Officials are urging residents to check their heating systems and carbon monoxide detectors after a family staying together in Weymouth before a trip to Disney last month was exposed to potentially deadly concentrations of the gas. Weymouth fire Chief Keith Stark said Wednesday that firefighters were initially sent to the Summer Street home, where about 10 people were gathered ahead of a family trip, after a woman fell in the bathroom and her family called 911. Once firefighters were in the house, carbon monoxide detectors that they wear alerted them to the deadly gas. Stark said the house was evacuated and three people were taken to the hospital.