The EPA should classify toxic fluorochemicals contaminating drinking water as hazardous wastes or use its authority under the nation’s chemicals law to demand more health information on the substances, states said.

Several states have already gone beyond the Environmental Protection Agency in setting drinking water standards for two common fluorochemicals—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)—but they asked for more federal direction for cleaning up the chemicals.

Officials from six states peppered EPA officials with questions and recommendations...