BRISTOL – The Silva family awoke early Sunday morning to the sound of the family’s oldest daughter vomiting in the bathroom. Though they did not yet know it, carbon monoxide had slowly begun to fill their home.

Officials would later determine that the leak was the result of a back draft, the fault of a two-year-old, gas-fired stove located in the family room — the same room where Bristol Warren Regional School Committee vice chairman Paul Silva, his wife and his five children had spent the majority of the day.

A combination of chance occurrence led Mr. Silva to call the police. Although it is impossible to be sure, it was a decision that may have saved his family’s life.