ALLENTOWN, Pa. (CBS) – A Lehigh County hospital shut down its emergency department entrance Thursday afternoon due to a possible hazmat situation.

Authorities were called out to Lehigh Valley Hospital – Cedar Crest a little before 3 p.m. after reports that a female patient had been exposed to an unknown substance.

The emergency room remained open during an investigation, but patients were asked to use the ambulance entrance.

Authorities say the ER is expected to be open soon once the investigation has concluded.