An inquest is to begin today into the fire deaths three years ago of four members of a Sharon family. Kevin Dunsmuir, his wife Jennifer and sons Robert and Cameron became trapped on the upper floor of their home when smoke and fire blocked a stairway to the main floor. The Fire Marshal’s office said the lack of a main floor fire alarm was a main factor in the deaths – that the family was already trapped when they made the call to 911. It discounted suggestions that a delay in response time might have played a role. The response time for East Gwillimbury firefighters, many of whom are volunteers and had to first get to a fire hall, was 12 minutes. Central York Fire Service, which has a mutual aid agreement with East Gwillimbury, had a fully-staffed fire hall six kilometres away, but was not called.