A judge on Monday ordered Michigan’s top health official, Nick Lyon, to stand trial for involuntary manslaughter charges in two deaths linked to the Flint water crisis.

Genesee District Judge David Goggins determined that there was probable cause that Lyon committed involuntary manslaughter against Robert Skidmore and John Snyder in 2015. The two men died during an outbreak of Legionnaire’s disease, which researchers have connected to the devastating use of improperly treated water in Flint starting in 2014.

Lyon, the director of Michigan’s Department of Health and Human Services, is the highest-ranking official in the state to stand trial in connection with the catastrophe. An additional 14 current or former state and local officials have been criminally charged in connection with the water issues.

As Ars has reported previously, prosecutors allege that Lyon specifically had “willfully disregarded the deadly nature of the Legionnaires’ disease outbreak” and failed to warn the public in time to spare lives. He allegedly knew about the outbreak in early 2015 but waited until early 2016 to release a public advisory.

According to NPR, Judge Goggins read from his opinion Monday:

The victims’ deaths—that is Robert Skidmore and John Snyder—their deaths were caused by this neglect of the defendant, in [Nick Lyon’s] failure to act appropriately with regard to disseminating notices to the public."

Involuntary manslaughter is a felony punishable by up to 15 years in prison. Lyon is also charged with felony misconduct in office for allegedly obstructing academic researchers from studying the outbreak, which carries a sentence of up to five years in prison. Last, he faces a misdemeanor charge of willful neglect in office.

When the judge announced the decision that Lyon must face trial, a woman in the gallery let out a “yes, yes, yes,” according to the Associated Press.

In comments to reporters after the hearing, Lyon’s defense attorney, John Bursch, said that they will “absolutely file a motion to quash” the judge’s decision. He was confident that the “circuit court, and if not there the court of appeals, are going to look at this, and they’re going to reverse [this] so fast it’ll make your head spin.”

Deadly drink

The trouble for Flint residents and Lyon all began in 2014, after state-appointed emergency managers switched the city’s water supply to save money. They went from buying treated water sourced from Lake Huron and the Detroit River to the less-expensive option of using water from Flint River. But they did not ensure that the water was properly treated to prevent corrosion in old plumbing. This caused lead and other metals to leach into the water, exposing residents and risking permanent neurological damage to local children.

The improper water treatment also interfered with disinfectants and caused the release of iron and other bacterial nutrients into the water, which can spur the spread and growth of Legionella bacteria. When those germs are aerosolized and inhaled from sources such as hot showers, humidifiers, and water coolers, they can cause a deadly form of pneumonia called Legionnaire’s disease, so named for an outbreak at an American Legion convention in 1976.

Flint experienced a surge in Legionnaire’s disease after the water switch, with cases totaling around 100 and leading to at least 12 deaths, including Skidmore and Snyder’s. Researchers with the Centers for Disease Control and Prevention genetically linked the bacteria infecting patients to those found in the city’s water.

State officials now say that the city’s water meets federal standards for lead and other contaminants. However, the water can still pick up toxic ingredients from contaminated pipes. For now, residents need to continue drinking bottled or filtered water until the city’s plumbing is replaced, which the city is working to do by 2020. In April, Michigan Governor Rick Snyder announced that the state will stop providing free bottled water to Flint residents.