Almost 100 shampoos and personal-care products sold in California carry cancer-causing chemicals, an environmental group charges.

Almost 100 shampoos and personal-care products sold in California carry a cancer-causing chemical, according to an environmental group that has filed a lawsuit against four companies.

The Center For Environmental Health, based in Oakland, Calif., named four defendants in papers filed Tuesday in the Superior Court of the State of California.

The lawsuit claims that 98 products, including brand-name items such as Prell and Colgate Palmolive, do not carry labels warning consumers that they are being exposed to cocamide DEA, an ingredient made from coconut oil.

Those products are carried by such stores as Walmart, Kmart and Target.

Cocamide DEA is a toxic chemical that is used as a thickening or foaming agent in products such as shampoos, liquid soaps, body wash and bubble bath.

“Most people believe that products sold in major stores are tested for safety, but consumers need to know that they could be doused with a cancer-causing chemical every time they shower or shampoo,” Michael Green, executive director of CEH, said in a news release.

CEH, which is non-profit environmental advocacy group, says it bought the shampoos and other products at Bay Area locations of major retailers and from online retailers before getting an independent lab to conduct tests.

In 2012, California added cocamide DEA to its list of known carcinogens under Proposition 65 .

The voter-approved initiative, otherwise known as Safe Drinking Water and Toxic Enforcement Act of 1986, requires “businesses to notify Californians about significant amounts of chemicals in the products they purchase, in their homes or workplaces, or that are released into the environment.”

The four companies named in the lawsuit, filed in the Superior Court of the State of California, are Walgreen Co; Lake Consumer Product Inc; Todd Christopher International Inc; and Ultimark Products LLC.

The lawsuit seeks $2,500 in penalties per day for each violation from each defendant, along with a permanent injunction against selling the products in California without “clear and reasonable warnings.”

Meanwhile, in Canada, there are some restrictions on the use of cocamide DEA in cosmetics, but only when it is used with other agents that can cause the formation of nitrosamines.

This restriction is similar to regulations in the European Union.