The GHS pictograms are the nine standardized hazard symbols that OSHA requires on chemical labels and safety data sheets under the Hazard Communication Standard at 29 CFR 1910.1200. Each one is a black image on a white background inside a red diamond-shaped border, and each stands for a specific category of chemical danger: explosion, fire, oxidizer, compressed gas, corrosion, acute toxicity, long-term health effects, milder health effects, and environmental toxicity. Together they let a worker read a container at a glance, without needing to parse the chemistry.
The Nine Pictograms and What Each One Means
Some chemicals carry a single pictogram; others carry several. The combination is the message.
Exploding Bomb
Covers explosives, self-reactive chemicals, and organic peroxides capable of detonation or violent reaction. The material can go off under heat, shock, or friction.
Flame
Applies to flammable gases, liquids, and solids, pyrophoric materials that ignite on contact with air, self-heating substances, chemicals that emit flammable gas when wet, certain self-reactive chemicals, organic peroxides, and desensitized explosives. It is the pictogram you see most often in manufacturing and construction because it covers such a wide range of ignition hazards.
Flame Over Circle
Identifies oxidizers, which supply oxygen to a fire even in low-oxygen environments. Storing an oxidizer next to a flammable is one of the most dangerous mistakes in chemical warehousing, because the oxidizer feeds the fire from within.
Gas Cylinder
Compressed, liquefied, dissolved, or refrigerated gases under pressure. The hazard is not only the gas itself; a damaged valve or ruptured cylinder becomes a projectile.
Corrosion
Shows liquid eating through a hand and a metal surface. It marks chemicals that cause severe skin burns, irreversible eye damage, or degradation of metal containers. Workers often underestimate splash distance during transfer operations, which is where this symbol earns its keep.
Skull and Crossbones
Reserved for the most dangerous acute toxicity categories. A single exposure by ingestion, skin contact, or inhalation can be fatal or severely toxic. The danger is immediate, not from long-term buildup.
Health Hazard
A silhouette with a starburst on the chest. It represents serious long-term effects: carcinogens, mutagens, reproductive toxins, respiratory sensitizers, chemicals that target specific organs over repeated exposure, and aspiration hazards. Symptoms may not show for months or years, which is precisely why the pictogram is on the label.
Exclamation Mark
Covers less severe health effects: skin and eye irritation, skin sensitization, lower-category acute toxicity, narcotic effects, and respiratory tract irritation. Many common industrial solvents carry this symbol because they cause dizziness or skin reactions that ventilation and protective equipment can prevent.
Environment
A dead fish and a dead tree. Marks chemicals toxic to aquatic life or hazardous to the ozone layer. OSHA treats this pictogram as non-mandatory for workplace labels, but it appears frequently on containers because the same chemicals must meet EPA and Department of Transportation requirements during shipping and storage.
Which Pictogram Wins When More Than One Applies
A chemical can technically qualify for two pictograms that describe the same kind of harm at different severities. To keep labels readable, Appendix C of 29 CFR 1910.1200 sets precedence rules so only the more severe symbol appears.
- Skull and crossbones overrides the exclamation mark when both would apply for acute toxicity. A chemical that is fatal on contact does not also need a “harmful” warning.
- Corrosion overrides the exclamation mark when both would apply for skin or eye effects. Severe burns already communicate that irritation will occur.
- The health hazard pictogram overrides the exclamation mark when both would apply for sensitization or irritation and the health hazard pictogram is present for respiratory sensitization.
- “Danger” overrides “Warning” as a signal word. A label never displays both.
What a Compliant Pictogram Looks Like
Every compliant GHS pictogram uses the same format: a black hazard symbol centered on a white background, inside a red diamond (technically a square set on its point). OSHA does not specify the border width in millimeters, but the standard requires the red frame to be “sufficiently wide to be clearly visible.”
The red border is not optional on U.S. workplace labels. Some international shipping standards allow a black border, but under the Hazard Communication Standard, workplace labels in the United States require the red frame.
Blank red diamonds are a common compliance trap. Pre-printed label stock sometimes includes extra empty frames for chemicals that do not need all nine pictograms. OSHA explicitly prohibits blank red frames on labels. Printing “Intentionally Blank” or an “X” inside an unused diamond does not fix the problem. The only acceptable approach is to completely cover or black out unused frames. A red diamond without a hazard symbol inside it is not a pictogram, and it is not permitted.
Where the Pictograms Appear
Manufacturers, importers, and distributors must label every shipped container of hazardous chemicals with six elements grouped together: the product identifier, a signal word (“Danger” or “Warning,” never both), hazard statements, precautionary statements, the applicable pictograms, and the supplier’s name, address, and phone number. Those elements must stay grouped and remain legible in English throughout the product’s use.
On very small containers, full labeling is not always physically possible, and the standard provides two tiers of relief. Containers of 100 milliliters or less must still display the product identifier, pictograms, signal word, and manufacturer’s name and phone number, plus a note that full label information appears on the outer package. For containers of 3 milliliters or less, where any label would interfere with normal use, only the product identifier is required on the container itself. In both cases, the immediate outer package must carry the complete label, and the small container must be stored inside that package when not in use.
Secondary containers, meaning any bottle, beaker, bucket, or jug a worker fills from a larger source, need their own labels once they leave the “same shift, same worker, same area” exemption. If you pour a chemical into a portable container and use the entire contents during that shift without leaving the area, no label is required. If the shift ends, if you walk away, or if someone else might encounter the container, it needs a label showing at minimum the chemical’s identity and its hazards. Employers who lean too hard on the same-shift exemption are a frequent citation target, because in practice chemicals sit in unlabeled containers far longer than anyone intends.
Every hazardous chemical also has a safety data sheet in a standardized 16-section format. The pictograms appear in Section 2 (Hazard Identification), alongside the signal word, hazard statements, and precautionary statements. In digital formats where the graphic is impractical, the SDS may list the pictogram by name, such as “flame” or “skull and crossbones,” instead of showing the image.
Labels You See in 2025 and 2026 May Follow Different Versions
OSHA published a major update to the Hazard Communication Standard in May 2024, aligning it more closely with Revision 7 of the GHS. The update added new hazard categories (including desensitized explosives, subcategories for flammable gases, and nonflammable aerosols), revised health hazard definitions, and updated classification criteria.
On January 15, 2026, OSHA extended the compliance deadlines by four months across the board. Manufacturers, importers, and distributors must evaluate and reclassify substances by May 19, 2026 (originally January 19, 2026), with the corresponding mixtures deadline around November 2027. Employers must update workplace labels, written programs, and training for substances by roughly November 2026 (originally July 20, 2026), and for mixtures by roughly May 2028.
During the transition, manufacturers, importers, distributors, and employers may comply with the previous version of the standard, the updated version, or both. The practical consequence: for the next couple of years, workers may see labels and safety data sheets formatted under different versions of the standard on chemicals sitting side by side. The nine pictograms themselves do not change, but the classification thresholds and hazard statements paired with them can.