It was a hard lesson in the importance of calling before you dig with significant damage caused to a pair of East London townhouse condominium units Wednesday afternoon.

The fire broke out at the rear of 195 Barker Street around 1 p.m. when a contractor drilling a post hole hit a natural gas line.

Fire officials believe the machinery being used ignited the gas sending flames up the back of the townhouse. They then spread to a neighbouring unit.

There was further damage to the inside of both units.

Inspectors estimate the damage at about 50 thousand dollars but say there were no injuries as a result of the blaze.

Union gas officials were able to shut off the gas and firefighters were able to control the fire before any more damage could be done.

London Fire Department Platoon Chief David Walmsley says one call could have made the difference, “I just want to stress how important it is to call for service locates so that these types of things, which is completely avoidable, just don't happen.”