Clandestine chemistry is chemistry carried out in secret, and particularly in illegal drug laboratories. Larger labs are usually run by gangs or organized crime intending to produce for distribution on the black market. Smaller labs can be run by individual chemists working clandestinely in order to synthesize smaller amounts of controlled substances or simply out of a hobbyist interest in chemistry, often because of the difficulty ascertaining the purity of other, illegally synthesized drugs obtained on the black market. The term clandestine lab is generally used in any situation involving the production of illicit compounds, regardless of whether the facilities being used qualify as a true laboratory.