Denver International Airport is one of many locations nationwide where concessions employees who work for HMSHost are picketing and distributing leaflets until 1 p.m. Thursday in an effort to join a union that represents over 1,000 airport workers.

HMSHost, which operates in over 120 airports worldwide, won a contract in 2017 to manage three Starbucks stores in the airport. The company’s website indicates that it is also responsible for operating Great Divide Brewhouse, CRU Wine Bar and ChopHouse.

A press release from the airport union, UNITE HERE Local 23, alleges that since employees of the company have attempted to unionize, “HMSHost managers in Denver have intimidated and interrogated workers, created the impression that employees’ union activities were under surveillance, and tried to prevent workers from talking about the union at work.”

“I have worked at Starbucks for HMSHost for 20 years,” said Hiwot Fekadu, a Starbucks barista at DIA. “I came to this country with a dream to go to school and have a decent life. Instead, I have to work two jobs and hardly sleep.”

HMSHost did not immediately respond to a request for comment.

This week, UNITE HERE released its own survey of 309 Starbucks employees at HMSHost-operated locations, which found pay disparities, workers living in poverty and alleged incidents of offensive comments from managers related to sexual orientation and gender identity.