Norfolk, MA – A propane leak within a heating unit was the cause of an explosion last week at a condominium that was under construction in Norfolk, officials said Wednesday.

The blast at 27 Wildwood Way critically injured three workers who were in the basement working on the heating unit prior to the explosion on Friday. One of the workers later died. Three other people and two firefighters were also injured.

The building housed two condominium units, one occupied and one under construction where the explosion occurred.

“The damage indicates that there was a release of propane. Pressure tests of the underground propane storage tank and the piping to the meter indicate they were secure and not the source of the leak. The damage to the heating system is consistent with an explosion and high heat from a propane-fueled fire on the house side of the meter,” said Fire Marshal Stephen Coan.

On the day of the explosion, Energy USA conducted an immediate inspection of all above-ground parts of the propane distribution system on the River’s Edge property that concluded late that night.

A small leak was detected at another tank on the property fueling an occupied building. The tank was emptied and the leak was repaired.