The Environmental Protection Agency is back working on the Gold King Mine in Colorado almost a year after the agency spilled 3 million gallons of toxic sludge into the waterways of three states.

EPA said Friday that it's back to clean up the mess it caused last August, while taking steps to ensure nothing unexpected occurs.

The Gold King Mine blowout has been pinned on EPA "negligence" by GOP critics on Capitol Hill, with the House Natural Resources Committee leading a probe into the incident. New Mexico is currently suing EPA for damages related to the spill.

EPA is mobilizing contractors to begin work on Saturday to complete work it started last fall at the abandoned mine, it said Friday. It will seek to stabilize the mine's opening that EPA contractors last summer opened causing the 3-million gallon blowout.

"EPA's contractor will begin this work on Saturday, July 9, and will continue work through October 2016," the agency said in its announcement.

This time around, however, the agency has a plan in place to deal with another blowout, if one where to occur. It says it has a water treatment plant in place, and has an early warning system to alert state authorities if something uneventful occurs. One of the key criticisms of the agency by states is that it didn't alert states soon enough after the spill occurred.

"We anticipate that the interim water treatment plant at Gladstone will continue to capture and treat any discharge from the mine," the agency explained. "However, should any of this work impact downstream watersheds, EPA will notify stakeholders in accordance with the Gold King Mine Stakeholders Alert and Notification Plan."

EPA said it issued a memo in March outlining how its regional offices could better prepare for work at mining and mineral processing sites where there it the possibility of "fluid hazards."

"The memo includes precautionary measures intended to prevent the type of event that occurred at [Gold King Mine] on Aug. 5, 2015, including headquarters technical consultation," the agency explained. "The consultation process for GKM has been completed, including review of site-specific work plans, a technical assessment of the potential for a fluid release, and verification of a carefully designed and coordinated contingency plan."