Terminal C at Boston's Logan International Airport was temporarily evacuated on Sunday night due to high levels of carbon monoxide, believed to be caused by a snow-melting machine, Massachusetts State Police said.
A photo from the scene showed a large crowd of people huddled together in the cold outside the terminal. Massport said the pre-security areas of the terminal were evacuated around 6 p.m. "out of an abundance of caution" after a carbon monoxide alarm sounded.
Massport released a statement following the evacuation. "The issue has since been resolved and the Terminal has returned to normal operation," it said.
Police said the terminal was vented and reopened around 6:30 p.m.