ALBUQUERQUE, N.M. — Local officials in towns downstream from where millions of gallons of mine waste spilled into a southwest Colorado river are demanding answers about possible long-term threats to the water supply.

Colorado and New Mexico declared stretches of the Animas and San Juan rivers to be disaster areas as the orange-colored waste stream made its way downstream toward Lake Powell in Utah after the spill Wednesday at the abandoned Gold King mine near Silverton, Colorado.

The 3 million gallons of mine waste included high concentrations of arsenic, lead and other heavy metals. Workers with the EPA accidentally unleashed the spill as they inspected the abandoned mine site.

EPA officials said Monday that there was no leading edge of contamination visible in downstream sections of the San Juan River or Lake Powell. But that has done little to ease concerns or quell the anger caused by the spill.

The Navajo Nation, which covers parts of New Mexico, Utah and Arizona, declared an emergency as it shut down water intake systems and stopped diverting water from the San Juan River.

Members of the tribal council were frustrated during a special meeting Monday and echoed the sentiment of New Mexico and Utah officials that the federal government needs to be held accountable.

Utah Attorney General Sean Reyes discussed the legal implications with his New Mexico counterpart, Hector Balderas, and planned to hold a similar call with Colorado Attorney General Cynthia Coffman, Reyes’ office said Monday.