Human exposure to 2-Naphthylamine

2-Naphthylamine formerly was used commercially as an intermediate in the manufacture of dyes, as an antioxidant in the rubber industry, and to produce 2-chloronaphthalene (IARC, 2010).

Because of its carcinogenicity, the manufacture and use of 2-naphthylamine have been prohibited in the European Union (EU) since 1998, in Italy since 1960, in the United Kingdom since 1952, and in Switzerland since 1938. Production and use of dyestuffs containing 2-naphthylamine have been banned in Japan since 1972 (Olfert et al., 2006).

Human exposure

In the United States of America (USA), 2-naphthylamine is a carcinogen regulated by the Occupational Safety and Health Administration (OSHA). As such, exposure must be strictly controlled through mandatory use of engineering controls, safe work practices, and personal protective equipment (OSHA, 2011).

Small quantities of 2-naphthylamine are used in laboratory research (IARC, 2010). The substance has been found as a contaminant in other chemicals and industries (Olfert et al., 2006). Phenyl-β-naphthylamine (PBNA) has been used as a substitute; however, it partially metabolizes in the body to 2-naphthylamine (Olfert et al., 2006).

In the past, occupational exposure to 2-naphthylamine mainly occurred during its production and when it was used in the manufacture of azo dyes. Exposure may still occur in laboratories where it is used as a model compound in cancer research, when workers are exposed to pyrolysis fumes containing 2-naphthylamine (e.g. foundry fumes, second-hand tobacco smoke, heated cooking-oils), to 2-nitronaphthalene (e.g. foundry workers), a nitro-PAH that can be metabolized to 2-naphthylamine, or to products containing 2-naphthylamine as a contaminant, such as certain rubber chemicals (IARC, 2010).

Countries in which exposure was reported include: Italy, Japan, the Russian Federation, the United Kingdom, and the USA (IARC, 2010). CAREX (CARcinogen EXposure) is an international information system on occupational exposure to known and suspected carcinogens, based on data collected in the European Union (EU) from 1990 to 1993. The CAREX database provides selected exposure data and documented estimates of the number of exposed workers by country, carcinogen, and industry (Kauppinen et al., 2000).