The Coal Impoundment Location & Information System says the dam has a maximum capacity of about 505 million gallons of soupy gray slurry, or the equivalent of about 765 Olympic-sized swimming pools.

Slurry is a byproduct of washing coal to help it burn more cleanly. Companies have disposed of the dirty water and solids in various ways over the years, injecting it into abandoned mines, damming it in huge ponds.

Labor officials want U.S. District Judge John Preston Bailey to immediately halt use of the EMCI impoundment and to limit access only to certified inspectors. They also seek an order demanding that EMCI pay nearly $13,000 in long-overdue fines and an order that a professional certification be done within 30 days of the preliminary injunction.

Federal officials say impoundment failures are a major threat to people and property, pointing to the 1972 collapse of a dam in Logan County. A 30-foot wave of sludge roared down Buffalo Creek hollow, killing 125 people, injuring 1,200 and leaving more than 4,000 homeless.

More recently, in October 2000, the bottom of an impoundment in Martin County, Ky., burst into an abandoned underground mine and through the mountain, flooding the watershed with black waste.

"While no one was injured," Ihlenfeld notes, "it has been called the worst environmental disaster since the Exxon Valdez oil spill."

In all, there are 596 coal slurry impoundments in 21 states. West Virginia has 114, more than any other state.

Though they seldom fail, one man died in an embankment failure last fall. On Nov. 30, a section of embankment at the massive Robinson Run prep plant impoundment near Lumberport collapsed, sucking a bulldozer and two pickups into the muck. Two other men survived, but the body of dozer drive Markel Coon was recovered two weeks later.

Consol was working to raise the elevation of the impoundment when the accident happened, but the company and federal investigators have declined to speculate on what caused the failure.

The Robinson Run impoundment is massive in comparison with the EMCI dam, encompassing about 78 acres and holding about 1.6 billion gallons of wastewater, or the equivalent of more than 2,500 Olympic-sized pools.

MORGANTOWN, W.Va. -- The U.S. Department of Labor wants a federal judge to order the immediate shutdown of a potentially dangerous West Virginia coal slurry impoundment it says hasn't been certified by a professional engineer for two years.

In a filing in federal court, U.S. Attorney William Ihlenfeld argued Thursday that Energy Marketing Co. Inc. and owner Dominick LaRosa of Potomac, Md., are flouting federal law, ignoring violations and fines, and putting the public at risk.

The 101 North Hollow Coal Refuse Impoundment near Century, Barbour County, is associated with the nonproducing Century 101 mine. The Mine Safety and Health Administration has labeled it "high hazard," meaning a failure would likely cause fatalities.

MSHA says it was not certified for structural integrity as required by law in either 2011 or 2012. MSHA records also show EMCI has operated the mine and impoundment since Jan. 1, 2009, and has been cited for problems about two dozen times.

LaRosa didn't immediately return telephone messages, and his legal team has yet to file a response with the court.

"While there is no known or obvious danger posed by the dam at this time, the continued failure to have the dam examined by a professional engineer means that there may be a problem that MSHA has not identified," Ihlenfeld wrote in a memorandum supporting the Labor Department's request for a preliminary injunction.

"MSHA's inspections are not an acceptable substitute for the certification of an independent professional engineer," he added. Those engineers must analyze a full year's worth of records for an impoundment, then certify whether the work was done in accordance with approved plans.

Ihlenfeld is the U.S. attorney for the Northern District of West Virginia.

"MSHA inspectors generally are not qualified to perform such a review and their inspections are generally focused on conditions as they exist at that time," Ihlenfeld wrote. "EMCI and LaRosa's continued failure to comply with the certification requirements hampers MSHA's ability to evaluate ... and adequately protect the public and the environment from this potentially deadly hazard."

The Coal Impoundment Location & Information System says the dam has a maximum capacity of about 505 million gallons of soupy gray slurry, or the equivalent of about 765 Olympic-sized swimming pools.

Slurry is a byproduct of washing coal to help it burn more cleanly. Companies have disposed of the dirty water and solids in various ways over the years, injecting it into abandoned mines, damming it in huge ponds.

Labor officials want U.S. District Judge John Preston Bailey to immediately halt use of the EMCI impoundment and to limit access only to certified inspectors. They also seek an order demanding that EMCI pay nearly $13,000 in long-overdue fines and an order that a professional certification be done within 30 days of the preliminary injunction.

Federal officials say impoundment failures are a major threat to people and property, pointing to the 1972 collapse of a dam in Logan County. A 30-foot wave of sludge roared down Buffalo Creek hollow, killing 125 people, injuring 1,200 and leaving more than 4,000 homeless.

More recently, in October 2000, the bottom of an impoundment in Martin County, Ky., burst into an abandoned underground mine and through the mountain, flooding the watershed with black waste.

"While no one was injured," Ihlenfeld notes, "it has been called the worst environmental disaster since the Exxon Valdez oil spill."

In all, there are 596 coal slurry impoundments in 21 states. West Virginia has 114, more than any other state.

Though they seldom fail, one man died in an embankment failure last fall. On Nov. 30, a section of embankment at the massive Robinson Run prep plant impoundment near Lumberport collapsed, sucking a bulldozer and two pickups into the muck. Two other men survived, but the body of dozer drive Markel Coon was recovered two weeks later.

Consol was working to raise the elevation of the impoundment when the accident happened, but the company and federal investigators have declined to speculate on what caused the failure.

The Robinson Run impoundment is massive in comparison with the EMCI dam, encompassing about 78 acres and holding about 1.6 billion gallons of wastewater, or the equivalent of more than 2,500 Olympic-sized pools.