A group of experts at the International Agency for Research on Cancer (IARC) recently determined that four nitrobenzenes and four other industrial chemicals are “possiblycarcinogenic to humans.” Based on the agency’s findings, the eight chemicalsubstances were given ‘Group 2B’ designations. “Group 2B” is IARC’sclassification of carcinogens with “sufficient evidence of carcinogenicity inexperimental animals” and without or “inadequate evidence” in humans.
Both experimental animals and humans are exposed to nitrobenzene by inhalation of the surrounding air, drinking contaminated water and skin contact with contaminated products. The classification will prompt California’s Office of Environmental Health Hazard Assessment (OEHHA) to propose the listing of the chemicals listed as carcinogens under Proposition 65.
The eight substances and their typical uses are:
- Ortho-phenylenediamine and its dihydrochloride salt which is already listed as a carcinogen under Proposition 65 are used in the production of pigments, corrosion inhibitors, pharmaceuticals and agrochemicals;
- 2-chloronitrobenzene which is used as a lumber preservative and in the production of pigments, corrosion inhibitors, agricultural and other chemicals;
- 4-chloronitrobenzene which is already listed in the Prop 65 list of carcinogens is used in the production of pigments and paints, plastics, pharmaceuticals, and other industrial processes;
- 1,4-Dichloro-2-nitrobenzene and 2,4-dichloro-1-nitrobenzene which are both used as intermediates in the production of pharmaceuticals, agrochemicals, diazo pigments, and ultraviolet absorbents;
- 2-Amino-4-chlorophenolwhich is used in the production of pharmaceuticals and dyes for textiles and some consumer products.
- para-nitroanisole which is used in the production of synthetic dyes and N, N-dimethylacetamide which is used as a solvent for resin and in the production of agrochemicals,textile fibers, coatings and films. This chemical was found in the urine of theworkers in production facilities of synthetic fibers.
A working group of fourteen experts met at the IARC headquarters in Lyon, France in October. The participants included experts from the UK, the Netherlands, Germany and Italy, four experts from Japan, and six experts from the U.S.
By law, OEHHA is required under California’s Proposition 65 Labor Code listing mechanism to “list chemicals identified by IARC as possibly carcinogenic” and with Group 2B’ designations. Under evaluation as possible candidates forlisting.
Six of the eight substances classifiedby IARC are Group 2B carcinogens.
If OEHHA’s evaluation shows that the substances meet the statute and regulations criteria, the agency will issue a”notice of intent to list” and open a public comment period about the potential listing of the six substances.
The summary of the IARC’s’ analysis published in Lancet Oncology mentions that “J O’Connor”, a DuPont employee, was present at the experts’ meeting as an observer. DuPont uses N, N-dimethylacetamide in the production of some of its products.