52 Laboratory Safety Symbols, Signs, and Meanings

Signs and symbols are figures representing specific instructions about what to do and what not to do or representing some specific material or situation ahead. They alert us about some potential hazards, instruct us to follow specific measures, or notify us of some specific object/situation/location.

A laboratory is an uncompromising place where rigorous rules and practice must be followed; otherwise, there is a chance of a deadly accident – with a potential threat not only to an individual but also to the whole surrounding environment. In a lab, there are several hazardous materials, equipment with a potential threat, several restricted areas with limited access, areas where strict measures must be followed, and specified areas for a specific task. These places must be indicated to ensure that every person understands the situation and/or permitted actions and work accordingly to maintain laboratory safety.

You will find several signs and symbols painted or attached in different areas of a lab. They may be different in labs with different facilities and activities performed; however, a sign/symbol always represents a specific instruction nevertheless the type/location of a lab.

In this article, we will describe some common signs and symbols you will find in biology (pathology, microbiology) and chemistry laboratory.

A. Warning and Hazard symbols in the lab

These signs/symbols indicate some possible threats in that area. If you see such symbols, you must be alert and take extra care while working in such a zone. It is better to be properly instructed to work in areas with these symbols.

Name of Symbol	Symbol	Indication
General Warning		Presence of possibly hazardous materials/environment
Health Hazard		Presence of chemical, physical, or biological factors with the potential to have a negative effect on our health

Biological hazard symbols in the lab

These symbols represent biological substances that have the potential to negatively affect human health or the health of any living beings. The presence of pathogenic microorganisms, toxins, viruses, virulent proteins, body fluids, and body fluid-contaminated materials is indicated by the biohazard symbol.

Name of Symbol	Symbol	Indication
Biological Hazard		Presence of Biohazardous materials
Biosafety Level 1		Presence of biosafety level 1 (Risk Group 1) organisms. (Presence of organisms that usually don’t cause disease in healthy adults but are capable of causing infections, have a minimum potential hazard to environment and laboratory personnel, and have effective treatment measures.)
Biosafety Level 2		Presence of biosafety level 2 (Risk Group 2) organisms. (Presence of organisms capable of causing mild infections, having moderate potential hazard to the environment and laboratory personnel, difficult to spread forming aerosol, and having effective treatment/preventive measures.)
Biosafety Level 3		Presence of biosafety level 3 (Risk Group 3) organisms. (Presence of organisms capable of causing severe infections and spreading via aerosol. They have high individual risk and moderate community risk with some treatment and prevention measures available.)
Biosafety Level 4		Presence of biosafety level 4 (Risk Group 4) organisms.  (Presence of organisms having a high potential of causing serious infection to individuals and communities. They have a very high transmission rate and have no available treatment and preventive measures.)

Chemical hazard symbols in the lab

These symbols represent the presence of specific chemical substances/substances with the potential to harm humans or any other living objects.

Name of Symbol	Symbol	Indication
Poison/ Poisonous Materials		Presence of toxic materials
Carcinogenic		Presence of carcinogenic materials
Corrosive Material Hazard		Presence of corrosive substances
Harmful Irritants		Presence of harmful chemicals causing irritations

Physical material hazard symbols in the lab

These symbols represent the presence of a specific substance, condition, or factor with the potential to harm humans or any other living objects in contact with them. Physical hazards may be physical conditions like heat, cold, pressure, vibration, etc., sound, radiation, and electricity.

Name of Symbol	Symbol	Indication
High Voltage		Supply of high-voltage electricity
Electric Hazard		Risk of getting electric shock. (The device might give mild to severe electric shock.)
Cryogenic Hazard		Low-temperature zone
Flammable Material		Presence of combustible materials (a substance that can easily burn)
Oxidizing Material		Presence of oxidizing chemicals
Explosive Material		Presence of explosive and/or self-reactive substances
Hot Surface		Risk of burning if you touch with naked hands
Ionizing Radiation (Radiation) Hazard		Presence of radioactive materials emitting ionizing radiation or the presence of electromagnetic waves having the capacity to ionize an atom
Non-ionizing Radiation Hazard		Presence of electromagnetic waves that don’t have ionizing capacity but have the capacity to excite electrons
UV Radiation Hazard		Presence of UV light
Laser Hazard		Presence of laser radiation
Glassware Hazard		Presence of broken glasses

B. Entry/Working requirement symbols in the lab

These symbols indicate what must be done before entering or working in the zone. They indicate what personal protective equipment must be used by personnel intending to do a specific job in a particular area.

Name of Symbol	Symbol	Indication
Gloves Required		Must use protective gloves in this area/while working in this area
Safety Glasses Required		Must use protective/safety goggles in this area/while working in this area
Safety Shoes Required		Must use closed-toe shoes in this area/while working
Lab Coat Required		Must wear lab coat (apron) while in this area
Protective Clothing Required		Must wear full protective clothing
Respirator Required		Must wear a breathing mask/respirator; the presence of contaminated air
Face/Safety Mask Required		Must wear face/dust/safety masks
Face Shield Required		Must wear face shield while working
Hair Protection Required		Must wear hair protection before working
Hearing Protection Required		Must wear a hearing protection device while working

C. Different stations symbols in the lab

These symbols specify a location/station where a specific task is expected to be performed. You must only do the work represented by the symbol, but not any other tasks that can be done with the available materials (for instance, you must not wash your hand in the eye washing station).

Name of Symbol	Symbol	Indication
Hand Wash Station		Place to wash your hands.
Eye Wash Station		Place to wash your eyes.
Shower Station		The place to take a shower
Hand Sanitization Station		The place to sanitize your hand
Emergency Meeting Station		The place for all lab personnel to meet for an emergency meeting or during emergency

D. Location symbols of a specific object in the lab

These symbols indicate the location of specific materials/devices for use on specific occasions. It includes first aid boxes, fire extinguishers, fire blankets, alarm systems, etc.

Name of Symbol	Symbol	Indication
Fire Extinguisher		The location where the fire extinguisher is placed
First Aid		The place with the first aid box and materials
Drinking Water		Indicates safe water for drinking
Fire Blanket		The location where the fire blanket is placed
Fire Hose		The location where the hose with water or any fire retardant is placed
Emergency Bell		Bell to be pressed during an emergency like fire or accident.

E. Prohibition symbols in the lab

These symbols indicate what actions or objects are not permitted to do or carried within the specific area. These symbols are usually a figure crossed with a red mark.

Name of Symbol	Symbol	Indication
Restricted Entry		Entry is allowed for authorized personnel only
Food and Drink Prohibited		Not allowed to eat or drink anything in this area
No Open Flame		Don’t use an open flame in this area; the presence of highly flammable or temperature-sensitive materials.
No light		Maintain dark, photo-sensitive materials.
No Open Shoes		Not allowed to wear open-toe shoes
No Open Hair		No open hair allowed while working here
No Electronics		Not permitted to use/take any electronic devices
No Gloves		Gloves must be removed.

Advantages of Laboratory Safety Symbols

• Prevent accident.
• Notify personnel about potential hazards so that they can be prepared before becoming a victim of a preventable accident. 
• Remind personnel about their duty and task.
• Indicate the location of specific materials and allow for their quick access. 
• Notify the intended purpose of objects/areas. 

Conclusion

A laboratory is a place where there are several hazardous substances and devices and places with a high risk of severe accidents. This is a rigorous place where strict rules must be followed without compromise. To represent all these rigorous actions, places to perform specific actions, substances, or hazards in a lab, signs and symbols are used.

Symbols will be attractive and informative, whereas mentioning in a language will be lengthy, and no one will spend time reading the literature.

Symbols in a lab must be free from any ambiguity and errors. They must be precisely drawn with proper coloring. Symbols must be placed in the most appropriate place. Otherwise, it will cause doubt. 

Most of the symbols are easy to read, but some representing technical and/or scientific things might be difficult to understand. Therefore, one must know each and every sign and symbol labeled in a lab. Knowing symbols and their indications will be very helpful in adopting GLP (Good laboratory practices) and preventing any possible accidents.

References

1. List of Laboratory Safety Symbols and Their Meanings – Laboratoryinfo.com
2. Laboratory and Lab Safety Signs, Symbols, and Their Meanings – Owlcation
3. Lab Safety Symbols and Hazard Signs, Meanings | EdrawMax Online
4. Classification of infective microorganisms by risk group (WHO) Archives – Laboratory Safety Manual (alfaisal.edu)
5. Science Laboratory Safety Symbols and Hazard Signs, Meanings (labmanager.com)
6. Science Safety Symbols: Laboratory Safety Symbols & Meanings (mynewlab.com)
7. Science Laboratory: Symbols, Signs and their Meanings – Scienceequip.com.au
8. CDC LC Quick Learn: Recognize the four Biosafety Levels
9. Hazard symbol. (2022, December 27). In Wikipedia. https://en.wikipedia.org/wiki/Hazard_symbol