Self-Reactive Substances

Self-reactive chemicals display a very wide range of properties. While the most hazardous type of self-reactive chemicals are too dangerous to transport commercially, they can be stored safely with appropriate precautions. The self-reactive classification also includes substances that only decompose slowly at temperatures well above normal storage and transport temperatures [e.g., 75 °C (167 ºF)]. The decomposition of self-reactive chemicals can be initiated by heat, contact with catalytic impurities (e.g., acids, heavy metal compounds, or bases), friction, or impact. The rate of decomposition increases with temperature and varies with the chemical. Decomposition, particularly if no ignition occurs, may result in the evolution of toxic gases or vapors.

For certain self-reactive chemicals, the temperature must be controlled, while others may decompose explosively, particularly if confined. This characteristic may be modified by the addition of diluents or by the use of appropriate packaging’s. Some self-reactive chemicals burn vigorously.

Definition

Self-reactive chemicals are thermally unstable liquid or solid chemicals liable to undergo a strongly exothermic decomposition even without participation of oxygen (air). This definition excludes chemicals classified as explosives, organic peroxides, oxidizing liquids, or oxidizing solids.  A self-reactive chemical is regarded as possessing explosive properties when in laboratory testing the formulation detonates, deflagrates rapidly, or shows a violent effect when heated under confinement.