The findings of the Organic Consumers Association, a consumer advocacy group, show many items that tested positive are well-known brands sold in retail stores across the United States. These include Kiss My Face, Alba, Seventh Generation and Nature's Gate products, the Los Angeles Times reported.

Of the 100 products tested, 47 had detectable levels of 1,4-dioxane, the report said. The U.S. Environmental Protection Agency has declared it a probable human carcinogen.

"We need standards," said consumer advocate and author David Steinberg, who directed the study.

"For companies to knowingly or even carelessly put a carcinogen into commerce in this day and age is barbaric, I think,"

The compound is a byproduct of a process used to soften harsh detergents, the study says.

The findings are causing a stir in the natural products industry, many of whose leaders are currently attending a national trade show in Anaheim, Calif.