The San Francisco Fire Department is investigating a small fire that ignited among five storage containers within a secure area of San Francisco International Airport on Friday afternoon. There were no injuries reported, and the cause is undetermined. 

Travelers posted photos online of a plume of black smoke rising from a cargo area parallel to Highway 101. SFO spokesperson Doug Yakel said there was no impact on flight operations, but service on the AirTrain Blue Line was temporarily cut. The airport launched a backup bus plan to shuttle travelers to the Rental Car Center and Long-Term Parking while the AirTrain line was down. 

Around 2:15 p.m., SFFD, with help from San Mateo County fire agencies, responded to the scene of the one-alarm fire on the 500 block of North McDonnell Road. A spokesperson for SFFD said that five Conex storage boxes were impacted. They are thought to be owned by United Airlines. A representative for the airline referred questions to SFFD. 

The containers held toiletries, headphones and hand wipes. The SFFD spokesperson said it’s unknown at this time if there were any electronics involved. The fire was contained by 3:33 p.m.

The SFFD spokesperson told SFGATE that since the fire was in a secure area, there will be an investigation, but there’s nothing to imply foul play at this time.