Amagansett firefighters are working to contain a fire in a guest house on the art dealer Larry Gagosian's Further Lane property. The fire, which was suspected to be electrical in origin, was reported after an alarm went off around 4:45 p.m. Firefighters reported light smoke in the crawl space, and they were checking behind walls with thermal imaging cameras.The iconic 11,000-square-foot house, designed by the late Charles Gwathmey, was heavily damaged in a June 2011 fire that was linked to plumbing work.Due to the long, narrow driveway, firefighters were directed to station their vehicles in a staging area along Futher Lane and Skimhampton Road. Mr. Gagosian bought the property, known as Toad Hall, in 1990 for $8 million. He represents such artists as Jeff Koons, Richard Serra, Julian Schnabel, and John Currin.The East Hampton Town Fire Marshal's office was called to the scene.