WASHINGTON (AP) -- The chemical spill that contaminated water for hundreds of thousands in West Virginia was only the latest and most high-profile case of coal sullying the nation's waters.
For decades, chemicals and waste from the coal industry have tainted hundreds of waterways and groundwater supplies, spoiling private wells, shutting down fishing and rendering streams virtually lifeless, according to an Associated Press analysis of federal environmental data.
But because these contaminants are released gradually and in some cases not tracked or regulated, they attract much less attention than a massive spill such as the recent one in West Virginia.
"I've made a career of body counts of dead fish and wildlife made that way from coal," said Dennis Lemly, a U.S. Forest Service research biologist who has spent decades chronicling the deformities pollution from coal mining has caused in fish.
"How many years and how many cases does it take before somebody will step up to the plate and say, 'Wait a minute, we need to change this'?"
The spill of a coal-cleaning chemical into a river in Charleston, W.Va., left 300,000 people without water. It exposed a potentially new and under-regulated risk to water from the coal industry when the federal government is still trying to close regulatory gaps that have contributed to coal's legacy of water pollution.
From coal mining to the waste created when coal is burned for electricity, pollutants associated with coal have contaminated waterways, wells and lakes with far more insidious and longer-lasting contaminants than the chemical that spilled out of a tank farm on the banks of the Elk River.
Chief among them are discharges from coal-fired power plants that alone are responsible for 50 percent to 60 percent of all toxic pollution entering the nation's water, according to the Environmental Protection Agency.
Thanks to even tougher air pollution regulations underway, more pollution from coal-fired power plants is expected to enter the nation's waterways, according to a recent EPA assessment.
"Clean coal means perhaps cleaner atmosphere, but dirtier water," said Avner Vengosh, a Duke University researcher who has monitored discharges from power plant waste ponds and landfills in North Carolina.
In that state, Vengosh and other researchers found contaminants from coal ash disposal sites threatening the drinking water for Charlotte, the nation's 17th-largest city, with cancer-causing arsenic.
"It is kind of a time bomb that can erupt in some kind of specific condition," Vengosh said. The water shows no signs of arsenic contamination now.
In southeastern Ohio, tainted water draining from abandoned coal mines shuttered a century ago still turns portions of the Raccoon Creek orange with iron and coats the half-submerged rocks along its path white with aluminum.
Public drinking water systems in 14 West Virginia counties where mining companies are blasting off mountaintops to get to coal seams exceeded state safe drinking water standards seven times more than in nonmining counties, according to a study published in a water quality journal in 2012. The systems provided water for more than a million people.
The water quality monitoring in mining areas is so inadequate that most health violations likely were not caught, said Michael Hendryx, the study's author and a professor of applied health at Indiana University.
The EPA, in an environmental assessment last year, identified 132 cases where coal-fired power plant waste has damaged rivers, streams and lakes, and 123 where it has tainted underground water sources, in many cases legally, officials said.
Among them is the massive failure of a waste pond at a Tennessee Valley Authority power plant in 2008. More than 5 million cubic yards of ash poured into a river and spoiled hundreds of acres in a community 35 miles west of Knoxville.
Overall, power plants contributed to the degradation of 399 bodies of water that are drinking water sources, according to the EPA.
There are no federal limits on the vast majority of chemicals that power plants pipe directly into rivers, streams and reservoirs. The EPA just last year proposed setting limits on a few of the compounds, the first update since 1982. More than five years after the Tennessee spill, the EPA has yet to issue federal regulations governing the disposal of coal ash.
Experts say the agency is playing catch-up to solve a problem that began when it required power plants in the 1990s to scrub their air pollution to remove sulfur dioxide. An unintended consequence was that the pollutants captured were dumped into landfills and ponds, many unlined, where they seeped into underground aquifers or were piped into adjacent rivers, reservoirs and lakes.