More than 100 workers at an Amazon air hub in Southern California have walked off the job, claiming that they've been retaliated against for union activity. 

The hub in San Bernardino is the largest of its kind on the West Coast, where packages shipped by air are processed and loaded on and off planes. Workers there have organized with the Teamsters, and say that they've led "numerous walkouts and strikes" at the facility in the past over alleged unfair labor practices, wages, working conditions and safety measures. In this instance, they walked out on July 22, days after Amazon's Prime Day event that brought in $14.2 billion in sales, according to CNBC. 

"Amazon is one of the most profitable companies in the world, but it consistently treats its workers like trash," Amazon air hub worker Anna Ortega said. "We are standing up for our right to organize and to fight for a better future at Amazon."

This is far from the first time Amazon has been accused of union busting, with allegations at various warehouses over the years ranging from retaliatory firings to illegal surveillance of union activity. Most recently, workers at Amazon's Coventry warehouse in the U.K. alleged that they had been pressured to attend seminars where it was implied that unionization would adversely affect their wages, overtime and benefits. A union recognition vote at that warehouse was defeated by a 28-ballot margin in July.