Glossary / Stability & reactivity
Hazardous decomposition products
Hazardous decomposition products are the harmful substances created when a chemical breaks down, usually from heat, fire or contact with an incompatible material. They often include toxic or corrosive gases that differ from the original product.
Explanation
A material that seems moderate in its normal form can release much more dangerous substances when it burns or overheats. Carbon monoxide and carbon dioxide are typical from organic materials. Nitrogen-containing products can give nitrogen oxides, sulfur compounds can give sulfur oxides, and chlorinated or fluorinated compounds can give hydrogen chloride or hydrogen fluoride.
This matters most in fires and in processes involving high temperatures, such as welding, heating, drying ovens or heat sealing. Firefighters use the information to decide on breathing apparatus and protective clothing, and workers use it to plan ventilation where hot processes occur.
The SDS lists these products in Section 10, and Section 5 may repeat the key ones for fire-fighting. The lists are not exhaustive and are based on the supplier's knowledge of the formulation, which means a product with unknown additives may produce others.
Do not confuse decomposition products with hazards of normal use. Under normal storage and handling the SDS usually states that no hazardous decomposition occurs. The warning applies when conditions listed in the same section, such as high heat or open flame, are present.
What to do and watch for
- Wear suitable respiratory protection and ventilate when heating products near their limits.
- Tell emergency responders what is stored in a building so they can plan for fire fumes.
- Do not assume smoke from any chemical fire is just smoke.
Where it appears on an SDS
- Section 10: Stability and reactivity. A list of hazardous substances produced when the material decomposes, and the conditions that cause it.
- Section 5: Fire-fighting measures. Hazardous combustion products for fire-fighters and the protective equipment they need.
SDS content and wording vary by supplier. This page is general reference and does not replace the current SDS for your product.