Gus Harrison Correctional Facility of the Michigan Department of Corrections has reported more than 600 new cases of the coronavirus.

According to the Detroit Free Press, MDOC spokesman Chris Gautz says that the majority of the 773 new cases have come from his facility, as 612 inmates have tested positive for the virus since the Michigan National Guard conducted mass testing on May 12. Gautz says almost all of those who tested positive were asymptomatic.

“The prisoners had no idea they were asymptomatic. This speaks to the danger of this virus,” he said. “Our expectation was we were going to see somewhat of a large increase. We knew there were going to be carriers who didn’t have symptoms.”

The MDOC currently holds 37,000 inmates and every one of them has reportedly been tested.

There are now 716 total cases among Gus Harrison inmates, which is the second most in the state’s prison system. Two of the inmates at the facility have passed away from the disease.

Officials working at Gus Harrison are separating positive inmates from the general population on site. Gautz said four facilities on the southern end of campus will house positive inmates.

Lakeland Correctional Facility currently has the most cases of COVID-19 among prisons with 793. The MDOC has instituted the same distancing measures as did at Gus Harrison and discovered nearly 80 percent of its positive inmates at Lakeland were asymptomatic after mass testing.

31 staff members at Gus Harrison have also tested positive for the coronavirus. Gautz said many of them are expected to return to work within the next two weeks.