asking permission.

For a practical example of how SDSs work for a specific chemical, see our guide to the hcl safety data sheet, which walks through a real hydrochloric acid SDS section by section.

Under the hazard communication standard, what is the employer responsible for?

This is the question OSHA compliance officers ask when they walk in the door. Under 29 CFR 1910.1200, the employer's responsibilities are specific and layered. ^[2]

First, you must maintain a written hazard communication program. It's a documented description of how your workplace implements the standard: how you label containers, where SDSs are kept, how you train workers, and how you handle non-routine tasks involving chemicals. Inspectors ask for this on the spot.

Second, you must compile and keep a current chemical inventory. The list must include every hazardous chemical in the workplace. It doesn't have to be fancy. A spreadsheet works fine, but it has to be accurate and tied to your SDS collection.

Third, you must make sure every hazardous chemical in your workplace has a proper label at all times. You cannot remove, deface, or cover the label that came from the manufacturer. If a label falls off or becomes illegible, replace it before the container goes back into use.

Fourth, you must train workers. OSHA requires training at initial assignment (before the worker starts the job) and whenever a new hazard is introduced. ^[2] Training must cover how to read labels, what each pictogram means, how to find and read an SDS, and the specific hazards of the chemicals in your workplace. A generic chemical safety video won't satisfy this on its own; the training has to be specific to your chemicals and your workplace.

Fifth, you must deliver that training in a language workers understand. If your workforce includes non-English speakers, the standard's intent is plain: training in a language they can't follow doesn't count as training. OSHA has reinforced this in multiple letters of interpretation.

If you need your written hazard communication program built fast, a tool like SafetyFolio can generate a compliant, customized program in about 15 minutes, which helps if you're building from scratch or your existing document is years out of date.

Hazard communication sits consistently in OSHA's top 10 most-cited standards, holding the number two spot in fiscal year 2023 with 3,213 violations. ^[4] The most common citation is failing to have a written program, followed by inadequate training. Neither is an expensive fix. They just require actually doing them.

How does the Globally Harmonized System differ from the old MSDS and NFPA diamond system?

If you've been in business more than 15 years, you remember the old system. Material Safety Data Sheets (MSDSs) had no required format, so some ran two pages and others ran 30, with the hazard information buried wherever the manufacturer decided to put it. The NFPA 704 diamond and the HMIS labeling system both used numerical scales (0-4) with color coding for health, flammability, and reactivity, but they weren't standardized internationally and they said almost nothing about chronic versus acute hazards. ^[5]

The GHS shift brought three concrete improvements. One: the SDS now has a mandatory 16-section structure, so a worker or emergency responder always knows where to find exposure limits (Section 8) or spill response (Section 6), no matter who made the product. Two: hazard categories are more granular, separating a chemical that's immediately fatal (skull and crossbones) from one that harms over time (health hazard silhouette). Three: international alignment means a chemical labeled in Germany, Japan, or Brazil carries the same pictograms in the U.S., cutting confusion for imports and for workers who move between countries.

The NFPA diamond and HMIS systems aren't banned. They just aren't OSHA's required system for shipped containers. Some facilities keep them on fixed equipment (storage tanks, for example) as supplemental information, which OSHA permits as long as the GHS elements are present and workers are trained on both. ^[2] Running two systems in the same shop is a training burden most small businesses don't need. If you're switching over, drop the HMIS binders and go GHS-only.

What training do workers need on hazard communication symbols?

OSHA is specific about content and loose about format. The standard says training must cover the methods workers use to detect the presence or release of a hazardous chemical, the physical and health hazards of the chemicals in the work area, the protective measures available, and how the hazard communication program works, including reading labels and SDSs. ^[2]

In practice, every worker who handles or works near hazardous chemicals needs to look at a label and explain what each pictogram means, know where the SDSs are and how to find a specific one, understand the actions the precautionary statements call for, and know what to do after a spill or exposure.

For osha training purposes, hazard communication is a core topic in both OSHA 10 and OSHA 30 courses. Finishing an osha 30 course does not by itself satisfy the site-specific training requirement under 1910.1200, but it builds a foundation that makes the site-specific piece much faster.

OSHA sets no minimum number of training hours for hazard communication. The standard says training must be effective, meaning the worker can actually demonstrate understanding, more than sit in a room for an hour. For most small businesses with a moderate chemical inventory, a 60- to 90-minute hands-on session using the actual products workers touch, followed by a short written or verbal check, is realistic and defensible.

Documentation matters. Keep a record of who was trained, when, what was covered, and who delivered it. If OSHA shows up and you have no records, you have no proof the training happened, even if it did.

Which industries are most at risk and which chemicals trigger the most hazard symbols?

Hazard communication violations cluster in industries that use chemicals heavily and train workers least: construction, manufacturing, automotive repair, printing, agriculture, and janitorial and cleaning services. ^[4] Small businesses in these sectors get cited more because they often have no dedicated safety person, and hazcom training gets treated as a someday task.

Chemicals that commonly carry multiple pictograms, and therefore demand the most thorough training, include:

• Paints and coatings (often flame, health hazard, and exclamation mark)
• Cleaning solvents like acetone and methyl ethyl ketone (flame, exclamation mark, sometimes health hazard)
• Industrial degreasers (health hazard, corrosion, exclamation mark)
• Epoxies and adhesives (corrosion, health hazard, skin sensitizer)
• Welding fumes (health hazard, since hexavalent chromium and manganese fumes carry carcinogen classifications)
• Hydrochloric and sulfuric acid (corrosion, skull and crossbones at high concentrations)
• Compressed gases like propane or acetylene (gas cylinder, flame, exploding bomb for acetylene)

BLS data shows chemical exposures account for tens of thousands of nonfatal workplace injuries and illnesses requiring days away from work each year, with skin and eye contact the most common routes. ^[6] Turn label reading into a habit and you cut directly into that number.

For workplaces that handle physical energy hazards alongside chemicals, tying hazard communication training to lockout tagout procedures makes sense, because workers often manage both at once during maintenance.

What happens if a label is damaged, missing, or a container is unlabeled?

This happens more than it should, and it's a real compliance problem. Under 29 CFR 1910.1200(f)(9), if an existing label is removed or defaced, the employer must immediately re-label the container with the required information. ^[2] "Immediately" in OSHA enforcement practice means before the container is used again, not by Friday.

For secondary containers, meaning anything you've transferred a chemical into from the original, you need a label with at minimum the product identifier and words, pictures, or symbols that convey the hazard information. A blank squeeze bottle of solvent with a handwritten note saying "acetone" is not compliant. It also has to convey that acetone is flammable and an irritant.

The exception covers portable containers for immediate use by the worker who filled them. Pour a little solvent into a cup to clean a part, use it right now, don't walk away from it, and OSHA doesn't require a label on that container. ^[2] Let it sit overnight and the exception is gone.

Unlabeled containers create a second problem beyond citations. In an emergency, responders don't know what they're dealing with. That gap can turn a minor spill into a serious injury. The label isn't a regulatory checkbox. It's the first line of response information.

How do you build a compliant written hazard communication program?

OSHA requires the written program to be specific to your workplace. A one-size-fits-all document downloaded from a trade association site is a starting point, not a finished program. At minimum, your written hazcom program must describe how you keep containers labeled, where SDSs live and how workers reach them, how you train new employees and retrain when new hazards appear, how you handle non-routine tasks with unusual chemical hazards, and how you manage contractors who bring their own chemicals onto your site. ^[2]

The contractor piece is something small businesses consistently miss. If a painting contractor shows up with their own solvents, you and that contractor both carry hazcom obligations. You have to tell them about any chemicals in the areas they'll work; they have to give you SDSs for what they bring in and make sure their own workers are trained. OSHA's standard puts that coordination duty explicitly on both parties.

For the actual document, you can build it from OSHA's model program (available on OSHA.gov ^[2]), hire a consultant, or use a generator tool. If you want an OSHA-ready program done fast, SafetyFolio's safety program generator walks you through a set of workplace-specific questions and produces a complete written program, including the hazard communication section, in about 15 minutes.

Once you have the program, review it at least annually and whenever your chemical inventory shifts meaningfully. A program that covers the chemicals you used three years ago but not what's in your shop today is a compliance gap waiting to become a citation. For more on building your overall compliance foundation, see our full guide to hazard communication.

What are the OSHA penalties for hazard communication violations?

OSHA penalty amounts adjust annually for inflation. As of 2024, the maximum penalty for a serious violation is $16,131 per violation, and willful or repeated violations can reach $161,323 per violation. ^[7] Hazard communication violations are almost always classified "serious" because the harm potential is real and well-documented.

The more useful number is the average penalty. OSHA frequently groups multiple hazcom deficiencies (no written program, inadequate training, missing labels) into a single citation or settles cases at a discount. A small employer with a first-time violation and a cooperative attitude usually sees penalties well below the statutory maximum. But "usually" is not a guarantee, and some OSHA area offices run stricter than others.

The real cost of a citation also includes the time to fix the deficiencies, the informal conference, and the reputational hit once the citation goes public, which every OSHA citation does. OSHA publishes citation data in a searchable database. Customers, general contractors, and insurers read it.

Avoiding citations is straightforward: have a written program, keep containers labeled, keep SDSs accessible, and train your workers with documentation. None of that needs a consultant or an expensive software platform. It needs time and follow-through. If you want to see what an incident report looks like after a chemical exposure and how it connects to your hazcom obligations, that's a natural next step once your labels and training are in order.

Frequently asked questions

How many GHS pictograms are there under OSHA's Hazard Communication Standard?

There are nine GHS pictograms recognized under 29 CFR 1910.1200: flame, flame over circle, exploding bomb, skull and crossbones, exclamation mark, health hazard, corrosion, gas cylinder, and environment. The environment pictogram is not mandatory under the federal OSHA standard but may appear on products and is required in some state-plan states. A single product can carry multiple pictograms.

What does the exclamation mark symbol mean on a chemical label?

The exclamation mark pictogram signals a hazard that is serious but not immediately life-threatening the way skull-and-crossbones is. It covers acute toxicity category 4, skin irritants, eye irritants, skin sensitizers, respiratory irritants, and chemicals hazardous to the ozone layer. Don't treat it as minor. Skin sensitization from repeated low-dose exposure can become a permanent condition.

What does the health hazard symbol look like and what does it mean?

The health hazard pictogram is a silhouette of a person with a starburst on the chest. It means the chemical is linked to long-term or serious health effects: carcinogenicity, reproductive toxicity, respiratory sensitization, target organ toxicity (single or repeated exposure), mutagenicity, or aspiration hazard. This is the symbol most often undertrained in small workplaces because the risks are chronic rather than acute.

Can an employer remove a GHS label from a container?

No. Under 29 CFR 1910.1200(f)(9), employers cannot remove or deface existing labels on incoming containers unless they immediately replace them with a label carrying all required elements. If a label tears or becomes illegible, replace it before the container is used again. This applies to all containers, including drums and totes received from suppliers.

What is the difference between 'Danger' and 'Warning' signal words on a chemical label?

Both are GHS signal words that appear on labels along with pictograms. 'Danger' indicates a more severe hazard category; 'Warning' indicates a less severe one. When a product has multiple hazards at different severity levels, only 'Danger' appears on the label because listing both would be redundant. The signal word alone doesn't tell you the type of hazard; the pictograms and hazard statements do that.

Under the hazard communication standard, who is responsible for labeling containers?

Chemical manufacturers and importers label shipped containers with all required GHS elements before they leave the facility. Employers keep those labels in place, legible, and never removed or defaced. Employers also label any secondary or workplace containers they fill themselves, with at minimum a product identifier and hazard information conveyed through words, pictures, or symbols.

Do the GHS pictograms apply to construction sites as well as general industry?

Yes. OSHA's Hazard Communication Standard applies to construction under 29 CFR 1926.59, which incorporates the requirements of 1910.1200 by reference. Construction workers who handle paints, adhesives, solvents, concrete, and similar materials must get the same label and SDS training as general industry workers. Construction is one of the industries with the highest rates of hazcom citations.

How often does OSHA require hazard communication training?

OSHA requires training before a worker's initial assignment to work with or near hazardous chemicals, and whenever a new hazard is introduced into the workplace. There is no fixed annual recertification requirement in the standard itself, but OSHA expects training to be effective and may cite employers if workers cannot demonstrate understanding of labels and SDSs during an inspection. Practical recommendation: retrain whenever your chemical inventory changes meaningfully.

Is the environment (dead fish and tree) pictogram required on OSHA labels?

At the federal OSHA level, the environment pictogram is not mandatory; it 'may' be used according to OSHA's standard. Some state-plan states have added requirements, and the GHS framework itself classifies the aquatic toxicity hazards that carry this symbol. Products imported from countries where the environment pictogram is required may display it regardless. Workers should still be trained to recognize it.

What is the difference between a GHS label and a Safety Data Sheet?

The GHS label is the physical marking on the container, giving immediate hazard information in a standardized visual format: pictograms, signal word, hazard statements, and precautionary statements. The Safety Data Sheet (SDS) is a detailed 16-section document covering the same hazard classifications in depth, plus exposure limits, first aid measures, handling and storage instructions, and emergency response. Both are required; they work as a system.

What does the gas cylinder pictogram mean and which chemicals carry it?

The gas cylinder pictogram indicates a gas under pressure, meaning the container could explode if heated or punctured. It applies to compressed gases, liquefied gases, refrigerated liquefied gases, and dissolved gases. Common examples include propane, oxygen, acetylene, carbon dioxide, nitrogen, and refrigerants. Acetylene also typically carries the exploding bomb pictogram because of its instability.

How do GHS hazard categories work and why does the category number matter?

GHS hazard categories rank severity within a hazard class, where Category 1 is almost always the most severe. A flammable liquid Category 1 has a flash point below 23°C and an initial boiling point at or below 35°C (think diethyl ether), while Category 4 has a flash point of 60 to 93°C. The category determines which signal word and hazard statements appear on the label and which precautionary measures are required. SDS Section 2 gives you the exact category.

Can workers refuse to work with a chemical if there's no label or SDS?

Workers have the right under Section 11(c) of the OSH Act to refuse work they reasonably believe poses imminent danger, and the absence of hazard information would support a reasonable belief of unknown risk. More directly, OSHA's Hazard Communication Standard makes the employer provide that information before work begins. A worker who raises the concern to a supervisor or to OSHA cannot be retaliated against for doing so.

What should a written hazard communication program include?

At minimum: how you keep containers labeled, where SDSs are kept and how every worker reaches them on every shift, how initial and updated training happens, how you handle non-routine tasks with unusual chemical hazards, and how you coordinate with outside contractors who bring their own chemicals. OSHA provides a free model written program on OSHA.gov as a starting template, but you must customize it with your specific chemicals and procedures.

Sources

1. United Nations, Globally Harmonized System of Classification and Labelling of Chemicals (GHS) overview: GHS is a United Nations framework for standardized chemical hazard communication internationally adopted by the U.S. through OSHA's 2012 HazCom revision.
2. OSHA, 29 CFR 1910.1200 Hazard Communication Standard: Specifies all employer obligations under the Hazard Communication Standard including labeling requirements, SDS accessibility, written program, and training content.
3. OSHA, GHS Hazard Communication: Pictograms: The environment pictogram is not mandatory under the federal OSHA standard but may be used voluntarily; OSHA lists all nine GHS pictograms and their associated hazard classes.
4. OSHA, Top 10 Most Frequently Cited Standards, Fiscal Year 2023: Hazard Communication (1910.1200) was the second most frequently cited OSHA standard in FY2023 with 3,213 violations.
5. NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response: NFPA 704 used a numerical 0-4 scale for health, flammability, and reactivity hazards; this system was not internationally harmonized with GHS pictograms.
6. Bureau of Labor Statistics, Nonfatal Occupational Injuries and Illnesses Involving Days Away from Work: Chemical exposures account for tens of thousands of nonfatal workplace injuries and illnesses requiring days away from work annually, with skin and eye contact as common routes.
7. OSHA, Civil Penalty Inflation Adjustments (Federal Civil Penalties Inflation Adjustment Act): As of 2024, the maximum OSHA penalty for a serious violation is $16,131 per violation; willful or repeated violations can reach $161,323 per violation.
8. OSHA, 29 CFR 1926.59 Hazard Communication (Construction): Construction industry hazard communication requirements are found in 29 CFR 1926.59, which incorporates the general industry standard at 1910.1200 by reference.