In the wake of a fatal Stamford house fire, a local contractor and insurance agent are advising residents about the risks of hiring workers to repair their homes. Marty O'Neill, a Norwalk insurance agent, says homeowners need to be aware of all possible loopholes. He says people should always have an updated certificate of their contractor's insurance and should make sure the company has general liability and worker's compensation coverage. AJ Izzo, who heads the Building Department of Appeals in Westport, says work site injuries are always a possibility when dealing with construction. Utica First Insurance is trying to avoid paying a claim over the Christmas Day fire that killed three girls and their grandparents in Stamford.