Elon Musk’s tweets have gotten him into trouble.

A California judge ruled Friday that the Tesla CEO and other company executives have been illegally sabotaging employee efforts to form a union.

The administrative judge, Amita Tracy, pointed to 12 company actions that violated US labor laws. That includes letting security guards harass workers who were passing out union pamphlets in the parking lot, banning employees from wearing pro-union T-shirts and buttons, repeatedly interrogating union organizers, and eventually firing one of them.

Then there is the matter of Musk’s tweets. The judge said several anti-union messages he posted on Twitter in May 2018 were illegal too. Like this one:

Nothing stopping Tesla team at our car plant from voting union. Could do so tmrw if they wanted. But why pay union dues & give up stock options for nothing? Our safety record is 2X better than when plant was UAW & everybody already gets healthcare. — Elon Musk (@elonmusk) May 21, 2018

These are known as unfair labor practices. And what is the financial penalty for this? There isn’t one.

That’s because the law that governs collective bargaining doesn’t let judges fine companies that break the law. Basically, Tesla just has to stop sabotaging union efforts and hire back the fired employee, plus pay him lost wages. Musk has to also read a notice to his employees saying that they have a right to unionize and that the company will not interfere with that. (Tesla has not yet responded to Vox’s request for comment.)

If Tesla doesn’t comply, the National Labor Relations Board, an independent federal agency that enforces collective bargaining laws, would have to petition a federal appeals court to enforce the order.

So this is more like a slap on the wrist.

Still, it’s a big victory for workers who build Tesla’s luxury electric cars. Since 2016, a group of them have been trying to form a labor union at the company’s factory in Fremont, California, which employs about 12,000 people. The organizers had complained about high injury rates and low wages and wanted to join the United Auto Workers union, which represents workers at GM, Ford, and Fiat Chrysler. Right now, Tesla is the only large US automaker without a unionized workforce.

But the company has made it nearly impossible for workers to organize. The new ruling from the National Labor Relations Board judge means workers will have a much better chance of forming a union to negotiate better pay and safer working conditions.

Workers were worried about their safety

In the fall of 2016, Jose Moran, a Tesla factory employee, reached out to United Auto Workers to ask about about starting a union. By early 2017, a group of organizers called it the Fair Future at Tesla campaign.

In February 2017, the effort went public when Moran wrote a blog post on Medium titled, “Time for Tesla to Listen.” He said factory workers were constantly getting hurt because the company made them work long hours on machinery that wasn’t ergonomically safe. He also said the company had a shortage of workers and kept pushing employees to work faster. He then pointed out that Tesla employees were paid less than other employees in the auto industry and made the case for joining a labor union.

“I often feel like I am working for a company of the future under working conditions of the past,” Moran wrote in the blog post. It quickly caught the attention of Tesla executives, according to the NLRB complaint.

Tesla tried to sabotage union efforts

Tesla tried many different tactics to stop workers from forming a labor union.

The day after Moran published the blog post, he and three colleagues began distributing union leaflets in the factory parking lot during his time off. They were harassed by three security guards, who all took pictures of their badges, according to the complaint. The guards told the employees that they didn’t have permission to be there, that they should leave.

Moran and his coworkers said they have a right to distribute the leaflets in the parking lot — and they do, according to the judge, Amita Tracy, who oversaw the administrative trial through the NLRB. The next month, in March, a supervisor warned employees that they could be fired if they distributed pro-union stickers and pamphlets — that was illegal, according to the judge.

In May, an HR representative questioned two union organizers about who accessed the company’s safety logs, which were the basis of a Guardian investigation of Tesla’s high employee injury rate at the time.

In June, workers delivered a petition to Elon Musk, saying that they were worried about their safety at work and that they wanted to form a labor union.

“We should come to work knowing we will return home to our families without being injured at work,” they wrote, according to the complaint.

The next day, Musk summoned Moran into his office. The head of HR, Gaby Toledano, was there, too. The CEO asked Moran and a coworker Moran brought with him to tell him about his job at Tesla. Moran described his job and explained the safety concerns he and his coworkers had. He also complained that he had good performance reviews but never received a raise for them.

Musk tried to discourage the employees, according to the complaint: “According to Moran, [Toledano] then said, ‘You know, the majority of workers at Tesla don’t want a union and, you know, why do we want to pay for—why do we want to pay union dues?’ Moran responded that the employees have a right to form a union to have a voice to improve working conditions.”

That was illegal, too.

In the following days, Musk suggested hiring Moran and other union organizers to work full-time on safety issues, according to copies of emails cited in the decision. Toledano said that was a good idea, mentioning that they wouldn’t be able to unionize or advocate for a union if they were salaried employees.

“[H]er emails show extensive discussion and steps Toledano took to move four pro-union employees to management so they could no longer advocate for the Union,” the judge wrote in the decision.

That was illegal, the judge decided, and it was also illegal when the company later began enforcing its dress code, barring workers who were wearing union T-shirts and buttons.

It was also illegal when Tesla fired one of Moran’s coworkers for criticizing Tesla employees who spoke out against a union-backed bill in the California legislature.

But perhaps none of that did more damage than Musk’s own involvement. On May 2018, he posted multiple anti-union message on Twitter, including one that suggested employees would no longer have stock options if they formed a union.

Also, UAW did nada for job security in last recession. Dropped Fremont like a hot potato to protect their core base in Detroit. UAW *chose* to exit this plant before Tesla even arrived. We had nothing to do with UAW leaving, but everything to do with why people here have jobs. — Elon Musk (@elonmusk) May 21, 2018

“Musk’s tweet can only be read by a reasonable employee to indicate that if the employees vote to unionize that they would give up stock options. Musk threatened to take away a benefit enjoyed by the employees consequently for voting to unionize,” wrote the judge.

Among other things, Musk was ordered to read this to his employees:

“Federal law gives you the right to form, join, or assist a union, choose representatives to bargain with us on your behalf, act together with other employees for your benefit and protection, choose not to engage in any of these protected activities.”

In all, the judge cited the company for violating US labor laws 12 different ways. But there is little incentive for Tesla to change its ways since there is no financial penalty involved.