Google has fired another employee following a showing of internal activism, marking the latest in a series of controversial terminations at the search giant.

Kathryn Spiers, a security engineer at Google, told The Verge she was fired from the company last week after two years. As part of her duties at Google, Spiers was responsible for sending web browser notifications within the company. While Google employees navigated the web, relevant informational pop-ups would appear as employees viewed certain sites. Spiers, who worked on internal data security, had deployed similar notifications to discourage employees from acting irresponsibly with data, among other projects.

“This was a serious violation,” says Google

After news broke last month about Google employing a law firm known for its anti-union activities and firing four employees involved in internal activism, Spiers took it upon herself to set up a new notification for employees. When Googlers visited the law firm’s website or Google’s internal worker guidelines, they were sent a new message through a browser pop-up: “Googlers have the right to participate in protected concerted activities.” The message included a link to a labor rights notice Google was mandated to post.

Spiers says she was put on administrative leave hours after releasing the message and was told on Friday that she was being fired from the company. Google management, she says, argued that she had sent the code without proper approval and had endangered company security. She says she had proper approval for sending the code, and she disputes that it introduced any security concerns.

In a blog post released today, Spiers writes that “this kind of code change happens all the time” and that Google “has never reacted aggressively in response to a notification such as this in the past.”

The company has said that it fired the four other employees for accessing information beyond what was required to do their jobs, while the former employees have disputed that they broke company policy. Like the other employees, Spiers said she has filed unfair labor practice charges with the National Labor Relations Board.

Spiers says the company is “making Google less transparent”

A Google spokesperson declined to confirm Spiers’ termination, but they said the company had fired someone last week for misusing the browser notification, and it had also disciplined two others as part of the incident.

The spokesperson said the content of the message wasn’t at issue and that management would have taken similar action if the tool had been used to send any message not related to security. “We dismissed an employee who abused privileged access to modify an internal security tool,” the spokesperson said in a statement. “This was a serious violation.”

The recent terminations are only one sign of escalating tensions at Google where workers have protested for years against decisions like Google’s plans for a censored Chinese search engine, work with the Pentagon, and handling of sexual harassment allegations.

Last month, CEO Sundar Pichai said the company would scale back its weekly TGIF meetings, where employees hear directly from executives, and that the discussions would be limited to “product and business strategy.”

Spiers says Google’s stance toward employee activism will have damaging effects on the company as a whole. “The steps Google are taking are making Google less transparent and therefore less trustworthy,” she says.