Underground Gas Blasts Close Baltimore Streets

Underground gas explosions blew off at least three manhole covers and forced officials to close streets in Baltimore for several hours.

Tripropylene gas--the same substance that burned in a downtown tunnel derailment last month--accumulated in storm drains near the city’s Inner Harbor, officials said. There were no injuries and no aboveground damage reported.

A CSX Transportation tanker filled with tripropylene burned after a derailment inside the tunnel July 18. Officials said they did not know how tripropylene could have accumulated under the street but have not ruled out that possibility.