While the health risks of using hydroquinone are well-documented and the chemical has been banned in Japan, Europe and Australia, it is still legal and somewhat prevalent in skin products for ethnic skin in the U.S.
In 2006, the Food and Drug Administration (FDA) proposed an unsuccessful ban of hydroquinone and admitted to its potentially carcinogenic effects. It also reported that there were roughly 200 products available that contained the chemical at the time of the proposal.
The FDA claims that the chemical has been associated with yellow growths on the skin, discolored spots and a condition known as ochronosis.
The Environmental Protection Agency (EPA) says that hydroquinone is used to develop photography and X-ray films and is also an additive for industrial monomers. The federal agency reports that it is a skin irritant in humans and has been shown to contribute to tumor growth in mice.
Despite this, the EPA has not yet classified hydroquinone as a carcinogen and reports that no information is available on the cancer-causing properties of the chemical in humans.
However, CampaignForSafeCosmetics.org warns that the product is one of the most harmful substances that can be put on the skin. In addition to its possible carcinogenic effects, the chemical bleaches the skin, stripping away naturally protective melanin and making its user more susceptible to skin cancer.
The Environmental Working Group's Skin Deep database classifies hydroquinone as a carcinogen, an immunotoxicant as well as a developmental and reproductive toxicant.