An ambulance medical technician went into a Carle Place Dunkin' Donuts for coffee in the predawn hours of Friday, but it was a carbon monoxide scare that woke him up, Nassau police said.
The Nassau County emergency technician was wearing a personal carbon monoxide detector and it alerted him to high levels of the gas when he went into the store on Glen Cove Road just before 4 a.m., police said.
He escorted employees out and called authorities, police said.
The Carle Place fire department arrived and confirmed that carbon monoxide levels were 35 parts per million.
Investigators discovered an oven vent that was not working, police said.
No injuries were reported, police said.