Posted 8:15 a.m. | Updated 2:45 p.m.
New Mexico is suing the state of Colorado, saying its neighbor to the north should be held responsible for the contamination caused by the 2015 Gold King Mine spill as well as decades of acidic drainage from mines near the headwaters of the Animas River.
The New Mexico Attorney General's Office and the state Environment Department announced late Wednesday that they filed a complaint against Colorado with the U.S. Supreme Court.
“The Gold King Mine release is the result of two decades of disastrous environmental decision-making by Colorado, for which New Mexico and its citizens are now paying the price,” Attorney General Hector Balderas said in a press release.
It marks the second major legal salvo fired by New Mexico in the wake of the August 2015 spill, which fouled rivers in three states with a yellow soup of arsenic, lead and other heavy metals. New Mexico is also suing the U.S. Environmental Protection Agency.
Colorado's strategy of plugging draining tunnels in old mines has failed, said New Mexico Environment Department Secretary Ryan Flynn.
"They, essentially, authorized the transformation of Colorado mines into an enormous wastewater storage facility, ready to burst," Flynn said in a statement.
Colorado Attorney General Cynthia Coffman placed the blame on the EPA, which has accepted full responsibility for the spill.
"It’s unclear to me how suing Colorado furthers the states’ mutual goal of holding the EPA to its promise to ‘take full responsibility’ for turning our rivers yellow," Coffman said in a statement.
Gov. John Hickenlooper said in a statement he was "disappointed" that New Mexico chose litigation that could be "costly and time consuming."