The releases come from coal ash at Allegheny's Albright power plant in Preston County and violate the Clean Water Act, the West Virginia Highlands Conservancy, West Virginia Rivers Coalition, and the West Virginia Chapter of the Sierra Club said in a joint statement. Federal law requires a 60-day notice of intent to sue for Clean Water Act violations.
An Allegheny spokesman said the company has not seen the lawsuit and declined to comment.
The groups claim Allegheny's own information shows illegal arsenic discharges occurred between July and October last year from the 292-megawatt, coal-fired plant in Albright.
"Allegheny is responsible for keeping toxic runoff out of the water," Sierra Club spokesman Jim Sconyers said in a statement. "But they haven't done the job. It's time to do the job right, so people and aquatic animals don't pay for Allegheny's ash disposal with harm to our health and safety."
Arsenic in drinking water can cause cancer, nervous system damage and other problems.
The groups also claim that Allegheny is doing a poor job testing for selenium. The naturally occurring element is associated with coal mining in parts of West Virginia. Studies have found it's toxic to aquatic life and, in humans, high-level exposure can damage the kidneys, liver, and central nervous and circulatory systems.
Greensburg, Pa.-based Allegheny provides electric service to more than 1.5 million customers in Pennsylvania, West Virginia and Maryland.