Lab safety symbols

About lab safety symbols

Lab safety symbols are the signs on laboratory doors, benches and equipment. Most are ISO 7010 safety signs, and their shape and colour say what kind of message each one is before you read the picture. ISO 3864-1 sets the four kinds: a blue circle with a white symbol means an action is required, a red ring with a diagonal bar means something is forbidden, a yellow triangle with a black symbol warns of a hazard, and a green square shows where safety equipment is. A lab door sign usually combines several of them with the chemical and biological hazard symbols, and the University of Houston’s safety office describes its door signs as showing the minimum protective equipment for entry, the hazards present and the safety equipment in the lab.

Protective equipment

The blue circles ask for something to be worn: eye protection (M004), protective gloves (M009), protective clothing such as a lab coat (M010), a face shield (M013), a mask (M016) or respiratory protection (M017). Great Britain’s 1996 safety signs regulations word the same signs as statements, such as “Eye protection must be worn”.

Emergency equipment

Green squares mark the eyewash station (E011) and the safety shower (E012). OSHA’s appendix on laboratory chemical hygiene lists location signs for both among the signs a lab should post.

Prohibitions and warnings

The red rings in labs are most often no eating or drinking (P022) and no open flame (P003). The yellow triangles include the hot surface warning (W017) and the low temperature warning (W010), which marks cryogens.

Biological and chemical hazards

The biosafety level sign gives a lab’s level, BSL-1 to BSL-4, as set out in the CDC and NIH’s Biosafety in Microbiological and Biomedical Laboratories. The biohazard symbol has a page of its own; in the United States OSHA’s bloodborne pathogens standard puts its warning label on containers of regulated waste, which includes contaminated sharps. The chemical pictograms on labels are the GHS hazard symbols, and the diamond with numbers is the NFPA 704 fire diamond. The four sign types themselves, with the full list of ISO 7010 protective equipment signs, are under safety signs.

These pages describe what each sign means and which standard sets it. What to do in a lab is set by the lab’s own rules and trained staff.