WASHINGTON — Two firefighters who had stopped to get lunch at a Subway in Lanham, Maryland, during their noon break found more than sandwiches Friday. Their portable carbon monoxide detectors alerted them to high levels of the poisonous, odorless gas in the eatery, a fire official said in a statement. Quickly, the two firefighters called it in and additional teams arrived. The shopping plaza where the Subway was located, in the 9900 block of Greenbelt Road, was evacuated for a few hours. No injuries were reported.

With dangerous concentrations of carbon monoxide, firefighters had to suit up in gear to handle hazardous materials. They found the source of the gas leak from a broken exhaust vent of a boiler/HVAC unit that was funneling carbon monoxide into the stores rather than into the open air, Battalion Chief Mike Linynsky said. Firefighters shut down the system and brought CO levels down. Washington Gas came to turn off natural gas to the building so the unit could be fixed.

Update 9900 Greenbelt Rd., source of CO leak found and secured. Shopping center reoccupied. No injuries reported

— PGFD PIO (@PGFDNews) October 14, 2016