How EPA workers accidentally ripped a hole in a toxic mine that's ruined a Colorado river

Last week, the Animas River, which flows from southwest Colorado to New Mexico, started filling up with a toxic yellow stew from an old gold mine.

It's changed the color of the river to a mustard yellow, and so far it's stretched more than 100 miles, heading toward the Colorado River.

The Environmental Protection Agency was working on the mine when the spill occurred, dumping millions of gallons into the river.

So how did it happen?

Here's what we know:

• The Gold King Mine, where the spill happened, has been closed since 1923.
• The Environmental Protection Agency was using heavy machinery to try and make a safe way to get into the old mine. They were hoping to access the contaminated water so they could investigate what was in it.
• The goal was to treat the water so that there was less metal pollution coming out of the mine.
• Ironically, actual iron, copper and zinc began to pour out after a plug holding it all in was released.
• Water tested by the EPA has also come back with higher levels of arsenic and lead.
• About 3 million gallons were spilled into the Animas, which flows into the San Juan River and later meets up with the Colorado River.
• This isn't the only mine with toxic waste - there are thousands across the western United States.
• The EPA says it's not harmful to humans, and the fish they've monitored after the spill haven't had extraordinary death rates (about one fish died per 108 fish tested).
• Some stretches of the river are closed to recreation and drinking, and officials have advised boaters and fishers to steer clear of especially contaminated areas at least until August 17.

What we still don't know:

People living along the river and relying on it for drinking water are concerned with long-term health problems associated with the spill. The EPA says the water's moving fast enough so that the metals will disperse along the river until they return to normal levels.

For now, only time will tell.

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