(Reuters) - A Michigan judge on Friday ordered the state’s chief medical officer to stand trial on charges of involuntary manslaughter in connection to the contamination of the city of Flint’s water supply, a crisis that resulted in 12 deaths.

Eden Wells, a physician who serves as the state medical executive, faces the manslaughter charge for her alleged failure to stop an outbreak of Legionnaires’ disease while the city was taking its water from the Flint River. The charge carries a possible prison sentence of 15 years.

Wells was ordered to stand trial by Judge William Crawford, according to a spokeswoman from Flint District Court in Genesee County, Michigan. She also faces charges of lying to a special police agent and obstruction of justice, The Detroit News said.

“Our client is not guilty of these charges and we will move on to the next steps,” Jerold Lax, Wells’ attorney, said in a phone interview. Lax declined to elaborate.

Michigan Governor Rick Snyder defended Wells in an emailed statement on Friday and said she would remain on the job. “Dr. Wells has been tremendously effective in helping with the full recovery of Flint and additional challenges facing the state,” he said.

Wells is the second high-ranking state official ordered to stand trial, the Lansing State Journal reported. Nick Lyon, director of Michigan Department of Health & Human Services, was ordered to stand trial in August.

In June 2017, six current and former state and city officials, including Wells and Lyon, were charged for their roles in the crisis, which drew national attention beginning in 2014.

The city had switched its water supply to the Flint River from Lake Huron in April 2014 to cut costs. The corrosive river water caused lead to leach from pipes, contaminating the drinking water.

Flint switched back to Lake Huron water in October 2015, but the contamination continued. In addition to the 12 deaths, more than 70 people were sickened.

The water situation prompted dozens of lawsuits and criminal charges against former government officials.

The U.S. Supreme Court in March allowed two class-action lawsuits filed by Flint residents, who are pursuing civil rights claims against local and state officials over lead contamination in the city’s water supply.

A federal judge in August removed Snyder, a former Flint mayor, along with the state government from a list of defendants in a class-action lawsuit.

Legionnaires’ disease is a serious form of pneumonia caused by the Legionella bacteria and typically spread through water found in places like water towers or air conditioning systems. People can get sick when they inhale mist or swallow water containing the bacteria.

The U.S. Environmental Protection Agency was slow and ineffective in its response to the 2014 water crisis in Flint, Michigan, and needs to improve its communications with state and local regulators when citizen complaints arise, its internal watchdog said in July.