MEXICO CITY - Two Mexican textile factories that supply clothing for global fashion brands such as Levi's are dumping toxic chemicals into the environment, Greenpeace said Wednesday.

The environmental group said it found hazardous chemicals in samples taken from waste water discharges at the two facilities, run by Mexico's Lavamex and Kaltex companies, which dye and wash denim textiles.

"What we have in Mexico is a classic tale of big brands hiding behind lax regulation and secretive discharge methods," Pierre Terras, the toxics campaign coordinator at Greenpeace Mexico, said in a statement.

"For all their grandiose statements about restoring the environment and doing what's good for the planet, Levi's uses suppliers that are polluting Mexican rivers," Terras said.

The waste water discharged by the Lavamex facility, located in the city of Aguascalientes in central Mexico, is the only source of a network of streams that are used for agriculture in the area, Greenpeace said.

Diluted wastewater can reach the San Pedro River during rainy season.

The Kaltex facility in San Juan del Rio, in the central state of Queretaro, discharges wastewater into the San Juan River as well as a field, the environmental organization said.

Lavamex and Kaltex representatives could not be reached for comment. Greenpeace said Kaltex stated that it was going "beyond required environmental regulations" and was not the polluter of San Juan River.

Levi Strauss & Co confirmed that it works with both factories but said it was one of the first companies to have developed a Restricted Substance List (RSL), banning chemicals that could harm consumers, workers or the environment.

The Levi's list includes nonylphenol, a chemical that was found in the Lavamex samples by Greenpeace.

"The reality of apparel manufacturing is that many products, from different companies, are often produced in the same factory," the US company said in a statement, calling for industry-wide collaboration to reduce the environmental impact from supplier factories.

Greenpeace said Gap and Walmart have had business ties with Lavamex while LVMH and C&A confirmed that Kaltex supplies them. Nike stated that Kaltex is an "indirect supplier to an affiliated Nike brand."