Manufacture, Importation and Use of DNOC

Globally, DNOC is used mainly in the plastics industry as an inhibitor of polymerization in styrene and aromatic vinyl products; it is also used as an intermediate in the synthesis of fungicides, dyes and pharmaceuticals (IPCS, 2000; UNEP/FAO, 2002).

Two Canadian companies reported manufacture or import of DNOC in 1986, with amounts in the range of 100-1000 tonnes (Environment Canada, 1990). Historically, DNOC was used in Canada as an antioxidant, corrosion inhibitor, tarnish inhibitor and antiscaling agent, for a total of 99.9% of the Canadian market (Environment Canada, 1990).

An industry survey conducted by Environment Canada resulted in use pattern information for the year 2000 (Environment Canada, 2003a). Under Section 71 of CEPA 1999, this Notice with Respect to Certain Substances on the Domestic Substances List applied to any person who, during the 2000 calendar year, manufactured or imported DNOC, whether alone or in a mixture or in a product, in a total quantity greater than 10 000 kg. The survey indicated that DNOC is not manufactured in Canada; however, between 100 and 1000 tonnes of DNOC were imported in 2000 (Environment Canada, 2003a).