Other European PCN tradenames included Seekay (UK, from ICI), Clonacire (France), Cerifal (Italy) and Woskol (Poland).

In the United States, the largest volume PCN products were called Halowax, from a New York company of the same name that was later owned by Union Carbide and then taken over by Koppers of Pittsburgh, PA, now Beazer East.

Although trace amounts of PCNs may be released by natural processes such as wildfires, their industrial uses increased the apparent rates of accumulation in the environment by factors of 10,000 or more.

Until recent years duPont produced a synthetic rubber, Neoprene FB, made in Northern Ireland using pentachloronaphthalene.

[12] In 2013, the 9th meeting of the Persistent Organic Pollutants Review Committee, established under the Stockholm Convention on Persistent Organic Pollutants proposed di-,tri-,tetra-,penta-,hexa-, hepta- and octa-chlorinated naphthalenes, for listing in Annexes A and C to that Convention.