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.

Laboratory Safety Symbols, Signs, and Meanings
Laboratory Safety Symbols, Signs, and Meanings

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

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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 SymbolSymbolIndication
General WarningGeneral WarningPresence of possibly hazardous materials/environment
Health HazardHealth HazardPresence 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 SymbolSymbolIndication
Biological HazardBiological HazardPresence of Biohazardous materials
Biosafety Level 1Biosafety Level 1Presence 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 2Biosafety Level 2Presence 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 3Biosafety Level 3Presence 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 4Biosafety Level 4Presence 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 SymbolSymbolIndication
Poison/Poisonous MaterialsPresence of toxic materials
CarcinogenicCarcinogenicPresence of carcinogenic materials
Material Hazard
Corrosive Material HazardPresence of corrosive substances
Harmful IrritantsHarmful IrritantsPresence 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 SymbolSymbolIndication
High Voltage High VoltageSupply of high-voltage electricity 
Electric HazardElectric HazardRisk of getting electric shock. (The device might give mild to severe electric shock.)
Cryogenic HazardCryogenic HazardLow-temperature zone
Flammable MaterialFlammable MaterialPresence of combustible materials (a substance that can easily burn)
Oxidizing MaterialOxidizing MaterialsPresence of oxidizing chemicals 
Explosive MaterialExplosive MaterialPresence of explosive and/or self-reactive substances 
Hot SurfaceHot SurfaceRisk of burning if you touch with naked hands
Ionizing Radiation (Radiation) HazardRadiation Hazard
Presence of radioactive materials emitting ionizing radiation or the presence of electromagnetic waves having the capacity to ionize an atom 
Non-ionizing Radiation HazardNon-ionizing Radiation Hazard
Presence of electromagnetic waves that don’t have ionizing capacity but have the capacity to excite electrons 
UV Radiation HazardUV Radiation HazardPresence of UV light
Laser HazardLaser HazardPresence of laser radiation 
Glassware HazardGlassware HazardPresence 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 SymbolSymbolIndication
Gloves RequiredGloves RequiredMust use protective gloves in this area/while working in this area
Safety Glasses RequiredSafety Glasses RequiredMust use protective/safety goggles in this area/while working in this area
Safety Shoes RequiredSafety Shoes RequiredMust use closed-toe shoes in this area/while working
Lab Coat RequiredLab Coat RequiredMust wear lab coat (apron) while in this area
Protective Clothing RequiredProtective Clothing RequiredMust wear full protective clothing 
Respirator RequiredRespirator RequiredMust wear a breathing mask/respirator; the presence of contaminated air 
Face/Safety Mask RequiredFace Mask RequiredMust wear face/dust/safety masks 
Face Shield RequiredFace Shield RequiredMust wear face shield while working 
Hair Protection RequiredHair Protection RequiredMust wear hair protection before working 
Hearing Protection RequiredHearing Protection RequiredMust 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 SymbolSymbolIndication
Hand Wash StationHand Wash StationPlace to wash your hands.
Eye Wash StationEye Wash StationPlace to wash your eyes.
Shower StationShower StationThe place to take a shower 
Hand Sanitization StationHand Sanitization StationThe place to sanitize your hand
Emergency Meeting StationEmergency Meeting StationThe 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 SymbolSymbolIndication
Fire Extinguisher Fire ExtinguisherThe location where the fire extinguisher is placed 
First Aid First AidThe place with the first aid box and materials 
Drinking WaterDrinking WaterIndicates safe water for drinking 
Fire BlanketFire BlanketThe location where the fire blanket is placed
Fire HoseFire HoseThe location where the hose with water or any fire retardant is placed
Emergency Bell Emergency BellBell 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 SymbolSymbolIndication
Restricted EntryRestricted EntryEntry is allowed for authorized personnel only
Food and Drink Prohibited Food and Drink ProhibitedNot allowed to eat or drink anything in this area
No Open Flame No Open FlameDon’t use an open flame in this area; the presence of highly flammable or temperature-sensitive materials. 
No lightNo lightMaintain dark, photo-sensitive materials.
No Open ShoesNo Open ShoesNot allowed to wear open-toe shoes
No Open HairNo Open HairNo open hair allowed while working here 
No ElectronicsNo ElectronicsNot permitted to use/take any electronic devices 
No GlovesNo GlovesGloves 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. 


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.


  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

About Author

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Prashant Dahal

Prashant Dahal completed his bachelor’s degree (B.Sc.) Microbiology from Sunsari Technical College, affiliated with Tribhuvan University. He is interested in topics related to Antimicrobial resistance, the mechanism of resistance development, Infectious diseases (Pneumonia, tuberculosis, HIV, malaria, dengue), Host-pathogen interaction, Actinomycetes, fungal metabolites, and phytochemicals as novel sources of antimicrobials and Vaccines.

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