Two Republican senators on Tuesday formally requested a federal criminal probe of the Gold King Mine spill, saying enough evidence exists to suggest laws might have been broken in the August disaster.

John McCain, R-Ariz., and John Barrasso, R-Wyo., said in a letter to U.S. Attorney General Loretta Lynch that Environmental Protection Agency employees and contractors should be investigated for wrongdoing.

“(The justice department’s) involvement is necessary to affirm that the government is willing to hold itself to the same level of accountability as it holds private companies whose negligence results in serious environmental damage,” the letter says.

DOCUMENT: Read the entire letter to Loretta Lynch

McCain first requested a federal probe of the spill on April 22 during a congressional field hearing in Phoenix on the disaster.

Barrasso is the chair of the Senate Committee on Indian Affairs, on which McCain sits. Both have been highly critical of the EPA’s response to the Gold King spill, calling for the agency to hold itself properly accountable.

The EPA-triggered accident happened Aug. 5 above Silverton and sent more than 880,000 pounds of metals cascading through three states and American Indian land.

The agency has spent more than $22 million on response to the spill. That includes about $1 million in compensation to impacted states, counties, towns and tribes.

The U.S. Department of Interior, which conducted an independent investigation of the Gold King disaster on the behest of the EPA, found the spill was preventable.

The review, however, did not assign specific blame for the disaster, much to the frustration of some who questioned the breadth of the DOI’s work.

The EPA said Tuesday in response to the senators’ letter that it has taken responsibility for the spill’s cleanup and internal review. The agency says it is also awaiting a report from its Officer of Inspector General.

“These reports will help inform EPA’s ongoing efforts to work safely and effectively at mine sites as we carry out our mission to protect human health and the environment,” the EPA said in a statement.

McCain and Barrasso said while the EPA has accepted responsibility for the spill, there needs to be a determination if any crime was committed in connection with the disaster.

The senators said they were specifically worried about criminal negligence, violations of federal environmental laws and obstruction.

The justice department said it is aware of the letter and is reviewing it.

Jesse Paul: 303-954-1733, jpaul@denverpost.com or @JesseAPaul