Science Laboratory Safety Symbols and Hazard Signs, Meanings
In order to maintain a safe workplace, avoid health hazards, and flammable accidents, lab safety symbols and health hazard signs need to be posted throughout the workplace
Depending upon the scientific research being conducted, a lab can be filled with dangerous chemicals, radioactive substances, biological specimens, sharp instruments, breakable glassware, and flammable objects. Thus, those working in labs need to be keenly aware of the many dangers associated with these items. In order to maintain a safe workplace, avoid health hazards, and flammable accidents, lab safety symbols and health hazard signs need to be posted throughout the workplace. Researchers, staff, and visitors should note and understand the hazard communication information on the laboratory safety signs, including specific hazardous agents (biological, chemical, radiological), physical hazards (lasers, magnetic fields) present in the space, stated precautions (no food or drink allowed), and required personal protective equipment (lab coats, eye protection, gloves, etc.).
The following laboratory safety symbols warn of possible dangers in the laboratory to help lab professionals keep safe and informed.
Disclaimer: Please note that the graphics below represent our own creative take on the standard laboratory safety signs and hazard symbols and are not meant to be used in the laboratory. For the official red diamond GHS lab safety symbols, see the OSHA QuickCard.
Physical Safety Symbols
1. Gloves Required
Look for the gloves safety symbol and hazard signs to identify when hand protection should be worn for handling hazardous materials, even in small quantities. It is important to choose the appropriate type of glove for the hazard present, such as chemical resistant gloves, heat resistant gloves, etc. Be aware that no chemical resistant glove protects against all chemical hazards. Read the Material Safety Data Sheet for guidance on the appropriate type of glove to wear, or consult with lab supply distributors for glove vs chemical comparison charts when choosing chemically resistant gloves. Be aware that some materials may cause reactions in some workers such as allergies to latex. Make sure the gloves fit properly.
2. Boots Required
The laboratory boots required safety signs and symbols indicating when street shoes are not adequate for certain lab-related tasks. Chemical resistant overshoes or boots should be used to avoid possible exposure to corrosive chemicals or large quantities of solvents or water that might penetrate normal footwear. Leather shoes tend to absorb chemicals and may have to be discarded if contaminated with a hazardous material. In a lab, dropping a beaker of acid will soon destroy an ordinary pair of shoes. Specialized laboratory footwear is designed for specific applications and settings.
3. Protective Clothing
The protective clothing safety symbol indicates that a lab coat or other protective clothing needs to be worn. There are several types of lab coats for different types of protection. Cotton protects against flying objects, sharp or rough edges, and is usually treated with a fire retardant. Since many synthetic fabrics can adhere to skin when burning, cotton is the most preferred laboratory clothing fabric. Wool protects against splashes of molten materials, small quantities of acid, and small flames. Synthetic fibers protect against sparks and infrared or ultraviolet radiation. Aluminized and reflective clothing protect against radiant heat.
4. Safety Glasses
The eye protection safety sign indicates there is the possibility of chemical, environmental, radiological, or mechanical irritants and hazards in the laboratory. Eyeshields, also called safety glasses, goggles, or spectacles, not only provide protection against flying debris and chemical splashes in the lab, but may also protect against visible and near visible light or radiation from UV rays, depending on the lens material. The most popular lens material for lab safety eyewear is polycarbonate. This material has less than half the weight of glass, making the eyewear more comfortable to wear. Modern eyeshield designs offer anti-slip nose bridges, anti-fog lenses, and coatings, which make them resistant to acids, caustics, and hydrocarbons.
5. Breathing Masks
Respirators are designed to prevent contaminated air from entering the body. “Half mask” respirators cover just the nose and mouth; “full face” respirators cover the entire face; and “hood” or “helmet” style respirators cover the entire head. Respirators can protect the user in two ways: By cleaning the “dirty” outside air that passes through a filter or adsorption bed or both when one inhales; or by supplying clean breathing air from a remote source. The clean air can either be delivered via a supply line, or the clean air is packaged and carried with you in a tank. The breathing mask safety signs and symbols let you know that you’re working in an area with potentially contaminated air.
6. Face Shields
The face protection safety symbol lets lab personnel know that a large face shield, similar to the glass shield on a motorcycle helmet, must be worn when executing experiments that carry the potential of causing an explosion inside of the hood. Full face (and possibly throat) protection from splash and/or impact is commonly required for work on or in the presence of human pathogens, some laboratory chemicals, explosion hazards, heavy grinding and heavy spraying or splashing, and with large (2 L and larger) quantities of dangerous liquids such as acids, bases, and many organic liquids. A face shield can also afford extra protection against extreme temperatures.
7. Hearing Protection
Noise in laboratories has become a growing concern. While the noise levels in most laboratories are below the threshold level that damages hearing, laboratory noise can be fairly loud. The operation of large analyzers (e.g., chemistry analyzer), fume hoods, biosafety cabinets, incubators, cell washers, tissue homogenizers, and stirrer motors, all contribute to the noise level. There is a wide variety of hearing protection devices available. Different devices are designed to protect against different severities of noise. The ear protection safety symbol indicates that lab workers are in a dangerously high decibel noise range.
8. Eye Wash Station
The eye wash safety sign indicates the location of an eyewash station. Eye wash stations provide a continuous, low-pressure stream of aerated water in laboratories in which chemical or biological agents are used or stored and in facilities where nonhuman primates are handled. The eyewash station should be easily accessible from any part of the laboratory and, if possible, located near the safety shower so that, if necessary, the eyes can be washed while the body is showered.
9. Safety Shower
Safety showers need to be installed in all areas where laboratory employees may be exposed to splashes or spills of materials that may be injurious to the eyes and body. As a general rule, new shower installations should adhere to the recommendations for shower location and minimum performance requirements established in American National Standard Z-358.1 (1998). Showers should be placed as close to the hazard as possible, but in no case more than 10 seconds' travel time from the hazard. Safety shower signage should be prominently displayed close to the shower.
10. Wash Hands
Hand washing is a primary safeguard against inadvertent exposure to toxic chemicals or biological agents. The wash hands safety sign lets lab personnel know to wash their hands after removing soiled protective clothing, before leaving the laboratory, and before eating, drinking, smoking, or using a rest room. Workers should also wash their hands periodically during the day at intervals dictated by the nature of their work. Wash with soap and running water, with hands held downward to flush the contamination off the hands. Turn the tap off with a clean paper towel to prevent recontamination, and dry hands with clean towels.
11. Food & Drink Prohibited
A no food and drink safety sign lets lab personnel know that eating and/or drinking where hazardous materials are used, handled, or stored is not permitted, as such activity can result in the accidental ingestion of hazardous materials (chemical, biological, and/or radiological). Food or beverage containers may not be stored in the laboratory and washed drinking cups, food containers, or eating utensils may not be dried on laboratory drying racks. Refrigerators used for storage of research materials must not be used for storage of food or beverages.
12. No Pacemakers or Metallic Implants
The no pacemakers or metallic implants lab safety sign is used to warn lab staff of a strong magnetic field hazard. This is caused by lab instruments that use superconducting magnets such as nuclear magnetic resonance spectrometers (NMR). Staff with pacemakers or metallic implants cannot work in such areas of the lab and other staff should take care to remove metal objects such as jewellery, watches, loose change, etc. before entering these areas, in order to prevent injuries.
Fire Safety Symbols
13. Fire Extinguisher
Fires can happen anywhere, but lab fires can be even more dangerous due to Bunsen burners, flammable liquids, research documents, laptops, and lab equipment that might be present at any given time. Due to these unique circumstances, it’s important that every lab be prepared with the correct fire extinguisher, inspection requirements, and training. It is essential that the occupants of a laboratory are fully aware of the risks and the appropriate extinguishing media. A fire extinguisher safety sign indicates the exact location of a lab’s fire extinguisher.
14. Fire Blanket
The fire blanket safety sign indicates where a fire blanket is located in the lab. Housed in a case or not, the woolen blanket is used for smothering fires and for containing and controlling chemical spills.
If someone in the lab should catch fire, he or she should get on the ground and start rolling to extinguish the flames. Lab personnel can assist by using the blanket to speed extinguishing the fire, preventing further injury. Fire blankets are large enough to entirely cover most people, depriving the fire of the oxygen that it needs to continue burning.
15. Fire Hose
A fire hose connection safety sign informs individuals of the location of hose connections in their lab. Those locations should be clearly and accurately marked so they can easily be found. The best safety practice is to post a fire hose location sign above the actual equipment and then install directional versions of the fire hose location sign (which point towards the direction to the equipment) wherever people cannot actually see a fire hose’s location or its “above-the-equipment” sign.
16. No Open Flames
Bunsen burners, lighters, matches, and any other flame-producing devices are considered “open flame devices.” Open flame devices carry with them the risk of unintentional fire and serious consequences when not used appropriately. Most organic chemicals are flammable. The chance of a fire is substantially increased when open flames are present. No open flames safety signage indicates to lab personnel the risk and prohibition of open flame devices.
First Aid Symbols
17. First Aid Station
The first aid station safety symbol indicates the availability of a first aid kit. The kit should be easily accessible to other lab locations that belong to a particular group. The first aid kit should contain the items recommended in the First Aid Kit Policy and Guidelines for Laboratories. It should be inspected monthly to ensure that no items are missing and that none of the remedies (e.g., saline solution, ointment) in the kit have expired.
18. AED or Defibrillator
The AED or defibrillator safety sign indicates the location of the laboratory’s automated external defibrillator (AED) so that it can be found quickly in the event of an emergency. This portable device, used to treat sudden cardiac arrest, checks the heart rhythm and can send an electric shock to the heart to try to restore a normal rhythm. Ideally, lab staff should be trained on how to use the AED, but each unit comes with instructions so that even untrained staff can operate it if necessary. Doing CPR in conjunction with using the AED can also improve chances of survival for someone experiencing sudden cardiac arrest in the lab.
19. Emergency Meeting Point
The emergency meeting point sign marks a safe place, either inside or outside the building, where laboratory employees should meet in the event of an actual emergency (chemical spill, fire, etc.) or emergency drill. In their safety training, employees should be made aware of the location of the emergency point, or the meeting point closest to their location if there are multiple meeting points. Such locations should be large enough to accommodate all employees in the event of an evacuation. It’s always a good idea to have a backup meeting point in case the primary one has been destroyed or is inaccessible due to the emergency taking place.
Hazard Symbols
20. General Warning
The general warning lab safety symbol consists of a black exclamation point in a yellow triangle. As you’d expect, it is a general warning to laboratory staff that a hazard exists. This symbol can be found on equipment, doorways, cupboards or other areas of the lab. It provides a good reminder to work safely and check if you are not sure of the safety procedures for certain equipment or areas in the lab.
21. Health Hazard
The health hazard sign denotes chemicals in the lab that can cause serious, often long-term health problems. Hazards include carcinogens, respiratory sensitizers, reproductive toxins, aspiration toxins, target organ toxins, and mutagens. An important step in protecting worker health is recognizing the various health hazards in the lab, as ignorance of the harmful effects of laboratory materials can have serious and even fatal consequences.
22. Biohazard
The biohazard lab safety sign warns of lab equipment such as fridges or freezers that either contains biohazardous materials or could be contaminated with biohazardous material such as blood samples. This sign also marks entire areas of the lab that either contain or are exposed to biohazards, for example, a lab working with infectious agents. Workers should always wear the proper PPE and follow proper procedures when working with such agents. Managers should also have an effective exposure control plan in place in case of an emergency. Regular cleaning and decontamination of areas and equipment that are exposed to biohazards is also a must.
23. Harmful Irritant
Substances labelled with the irritant symbol are not corrosive, but they can cause discomfort and reddening, irritation, or blistering of the skin. Laboratory workers should handle irritants carefully. Working with irritants in the fume hood can help individuals avoid inhalation. Examples of irritant substances include ammonia, chloroform, and chlorine.
24. Poison/Toxic Material
The toxic material symbol indicates the presence of substances that may harm an individual if they enter the body. Possible routes of exposure to toxic materials are through inhalation, skin contact, and ingestion. The hazards and health effects associated with toxic materials depend on the specific material in question, the route of exposure, and the concentration of the material.
25. Corrosive Material Hazard
The corrosive material hazard laboratory safety sign indicates corrosive substances in the lab that can eat away the skin if you come into direct contact with them. Such materials should always be stored at the proper humidity and temperature conditions in the proper cabinets. All employees who handle corrosive substances should be properly trained and wear gloves, protective clothing, and face protection.
26. Carcinogen Hazard
Carcinogen signs in a laboratory indicate the use of known human carcinogens. Carcinogenic substances commonly used in the lab include formaldehyde, methylene chloride, and benzene. When handling carcinogens, appropriate personal protective equipment must be worn. To keep carcinogens contained, thereby limiting unnecessary exposure, devices such as fume hoods, glove boxes, and HEPA filters are often used.
27. Explosive Hazard
The exploding bomb symbol will appear on chemicals in the lab that have explosive properties; these include unstable explosives (solid or liquid chemicals capable of a chemical reaction that damages surroundings), self-reactive substances and mixtures (substances and mixtures that may cause fire or explosion in the absence of air), and organic peroxides.
28. High Voltage
The high voltage warning symbol, which includes a lightning bolt arrow in a yellow triangle, warns of voltage high enough to cause serious injury or death. In general, you should stay away from equipment or areas of the lab marked with this symbol, though if you do need to work close to such hazards, protective clothing and rubber gloves should be worn.
29. Electrical Hazard
The electrical hazard safety symbol, which typically includes a frayed wire and a hand with a lightning bolt across it, indicates any electrical hazards in the lab. Such hazards can cause anything from a mild tingling to death. With direct current, a person can detect a "tingling" feeling at 1 mA and the median "let-go" threshold (the current at which one cannot release the conductor) is 76 mA. For 60 Hertz alternating current, the values are 0.4 mA and 16 mA, respectively. If an electrical hazard is suspected, the device in question should be disconnected immediately and the cause determined by a qualified technician. Equipment should always be turned off and unplugged when any work is being done on it.
30. Laser Beam Hazard
The laser beam hazard sign in the laboratory lets staff know that hazards from laser beams are present. Both the eyes and skin can be damaged from direct exposure to laser beams so proper eye protection and non-flammable clothing should always be worn at all times in these areas of the lab, whether the laser is being operated or not.
31. UV Light Hazard
The UV light hazard symbol will appear near ultraviolet (UV) light areas to warn personnel of the potential dangers. UV light is a type of electromagnetic radiation with a wavelength between 180 and 400 nm, which is shorter than those of visible light, but longer than those of X-rays. Health effects due to acute exposure to UV light include redness or ulcerations on the skin, while chronic exposure can lead to skin cancer.
32. Glassware Hazard
The broken glassware symbol may be placed on a container designated for the disposal of broken glass in the lab. Broken glass is a physical hazard and has the potential to be a health hazard if it is contaminated with toxic chemicals or infectious substances. Wherever possible, laboratories should use plasticware instead of glassware to avoid hazards. Laboratory workers should use appropriate gloves to handle broken glass, or use forceps, tongs, or a dustpan and brush to clean up pieces of broken glass.
33. Hot Surface
As you’d expect, the hot surface safety sign warns laboratory employees of burn hazards from hot surfaces. Such hazards can come from lab equipment such as lab ovens and autoclaves or from the building itself—if there are steam pipes, etc. Lab workers should avoid touching such surfaces, but if they could come into contact with hot surfaces during their daily work or must handle hot equipment, they should first be trained on how to properly use such equipment and always wear the correct PPE (ex. heat-resistant gloves, lab coats, eye protection, and closed-toed shoes).
34. Low Temperature Warning Symbol
The low temperature warning symbol warns staff of low temperature or cryogenic hazards in the lab. Such temperatures are usually much lower than freezing point and can be found in cold storage areas of the lab or where chemicals such as liquid nitrogen are stored. PPE for working with cryogenic or low temperature hazards may include: gloves designed for this purpose (thick and made from rubber and cloth, covering the skin up to the elbow), long pants, closed-toe shoes or boots, a rubber apron, and face shield.
Radiation Hazard Symbols
35. Ionizing Radiation Hazard
The ionizing radiation hazard safety sign indicates the presence of ionizing radiation. Ionizing radiation is radiation that carries enough energy to liberate electrons from atoms or molecules, thereby ionizing them. Sources of ionizing radiation in the lab include X-ray apparatus, medical beam cannons, and particle accelerators. Any laboratory possessing or using radioactive isotopes must be licensed by the Nuclear Regulatory Commission (NRC) and/or by a state agency that has been approved by the NRC, 10 CFR 31.11 and 10 CFR 35.12. Labs must limit entry of radionuclides into the human body to quantities as low as reasonably achievable and always within the established limits, and limit exposure to external radiation to levels that are within established dose limits and as far below these limits as is reasonably achievable.
36. Non-Ionizing Radiation Hazard
The non-ionizing radiation hazard sign warns staff of sources of non-ionizing radiation in the lab. Such radiation has a lower frequency and longer wavelength than ionizing radiation. Non-ionizing radiation includes the spectrum of ultraviolet (UV), visible light, infrared (IR), microwave (MW), radio frequency (RF), and extremely low frequency (ELF). Lasers, fluorescent lamps, and some photosensitive chemicals are examples of non-ionizing radiation hazards in the lab. Employee exposure to non-ionizing radiation from any source cannot exceed OSHA standards. Biological safety cabinets, PPE, and engineering controls are some of the measures used to minimize exposure to such hazards.
37. Optical Radiation Hazard
Optical radiation is another term for light, covering ultraviolet (UV) radiation, visible light, and infrared radiation. The optical radiation hazard safety signs warns of equipment that produces this type of radiation in the lab, such as high-powered lasers. When working with such hazards, proper eyewear should always be worn. For lasers in particular, proper SOPs should be in place, the beam path for the laser system should be enclosed, and users should perform a physical survey for any unwanted reflections before using the laser.
38. IAEA Ionizing Radiation Hazard
The International Atomic Energy Agency’s (IAEA) ionizing radiation hazard symbol supplements the regular trefoil symbol for radiation. It includes radiating waves, a skull and crossbones, and a running person to warn of large sources of ionizing radiation. The symbol is aimed more toward the general public, who may not be aware that the trefoil indicates radiation hazards, and is placed on sources of radiation that can cause death or serious injury. Typically it is placed on the device housing the radiation source, rather than doors or containers, to warn people not to take the device apart or get any closer to it.
Other Symbols
39. Dangerous to the Environment
This symbol indicates that the substance in question can cause damage to the environment, and is most often used to label chemicals that are toxic to aquatic wildlife. Environmental hazards are classified as either acute or chronic. Lab workers should dispose of environmentally hazardous materials properly, and ensure that they do not get washed down the drain.
40. Flammable & Combustible
The flammable and combustible symbol signifies substances that will ignite and continue to burn in air. Substances in this category may be gases, aerosols, liquids, or solids, and include many solvents and cleaning materials that are commonly used in the laboratory. Workers should always keep flammable materials away from open flames, heat, sparks, and ignition sources.
41. Oxidizing Agent
The symbol for oxidizing materials indicates the presence of chemicals that readily give off oxygen or other oxidizing substances. Oxidizing materials may intensify fires and cause explosions, and also may be toxic or corrosive. Although air is the usual source of oxygen for burning, oxidizing materials can support a fire even in the absence of air. Some common oxidizing liquids and solids found in laboratories are bromine, chlorates, nitrates, perchloric acid, and peroxides.
42. Compressed Gas
Compressed gases, as indicated by the symbol, are routinely used in laboratories. There are three major types of gases that get stored under pressure in cylinders: liquefied gases (gases that can become liquids when compressed at room temperature), non-liquefied gases (gases that do not become liquids when compressed at room temperature), and dissolved gases (gaseous reservoir hydrocarbons dissolved in liquid reservoir hydrocarbons). The high pressure within a cylinder makes compressed gases hazardous, as gas can flow rapidly from the cylinder and cause injury, fires, or explosions.
43. Flammable Gas
The flammable gas symbol represents gases that will burn or explode if mixed with air, oxygen, or other , in the presence of a source of ignition. Flammable gases used in laboratories include ethyl chloride, aerosols, and liquefied petroleum gas. Compressed flammable gases are common in many labs, and they are extremely dangerous to work with and around.
44. Non-Flammable Gas
The symbol for non-flammable gases signifies a division of gases found in labs that encompass compressed gases, liquefied gases, cryogenic gases, compressed gases in solution, and oxidizing gases. Specific examples of non-flammable gases include air, carbon dioxide, Freon, helium, and nitrogen. Although they are not a fire hazard, non-flammable gases displace oxygen and cause asphyxiation or death.
45. Strong Magnetic Field
Certain pieces of laboratory equipment generate strong magnetic fields. The strong magnetic field sign alerts lab members to the dangers that this type of equipment can pose. The risks are especially imminent for people wearing pacemakers and implants, which will tend to align themselves with the magnetic field lines, as will watches, clipboards, and certain tools.
46. Recycling symbol
The internationally recognized recycling symbol is formed of three arrows that point in a never-ending loop. The arrows form a triangle shape. The recycling sign is used in labs to indicate where recyclable items are gathered and sorted. Such items can include any plastic that is not characterized as a biohazard or radioactive hazard, Types 1 and 2 laboratory plastics, gloves, pipette tip boxes, Styrofoam containers, cardboard—all of these are readily recyclable in most lab facilities. Ask your EH&S or Facility Management representative about recycling in your facility.
For more on how to run a safe lab, see our "Running a Safe Lab" Big Picture article series.