The Environmental Protection Agency announced Tuesday that it was beginning an "emergency removal of hazardous substances" in Western Colorado.
An EPA analysis concluded that conditions at the Elizabeth Mining and Development site in Montrose County "represent a substantial threat to public health and the environment."
The site sits on the flood plain of the Uncompahgre River and is less than a quarter mile from a housing development.
Last year, the Elizabeth Mining an Development was found to be in violation of the Colorado Hazardous Waste Act, leading to a $405,000 fine for the company.
The company's owner, Steven Casebolt, was later charged with felonies for mishandling hazardous waste on company property.
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