The International Agency for Research into Cancer has classified lindane as a group 2B carcinogen. Group 2B includes agents or mixtures which are possibly carcinogenic to humans.
This category is used for agents, mixtures and exposure circumstances for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances an agent, mixture or exposure circumstance for which there is inadequate evidence of carcinogenicity in humans but limited evidence of carcinogenicity in experimental animals together with supporting evidence from other relevant data may be placed in this group.
I am advised that peer-reviewed scientific literature and consultation with experts in the field indicate that no evidence exists which establishes a link between exposure to lindane in the forms suggested and breast cancer.