A southeastern Minnesota ambulance service that failed to always keep two workers on duty must undergo an assessment and make sure it is fully staffed, according to an order by the Minnesota Emergency Medical Services Regulatory Board in November.

In June, the board reviewed about six weeks of schedules for Preston Ambulance Service, owned by the city of Preston. Regulators found the service was improperly staffed 17 percent of the time. State law generally requires continuous staffing. The service failed to respond to two calls on June 25, one day after Preston Ambulance claimed staffing coverage had increased to 97 percent.

The service was told to provide staffing schedules to the board and to local dispatchers for at least 12 months.