Passengers on a flight from Seattle to Dallas were turned around for an unusual reason over the weekend - a human heart was left on board.
However, many passengers were confused after finding out that a heart has limited time before it has to be transplanted.
The heart itself had not been intended for a specific patient.
Passengers were shocked when the captain explained that the heart was intended for delivery to a Seattle hospital after a previous flight from Sacramento, the Seattle Times reported.
While the heart should have been taken out of the cargo hold in Seattle, it was mistakenly left on the Southwest Airlines connecting flight, USA Today reported.
The airline turned the flight around because it was "absolutely necessary to deliver the shipment to its destination in the Seattle area as quickly as possible", Landson said.
A passenger on the flight told the Times that his fellow passengers were initially stunned by the news.
A spokesperson for organ-procurement organizations in Washington and California also told the Seattle Times that they never use commercial flights to transport organs, because of the time sensitive nature of organ transplants.
After returning to Seattle, a spokesperson for Southwest told PEOPLE that the fight was "taken out of service due to an unrelated mechanical issue". "There's a time limit to get where it needs to go". The Southwest flight spent about three hours in the air before landing back at Sea-Tac Airport.
It's always a risky move reaching into the back of a plane seat but that doesn't make this discovery any less off-putting.
Dr. Andrew Gottschalk, who was onboard the delayed flight, described the incident as a "horrific story of gross negligence".