A north Alabama water authority has filed a federal lawsuit against 3M and two other companies, accusing them of polluting the Tennessee River with cancer-causing chemicals.

The West Morgan-East Lawrence Water and Sewer Authority claims that manufacturing plants operated by 3M, its subsidiary Dyneon, and Daikin America have leaked perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) into the river, posing a threat to health.

These plants are located 13 miles upstream of the water authority’s facilities, AL.com reported.

The class action lawsuit, filed by the water company and three local residents, states that PFOA and PFOS can cause health problems like cancer, immune dysfunction, thyroid disease, ulcerative colitis and high cholesterol. The plaintiffs also claim that 3M has known for at least 14 years that the two chemicals “are not effectively treated by conventional wastewater treatment plant processes”.

3M medical expert Dr. Carol Ley disputed the allegations of health risks.

“In more than 30 years of medical surveillance we have observed no adverse health effects in our employees resulting from their exposure to PFOS or PFOA. This is very important since the level of exposure in the general population is much lower than that of production employees who worked directly with these materials,” Dr. Ley explained.

“We do not believe PFCs (perfluorinated chemicals) such as PFOA and PFOS present any harm to human health at levels they are typically found in the environment or in human blood,” she concluded.

William A. Brewer III, an attorney for 3M, said in a statement:

“The company is confident that its actions in Alabama are a credit to its well-known record of responsible environmental stewardship. Needless to say, 3M believes these claims lack merit. Although these types of lawsuits capture headlines, it is important to remember they are often based on groundless allegations. 3M believes there has been no harm to plaintiffs’ property due to the mere environmental presence of these materials.”