A COVID-19 outbreak among firefighters in one of the state's largest departments is reining in how far it can travel to back up other communities during an emergency, the fire chief said Monday.

The State Fire Marshal's Office is identifying fire departments in Bloomington and two much smaller ones west of the Twin Cities as now having "significant outbreaks" of cases among personnel.

The list is part of the fire marshal's new map that tracks and displays staffing levels daily at the 776 fire departments statewide. The information helps the state determine what departments need outside help or are unable to provide mutual aid to another community when requested.

"COVID-19 is a serious illness that can affect anyone, including firefighters," State Fire Marshal Jim Smith said in a statement announcing the mapping tool. "We are working with fire service leaders to make sure they have what they need to continue doing what they do best: keeping their communities safe."

Among Bloomington's 111 firefighters, 13 are sidelined in connection with COVID-19, said Fire Chief Ulie Seal.

The chief said the outbreak means his department must limit its ability to provide mutual aid to communities closest to Bloomington while still tending to the needs inside its borders.

"The reduced number [of personnel] affects the size of our crews and reduces our ability to send resources out of our normal day-to-day mutual response areas," Seal said.

In Plato, about 40 miles southwest of the Twin Cities, its Fire Department was the first to go out of service because of COVID-19.

As of Monday, Plato was back online but still feeling a significant impact from the deadly virus, along with the department in Hutchinson.

There are 43 departments with one or more COVID-19 cases among personnel but not enough to be considered significant. Another 377 are reporting no active cases, while 353 departments have yet to report in to the Fire Marshal's Office.

The ability for a community to receive mutual aid is a crucial option when answering calls for fires, explosions or other emergencies. When a department is unable to receive enough nearby mutual aid support, it can turn to the State Fire Marshal's intrastate mutual aid plan.

For example, the St. Paul Fire Department cast a wide net and asked for assistance from other departments during the rioting following George Floyd's death in late May. The state fire marshal located 27 pieces of equipment and helped coordinate 97 fire crews.

The two largest police departments in the Twin Cities also are coping with curtailed staffing because of the pandemic.

Since the virus took hold early in the spring, the Minneapolis Police Department has had 116 cases among its licensed officers.

In St. Paul, at least 45 police employees, including Chief Todd Axtell, have tested positive for COVID-19 since March. About 20 remain out of work as of Monday.

Staff writers Libor Jany and Liz Sawyer contributed to this report.