Commuters who use the Medical Center Metro Station should be aware of controlled explosions this week that could briefly prevent them from entering the station.

Montgomery County officials said they were planning a single underground blast on Monday and Thursday this week between 10:30 a.m. and 1:30 p.m. The blast is due to the ongoing work to build a pedestrian underpass near Route 355.

The blast is not expected to impact vehicle traffic. But pedestrians will be prevented from entering the station five minutes before the blast, and will not be allowed to go through faregates from one minute prior to the blast until the blast has ended.

Blasts could continue beyond this week as construction crews continue work on the crossing project. The project will allow pedestrians to use a shallow underpass connecting the National Institutes of Health and the transit center on the west side of Route 355 with Walter Reed National Military Medical Center on the east side. The project will also deepend elevators on the east side of Route 355.