California law places certain warning requirements on any person who in the course of doing business in that state knowingly or intentionally exposes another person to certain listed chemicals determined by the state to cause cancer or reproductive toxicity. Hundreds of substances, ranging from industrial chemicals to alcoholic beverages, when associated with alcohol abuse, are subject to California’s warning requirement. Violators can be liable for civil penalties. The list is updated at least once per year.
Effective July 24, 2012, California has added isopyrazam, a fungicide, and 3,3’,4,4’‑tetrachloroazobenzene, associated with certain herbicides, to the list of chemicals known to the state to cause cancer for purposes of Proposition 65.
See http://www.oehha.ca.gov/prop65/prop65_list/072012listR.html for the complete, updated chemical list.