Cetronia, Greenawalds, Woodlawn, Western Salisbury and Alburtis firefighters were dispatched during the afternoon of Feb. 27 to the Lehigh Valley Physicians Group building, 3080 Hamilton Blvd., South Whitehall.

Also responding were Cetronia Ambulance Corps personnel and South Whitehall township Police.

The 911 caller reported an odor of something burning coming from the heating vents as well as a light haze.

Uncertain of the cause, firefighters were prepared to fight a fire in the event one was discovered.

Investigation by South Whitehall Fire Marshal John Frantz revealed a faulty air handler was causing the problem.