Four people were treated Wednesday for exposure to carbon monoxide at a small strip mall in Lehigh County.
Firefighters and paramedics were called shortly before 11:30 a.m. to 7001 Route 309 in Upper Saucon Township as carbon monoxide detectors were sounding inside the Deering Dental office.
The dental office, along with a neighboring dry cleaning business and a daycare center were evacuated while firefighters sought the source of the gas.
The firefighters were able to determine that a flue on a boiler inside the dry cleaning business was blocked, causing CO fumes to build up inside, said Chief Chuck Castetter, Upper Saucon Fire Dept.
Four people were evaluated at the scene, but they refused further treatment, Castetter said.
The dental office and daycare center reopened about an hour later. The dry cleaning business will remain closed until the necessary repairs to the boiler can be made, Castetter said.