Firefighters returned on Sunday to the city’s transfer station, where a large mulch fire has been burning reigniting for the past week. Deputy Fire Chief Paul Wilson said crews responded to the burning mulch pile about 7 a.m. “For nearly 20 hours over the past week, fire crews used thousands of gallons of water to soak the pile as members of highways and bridges use heavy machinery to break down the pile,” Wilson said. “The smoldering fire causes a hazard to the Sikorsky Airfield as the smoke has been blowing in that direction.” Wilson said the mulch begins burning because the piles are “packed tight so the heat builds up inside to the point that it ignites.” Crews remained on site Sunday completely disassembling the pile to prevent future mulch fires at the transfer station.