Chemical Safety Symbols

A guide to meanings of common chemical safety/hazard symbols (a.k.a. warning labels, Danger symbols, Chemical safety labels...).  These are the European/international standard; I originally put them online as they didn't seem to be anywhere else; they seem to still be popular judging by the number of people who read this so I've carried them over to blogger as a bit of a public service... Click on the images to enlarge, for printable label size and suitable for downloading. Feel free to use these pictures. 

The poison symbol is self-explanatory. Whereas most chemicals are fairly dangerous if ingested or inhaled, many of these are dangerous even on contact.

Environmental hazard
Relatively rare with laboratory chemicals (most of which pose some environmental hazard if not got rid of correctly), these require particular care to be taken on disposal.

Will destroy or irreversibly damage another substance with which it comes in contact. The main hazards include damage to eyes, skin and tissue under the skin, but inhalation or ingestion are also very risky.  Avoid contact, and bear in mind that these can (under some circumstances) rust chemical cupboards.  

Again, fairly self-explanatory, though fairly seldom seen in the average lab. Bear in mind that noise and movement can also trigger explosion (not just sparks/flames!).

Flammable or extremely flammable
Chemicals to be stored in flame-resistant cupboards. Volatile solvents can be a particular problem as they are prone to spread around from unsealed containers. This also covers pyrophoric materials (that catch fire spontaneously on exposure to air).

Irritant or Harmful
This symbol covers a wide range of (sometimes relatively minor) hazards - with precautions such as avoid contact with the skin, do not breathe, etc. - best to refer to relevant data sheet for details.

Oxidising chemical
Oxidising chemicals are materials that spontaneously evolve oxygen at room temperature or with slight heating, or that promote combustion. To be kept away from flammable chemicals at all costs! 

Whereas the square symbols above (which tend to be the most familiar ones) will be found on bottles & jars, diamond shaped symbols are used in transport (mainly as they can be slotted into holders on the backs of trucks & tankers to identify what the mess is (and how dangerous it is) in the event of a leak.

Poisonous Gas
Used for transport of a poisonous gas - on gas cylinders, or sometimes as an indicator on vehicles.

Miscellaneous danger
Catch-all symbol for all other dangers (usually specified in the space).

More general symbol for the transport of poisonous materials (not necessarily a gas).

Flammable Solid
Flammable solid.

Stow away from foodstuffs
Harmful material to be kept away from edible material.

Dangerous when wet
This generally means that it will react fairly violently with water... 

Flammable Gas
Safety symbol used for the transport or storage of a flammable gas.

Non flammable gas
Safety symbol used in the transport of non flammable (and hence often non hazardous, at least out in the open) gases.

Organic Peroxide
Chemical safety symbol used in the transport and storage of organic peroxides.

The corrosive symbol is used in the transport of corrosive materials - again, avoid contact with the skin. 

Inhalation Hazard
Inhalation hazard transport/storage symbol.

Marine Pollutant
Marine pollutant - do not dispose of in sewer system.

Used in the transport of explosive materials.

Spontaneously Combustible
Spontaneously combustible material (treat with great caution!...).

Flammable Liquid
Used in the transport of flammable liquids.

Other good sources for these are the HSE website, which is very complete and also explains the precise meaning of these symbols and where they should be used, as well as including common workplace safety signs. In the US, the NIOSH website includes full safety information for many chemicals and chemical families. Try also the HSE leaflets, which explain some of the issues relating to chemical transportation and various aspects of laboratory safety.  Above all, remember that this explanation is for curiosity only - there's no guarantee that any of this is correct! 

See also...

Metal Foams & how to make them

Caius House, Battersea - rebirth of a youth club

Punting guide to the River Cam