If your business deals with chemicals every day, whether in a lab, manufacturing plant, or storage facility, you already know that safety isn’t optional. After all, one small mistake with a hazardous substance can lead to serious injuries, damaged property, or compliance violations. 

That’s why OSHA and the Globally Harmonized System (GHS) require specific hazard symbols on every chemical label and Safety Data Sheet (SDS). These aren’t just warning signs. Rather, they’re the universal language of chemical safety. They help workers instantly recognize what risks they’re dealing with. 

Still, many organizations face the same challenge: employees see these red diamond symbols daily but don’t always understand their meaning or the precautions they take. 

Look at the following questions: 

• “What exactly does this symbol warn me about?” 

• “Do I need special PPE for this chemical?” 

• “How serious is this hazard if exposure occurs?” 

If your team hesitates before answering these, it’s a sign that safety awareness needs a boost. Misinterpreting hazard symbols doesn’t just increased risk. It can also cost you regulatory penalties and employee trust. 

So, let’s simplify it. Here’s a clear, practical guide to the 8 OSHA-required hazard symbols, what they mean, and how they protect your team and your workplace from danger. 

 

Hazard Symbols: In Brief 

Hazard symbols are simple visual warnings that tell you what kind of danger a chemical or substance might pose. Such symbols are designed to help workers quickly recognize risks like flammability, toxicity, or corrosiveness. As a result, no one has to read a label in detail. These symbols are standardized under OSHA’s Hazard Communication Standard (HCS) and the Globally Harmonized System (GHS), so no matter where you work, they mean the same thing worldwide. 

In short, hazard symbols act as the first line of defense in chemical safety. They guide workers on how to handle, store, and dispose of materials safely. Whether it’s a flame symbol, it warns you that the substance is flammable. A skull symbol, on the other hand, signals that the chemical is toxic. Understanding these icons helps prevent accidents. It also ensures that everyone in the workplace stays protected. 

Top 8 Hazard Symbols and their Meaning 

 

1. Flame

The indicates that the material is flammable or can catch fire easily. Some may ignite from heat, friction, or even air contact. This type of symbol can be commonly found in paint shops, chemical storage rooms, and manufacturing areas that use solvents or cleaning agents.  

Examples of Flammable Substances: 

• Gasoline and diesel 

• Acetone and ethanol 

• Aerosol sprays and lighter fluids 

Required Safety Practices: 

• Keep these chemicals away from open flames or sparks. 

• Store them in cool, ventilated areas. 

• Use flame-resistant containers. 

• Always close the lid tightly after use. 

 

2. Human Silhouette

 This symbol warns that chemicals can cause serious long-term health effects. It doesn’t refer to immediate harm but rather to conditions that develop over time. Prolonged exposure could lead to life-threatening illnesses. You can find it in laboratories, paint factories, manufacturing units, or any place that handles solvents and industrial chemicals. 

Examples of Risks: 

• Cancer or mutations 

• Respiratory problems like asthma 

• Reproductive toxicity (affecting fertility or fetal development) 

• Damage to organs (like the liver or kidneys) 

Required Safety Practices: 

• Always wear proper Personal Protective Equipment (PPE) like gloves, masks, and goggles. 

• Work in a well-ventilated area to avoid inhalation of fumes. 

• Never eat or drink near these substances. 

• Follow your workplace’s SDS (Safety Data Sheet) guidelines carefully. 

 

3. Exclamation Mark

This symbol signals less severe health effects such as irritation, dizziness, or allergic reactions. The effects may be temporary but can worsen with prolonged exposure. You can find it at places where cleaning products, disinfectants, and adhesives are stored.  

Examples of Risks: 

• Skin irritation or redness 

• Eye damage 

• Drowsiness or breathing discomfort 

Required Safety Practices: 

• Avoid direct contact with skin or eyes. 

• Always wear gloves and safety glasses. 

• Wash your hands thoroughly after handling. 

• Ensure good ventilation to reduce inhalation risks. 

 

4. Gas Cylinder 

This symbol identifies gases that are stored under pressure. If exposed to heat or damaged, the container can explode or burst. Some gases can also cause frostbite or suffocation if released suddenly. Such symbols can be found in hospitals, welding workshops, laboratories, and industrial plants. 

Examples of Gases: 

• Oxygen, nitrogen, or helium cylinders 

• Propane or butane tanks 

Required Safety Practices: 

• Always keep cylinders upright and secure with a chain or strap. 

• Store them away from heat or direct sunlight. 

• Use the correct pressure regulators and check for leaks. 

• Handle with care, never drop or roll cylinders. 

 

5. Corrosion ️

This symbol warns that the substance can cause severe burns, eye damage, or corrode metals. These materials are extremely reactive and must be handled carefully. You can find these symbols in industrial cleaning areas, chemical laboratories, and wastewater treatment facilities. 

Examples of Corrosive Substances: 

• Hydrochloric acid 

• Sodium hydroxide (caustic soda) 

• Ammonia and bleach solutions 

Required Safety Practices: 

• Always wear acid-resistant gloves, goggles, and face shields. 

• Avoid mixing chemicals unless instructed. 

• Store corrosives in clearly labeled, corrosion-resistant containers. 

• In case of skin or eye contact, rinse immediately with plenty of water and seek medical help. 

 

6. Exploding Bomb 

This symbol represents chemicals that are explosive or self-reactive. They can detonate under heat, friction, or shock, causing fires or injuries. Such symbols can be seen in research labs, chemical production facilities, and industries that handle propellants or reactive materials. 

Examples of Explosives: 

• Organic peroxides 

• Nitroglycerin 

• Firework components 

Required Safety Practices: 

• Keep such materials away from heat and ignition sources. 

• Store in small quantities and in special containers. 

• Avoid rough handling or dropping. 

• Follow strict storage and disposal protocols as outlined in SDSs. 

 

7. Flame Over Circle 

This symbol indicates oxidizing materials, substances that release oxygen, and make other materials burn more easily. They don’t burn themselves but fuel fires. This type of symbol is used in laboratories, cleaning industries, and pool maintenance products. 

 

Examples of Oxidizers: 

• Hydrogen peroxide 

• Nitrates and chlorates 

• Ammonium perchlorate 

Required Safety Practices: 

• Keep away from flammable or combustible substances (like oil or wood). 

• Store separately in cool, dry areas. 

• Use non-reactive containers. 

• Always check compatibility before mixing with other chemicals. 

 

8. Skull and Crossbones ️

This is one of the most serious hazard symbols. It warns that a chemical is acutely toxic, meaning even a small amount can be fatal if swallowed, inhaled, or absorbed through the skin. This type of symbol can be found in pest control areas, chemical manufacturing units, and storage rooms for industrial cleaning agents. 

Examples of Toxic Chemicals: 

• Cyanide 

• Methanol 

• Pesticides and insecticides 

Required Safety Practices: 

• Handle with extreme care using gloves, masks, and eye protection. 

• Never eat, drink, or smoke near these substances. 

• Dispose of waste properly, following safety guidelines. 

• Know your emergency response procedure in case of accidental exposure. 

 

Why are these Symbols Necessary to Keep Safer Workplaces?   

1. Build Awareness and Responsibility:

 Hazard symbols help everyone become more aware of the materials they handle. Instead of guessing whether a chemical is harmful or flammable, the symbol tells them immediately.
This awareness creates responsibility. Naturally, workers become more careful when they know the potential risks. For example, seeing a corrosion symbol reminds them to wear gloves and goggles before touching the substance. Over time, this habit reduces careless mistakes and builds a culture where safety comes first. 

 

2. Improve Emergency Response: 

 In emergencies, quick action can make a huge difference. Hazard symbols help workers and first responders react faster and smarter. For instance, if a chemical spill occurs and the label shows a flame symbol, employees instantly know how to avoid sparks and heat sources. Similarly, a skull and crossbones icon signals that they should avoid inhaling fumes and evacuate immediately. When everyone understands what each symbol means, panic is replaced by preparedness, and response times improve dramatically. 

 

3. Strengthen Compliance and Reduce Legal Risks

Every organization that handles hazardous substances must follow OSHA and GHS labeling standards. Using the correct hazard symbols ensures your company meets those regulations and avoids costly fines or penalties. Beyond legal compliance, clear labeling also shows your commitment to employee well-being. When auditors or clients visit your facility, properly labeled containers reflect a professional and safety-conscious environment.
  

Conclusion 

Understanding OSHA hazard symbols is one of the simplest, yet most powerful, ways to protect your employees. So, take a moment today to walk through your facility, check your labels, and make sure every worker knows what those red diamonds truly mean.