The Environmental Protection Agency says the mine waste spill into Colorado river waters last Wednesday dumped about three times what the agency had initially estimated.
The EPA now estimates that three million gallons of heavy-metal laced water spilled from an adit at the Gold King Mine into the Animas River, turning the water a sludgy orange. This estimate is a sharp increase from the one million gallons the agency first estimated, after using a stream gauge from the U.S. Geological Survey to measure the disaster.
The agency has so far been unable to determine whether humans or marine life face any health risks as a result of the spill. However, EPA toxicologist Deborah McKean said the toxic water moved so quickly after the spill that it likely would not have "caused significant health effects" to animals that consumed the water.
Local officials were preparing to shut down two wells that serve Montezuma Creek in Utah, said Rex Kontz, deputy general manager for the Navajo Tribal Utility Authority.
The discolored water from the spill stretched more than 100 miles from where it originated just north of Colorado's historic mining town of Silverton, and moved toward the New Mexico municipalities of Farmington, Aztec, and Kirtland. The EPA is coordinating with officials in Colorado, New Mexico, and Utah, as well as the Southern Ute Tribe and the Navajo Nation, according to a statement.
In Colorado where the spill started, the EPA planned to meet with residents of Durango, downstream from the mine. The EPA tested the water near Durango, and it is still being analyzed.
The EPA has not said how long cleanup efforts will take. An EPA-supervised crew trying to enter the mine to pump out and treat the water caused the spill, the Christian Science Monitor previously reported.
The flow of water from the mine break is being diverted into newly constructed ponds and treated before it enters Cement Creek. Residents in the area are also being tasked with testing their well water. Water treatment appears to be effective thus far, according to EPA officials.
According to preliminary testing data the EPA released Sunday, arsenic levels in the Animas River were, at their peak, 300 times the normal level, and lead was 3,500 times the normal level. Officials said those levels have dropped significantly since the plume moved through the area, according to USA Today.
Exposure to arsenic and lead at high levels of concentration can pose potential health risks.
"Yes, those numbers are high and they seem scary," said Deborah McKean, chief of the Region 8 Toxicology and Human Health and Risk Assessment. "But it's not just a matter of toxicity of the chemicals, it's a matter of exposure."
This report includes material from the Associated Press.