United Airlines has begun the process of laying off unvaccinated workers

The airline will terminate roughly 600 employees — less than 1 percent of its workforce — who refused to comply with the company’s COVID-19 vaccine mandate.

United announced the news in a statement to its website.

The Chicago-based airline stated that 99 percent of its workforce provided proof of vaccination prior to a Monday deadline.

United will move to fire those who did not seek an exemption or provide proof of vaccination, however the carrier will give them one more chance to comply with the mandate during the separation process.

The percentage of vaccinated United employees excludes the less than 3 percent of the company’s 67,000 employees who sought a religious or medical exemption.

Six employees filed a lawsuit against the airline last week over its policy to put exempt employees on unpaid leave.

United is the only one to fire crew

Of the top four U.S. airlines, United is the only operator to fire employees who do not comply with a vaccine requirement.

Delta Air Lines will enact a $200 monthly surcharge on unvaccinated employees, while American Airlines and Southwest Airlines are only encouraging employees to get the shot.