Dozens of people were evacuated from their homes after a gas main fire in what police described as a "critical incident".
The incident happened at 1.40am in Coney Green Drive, a residential street in Longbridge, Birmingham.
Firefighters called to the scene found a man slumped unconscious in a gas main trench, and rescued him while the fire blazed nearby.
He was taken to hospital and held on suspicion of starting the fire, West Midlands Police said. No-one else was injured.
Emergency services set up a 50m cordon around the trench, and a second gas leak was found in an adjoining road, Hawkesley Crescent, triggering a second cordon.
Roads were closed and 45 people evacuated as emergency services tackled the fire and gas leaks, West Midlands Fire Service (WMFS).