Workers are feverishly trying to clean up a massive spill of toxic coal sludge that broke through the wall of a slurry sediment pond in southeastern Kentucky, collapsed an underground mine and then flowed into nearby creeks and rivers until some of it entered the Ohio River 60 miles away.

Laced with poisonous heavy metals--including mercury, lead and arsenic--210 million gallons of the sludge covered bridges and roads, fouled lawns and clogged municipal water intake pipes along the Kentucky-West Virginia border after bursting through an impoundment dam near Inez, Ky., Oct. 11.

Environmental officials called the spill one of the worst ecological disasters to hit the southeastern United States and said its effects could last for years. The spill left fish, snakes, turtles and other species smothered as the waste clung to the bottom and banks of creeks and tributaries of the Big Sandy River, which flows into the Ohio River downstream of Cincinnati.

Officials of Martin County Coal Corp., the operator of the mine, said they had 250 workers, four dredges and numerous vacuum trucks removing the sludge and putting it in temporary containment ditches until it can be dried out and hauled away.

Company spokesman Bill Marcum could not estimate how long the cleanup will take but said, "Our pledge is to clean it all up as soon as we can." Officials of the mining company, a subsidiary of Richmond-based A.T. Massey Coal Inc., said the disaster was caused by a "sudden and unexpected" collapse of a wall between the mine's 70-acre slurry sediment pond and a mine shaft below.

Federal and state mine safety records show that the mining company and regulatory officials knew at least six years ago after a similar--but smaller--spill from the same pond that there was a danger of a wall bursting because the heavy mixture of water and coal slurry was stored above the mine.

A 1994 accident investigation report by the Labor Department's Mine Safety and Health Administration said that a coal seam under the impoundment pool had been heavily mined without "additional precautions to prevent this type of occurrence." The MSHA report said, "The recommendation of the investigation team is to modify the impoundment plan to insure against a similar occurrence."

J. Davitt McAteer, assistant labor secretary and the head of the mine safety agency, said that after the 1994 spill the mining company drafted an impoundment pool modification plan "based on the engineers' assessment of what went wrong." He said his agency approved the plan.

"The question is, was the approved plan inadequate or did they fail to implement it? We won't know the answer to that until the investigation is complete," McAteer said in an interview. "What is true is that there is no question the [wall] has failed a second time and that is of grave concern to us."

McAteer said he ordered thorough inspections of about 600 coal mine waste impoundment dams last week throughout Appalachia. He said MSHA inspectors are being dispatched immediately to impoundment sites identified as having the "potential to fail and pose a threat to the lives or property of workers and citizens in the surrounding community."

According to mine safety records, in 1997 the MSHA studied maps and plans of all mine waste impoundment pools across the country and found that the Martin County Coal pool had a "moderate potential" of failing. McAteer said 219 slurry ponds were identified as "potential problems."

Agency engineers said then that the man-made barrier between the sediment pool and the mine works may not have been designed to prevent slurry from breaking through the walls and pouring into the abandoned mine shaft below.

Before mine workers frantically bulldozed boulders and earth to plug the gap and contain 2.2 billion gallons of sludge at the Inez mine, 210 million gallons poured into the mine and flowed into two creeks that flow into the Tug Fork of the Big Sandy River. The spill, up to 70 yards wide, closed water intake valves in several West Virginia and Kentucky towns and traces of the sludge made it to the confluence of the Big Sandy and Ohio rivers. The faster-moving Ohio created pressure against the Big Sandy at the confluence and prevented most of the sludge from moving closer to Cincinnati, state water officials said.

MSHA spokesman Rodney Brown said the Inez mine got a "C" rating for potential for a breakthrough based on company maps and records and a high-risk rating for potential impact on miners and the surrounding residents in the event of a breakthrough. Brown said the agency is conducting on-site inspections of the worst-rated impoundment ponds and was far from reaching the Inez mine's category when McAteer announced the inspections.

McAteer acknowledged that the impoundment monitoring system "didn't work" in this case, and he said the investigation of the spill was intended to find out why. Recalling the 1972 Buffalo Creek disaster just two counties away, in which 125 people died and 4,000 were left homeless after a similar slurry spill, McAteer said, "It could have been worse. Thank God nobody was hurt."

Marcum, the Martin County Coal spokesman, said the mine "followed all of MSHA's recommendations in 1994 but that he was not aware of "specific activities" and that company officials were too busy with the cleanup effort to check its records. He said his understanding was that MSHA made no modification recommendations as a result of the 1997 nationwide survey of impoundments and that the mine was in compliance with the law.

However, environmentalists are furious and say that Martin County Coal, A.T. Massey Coal, and their parent firm, the California-based Fluor Corp., should be held accountable, along with state and federal regulatory agencies.

"It's an abomination. We're tired of it. Who are they protecting?," asked Patty Wallace, past chairwoman of the environmental group Kentuckians for the Commonwealth and currently a member of Gov. Paul Patton's advisory panel, the Environmental Quality Commission. Wallace said that with less than 100 feet between the 2.2 billion gallons of sludge and the mine works below it, a disaster should have been foreseen by the company and mine safety officials.

But Wallace said that people who live in the hollows of economically depressed southeastern Kentucky depend on the mines as their only source of livelihood.

"As one fellow just said to me, 'We've turned our backs to this danger for years because we need the jobs, but we can't do it anymore,' " Wallace said.

Tom FitzGerald, director of the Kentucky Resources Council, an environmental group, said that mine safety records he obtained under the Freedom of Information Act show that the mining company and regulatory officials were aware of the danger of such a disaster years ago.

He said the company tried to avoid costly impoundment modifications by contending as far back as 1984 that the mine works were underneath the perimeter of the pond and therefore not likely to collapse under the weight of the sludge. However, FitzGerald said the records he obtained under the FOIA show that in 1994 the mine's consulting engineers drew maps showing the mine works were directly under the sludge pond, and they acknowledged the potential of the sludge sinking into the mine shaft.

An Oct. 26, 1999, letter from MSHA's district manager, Carl E. Boone II, to Martin County Coal safety coordinator Elmer Howard said that the firm's latest plan for impoundment pond modification had been turned down. An attached report said that because of the "high hazard classification of this site," several deficiencies in the plan needed to be addressed.

The report warned that expansion of the impoundment pool would put an additional load on the pillars of two coal seams and that "There is a concern that this load could cause further convergence of the pillars and consequently may cause [sinking]."

"Problems that may occur in the workings within the coal seams that could affect the impoundment include floor heave, pillar crushing and roof failure. These need to be addressed," the report added.

Federal mine safety officials said that these recommendations and all other aspects of the proposed modification of the Inez mine were under investigation.

"The company acknowledged the potential for subsidence [of the sludge]. MSHA expressed concern about a breakthrough. The state surface mining officials found evidence of numerous mines under impoundments and recommended stability analyses because of the potential for a breakthrough. What else did they need?" FitzGerald said.