Dandenong and Keysborough brigades responded to a new industrial area in Atlantic Drive and quickly blocked off the area.
Senior Station Officer Robert Cochrane said "After the worker severed the gas main with the bucket of his excavator there was little we could do to isolate the large damaged pipeline, so we told management of the adjoining factory to stop work and clear staff from the area".
Police also arrived to help secure the surrounds and keep others isolated from the venting gas. Firefighters used a gas detection meter to continuously measure the explosive levels of the atmosphere around the area checking pits and drains along the way.
A gas company repair crew arrived later on to isolate the leak and called in extra resources to help them. The leak was contained just after 11:30am.
Dandenong Pumper 2 left the scene around two and a half hours after the call came in.