New South Wales Government

Dangerous goods classes 4.1 and 4.2

Flammable solid class 4.1	Spontaneously combustible class 4.2

Flammable solids include metals in the form of powders or fine strips, nitrocellulose, sulphur powder, rags, some charcoal and vegetable matter containing oil. They are easily ignited or may ignite spontaneously. Some burn extremely fiercely making it almost impossible to extinguish fires. Some may ignite spontaneously in contact with air and have to be kept submerged under kerosene or ethanol. Some have to be kept cool to prevent self-heating leading to ignition and explosion.

 

Dangerous goods class 4.3

Dangerous when wet class 4.3

 

Dangerous goods class 4.3 includes sodium metal, calcium carbide, aluminium phosphide fumigants and some metal powders. When they come intocontact with water they produce large quantities of flammable gases, which may ignite spontaneously. Some of these gases are extremely toxic. Some substances may react already with the humidity in the air and must be kept submerged under kerosene.

 

Why they are dangerous

Some flammable solids burn extremely fiercely making it almost impossible to extinguish fires. Some may ignite spontaneously in contact with air and have to be kept submerged under kerosene or ethanol. Some have to be kept cool to prevent ‘run-away’ reactions leading to ignition and explosion.

 

Risk assessment

Finding out if you are at risk involves doing a risk assessment and identifying:

1. the type of product including its dangerous good classification name and number
2. how much is being stored or used

3. identifying and controlling particular risks identified in the Occupational Health and Safety Regulation 2001.

     

Protect yourself and others

Once you have completed your risk assessment, you will need to implement measures to protect yourself and others by:

 

1. eliminating the risk if reasonably practicable
2. remove the dangerous good or substituting for a less hazardous substance
3. ensuring you have adequate emergency exits
4. ensuring the physical separation of dangerous goods from people and property by distance or physical barriers
5. ensuring any spills or leaks are contained and that incompatible substances are not stored together
6. removing sources of ignition or controlling the risks in hazardous areas
7. controlling atmospheric emissions 
8. establishing appropriate administrative controls.

Note: use personal protective equipment (PPE) as a last resort to control risks and do not rely solely on PPE for protection.

 

Find out more

The Storage and Handling of Dangerous Goods: Code of Practice has more information about the storage of dangerous goods.

 

Call 13 10 50 for further information about flammable solids.