WASHINGTON -- Michigan's attorney general is charging three state and city officials with crimes for their involvement in the Flint water contamination crisis, where citizens were exposed to dangerously high levels of lead.

Steven Busch and Michael Prysby oversaw water issues for the Michigan Department of Environmental Quality, while Michael Glasgow was the utilities administrator for the city of Flint. Michigan Attorney General Bill Schuette (R) said Wednesday that the charges against Glasgow stem from his handling of drinking-water test results that showed the city's water to be safer than it really was. Prysby and Busch are charged with misconduct in office and conspiracy to tamper with evidence. Schuette also accused the state officials of misleading the federal Environmental Protection Agency about how Flint treated its water.

"They had a duty to protect the health of families and citizens of Flint," Schuette said at a press conference Wednesday. "They failed to discharge their duties. They failed in their responsibilities to protect the health and safety of families of Flint."

Flint's water first became toxic after the city, under the control of an emergency manager appointed by Michigan Gov. Rick Snyder (R), began using the Flint River as its water source in April 2014. The city's utility and its state supervisors failed to ensure the water was treated to prevent it from leaching lead from the city's pipes. Previously, the city had bought treated water from Detroit for the past 50 years.

Despite persistent complaints, city and state officials denied there was anything wrong with the water until last fall, when research showed lead levels had risen dramatically in Flint children after the water switch. The state admitted it had made a terrible mistake and switched Flint back to Detroit's water in October.

Glasgow, and attorneys for Busch and Prysby, did not immediately respond to requests for comment. Emails released by Snyder's office show that Glasgow warned state supervisors the city wasn't ready to begin pumping water from the Flint River. "If water is distributed from this plant in the next couple weeks, it will be against my direction," Glasgow wrote in an April 2014 email.

An investigation by MLive revealed the city had failed to collect water samples from homes with lead pipes, contrary to a federal law that dictates how cities are supposed to monitor for high lead levels. Glasgow told MLive the city struggled to find enough homes known to be connected to water mains via lead service lines.

In September, a Flint lawmaker asked Schuette to investigate whether government officials were to blame for the crisis. Schuette's office declined, saying there were already "multiple reviews by federal and state agencies," as well as "pending and potential federal court actions." A few weeks later, after national media attention to Flint increased, Schuette changed course, promising to launch an investigation "without fear or favor."

Schuette's office was already defending the state against a lawsuit in which Flint residents alleged that state and local government officials ignored evidence that the water pumped from the Flint River exposed the plaintiffs to "extreme toxicity, causing serious and dire injury." Attorneys general often act on behalf of both the state and its people, but the late timing of Schuette's investigation led progressives to question whether it was politically motivated. His office later wrote in a court filing that "a conflict wall has been established," and that Schuette "has not and will not be involved in representing any party to this action."

In late January, Schuette's office foreshadowed how the investigation was going to go when it picked sides in the civil case. In a court filing, his staff said there was a potential conflict of interest between the state and Snyder on one hand, and individual MDEQ employees on the other. A court agreed in February that the attorneys representing Snyder could withdraw as counsel for MDEQ defendants, including Busch and Prysby.

Many Michigan residents still seem to think the governor, who is not facing charges, shares the blame. In a recent survey by Michigan State University, 57 percent of respondents said Snyder and his administration, which includes MDEQ, are most responsible. Snyder is also facing his lowest approval rating since he took office in 2011.

Rep. Elijah Cummings (D-Md.), the top Democrat on the U.S. House of Representatives committee that has investigated the Flint crisis, praised the charges, but suggested they still fall short.

“The criminal charges against MDEQ officials are one step towards justice for the families of Flint who were poisoned as a result of the actions of Governor Snyder’s administration," Cummings said. "The people of Flint deserve accountability for the actions of Governor Snyder and his officials that caused this crisis.”

This story has been updated with additional remarks from Schuette.