Know Your Lab Safety Symbols

Dec 1, 2022 9:05:36 AM / by WSI Team

Pictograms have long held significance and have been used by ancient cultures all over the world. Today, they remain in common use, serving an important purpose in many environments including laboratories.


The Occupational Safety and Health Administration (OSHA) has adopted the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) in the United States. The GHS is part of OSHA’s Hazard Communication Standard (HCS) and includes nine important lab safety symbols anyone working in this type of environment should know. 


Each of the pictograms illustrates a type of hazard often found in labs. Their simple designs are planned so that anyone in a laboratory can recognize what they mean quickly. Let’s take a look at these safety symbols and what other information is required to ensure lab safety.

Lab Safety Symbols


Below are the nine safety symbols found in labs. It’s important to note that although these signs feature different hazard symbols, OSHA requires the following of each pictogram, according to Appendix C, Section C.2.3.1 of 29 CFR 1910.1200:


Pictograms shall be in the shape of a square set at a point and shall include a black hazard symbol on a white background with a red frame sufficiently wide to be clearly visible. A square red frame set at a point without a hazard symbol is not a pictogram and is not permitted on the label.


Flame Over Circle


lab safety symbols


The Flame Over Circle symbol identifies oxidizers. Oxidizers are a type of chemical that facilitate burning. They also make fires burn at a higher temperature and for a longer period of time.




lab safety symbols


The Flame symbol identifies flammable materials. This symbol also warns workers nearby that these hazardous materials may emit flammable gas or may self ignite when they are exposed to water or air.


Exploding Bomb



The Exploding Bomb symbol indicates explosives are present. Explosives include organic peroxides and any highly unstable material that is at risk for explosion. This includes environments where the substance is not exposed to air, called self-reactives.


Skull And Crossbones


lab safety symbols


The Skull and Crossbones symbol identifies substances that have an immediate and severe toxic effect. This is called acute toxicity, and examples of these substances include poisons and highly concentrated acids.





The Corrosion symbol indicates that a material can cause skin corrosion or burns. Corrosive substances can also damage eyes on contact, or may damage metals when the substances and metals come in direct contact.


Gas Cylinder


lab safety symbols


The Gas Cylinder symbol means that a gas is stored under pressure. Examples of substances stored in gas cylinders include ammonia and liquid nitrogen.


Health Hazard



The Health Hazard symbol indicates that a cancer-causing agent is present. In addition to carcinogens, the agents or substances present can also cause respiratory, reproductive or organ toxicity issues that can cause damage over time. In other words, the Health Hazard symbol warns of a long-term health hazard.




lab safety symbols


The Environment symbol alerts individuals that present chemicals are toxic to aquatic wildlife. It’s important to note that this is the only symbol listed here that is non-mandatory.


Exclamation Mark



The Exclamation Mark symbol indicates that the substance can cause immediate irritation, including to the skin, eye or respiratory tract. This symbol also indicates a narcotic.

Additional Information Required With Lab Safety Symbols



Employers are responsible for maintaining any labels that appear on containers, such as tanks and drums. OSHA has updated the requirements for labs that must label their hazardous chemicals. Under the Hazard Communication Standard, labels must have:


  • Pictograms (there can be more than one depending on the substance)
  • A signal word such as “Danger”
  • Hazard and precautionary statements
  • The product identifier 
  • Supplier identification


Hazard and precautionary statements can include a number of items, from directions on where to keep the substance to how to react if a fire occurs. Examples of hazard and precautionary statements include:


  • Highly flammable liquid.
  • May cause liver damage.
  • Store in a cool, well-ventilated place.
  • Do not open around an open flame.
  • No smoking.
  • Use only non-sparking tools.
  • Wear gloves and face masks.
  • Do not breathe vapors and wear protective gloves.
  • In case of fire (and include statements like “use dry chemical (BC) or a carbon dioxide fire extinguisher).
  • If on skin, remove any contaminated clothing and rinse skin with water.


The product identifier simply includes the product name and code, while the supplier identification should include the company’s name, address and emergency phone number.


Any additional information you feel is pertinent to maintaining the safety of your lab space can be included on the label as well.

Symbols Just One Part Of A Safe Lab


Ensuring you are using the right lab safety symbols that warn employees of any possible dangers is just one component of proper lab safety. 


There are many lab safety rules and guidelines that are critical to follow, from having a clear understanding of the substance you are working with to performing routine safety checks and wearing the proper protective clothing and other personal protective equipment (PPE) like eye protection.


There are many resources available through organizations like: 

Some of these organizations offer helpful tools such as training, safety videos and blueprints of standard operating procedures you can use to make your lab a safe environment for your workers.


laboratory furniture

Topics: Laboratory

WSI Team

Written by WSI Team

Employees of Workstation Industries who write on different topics to inform and educate.

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