On Thursday evening, a federal labor board filed a complaint against Tesla (PDF), alleging that the electric vehicle company had discouraged workers from distributing pro-union information, stopped them from talking about employee safety to the United Auto Workers (UAW) union, and in one case, prevented an employee from taking a picture of the Confidentiality Agreement they had to sign.

The Oakland, California-based regional office of the National Labor Relations Board (NLRB) consolidated the complaints of three former Tesla employees, Michael Sanchez, Jonathan Galescu, and Richard Ortiz, as well as complaints made by UAW.

Tesla and the NLRB will appear at a hearing in November before an administrative law judge.

The complaint alleges that on numerous occasions between February 2017 and May 2017, security guards and human resources agents working on behalf of Tesla told employees that they had to leave the Fremont, California, factory premises because they were distributing pro-union leaflets.

In addition, one employee says that over the course of two meetings, a Human Resources Business Partner and an Environmental Health Safety and Sustainability Specialist “interrogated the employee about the employee's Union and/or protected, concerted activities,” as well as the pro-union activities of other employees.

In March, the complaint claims, a supervisor told his employees during a pre-shift meeting that they could not distribute any stickers or pamphlets that hadn't been approved by Tesla first, or they would be fired. In another incident, a Human Resources Business Partner allegedly "attempted to prohibit an employee from discussing safety concerns with other employees and/or with the Union."

These allegations come after a Tesla employee wrote an article in February 2017 complaining of poor working conditions and advocating for unionization. At the time, Tesla CEO Elon Musk dismissed the claims, telling Gizmodo, “Our understanding is that this guy was paid by the UAW to join Tesla and agitate for a union.” Musk also blamed the UAW for killing New United Motor Manufacturing, Inc (NUMMI), which sold its Fremont factory to Musk in 2010.

In a statement from Tesla today, the company denied the claims made in the NLRB complaint, adding that the company would respond "as part of the NLRB process."

“As we approach Labor Day weekend, there’s a certain irony in just how far the UAW has strayed from the original mission of the American labor movement, which once advocated so nobly for the rights of workers and is the reason we recognize this important holiday," a Tesla spokesperson wrote.

The company called the complaint "entirely without merit" and said that UAW advocates have put out misleading and false information and have made "unsolicited and unwelcomed" visits to the homes of Tesla employees.