A group of up to 30 Amazon employees at one of the company’s Delaware warehouses will have the opportunity to vote today in an election that could establish the first-ever labor union representation at a U.S. Amazon facility.

The group, which consists of equipment technicians and mechanics, will be voting on whether they want to join the International Association of Machinists and Aerospace Workers. A simple majority — or half of those who vote plus one — is needed to establish the first-ever union shop inside an Amazon facility in the U.S., according to IAMAW spokesman John Carr.

Carr said the voting workers, who make up just a small fraction of the more than 1500 employees at the facility, are not most concerned with the wages they are paid. Rather, they’d like help negotiating for things such as vacation and promotion policies, seniority rules, as well as the possible creation of a safety committee, Carr said.

In the weeks leading up to the vote, the workers have been pulled into what unions call “captive audience meetings,” during which their superiors at Amazon attempt to persuade workers against unionization, according to Carr.

Amazon spokeswoman Mary Osako provided a prepared statement that read, in part, “We respect the individual rights of our associates and have an open-door policy that allows and encourages associates to bring their comments, questions and concerns directly to their management teams. We firmly believe this direct connection is the most effective way to understand and respond to the needs of our workforce and do not believe there is a need for third-party representation.”

The union vote is just the latest in a series of events that have shined a negative light on Amazon’s growing network of what it calls fulfillment centers. The company has been engaged in an ongoing battle with some of its German workers who have organized strikes and protests over the past year over wages and was also the subject of an unflattering BBC documentary about worker conditions.

And in the U.S., the Occupational Safety and Health Administration is currently investigating the December death of a 57-year-old temporary worker at a package sorting facility in New Jersey owned by Amazon, and managed by third-party logistics firm Genco.