SAN FRANCISCO — Four engineers fired by Google just before Thanksgiving said they plan to file a complaint with the National Labor Relations Board on Tuesday, asking the federal agency to investigate the company for what they called a sweeping illegal campaign to quash worker organizing.

Google fired the engineers, who ranged in seniority from 11 years at the company to less than two, for what it said were data security violations. But the move has widened a growing rift between Google and some of its employees over the company’s handling of employee activism.

The episode also adds fuel to a burning debate in the U.S. tech industry, where engineers and other tech workers are speaking out in unprecedented ways against the management of companies that for years have enjoyed a reputation for idealism. Google’s code of conduct still includes the line “don’t be evil,” a command that the fired engineers said the company hasn’t followed.

The four engineers, who spoke out for the first time in an interview Monday, said that Google’s attempts to discourage workplace organizing would backfire as workers take inspiration from the firings.

Download the NBC News app for breaking news

“When we win, it furthers our cause, and when we don’t win, it furthers our cause, too,” said Laurence Berland, who was a senior site reliability engineer at Google before he was fired.

“There doesn’t seem to be anything the company can do at this point,” he said.

Sophie Waldman, a software engineer who was with Google for a year and 10 months, said that before her firing, she witnessed a growing backlash within her Google office in Cambridge, Massachusetts. After one recent company misstep, she said, “Someone in that room pulled out their wallet and said, ‘OK, where do I send my union dues?’”

The four planned to issue a statement Tuesday on the website Medium, cataloging Google’s actions and calling on people still at the company to take up their cause.

Three of the Google former engineers who are calling for an investigation into the company. Google Walkout For Real Change

Google appears ready for a fight. The company has hired an anti-union consulting firm, IRI Consultants, as its workers explore unionization, including in Pittsburgh where Google contract workers voted in September to join the United Steelworkers Union.

Last year, thousands of Google employees staged a walkout to protest management’s handling of accusations of sexual misconduct by executives. Employees have expressed concern about the company possibly surveilling them and criticized company plans for a censored search engine in China and a Pentagon contract that could aid drone strikes.

Google on Monday did not make anyone available for an interview about the four fired engineers, but the company said it stood by the firings for reasons it laid out in a note to all employees last week.

In that note, Google said it had fired the four employees “for clear and repeated violations of our data security policies” — specifically, searching for, accessing and distributing “business information outside the scope of their jobs,” including the online calendars of others, according to Bloomberg News. Some of the information was subsequently shared externally, the note alleged. Google has not named the four.

In a statement on Tuesday, Google reiterated that it fired the four for data security violations "including systematically accessing and disseminating other employees' materials and work." The company said: "No one has been dismissed for raising concerns or debating the company's activities."

Waldman said she was told specifically after her interview by investigators that she was not in violation of any policy. "I asked them afterwards to confirm my understanding that I didn't need to do anything differently than before, and they replied in the affirmative," she said. "Either they're changing the policy retroactively or they needed an excuse, or both."

The fired engineers and their defenders also say that Google has long had a radically open culture that allowed employees to look at documents, including calendars, belonging to other teams at the company, and that the open culture was slowly closing.

“Workers built this company and they created the institution that is Google,” said Paul Duke, a New York-based software engineer who was at Google for more than eight years before he was one of the four who were fired.

“Executives want to wield the power that workers created,” he added. “This is about workers realizing that they have to band together and act collectively to hold that power accountable.”

The four engineers said they were wrongly fired and that the ways Google treated them were unlawful and violated workplace rights that Google itself agreed to in September in a settlement the company reached with the NLRB in a different case. Their NLRB complaint will allege unfair labor practices by Google, they said.

Each of the four said they were asked to provide names of other employees who were involved in organizing, a request that they interpreted as a part of an intimidation campaign. Duke said it felt “like McCarthyism.”

Berland, based in San Francisco, said the four would like a determination from the NLRB that Google acted unlawfully, and they want Google to be forced to change policies that they believe suppress organizing. They will also seek remedies as individuals, he said.

“The company is afraid of something,” Berland said. “We don’t know exactly what, but the more they act to crush us, the more we understand what’s really at stake here and the stronger we get.”

The four engineers said the timing of their firings just before Thanksgiving made the experience all the more disruptive. Berland said he was traveling and without phone service on the New York City subway when Google tried to call him, and that he learned of his firing only by reading an email with the subject line, “Information concerning your employment at Google.”

Rebecca Rivers, a software engineer in Boulder, Colorado, who was among the four, said each of them was given five days of health insurance, which given the timing meant that three of the days were holidays or weekend days when it would be difficult to see a provider.

“This week, I’m going to have to come up with a few hundred dollars to pay for medications,” she said, adding that health insurance could be thousands of dollars a month more.