BALTIMORE, MD (September 7, 2001) – The chemical suspected of leading to the explosions that lifted a manhole cover into the air along Light Street in Baltimore last month has been confirmed to be tripropylene, the same chemical that fueled the CSX train fire in the Howard Street tunnel in July. The Maryland Department of the Environment (MDE) confirmed the results today after an independent laboratory positively identified the substance by comparing samples taken from the storm drain and a pure sample from the supplier who loaded the original substance on the CSX train.

On July 18, a CSX train derailed in a tunnel under Howard Street in downtown Baltimore. A tanker car of tripropylene leaked and fueled a fire that spread to boxcars carrying paper products. The resulting fire burned for four days under city streets and the excessive heat also caused a tanker of hydrochloric acid to leak. Once the fire was extinguished and emergency workers could assess the damage, it was believed that all of the tripropylene burned off in the early stages of the fire.

Before 6 a.m. on August 11, a manhole cover near the intersection of Pratt and Light Streets popped into the air as a result of a fire and explosion in the storm system beneath the street. MDE’s Emergency Response Division, Baltimore City Fire and Department of Public Works, as well as U.S. Coast Guard crews, responded to the explosive situation and took immediate action to protect public health and safety. Over the next five days nearly 3,000 gallons of tripropylene was pumped from the city’s underground storm water drains and conduits in that area.

Since the manhole incident, members of MDE’s Emergency Response Division have been working with Baltimore City officials to search the extensive storm water system in the downtown area, lifting more than 100 manhole covers to inspect pathways below the streets. During that follow-up monitoring, no tripropylene was found in any other section of the system, although some residual traces were found in conduits near the intersection of Pratt and Light Streets. MDE crews took repeated air samples to ensure that unsafe levels of the material were not accumulating underground that could lead to further explosions.

Despite the lack of earlier evidence of a connection between the incidents, CSX has played a major role in cleanup efforts related to both the train fire and manhole explosions.

City and State officials continue their investigation to determine how the tripropylene made its way to Light Street and where it was in the weeks between the two incidents. Two monitoring wells will be installed by CSX to sample soils beneath the Howard Street tunnel for traces of the tripropylene.

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