Another day, another United Airlines scandal.

A Missouri woman flying on a Mesa Airlines flight from Houston to Kansas City, Mo., claims the flight attendants wouldn’t let her use the restroom, and, as a result, she had to use cups to urinate into instead. Mesa Airlines is a regional U.S. carrier that has operated as United Express for over 20 years, according to the Washington Post.

The woman, whose name is Nicole Harper, first wrote about her experience on the flight in a lengthly Facebook post.

About 30 minutes in to her flight she had the sudden urge to urinate, caused by her overactive bladder, she told the local news station KCTV News. When she attempted to stand up to go to the restroom, a flight attendant reportedly told her to sit down because the pilot was expecting turbulence. She said she responded by saying she would need a cup to relieve herself and then was given two cups, which she filled. She was then escorted to the bathroom to empty them, she told the network.

“The flight attendants treated me like I had committed a crime, stating they would be filing a report, calling in the hazmat team to clean the entire row (let me mention there was no mess involved) and told me I would need to talk with the pilot after the flight,” she wrote in her post.

But United is denying that the flight attendants told her to urinate in a cup as opposed to using the restroom.

In an email, a United spokesperson told Fortune that the airline is further investigating the incident, and has reached out to both Harper to better understand what happened. United also said Harper attempted to use the restroom during the aircraft’s descent, not in the first 30 minutes of the flight.

“At no point was Ms. Harper told to use the cups instead of the lavatory,” the spokesperson said. “Customer safety is always our first priority. Initial reports from the Mesa Airlines flight attendants indicate that Ms. Harper attempted to visit the lavatory on descent and was instructed to remain seated with the seat belt fastened per FAA regulations. At no point during the flight did flight attendants suggest that Ms. Harper use cups instead of the lavatory.”

Harper claims the incident took place on the same day a man named David Dao was forcibly removed from a different flight operated by United Airlines.