Any expert witness in this area should have an understanding of the chemistry of fire and the principles of combustion. Both basic and advanced training courses exist at various institutes, and these are commonly sought-after credentials. Laboratory personnel must usually be qualified at recognizing chromatographic patterns. Experts are also generally expected to be familiar with manufacturer and association tests and standards, not that there are any proficiency tests, but that belonging to a professional association goes a long way in qualifying as an expert and in keeping one's skills sharp. All forms of fire and explosion are subtypes of the larger term, combustion .
Fire is a fundamental chemical reaction based on oxidation .
Explosion is a two-tiered chemical reaction based on the volatility of mixing at least two substances. It is produced from the breaking and formation of chemical bonds. In a chemical reaction, atoms are not lost but merely redistributed. Molecules absorb energy when their chemical bonds are broken apart, and release energy when their bonds are reformed. Reactions also take place at various rates of speed .