HANNIBAL, Mo. (AP) – Four residents in the northeast Missouri town of Hannibal are filing suit, claiming the city’s water supply exposes them to potential carcinogens.

The class-action suit was filed Monday. It alleges that the Hannibal Board of Public Works has, for many years, provided unhealthy water. The suit also names the Missouri Department of Natural Resources, alleging lack of adequate oversight.

The suit alleges that dating to 2011, water provided in Hannibal has exceeded the federal threshold for trihalomethanes, a specific disinfection byproduct including chloroform and bromoform. The suit does not cite any specific health claims by residents.

James Lemon, an attorney for the city and the Board of Public Works, says city officials haven’t yet had time to thoroughly review the lawsuit. A DNR spokesman declined comment.