SXSW freebies may have caused long delays at Austin-Bergstrom International Airport this week. Passengers trying to head home from the South by Southwest festival kept setting off security alarms on Wednesday.

According to Austin-Bergstrom International Airport spokesman Jason Zielinski, a specific type of ink on some items may have made X-ray baggage scans more difficult, which forced security officials to screen bags individually, the Associated Press reports.

Zielinski wasn't sure of the exact cause of the problem but he thinks it may have been blamed on promotional items from the festival like stickers, magazine and other items. Zielinksi directed other questions to the Transportation Security Administration which wouldn't say what was causing the problem or how it was detected, out of concern for safety.

The TSA simply released a statement saying "if an item in a bag is unable to be clearly viewed as part of the screening process, or if an item alarms, additional screening may be needed before the bag is cleared."

"In this case, TSA suggests that bulky conference promotional materials be packed in carry-on bags and placed in a bin at the security checkpoint for faster screening," the statement said according to the AP.

Festival attendees who picked up SXSW admittance badges were given cloth bags with colorful logos that included big, glossy event programs. It wasn't clear if this was the problem. Some festival goers were given other promotional items like sunscreen, visors, umbrellas, bottle openers, lib balm and more. However some passengers took to Twitter to say that the festival magazine, stickers and brochures the screenings and flights to be delayed.

For instance, University of Southern California journalism professor Robert Hernandez, who was on an American Airlines flight from Austin to Los Angeles wrote about a flight announcement, saying "Our flight is delayed because a free magazine given out at #SXSW is registering as a bomb. And each bag must be inspected," he tweeted. "I'm serious."

Zielinski wouldn't say how many flights were affected.