WASHINGTON — Dozens of people were evacuated from their apartments in Silver Spring, Maryland on Tuesday night following a carbon monoxide leak. A Montgomery County Fire and Rescue spokesman says it happened around 9:30 p.m. at a building in the 7700 block of Eastern Avenue. Two people were evaluated by firefighters on the scene.

2nd UPDATE: 7700 blk Eastern Ave – still checking apts for CO – 2 occupants being evaluated – adjacent bldg clear – buses req for temp shelt

— MCFRSNews (@MCFRSNews) July 22, 2015

At this time, it is unclear what caused the leak, or when residents will be able to return to their homes. Fire officials are continuing to investigate the cause.