An explosion today trapped three workmen in a sewer tunnel under construction, and dangerous levels of methane gas forced rescuers to turn back. The workers’ condition was not immediately known.
Deputy Fire Chief Orville Peterson said the men were trapped about 2,000 feet into the tunnel and about 40 feet below the surface. Rescuers were waiting for equipment to remove the methane, a byproduct of decomposition believed responsible for the explosion, and pump in fresh air. Officials said 10 men had been in the tunnel when a detection device showed high levels of methane. All the men left the tunnel, then three went back in to check gas levels. That was when the explosion occurred.