Sandwich, MA – Firefighters were called to a Belmont Avenue home yesterday morning when an alarm began sounding inside the house and residents reported smelling “something electrical,” according to a fire department spokeswoman.

At about 6:20 a.m., firefighters arrived at the house and found a carbon monoxide detector was sounding in response to a potentially dangerous level of the poisonous gas inside the home.

A faulty furnace was the source of the carbon monoxide, the spokeswoman said, adding that residents of the home declined treatment.