A fire that broke out at Duryea’s Lobster Deck, a wholesale and retail seafood complex and restaurant on Fort Pond Bay in Montauk, could have been much worse had no one been there when it started on Saturday afternoon, fire officials said. The take-out business will even be serving up a “lobster lovers’ special” for Valentine’s Day weekend. David Browne, an East Hampton Town fire marshal whose office investigated the cause, said a rusted iron propane pipe was to blame. He said the pipes in the old building were well maintained, but a small portion at the entrance to the building, at 65 Tuthill Road, and in the kitchen, had rusted. A small leak ignited a fire that burned one wall behind the stove and went up into the attic. Firefighters were called out at 1:45 p.m. About 50 firefighters and five of the department’s trucks responded and saw flames through the roof on one side of the building. The chief called for SpeedyDry, a product that can provide traction on ice. They were back at headquarters an hour and 15 minutes later. “If it had been a worse leak and no one was there . . . .That could have been a catastrophe,” Mr. Browne said. “The breeze coming off the water could have helped dissipate the gas, too,” he said. Perry B. Duryea III, who sold the complex last year but still manages it, called 911 after seeing smoke in the kitchen while doing some maintenance work, Montauk Fire Department Chief Joe Lenahan said. Mr. Duryea was able to shut off the gas and power to the entire complex, he said. The exterior wall of the kitchen was damaged. “If no one was there it would have been worse,” Chief Lenahan said. There are plans in the works for a high-end restaurant on the property, but reportedly they have been put off for a year. Mr. Duryea’s grandfather bought into the business in the early 1930s. It and an adjacent property, as well as two underwater parcels, sold for $6.35 million to Sunrise Tuthill, an otherwise unidentified Delaware corporation, in March.