Hazchem - Emergency Action Code - HazChem Safety Parameters

HazChem Safety Parameters

Each EAC contains at least one letter, which determines which category the chemical falls under, and which also highlights the violence of the chemical (i.e. likelihood to spontaneously combust, explode etc.), what personal protective equipment to use while working around the chemical and what action to take when disposing of the chemical.

Each category is assigned a letter to determine what actions are required when handling, containing and disposing of the chemical in question. Eight 'major categories' exist which are commonly denoted by a black letter on a white background. Four subcategories exist which specifically deal with what type of personal protective equipment responders must wear when handling the emergency, denoted by a white letter on a black background. In Australia with the update of the Australian Dangerous Goods Code volume 7 as of 2010, the white letter on a black background has been removed, making BA a requirement at all large incidents regardless of whether the substance is involved in a fire.

If a category is classed as violent, this means that the chemical can be violently or explosively reactive, either with the atmosphere or water, or both (which could be marked by the Dangerous when Wet symbol).

Protection is divided up into three categories of personal protective equipment, Full, BA and BA for fire only. Full denotes that full personal protective equipment provisions must be used around and in contact with the chemical, which will usually include a portable breathing apparatus and water tight and chemical proof suit. BA (acronym for breathing apparatus) specifies that a portable breathing apparatus must be used at all times in and around the chemical, and BA for fire only specifies that a breathing apparatus is not necessary for short exposure periods to the chemical but is required if the chemical is on alight. BA for fire only is denoted within the emergency action code as a white letter on a black background, while a black letter on a white background denotes breathing apparatus at all times. When changing the background colour is not possible (such as with handwriting), the use of brackets means the same as a black background. "3E" means the same as a white letter on a black background.

Substance control specifies what to do with the chemical in the event of a spill, either dilute or contain. Dilute means that the chemical may be washed down the drain with large quantities of water. Contain requires that the spillage must not come in contact with drains or water courses.

In the event of a chemical incident, the EAC may specify that an evacuation may be necessary as the chemical poses a public hazard which may extend beyond the immediate vicinity. If evacuation is not possible, advice to stay in doors and secure all points of ventilation may be necessary. This condition is denoted by an E at the end of any emergency action code. It is an optional letter, depending on the nature of the chemical.