This chapter briefly discusses the application, chemical properties and physical properties of pyrocatechol. It presents detailed information on the air analysis and analysis of aqueous and nonaqueous samples of pyrocatechol. Pyrocatechol is used in photography and dyeing fur. It is a crystalline solid, which is soluble in water and most organic solvents. During the analysis of aqueous and nonaqueous samples of pyrocatechol, pH of aqueous samples is adjusted to below 2. Aqueous samples are extracted with methylene chloride and the extract is concentrated and analyzed by gas chromatography/mass spectrometry (GC/MS) or GC-FID. Alternatively, extract is exchanged into 2-propanol and derivatized with pentafluorobenzyl bromide. During the air analysis of pyrocatechol, airborne particles are collected on a sorbent cartridge containing polyurethane foam. Particulates deposited on the filter are extracted with methylene chloride.