The Pentagon metrorail station has been temporarily closed to investigate what WMATA has termed a “potential hazmat situation.” The closing was announced over the DC Text Alert system, and WMATA has posted this announcement on their website:

The Pentagon station is closed to investigate a potential hazmat situation. Hazmat experts are responding to the scene. No trains are permitted to go through the station. Trains are turning back at Arlington Cemetery and Pentagon City.

The Pentagon Bus Transit Center is also temporarily closed. Free bus shuttle service is being established to take Bus Transit Center customers Pentagon City to catch their buses there.

As they say, the story is developing. If anyone can provide details, drop it in the comments.

UPDATE, 11:28 a.m.: The D.C. Government emergency text alert system has announced the Pentagon station will re-open in “approximately 40 minutes.” The Post reports the Arlington County Fire Department found nothing suspicious at the station.
11:15 a.m.: The AP is reporting the station was closed around 10:10 a.m. after passengers complained of eye irritation.