Republican lawmakers grilled EPA Chief Administrator Gina McCarthy for not firing any agency employees or contractors after workers accidentally unleashed millions of gallons of toxic wastewater in a Colorado river last month.

When pressed by Republican senators during a Wednesday hearing about which individuals were responsible for the spill, McCarthy said the agency as a whole was responsible. McCarthy said she was waiting for the Department of the Interior to release its external review of the Gold King Mine blowout before she held individuals accountable.

McCarthy said she would not “make a judgement based solely on our internal review.” She added “the agency itself has been held accountable and we’re responding robustly.”

Her answer, however, didn’t sit well with Republicans, especially Arizona Sen. John McCain. The former presidential candidate slammed the agency for its slow response to the spill and how long it took for them to get in touch with Navajo Nation.

“Has anyone been fired for almost taking two days to notify the Navajo about the disaster?” McCain asked McCarthy. “Has anyone been fired for the Navajo’s complaint that the emergency response was inadequate?”

“In other words, you’ve done nothing,” McCain said to McCarthy when she said no one had been fired for its handling of the spill. She reiterated the EPA itself was being held accountable.

“Isn’t the agency composed of people?” McCain retorted. “Don’t you think someone is responsible for an accident that happened?”

“Someone should be held responsible because it happened,” McCain said. “So far, no one has been held responsible, except ‘the agency.’”

In early August, EPA contractors working under direction of the agency accidentally breached a retaining wall and unleashed an estimated three million gallons of wastewater from the Gold King Mine. The spill sent a plume of orange-colored toxic waste into Colorado’s Animas River which eventually made its way through New Mexico, Navajo Nation and Utah.

The spill initially caused rivers to become contaminated with heavy metals, like lead and arsenic, but EPA now says that water tests show that river quality has returned to pre-spill levels. State and tribal officials have been furious with EPA over its response to the spill. Navajo Nation has even threatened to sue the federal government over the mine waste polluting its waters.

“So this long after the spill, you’re still trying to determine who’s accountable for the spill?” North Dakota Sen. John Hoeven asked McCarthy.

Despite the grilling from lawmakers, McCarthy assured them the EPA would “address the cultural and other challenges this spill has thrust upon the Navajo.”

Right now there are two reviews being conducted by the federal government: one technical review by the Interior Department and another on criminal liability by the EPA’s inspector general.

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