Environmental Protection Agency Administrator Gina McCarthy argued Monday that the lead water crisis in Flint, Mich., is the state's fault, just ahead of this week's congressional hearings on the crisis.

In a Washington Post op-ed, McCarthy blamed the crisis on the 2014 decision to switch water sources in order to save money, a move that was approved by the City Council but ultimately approved by a state-appointed emergency manager.

McCarthy said in the ensuing months that the state deceived the EPA, a claim she repeated Monday.

"The EPA's relationship with states under the act is usually a strong and productive partnership. But looking back on Flint, it is clear that, from day one, Michigan did not act as a partner," she wrote. "The state's interactions with us were dismissive, misleading and unresponsive. The EPA's regional office was also provided with confusing, incomplete and incorrect information."

McCarthy wrote that state environmental officials didn't act with urgency to put corrosion control into the water supply, which would have kept the lead pipes going from the main city lines to homes from corroding. She said the EPA was repeatedly telling the state to add corrosion control.

One EPA employee, researcher Miguel Del Toral, was telling state officials to do that, but Del Toral was eventually silenced by administrators in the EPA's Region 5, which oversees Michigan.

Del Toral worked with a local Flint resident to test her water and knew in early 2015 that her home had severe lead contamination in the drinking water. Emails released by the state show that other EPA officials higher up in the regional office knew of this as well, and yet the EPA never told the public.

At one point, a preliminary report by Del Toral detailing lead water contamination in Flint was leaked to the public. The EPA apologized to state officials for the leak and told Del Toral to stop speaking publicly and testing Flint water.

"We missed opportunities late last summer to get our concerns onto the public's radar," McCarthy said.

An EPA spokesperson did not respond to questions about why the EPA remained silent if state officials were not acting as a partner and why the EPA decided to continue deferring to state officials if they were not acting as a partner.

Former EPA Region 5 Administrator Susan Hedman, who resigned from her post due to her decision to silence Del Toral, will testify in front of the House Committee on Oversight and Government Reform on Tuesday. Joining her will be a former Flint mayor, the emergency manager in charge of Flint when the water switch was made and an expert on water quality.

McCarthy and Michigan Gov. Rick Snyder, who has been under fire in his state for dragging his feet in response to the crisis, will both testify in front of the committee on Thursday.