A Delta Airlines flight from scheduled to fly from Amsterdam to Detroit turned around mid trip after maggots were discovered aboard the aircraft.

An airline spokesperson confirmed that flight 133 AMS-DTW “was interrupted due to an improperly packed carry-on bag” without providing additional details into the cause of the disruption. The spokesperson added that customers were compensated for the inconvenience, but did not elaborate on the amount or form of the remedy.

“The aircraft returned to the gate and passengers were placed on the next available flight,” Delta said in a statement. The airline added that the “aircraft was removed from service for cleaning.”

A passenger on the flight told Fox2Detroit that he saw about a dozen maggots fall from an overhead bin and land on a female passenger seated next to him. 

He initially believed the incident was a prank, but flight attendants traced the insects to a passenger’s carry-on bag, which contained “rotten fish” wrapped in newspaper, the passenger told the news outlet.

Flight tracking site FlightAware shows that the plane only got as far as the U.K. before doing a U-turn and returning to Amsterdam. 

Passengers are permitted to travel with food, including both fresh and frozen meat, seafood and vegetables, under Transportation Security Administration rules.

In September, unsanitary cabin conditions disrupted another Delta flight. A passengers’ explosive diarrhea forced a Delta flight from Atlanta to Barcelona because the incident amounted to a “biohazard issue.”