LYNN – Joe Cormier’s grease haulers were back in business before dawn Monday, minus the three American By-Product trucks destroyed in last Friday’s fire on Andrew Street.Cormier and his dozen workers led by General Manager Phillip Bruno saved four of the big trucks that make the rounds of restaurants daily collecting cooking grease and transporting it back to American for storage, then shipment to a firm near Springfield.The fire gutted the firm’s 14 Andrew St. office and garage along with two storefronts Cormier rents to a hearing aid company and a law firm. Firefighters kept the blaze confined to Cormier’s property but were forced to evacuate some of the elderly residents living in a building a half block from the fire.Bruno said the fire was started by a chemical reaction caused by the heating up of an industrial glove in order to dry it. The business was closed for the weekend when the fire broke out but an American By-Product worker walking by the business on his way to cash his paycheck spotted smoke coming from the building.Bruno spent the weekend arranging spare trucks and contracting with Lynn-based Cutillo Welding to start demolishing the fire-ravaged structure.By 4:30 a.m. Monday, the company that has been a Lynn staple since 1976 was sending drivers out on their routes.Cormier credited the city Inspectional Services Department and Economic Development and Industrial Corporation with providing initial assistance in the wake of the fire. He said fellow Lynn merchants, including the owners of the Porthole Pub, Meninno Construction and John’s Oil with coming to his aid.Tentative plans call for relocating Hatch Hearing and its two employees to a temporary office trailer parked in American’s lot opposite Cormier’s building. Bruno said two attorneys who leased a storefront from Cormier would move to another office they maintain.”We hope to stay right here,” Cormier said.