M Street Manhole Covers Explode

Cause Unknown, No Injuries Reported

By Andreas Andrea Hoya Staff Writer

Six manhole covers blasted from their conduits into the air on the 3100 block of M Street early last Friday afternoon, which, in combination with underground fires, caused the closure of the block to traffic and the evacuation of businesses in the immediate vicinity for the rest of the day. The explosions, in the area of Johnny Rockets and Old Glory, caused no injuries.

Loud blasts could be heard as each of the manhole covers launched in succession. The force of the explosions caused some portions of the street to rip open as well as store windows to shatter and concrete to break off buildings.

However, according to both Joseph Nwude, chief engineer for the district’s Public Service Commission, and Nancy Moses, spokewoman for Potomac Electric Power Co., there is nothing to indicate that Georgetown students and residents should fear another set of aggressive and assertive manhole dislocations.

Nwude, whose agency oversees Pepco on behalf of the district, said, “We have nothing to suggest” that the explosions could happen somewhere else in Georgetown. However, he did say that the Public Service Commission is making sure Pepco tests all the new lines they have installed where the accident occurred.

Accoring to both Nwude and Moses, the investigation may take a month, but Nwude said he is in contact with Pepco “two or three times a day.”

“We should have some preliminary information within a week, but we have sent the cable we have pulled out for replacement to a special company to investigate and examine it,” Moses said.

The most probable reason for the explosions at this point involves the snow and ice melting chemicals that were used to combat recent snowstorms. It is believed that those chemicals, draining into the sewer, ate away at the rubber insulation of the copper wires. Without the insulation, the copper wires may have overheated and caused the underground fires, which in turn led the manhole covers to pop off. Moses said this theory is “probably the first on the list of what could have happened.”

Although it is speculated that the antiquity of Georgetown’s infrastructure caused the blasts, Moses said that age had nothing to do with the initiation of the accident. “These lines weren’t that old,” she said indicating that the wires were less than 10 years old. According to Moses, the faulty lines that were taken out of the ground after the explosions were all insulated with rubber.

However, Moses did say that the one aspect unique to Georgetown, the use of clay as opposed to concrete in order to encase the wires, may be a factor in why so many manhole covers blew their lids. “The piping our wires go through is small. It is clay piping as opposed to concrete and there is not a lot of air space for heat to dissipate. That is particular to Georgetown,” she said.

Moses said any replacement of clay casing with concrete casing would cause a major disruption in the area. “It would block off parts of the street,” she said. She does not yet know whether this replacement is an option, however it will be looked at in the review of this accident.

According to Moses, Pepco regularly surveys its electrical lines, and this will continue to be done on the 3100 block of M Street. Pepco will also be checking for any natural gas leaks, which was also cited as a possible cause for the blasts, although oses thinks this reason is unlikely.

The accident on M Street is not an unusual occurrence in a heavily urban utility area, according to Moses. “Those kinds of things happen; it’s not an uncommon occurrence. We have had manhole covers that pop off for a variety of reasons. Usually one manhole cover dissipates the heat there is not a string of explosions when the first manhole cover comes off,” she said.

While Moses expressed understanding for those caught in the middle of the blasts, she believes that the area is safe for students and residents, especially since all the snow, mixed in with chemicals, has already melted. “I think it’s safe. This situation was unnerving to the people there. It is fortunate that no people were injured,” she said.

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