Quality problems prompted two of Michigan Governor Rick Snyder's top lawyers to urge that the city of Flint be moved back to the Detroit water system just months after a decision to draw water supply from the Flint River, according to emails released on Friday.

Several critics have urged Snyder to resign over concerns about the state's handling of the crisis.

Flint switched its water supply from Detroit to the Flint River in April 2014 in a bid to cut costs when the city was under a state-appointed emergency manager. 

While the city switched its water source back to Detroit in October 2015, corrosive water from the river had already leached lead from city pipes, posing a serious threat to public health.

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The governor's top aides discussed Flint's water quality problems as early as the fall of 2014, with one official calling the situation "downright scary," about a year before the switch back to the Detroit system was finally made. The Detroit Free Press and Detroit News earlier reported about the emails. 

“This crisis is the result of failures at all levels of government - city, state and federal," Snyder said in a statement. "As the one ultimately responsible for what happens in state government, I am taking steps to help correct what happened there.” 

Snyder, scheduled to testify to Congress on March 17, has repeatedly apologized for the state's poor handling of the crisis. 

Liberal group Progress Michigan again called for Snyder to resign, citing the emails.

“There's no reasonable person who can believe at this point that every top advisor to Rick Snyder knew that there was an issue, but Snyder knew nothing," Lonnie Scott, executive director of Progress Michigan, said in a statement. "He's clearly unfit to lead our state and he should resign immediately."

Valerie Brader, deputy legal counsel and Snyder's senior policy adviser, addressed problems over the quality of Flint River water in an email to the governor's Chief of Staff Dennis Muchmore and other top aides on Oct. 14, 2014. 

She argued that Flint should be returned to the Detroit water system, citing bacterial contamination and reduced quality that prompted General Motors Co to switch its supply away from the river due to rusted parts.

Michael Godola, then the governor's legal counsel and a Flint native, echoed her concerns in a response, calling the use of Flint River as a water source "downright scary."

Muchmore, who now works for a law firm, told the Free Press that cost was a major impediment in discussions over whether to return to the Detroit water system and those concerns were discussed with Snyder.