LYNN — A flash fire broke out at 626 Lynnway after a worker with a private demo company cut a pipe, according to the Fire Department’s Public Information Officer Dennis Ring.

The worker was transferred to Mass General Hospital with “minor burns,” Fire Chief Dan Sullivan said. The worker is expected to make a full recovery, he added.

Sullivan said the worker was carried out of the building to the ambulance by other workers, who helped tend to injuries before emergency services arrived.

It is still under investigation what caused the explosion, but it appears that it may have been from trapped gas, Sullivan said. It is unknown what type of gas it was.

Sullivan said upon assessing the structural stability of the building, it appears intact. As a precaution, the building was evacuated and the Fire Department is having National Grid assess the building to ensure there are no gas leaks.