If you've ever looked at a chemical container and noticed the red-bordered diamond symbols on the label, you've seen GHS pictograms. They're on everything from industrial solvents to the spray cleaner under your break room sink. Most people glance at them and move on. That's a problem — because those symbols are trying to tell you something specific about how that chemical can hurt you.
GHS pictograms are part of the Globally Harmonized System of Classification and Labelling of Chemicals, adopted by OSHA through the Hazard Communication Standard. There are nine pictograms total, each representing a distinct type of hazard. Eight are mandatory in the United States. They appear on manufacturer labels and Safety Data Sheets, and understanding them is a core part of the chemical safety training OSHA requires for every worker who handles hazardous materials.
This guide walks through each pictogram in plain language: what it looks like, what hazards it represents, and what you should do when you see it on a container in your workplace.
How GHS Pictograms Work
Every GHS pictogram follows the same format: a black symbol on a white background inside a red diamond-shaped border. This design was chosen deliberately — the red border stands out against any container color, and the standardized symbols communicate hazard information without relying on any specific language. A worker who doesn't speak English can still recognize a flame symbol and understand "flammable."
Pictograms never appear alone. They're one element of a complete GHS label, which also includes the product name, a signal word ("Danger" for more severe hazards or "Warning" for less severe ones), hazard statements describing the specific risk, precautionary statements explaining how to handle the chemical safely, and the supplier's contact information.
A single product can carry multiple pictograms if it presents more than one type of hazard — a solvent might be both flammable and an irritant, so you'd see both the flame and the exclamation mark on the label. Each pictogram appears only once per label, regardless of how many hazard classes it covers.
Under OSHA's Hazard Communication Standard, employers must train employees to recognize GHS pictograms and understand what they mean. During an inspection, OSHA may point to a pictogram on a product label and ask an employee to explain it. If they can't, the training program is considered deficient.
The Nine GHS Pictograms
1. Flame
What it looks like: A stylized fire.
What it means: The chemical is flammable. This is one of the most common pictograms you'll encounter in any workplace. It covers flammable liquids and solids, flammable gases, flammable aerosols, pyrophoric materials (chemicals that can ignite spontaneously on contact with air), self-heating substances, and chemicals that emit flammable gas on contact with water.
Where you'll see it: Gasoline, acetone, spray paints, certain adhesives, alcohol-based cleaners, WD-40, and most aerosol products.
What to do: Keep the container closed when not in use. Store away from heat sources, open flames, sparks, and direct sunlight. Follow the label's precautionary statements for the specific type of flammability — a pyrophoric material requires very different handling than a standard flammable liquid. Use in well-ventilated areas and pay attention to the flash point listed in Section 9 of the SDS.
2. Flame Over Circle
What it looks like: A flame sitting on top of a circle.
What it means: The chemical is an oxidizer. Oxidizers don't burn on their own, but they intensify fire by supplying oxygen. A fire near an oxidizer burns hotter and faster and is much harder to extinguish.
Where you'll see it: Hydrogen peroxide (at high concentrations), bleach, certain pool chemicals, potassium permanganate, and some industrial cleaning agents.
What to do: Keep oxidizers stored separately from flammable materials — this is a critical chemical storage requirement. Never mix an oxidizer with a flammable substance, organic material, or other incompatible chemical. If you see this pictogram, check Section 10 of the SDS for specific incompatibilities.
3. Exploding Bomb
What it looks like: A fragmenting explosion.
What it means: The chemical is explosive or self-reactive. It can detonate or explode under certain conditions — heat, friction, shock, or contamination. Under GHS Revision 7, desensitized explosives are now recognized as a distinct hazard class.
Where you'll see it: This pictogram is uncommon in most workplaces. You're most likely to encounter it in mining, demolition, pyrotechnics, or specialized manufacturing. Certain organic peroxides also carry this pictogram.
What to do: Follow the handling and storage instructions on the label exactly. These are among the most dangerous chemicals regulated under GHS, and improper handling can have catastrophic consequences. If you encounter this pictogram on a product you aren't specifically trained to handle, do not touch the container.
4. Skull and Crossbones
What it looks like: A skull with two crossed bones beneath it.
What it means: The chemical has high acute toxicity — it can cause serious illness or death through a single or short-term exposure. The exposure route could be inhalation, ingestion, or skin contact, depending on the specific chemical.
Where you'll see it: Certain pesticides, methanol, concentrated acids, some industrial chemicals, and laboratory reagents. This pictogram indicates a more severe hazard than the exclamation mark (which covers lower levels of acute toxicity).
What to do: This is one of the most serious pictograms. Do not handle the chemical without reading the full SDS first. Wear all PPE specified in Section 8 of the SDS. Work in a well-ventilated area or use respiratory protection as directed. Know the first aid procedures in Section 4 before you open the container — not after.
If a product carries the skull and crossbones pictogram, take it seriously. This symbol means the chemical can be fatal or toxic through normal exposure routes. Every employee who handles this product should be specifically trained on its hazards and emergency procedures.
5. Corrosion
What it looks like: A substance eating through a surface and a hand.
What it means: The chemical is corrosive. It can cause severe skin burns on contact, serious eye damage, and can corrode metals. This pictogram spans both health and physical hazards — the image depicts both a hand being damaged and a surface being dissolved.
Where you'll see it: Battery acid, drain cleaners, muriatic acid (hydrochloric acid), sodium hydroxide (lye), some industrial degreasers, and concentrated cleaning chemicals.
What to do: Wear chemical-resistant gloves, eye protection (goggles, not just safety glasses), and protective clothing as specified in the SDS. Know the location of the nearest eyewash station. If the chemical contacts skin or eyes, follow the first aid instructions immediately — corrosive burns worsen rapidly with delayed treatment.
6. Gas Cylinder
What it looks like: A compressed gas cylinder or tank.
What it means: The container holds gas under pressure. Compressed gases, liquefied gases, refrigerated liquefied gases, and dissolved gases all carry this pictogram. The hazard is twofold: the container can rupture or explode if damaged or exposed to heat, and the gas itself may displace oxygen in an enclosed space.
Where you'll see it: Welding gases (argon, acetylene, CO₂), propane tanks, nitrogen cylinders, oxygen tanks, and refrigerant containers.
What to do: Store cylinders upright and secured to prevent tipping. Keep them away from heat sources and direct sunlight. Never use a damaged cylinder. In enclosed spaces, be aware that inert gases like nitrogen and argon can displace breathable oxygen without any visible warning — oxygen monitors may be required depending on the setting.
7. Exclamation Mark
What it looks like: A bold exclamation point.
What it means: The chemical presents a lower-level acute health hazard. This covers skin irritation, eye irritation, respiratory tract irritation, narcotic effects (drowsiness or dizziness), skin sensitization (allergic reactions), and harmful effects if swallowed, inhaled, or absorbed through the skin.
Think of this as the "step down" from the skull and crossbones. The chemical can still hurt you, but the effects are typically less severe and less immediate. That doesn't mean you can ignore it — chronic exposure to irritants causes real damage over time.
Where you'll see it: This is probably the most common pictogram in everyday workplaces. Household cleaners, degreasers, some paints and stains, certain adhesives, and many industrial chemicals carry the exclamation mark.
What to do: Read the specific hazard statements on the label. "Causes skin irritation" requires different precautions than "May cause drowsiness." Wear the PPE specified for the particular hazard. Use in ventilated areas when the hazard involves inhalation.
8. Health Hazard
What it looks like: A silhouette of a person's upper body with a six-pointed star shape on their chest.
What it means: The chemical poses a serious long-term health hazard. This is one of the most important pictograms to recognize because it covers hazards that don't show symptoms immediately — the damage accumulates over time. Specific hazards include carcinogenicity (can cause cancer), mutagenicity (can damage genetic material), reproductive toxicity, respiratory sensitization (can cause asthma-like reactions), target organ toxicity (damages specific organs through repeated exposure), and aspiration hazard (can cause chemical pneumonia if swallowed and then enters the airways).
Where you'll see it: Certain solvents, some paints and coatings, formaldehyde-containing products, crystalline silica-generating materials, and various industrial chemicals. This pictogram often appears alongside others — a solvent might carry both the flame (flammable) and the health hazard (chronic toxicity).
What to do: Take this pictogram especially seriously. The hazards it represents often cause irreversible damage that only becomes apparent years or decades after exposure. Read Section 11 (Toxicological Information) of the SDS carefully. Follow all PPE requirements. Minimize exposure duration and frequency. If respiratory sensitization is listed, even brief unprotected exposure could trigger permanent sensitivity.
The health hazard pictogram is the one employees most often overlook because the effects aren't immediate. A chemical that causes cancer through repeated exposure doesn't burn your hand the first time you touch it — which makes it easy to underestimate. Training should emphasize that long-term hazards are just as serious as acute ones.
9. Environment
What it looks like: A dead tree and a dead fish.
What it means: The chemical is toxic to aquatic life and the broader environment. Improper disposal can contaminate water sources and harm ecosystems.
Where you'll see it: Certain pesticides, petroleum products, some heavy metal compounds, and various industrial chemicals.
Important note: This is the one GHS pictogram that OSHA does not require on workplace labels. It's part of the GHS framework but falls outside OSHA's enforcement scope since environmental hazards are regulated by the EPA and other agencies. You may still encounter it on products that carry internationally compliant labels, and it's worth understanding — improper disposal of these chemicals can trigger EPA violations and environmental liability.
Signal Words: Danger vs. Warning
Every GHS label includes one of two signal words alongside the pictograms: Danger or Warning. Only one signal word appears per label, and Danger always takes priority over Warning when both could apply.
Danger indicates the most severe hazard categories. If you see "Danger," the chemical presents a serious and potentially life-threatening risk.
Warning indicates a less severe but still significant hazard. It doesn't mean the chemical is safe — it means the immediate risk is lower than a "Danger" chemical.
The signal word provides a quick severity check. Two chemicals might both carry the skull and crossbones pictogram, but the one marked "Danger" is more acutely toxic than the one marked "Warning."
Putting It All Together: Reading a GHS Label
When you encounter a chemical container, read the label in this order for the fastest understanding of what you're dealing with.
Pictograms first. They tell you the type of hazard in an instant — flammable, toxic, corrosive, health hazard, or a combination.
Signal word next. Danger or Warning tells you the severity level.
Hazard statements. These short sentences describe the specific hazards: "Causes serious eye damage," "May cause cancer," "Highly flammable liquid and vapor." This is where the pictograms get translated into specific risks.
Precautionary statements. These tell you what to do: how to store it, what PPE to wear, what to do if exposed, and how to dispose of it.
If you need more detail than the label provides — especially about first aid procedures, PPE requirements, or long-term health effects — the Safety Data Sheet contains the full picture. Every chemical with a GHS label has a corresponding SDS that your employer is required to keep accessible.
Using This for Training
If you're a manager or business owner, this guide can serve as the foundation for a GHS pictogram training session. OSHA requires that every employee who works with hazardous chemicals can identify the pictograms on the products they use and understand what hazards they represent.
A practical approach: pull five or six products from your actual workplace, line them up, and walk your team through the pictograms on each label. Ask them to identify the pictograms, state the hazard type, and find the corresponding SDS. When training uses real products from the employee's own work area, retention is dramatically better than a generic slide deck.
Document the training with dates, topics covered, and employee signatures. This record is what you'll show an OSHA inspector to demonstrate that your HazCom training program covers pictogram recognition.
Post a pictogram reference chart in work areas where chemicals are stored or used. A simple poster showing all nine pictograms with one-line descriptions gives employees a quick reference they can check without pulling up the SDS. It's not a substitute for training, but it reinforces the knowledge daily.
The Bottom Line
GHS pictograms exist because chemical hazards need to be communicated instantly, universally, and without ambiguity. Nine symbols cover the full spectrum of physical and health hazards. Every employee who works with chemicals should be able to look at a label, identify the pictograms, and understand — at minimum — what type of hazard they're dealing with and where to find more information.
The flame, the skull, the exclamation mark, and the health hazard silhouette are the four you'll encounter most often in a typical workplace. Know those four cold, and you've covered the vast majority of chemical products your employees will handle. Know all nine, and you've given your team a safety skill they'll carry with them through every job for the rest of their careers.