Condensation coming off a freshly washed airplane engine forced a Delta commuter flight to return to the Memphis airport Thursday, operator Pinnacle Airlines said.

Pinnacle spokesman Joe Williams said the pilots saw what they thought was smoke coming from an engine shortly after taking off for Atlanta around 7 a.m.

They returned to the airport 30 minutes later and it was determined that the smoke was really condensation from leftover washing solution. Williams said the two-engine CRJ900 jet had been washed just before takeoff.

No one was injured and the 56 passengers aboard Delta flight 2024 were put on later flights. The plane was taken out of service for an overall inspection as a routine precaution.