No injuries were reported when the Marion E. Zeh Elementary School in Northborough was evacuated this morning after a carbon monoxide detector went off, according to the Northborough Fire Department.
Fire officials said the school was fully evacuated by the time firefighters arrived on scene at approximately 9:30 a.m. Firefighters found elevated levels of carbon monoxide in the building, forcing students and staff to remain outside for approximately two hours while crews ventilated the school.
As of 11:15 a.m., crews were preparing to allow people back into the building, the fire department said. Classes are expected to continue as normal for the remainder of the day.
Zeh Elementary School, located on Howard Street, contains students in kindergarten through fifth grade, according to the school’s website. It is one of four elementary schools in Northborough.
School officials were unavailable for immediate comment.
-- Brian Benson, Globe Correspondent