This International Standard gives general guidance for the sampling and analysis of airborne organic isocyanate (NCO) compounds in workplace air.This International Standard is appropriate for a wide range of organic compounds containing isocyanate functional groups, including isocyanate monomers and prepolymers. Examples of aromatic monomers include toluene diisocyanate (TDI) (both 2,4- and 2,6-diisocyanatotoluene), naphthyl diisocyanate (NDI) (1,5-diisocyanatonaphthalene) and methylenebis(4-phenylisocyanate) [MDI, systematically named as di-(4-isocyanatophenyl)methane]. Examples of aliphatic monomers include isophorone diisocyanate (IPDI, systematically named as 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane), methylenebis(cyclohexylisocyanate) (hydrogenated MDI, HMDI) and 1,6-diisocyanatohexane (HDI) (also known as 1,6-hexamethylenediisocyanate). Monomers containing a single isocyanate moiety (e.g. methyl isocyanate, ethyl isocyanate, phenyl isocyanate, hexyl isocyanate) are produced during thermal degradation of polyurethanes, i.e. flame bonding and laser cutting. Isocyanate polymers, also called polyisocyanates, homopolymers, oligomers or prepolymers, are derived from the diisocyanate monomers by self-condensation or reaction with polyols. Polymeric diisocyanates are widely used in the polyurethanes, paints and coatings, and adhesives industries.