What chemical in neoprene causes cancer?

Chloroprene: Neoprene is polychloroprene This is synthetic rubber The EPA classifies Chloroprene as a group D chemical this makes its carcinogenicity inconclusive The International agency for Research on cancer IARC classified it as group 2 B ( possibly carcinogenic) This is likely to occur mainly as industrial exposure and may be linked to skin and lung cancers

Not concerned: Neoprene is polymerized chloroprene. Chloroprene monomer has caused cancer in a few obscure animal experiments, just as most anything else can be made to do as a promoter. There is talk of genotoxicity, but in its polymerized form it couldn't reach the genes in any case. Folks working with chloroprene aren't showing up with extra cancers. Don't throw away your wetsuit.