Arizona Sen. John McCain, R-Ariz., and Rep. Ann Kirkpatrick, D-Ariz., are accusing the U.S. Environmental Protection Agency of neglect for the agency’s response to Navajo communities after a Colorado mine spill polluted the San Juan River last August.

“Native people here in Arizona deserve better answers,” McCain said during a U.S. Committee on Indian Affairs oversight hearing last week. He called for a criminal probe.

The committee held the hearing at Phoenix City Council chambers to examine the EPA’s “unacceptable response to Indian tribes” inside Phoenix City Council chambers.

Kirkpatrick represents many Native American tribes in northeastern Arizona and began the hearing by discussing the impact the EPA spill had on Arizona tribes.

“The Gold King Mine Spill in August of 2015 sounded many alarms not only as an environmental and economical disaster, but also as a failure by the EPA on multiple fronts,” Kirkpatrick said.

The Navajo tribe declared a state of emergency, along with Colorado and New Mexico, after a cleanup crew working for the EPA accidentally opened a tunnel at the abandoned mine in Silverton, Colo., on Aug. 5.

The accident released a flood of wastewater that had collected in the tunnel, sending a toxic plume of zinc, lead, iron and arsenic into the Animas, which is part of the Colorado River basin.

The Navajo were directly affected because the Animas runs into the San Juan River, which runs through 215 miles of tribal lands and is a major agricultural resource. The spill also threatened the region’s drinking water, on and off the reservation.

“The contaminated water entered the Animas River, an important water source for Arizona’s tribal communities, agriculture, recreation and small businesses,” Kirkpatrick said in a statement.

“A failure to respond swiftly and transparently, a failure to immediately engage tribal government and a failure to mitigate the short and long term burdens on our tribes from this agency created disaster,” Kirkpatrick said.

McCain asked EPA Assistant Administrator Mathy Stanislaus whether he thought there should launch a criminal probe on the matter. Stanislaus said no.

McCain said the hearing was just one step in an examination of the spill.

“We’re a long way from finished with the issue,” McCain said.

Cronkite News reporter Sara Weber contributed to this article.