Selectmen gave the go-ahead on Tuesday night for a grant application to fund the cost of four new firefighters for fiscal 2020, which begins July 1. Fire Chief James Vuona made the request after detailing the critical need for additional staff. The department’s staffing level has not changed since 1987, even though the town’s population has almost doubled and the number of calls for service has increased from 789 in 1987 to 4,055 last year. The application is for a Staffing for Adequate Fire and Emergency Response grant. SAFER grants cover 75 percent of the cost to employ a firefighter the first two years and 35 percent in the third year. The municipality assumes full responsibility beginning in the fourth year. The Fire Department has 38 full-time firefighters, less than the state and national averages and less than neighboring Westborough, which has about half the population.