Lansing — A federal judge on Monday allowed a major class-action lawsuit over the Flint water contamination crisis to move forward and reinstated claims against former Gov. Rick Snyder.

The decision by U.S. District Court Judge Judith Levy authorizes new evidence in the case that plaintiff attorneys argue shows Snyder was aware of significant risks posed by Flint River water as early as April 2015 but did not inform residents until five months later, when the crisis could no longer be denied.

Levy had dropped Snyder from the case in the fall 2018. But new allegations, if proven true, would show Snyder was “deliberately indifferent” and showed “callous disregard” for the health and safety of Flint residents, she wrote in a 128-page decision reinstating Snyder as a defendant and addressing other claims.

The consolidated class-action lawsuit was filed on behalf of Flint residents claiming personal injury and/or property damage as a result of the city's water contamination crisis, including those exposed to lead and at least one person who died due to possible Legionnaires’ disease.

Private lawyers who had represented Snyder in the Flint lawsuit did not respond to a request for comment, and it's unclear if they will rejoin the case or if that responsibility now falls to Attorney General Dana Nessel's office. A criminal defense attorney who has represented Snyder in other matters referred questions about the civil case to Nessel.

"We are reviewing the 128-page decision, and it would be inappropriate for us to comment on it until our review is complete," Nessel spokesman Dan Olsen said.

Theodore Leopold, an attorney for plaintiffs, said they are "pleased with today’s decision in that now Gov. Snyder will be held accountable for his gross misconduct and bad decisions he made towards Flint.”

“Those actions played a large part in causing great harm to the citizens of Flint,” Leopold said in a statement emailed to The Detroit News.

Levy on Monday also rejected motions to dismiss “bodily integrity” claims against former Michigan Treasurer Andy Dillon, several other state officials and former Flint emergency managers Darnell Earley and Gerald Ambrose.

She did, however, dismiss claims against some defendants, including former Michigan Health and Human Services Director Nick Lyon, former Department of Environmental Quality Director Dan Wyant, former emergency manager Ed Kurtz and former Flint Mayor Dayne Walling.

Flint was run by an emergency manager when it began using river water as its primary drinking source in April 2014. State regulators failed to ensure the city used proper corrosion control chemicals in the harsh water, which ended up leaching lead from aging pipes.

Snyder has publicly apologized for the Flint water crisis but fought claims against himself and the state. Shortly before leaving office due to term limits on Jan. 1, the Ann Arbor Republican said he'll "always have issues" with the crisis and how the water switch was handled by the "so-called" experts who worked for him.

The amended complaint allowed under Monday’s decision alleges that Snyder did not do enough to intervene in the lead contamination crisis or warn the public about outbreaks of deadly Legionnaire’s disease.

On April 28, 2015, Snyder’s chief of staff Dennis Muchmore emailed the governor and executive staff warning that the Flint water issue “continues to be a danger flag” for the administration.

Later that summer, Director of Urban Initiatives Harvey Hollins spoke “directly to Governor Snyder and advised him of the growing concerns among Flint residents they were being exposed to toxic levels of lead,” according to the complaint.

Muchmore again emailed Snyder on Sept. 25, 2015, and suggested officials in Flint were trying to turn childhood lead exposure into “a political football.”

Snyder publicly acknowledged the Flint water and lead exposure crisis on Oct. 1 of that year.

Similarly, the complaint alleges that Snyder first learned that Flint residents were at risk of Legionella exposure in December 2015 but did not publicly disclose that risk until declaring a state of emergency on Jan. 5, 2016. He requested a federal declaration Jan. 14 and publicly warned about the Legionnaires' disease outbreak on Jan. 16, 2016.

The Legionnaires' outbreaks in Genesee County during 2014 and 2015 killed at least 12 people and sickened another 79 people.

The complaint targets the former governor for alleged “injuries he caused to plaintiffs resulting from his deliberately indifferent deprivation of plaintiffs’ constitutional and civil rights.”

In her decision, Levy called the plaintiffs' claims against Snyder “plausible” and worthy of additional consideration in court.

The judge noted early warnings within the Snyder administration that switching to Flint River water could be a “potential disaster,” public outcry following the switch and a decision by General Motors Co. to stop using the water because it was corroding machinery.

“Plaintiffs also plead facts which, when taken as true, show that Governor Snyder was deliberately indifferent,” wrote Levy, who was appointed by President Barack Obama. Based on evidence in the case, it is “reasonable to infer” that Snyder knew residents of Flint faced a substantial risk of serious harm.

Furthermore, Levy said, plaintiffs “plausibly state” that Snyder showed a “callous disregard” for the plaintiffs right to bodily integrity. Viewed as a whole, the allegations plausibly describe ‘conscience shocking’ conduct,” she wrote.

“For the first time, a court has stripped former Gov. Snyder bare so that everyone who has been harmed by him can see exactly how naked he stands in this whole catastrophe,” said Michael Pitt, an attorney for plaintiffs, who also allege an attempt to "cover up" the water crisis.

The Flint case consolidated nine lawsuits against the state, city and water consultant companies.

Named plaintiffs include 79-year-old Flint resident Elnora Carthan, who allegedly suffered skin legions, neurological disorders and other injuries as the result of exposure to toxic water; and Michael Snyder, whose 83-year-old father died in 2015 after contracting pneumonia caused by exposure to Legionella bacteria. John Snyder's death was one of two cited in getting Lyon bound over for trial on an involuntary manslaughter charge and other criminal charges.

The class includes about 25,000 individuals but could grow if plaintiffs' attorneys and the state reach a settlement in the case, Pitt said.

Settlement negotiations had stalled under Snyder but new Gov. Gretchen Whitmer’s administration has “reinvigorated the discussions and is showing some real strong and promising good-faith efforts to get the matter resolved,” Pitt said.

“Unfortunately, it’s a very slow train, because it’s about 10 miles long, one of the longest trains I’ve ever been involved with,” he added. “It’s slowly chugging up the hill.”

Levy rejected plaintiffs' claims of wealth-based or racial discrimination by Snyder or other defendants, ruling the evidence did not support the claims.

The judge allowed professional negligence claims to move forward against Lockwood, Andrews & Newman and Veolia LLC, which did paid consulting work for Flint before and after the city began using river water in April 2014. But Levy did dismiss claims for exemplary and punitive damages, rather than actual damages.

joosting@detroitnews.com