Hazchem is not the ADR Hazard Identification Number (HIN), also known as the Kemler Code, as this is a different warning plate carried by vehicles in the rest of the EU. The main difference is the HIN details the nature of the hazard presented by the goods as opposed to the actions to be taken when dealing with them.
The top-left section of the plate gives the Emergency Action Code (EAC) telling the fire brigade what actions to take if there's an accident. The middle-left section gives the UN Substance Identification Number describing the chemical. The lower-left section gives the telephone number that should be called if special advice is needed. The warning symbol at top-right indicates what danger the chemical presents. The bottom-right of the plate carries a company logo (the flower is a sample logo).
There is also a standard null Hazchem plate to indicate the transport of non-hazardous substances. The null plate does not include an EAC or substance identification.
|1||coarse water spray (jets)|
|2||fine water spray (fog)|
|4||dry agent (powder)|
The digit indicates what type of fire suppressant should be used to extinguish a fire involving the chemical:
|letter||violent reaction possible?||kit||spillage|
The first letter of the EAC is selected from eight possibilities, giving three items of information regarding how to handle an accident:
The optional second letter of the EAC is E, which indicates that an accident poses a public hazard beyond the immediate vicinity. In an accident involving such a chemical, the nearby populace may need to be evacuated, and if not should be warned to stay indoors with doors and windows closed.
A very commonly seen example is 3YE on petrol tankers. This means that a fire must be fought using foam, that it can react violently, that fire fighters need only wear BA and not a full containment suit, and that the run-off needs to be contained. It also indicates to the incident controller that evacuation of the surrounding area may be necessary.