In fire protection, an accelerant is any substance or mixture that accelerates or speeds the development and escalation of fire. Accelerants are often used to commit arson, and some accelerants may cause an explosion. Some fire investigators use the term "accelerant" to mean any substance that initiates and promotes a fire without implying intent or malice.
A fire is a self-sustaining, exothermic oxidation reaction that emits heat and light. When a fire is accelerated, it can produce more heat, consume the reactants more quickly, burn at a higher temperature, and increase the spread of the fire. An accelerated fire is said to have a higher "heat release rate," meaning it burns more quickly.