An 11-year-old boy died after taking shelter from the cold temperatures caused by this week’s blizzard.

The boy, whose name has not been released, was working outside with his father when he was told to take shelter inside the family vehicle. The father left the car’s engine running, unaware that the vehicle’s exhaust had become blocked by the mounting snowbank.

The car began to fill with toxic carbon monoxide gas. The father later experienced respiratory arrest and was transported to a nearby emergency room for treatment. The boy was also transported to the emergency room where he was pronounced dead soon after his arrival.

The Boston area, where the 11-year-old lived with his family, was hit particularly hard by Winter Storm Nemo. Boston Mayor Thomas Menino urged people to remain in the shelter of their homes unless travel was absolutely unavoidable.

Winter Storm Nemo reportedly claimed a total of seven lives.