EPA Administrator Gina McCarthy is expected to navigate the site of a toxic river spill in Colorado Wednesday amid mounting anger and possible legal action over the spill caused by EPA workers that turned the Animas River a deep mustard color by contaminating it with sludge laden with lead, arsenic and other heavy metals.

McCarthy traveled Wednesday to the southwestern city of Durango, where she was accompanied by attorneys general from Colorado, New Mexico and Utah. The attorneys general were to discuss options available to them and could announce legal action against the EPA.

EPA officials have revealed that waste continues to surge from the abandoned Gold King Mine in Durango, Colo., into the river at a rate of up to 700 gallons per minute since the spill, which occurred while an EPA crew was inspecting an abandoned mine near Silverton, Colo., using heavy equipment.

The crew was supposed to pump out and decontaminate the sludge, but instead released it into tiny Cement Creek. From there, it flowed into the Animas River and made its way into larger tributaries, including the San Juan and Colorado rivers.

“I am absolutely deeply sorry that this ever happened, but I want to make sure that we react positively and in a way that’s credible and we move this forward,” McCarthy said Tuesday at a press conference in Washington.

McCarthy said the incident “pains me to no end” and pledged that she would use the “full breadth of the agency” to clean up the mess and committed to a full review to ensure that the type of accident wouldn’t happen again.

The agency estimated that more than 3 million gallons of sludge has already flowed at least 100 miles downstream to New Mexico.

McCarthy’s visit to the area comes amid growing anger from local residents and businesses affected by the accident. Tuesday marked the first day those affected could file claims with the EPA, with many communities and farms forced to stop using river water. It was unclear when the water would be usable again for irrigation.

Navajo Nation President Russell Begaye – head of the nation’s largest Native American reservation which extends into Utah, New Mexico and Arizona – told the Associated Press that farmers no longer had water for corn crops and ranchers were scrambling to get cattle and other livestock away from the polluted San Juan River, while bottled water is becoming increasingly scarce.

"When EPA is saying to me it's going to take decades to clean this up, that is how long uncertainty will exist as we drink the water, as we farm the land, as we put our livestock out there near the river," he said. "That is just, to me, a disaster of a huge proportion."

The Navajo Nation feels even more slighted given its status as a federally recognized tribe and sovereign nation.

Begaye said he has yet to receive a call from President Obama. "It seems like the Obama administration just closed their doors and disappeared," he said.

Heavy metals from Gold King and other defunct mines in Colorado have been leaching out and killing fish and other species for decades as rain and snowmelt spills from abandoned, exposed sites.

The EPA has considered making part of the Animas River in Colorado a Superfund site for a quarter-century.

The designation would have provided more resources for a cleanup, but some people in Colorado opposed the status, fearing the stigma and federal strings attached, so the EPA agreed to allow local officials to lead cleanup efforts instead.

Fox News’ Joseph Kolb, Alicia Acuna and The Associated Press contributed to this report.