Navajo Nation officials said Monday they intend to file a lawsuit against the Environmental Protection Agency in the wake of last summer’s Gold King Mine spill.

Tribal officials plan to hold a news conference Tuesday to discuss how and why they have directed their legal representation to move forward with the legal action.

Navajo Nation President Russell Begaye, Vice President Jonathan Nez and Attorney General Ethel Branch are expected to speak in Shiprock, N.M., along the banks of the San Juan River.

The 3 million gallons of contaminated water that spilled from the Gold King on Aug. 5, 2015, flowed into the Animas River before eventually draining into the San Juan. Navajo officials closed irrigation ditches in the disaster’s wake, leaving farmers with bone-dry land and dead crops.

The agricultural communities in and around Shiprock were hardest hit.

In May, the state of New Mexico filed a lawsuit against the EPA for causing the spill and its subsequent response. Then, a month later, New Mexico filed a lawsuit against Colorado in the nation’s highest court alleging the state should be held responsible for the spill and its handling of the contaminants that have leached from surrounding mines for decades.

There is an ongoing criminal investigation into the spill.

The Navajo Nation has pledged since the days after the spill to take legal action against the EPA. Begaye has repeatedly lambasted the agency for its response to the disaster.

“Our people have not been compensated,” he said during an April congressional hearing on the spill.