WASHINGTON, March 13, 2009 (AFP) - Dozens of popular children's bath products marketed in the United States contain two cancer-causing chemicals, a consumer safety watchdog group said in a report published Friday March 13.

The Campaign for Safe Cosmetics commissioned an independent laboratory to test 48 top-selling children's products for 1,4-dioxane and 28 of them for formaldehyde.

Used for embalming corpses and, in the United States, as glue in chipboard, formaldehyde is a by-product of a preservative added to the products to prevent bacteria growth and extend their shelf-life.

The 1,4-dioxane chemical is used as a foaming agents in some products.

Twenty-three of the 28 products tested for formaldehyde were shown to contain the chemical, and 17 of those products contained both formaldehyde and 1,4-dioxane.

Among those were the highly popular Johnson's Baby Shampoo, L'Oreal Kids Extra Gentle 2-in-1 shampoo and Pampers Kandoo foaming hand soap, which contained enough formaldehyde to trigger a skin reaction in highly sensitive people, the Campaign for Safe Cosmetics said in its report.

According to the US National Cancer Institute, studies of workers exposed to formaldehyde have linked the chemical to cancers of the nasal sinuses, nasopharynx, brain and possibly leukemia.

Thirty-two of the 48 products tested, or 67 percent, contained 1,4-dioxane.

The US Consumer Product Safety Commission has said that even trace amounts of 1,4-dioxane give "cause for concern," while the Environmental Protection Agency (EPA) and Department of Health and Human Services have both identified dioxane as causing cancer in animals and as a "probable human carcinogen."

"If chemicals are causing cancer in animals, we really shouldn't be putting them on babies' heads," said Stacy Malkan of the Campaign for Safe Cosmetics.

The Personal Care Products Council dismissed the study's finding as "patently false" and accused the Campaign for Safe Cosmetics of "preying upon parental worries."

"The levels of the two chemicals the group reportedly found are considered to be 'trace' or extremely low, are well below established regulatory limits or safety thresholds and are not a cause for health concern," the US trade association for the cosmetic and personal care products industry said.

"When present, these chemicals would likely be found at very low levels precisely because companies have gone to great lengths in the formulation and manufacturing processes to ensure that the products are safe and gentle for children and also protected from harmful bacterial growth," the organization said.

Malkan said the study gave cause for concern because "children are more vulnerable to the toxic effects of chemicals."

The two chemicals are "completely unregulated" in the United States, while 1,4-dioxane is banned in Europe and formaldehyde is restricted, she said.

"I don't think parents need to be alarmed but I feel outraged because there's no need for these products to contain carcinogens," she added.