ALBUQUERQUE, N.M. (AP) — One of the nation's largest American Indian tribes is planning to sue over damages caused by a massive mine waste spill in southwestern Colorado.

Navajo Nation President Russell Begaye, Navajo Attorney General Ethel Branch, and other tribal officials will announce Tuesday that they have directed their attorneys to file a lawsuit over what they describe as an "unprecedented environmental disaster."

Begaye recently renewed the call for the federal government to reimburse Navajo farmers, saying the U.S. Environmental Protection Agency's actions in the wake of the 2015 spill have created a culture of distrust.

An EPA-led crew triggered the spill during preliminary cleanup work. Three million gallons of wastewater carrying arsenic, lead and other heavy metals tainted rivers in Colorado, New Mexico and Utah.

The EPA has said it takes responsibility for the spill.