LYNN – Firefighters from Lynn and other communities fought a stubborn three-alarm fire Friday in the American By-Products garage and office on Andrew Street that began in the afternoon and lasted well into the evening.Half a dozen fire trucks blasted water onto the fire and, with the help of heavy rain, confined the flames to the rear of 14 Andrew St. as a heavy cloud of brown smoke billowed toward Lynn Common.While the flames didn’t spread to nearby buildings, Division Fire Chief Bill Curran said the structure continued to smolder with the help of “multiple ceiling levels” that trapped the fire in between the first-floor ceiling and the roof, making it difficult for firefighters to reach.American By-Products collects commercial cooking grease, fat and bone and “renders” or processes it into tallow, a common ingredient used in making candles.Donna Vangelist said most of the firm’s workers had left for the weekend when an employee ran into the office at 2:30 p.m. yelling the garage was on fire.Police shut down Andrew Street at Market and Washington streets as fire trucks crowded onto Andrew. By 8 p.m., officers were also forced to close Washington Street because too much water and debris had flooded the road.Three MBTA buses were on hand around the same time just in case nearby residents would need to be evacuated, but no evacuation orders were issued at that time.”I’m not concerned for the residential building catching fire as much as the smoke making it unhealthful,” Curran said.Swampscott and Salem firefighters assisted their Lynn colleagues while Revere, Marblehead and Wakefield firefighters provided mutual aid at Lynn fire stations.Lynn Sign employee Gary Robinson watched firefighters extinguish the flames from an alley off Oxford Street. He described American By-Products owner Joseph Cormier as a community-minded merchant who provided Lynn Sign with a break on its rent when the company rented space from Cormier.”It’s a shame,” he said as he watched firefighters hose down Cormier’s smoldering garage.