any hazard that results from the accidental, deliberate or potential release of a noxious substance into the environment

(nautical) a horn on a floating mine which, upon contact, releases an electrolyte that makes an electrical connection and initiates the explosion

physical and psychological dependency on an addictive drug

(chemistry) the unique combination of analytical results from a number of techniques that identifies a particular compound in a sample

any laser that obtains its energy from a chemical reaction

(chemistry) Any mixture of compounds whose relative concentrations oscillate, and in which such change is marked by a visible rhythmic change in colour.

(chemistry) the fragmentation of any compound into elements or smaller compounds

(chemistry) any substance used to classify another, often by changing colour

Any symptom, such as erythema, edema, and vesiculation, caused by exposure of the skin to a chemical compound.

The study of the chemistry of the oceans.