A flight from Birmingham to Atlanta was delayed Wednesday morning because officials were investigating an "unknown substance."

According to ABC 33/40, an official at the Birmingham-Shuttlesworth International Airport confirmed that hazmat crews were investigating a substance found on the side of an airplane after a gate agent noticed it.

The delay wasn't impacting any other flights and passengers weren't being asked to exit the plane. No other details were provided by the airport.

This was a picture outside the gate.