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National Transportation Safety Board investigators found unprotected electrical connections near the McPherson Square Metro station, where a fire broke out this week, the Associated Press reports. A Metro spokesperson, however, advised caution about the report.

An unnamed federal official told the AP that NTSB sent investigators to the scene, where they saw that “unburned cables’ connections to the power supply weren’t insulated.” A Metro spokesperson says that the transit agency “has no record” of federal officials being at the scene of the investigation.

A fire broke out near the station early Monday morning and resulted in the complete closure of the rail system on Wednesday, so Metro could conduct a systemwide inspection of 600 “jumper cables” and perform repairs as needed.

“The investigation is ongoing,” another Metro spokesperson said in an emailed statement. “We expect to brief the public fully at the Board Safety Committee meeting next week.”

Following a fatal smoke incident near the L’Enfant Plaza station in 2015, the NTSB found instances of cable connectors in the rail system that lacked “sealing sleeves” to keep out moisture and other materials from electrical conductors. After this week’s incident, Metro General Manager Paul Wiedefeld said “that about half of the faulty boots have been upgraded, but months of work on that project still remains,” the Washington Post reported.

Asked to comment on the AP report, an NTSB spokesperson said the agency could not and provided a statement released following Monday’s incident:

The Washington Metropolitan Transit Authority informed the NTSB of Monday’s electrical arcing incident in a train tunnel near McPherson Square. In response, an NTSB investigator observed the equipment involved in the event. It appears that Monday’s electrical arcing event is of a similar type as the one involved in the January 2015 L’Enfant Plaza accident.

The NTSB is gathering information about this latest incident in support of our ongoing investigation of the L’Enfant Plaza accident, which is expected to be completed in early May.

NTSB had no role in the decision to shut down the Metro system.  The NTSB is not a regulatory authority and will have no role in equipment inspections or return to service decisions.

Photo by Darrow Montgomery