At 12 noon Station 15, engine / rescue 29 and engine 6 were dispatched for a gas odor inside the residence. Rescue 15 arrived at 12:05 hours with the crew investigating the odor. Across the street a company was doing some sewer testing and that was the results of the odor inside the residence. Captain Hughes (15 Captain 3) placed the situation under control with Rescue 15 clearing at 12:08 hours. Responding units: Rescue 15, 15-9C and 29-4.