Roughly a month after workers at a Staten Island Amazon (AMZN  ) warehouse voted to join the Amazon Labor Union, the company has laid off more than six senior managers at the location. The firings were made outside of the company's usual employee review cycle, and several of the managers had been with Amazon for more than six years, according to The New York Times.

The successful union vote at the Staten Island warehouse, the only Amazon fulfillment center in New York City, has had widespread effects on the labor market. Lawmakers, and celebrities alike have come out to support labor organizing, and the number of unionization petitions submitted to the National Labor Relations Board (NLRB) is about to reach an all-time high.

Following Amazon workers' lead, employees at other companies like Apple (AAPL  ) and apparel retailer REI have also begun organizing. Starbucks (SBUX  ) workers have arguably made the most headway, with 50 locations successfully unionizing since December 2021.

In another big win for the Amazon Labor Union, the union's president Christian Smalls testified before a Senate committee on May 5. The hearing was regarding whether or not companies that break labor laws should be eligible for federal contracts. Later that day, Smalls attended a White House meeting and directly asked President Joe Biden to pressure Amazon to respect the union.

However, as union efforts increase, so too do the anti-union efforts from the companies involved.

Long before the recent firings, Amazon pushed back hard against the Staten Island unionization efforts, holding 20 mandatory or "captive audience" meetings per day. At these meetings, senior managers, company officials, and anti-union consultants told workers not to vote in favor of the union.

Among the claims made at the meetings, the Amazon officials told workers that collective bargaining could result in them losing compensation, a claim that labor experts say is misleading due to how exceedingly uncommon it is that unionizing results in lower wages.

Amazon is now contesting the Staten Island vote, arguing that the NLRB is biased in favor of the union and that the union used coercive tactics to curry votes.

The senior managers who were fired have not been connected to organizing efforts, but they have been connected to Amazon's failed attempt to fight the vote. Employees told NYT that at least some of the former managers were known for being capable performers who received positive employee reviews. Amazon told the workers that the firings were made as part of an "organizational change", according to worker reports.

"Part of our culture at Amazon is to continually improve, and we believe it's important to take time to review whether or not we're doing the best we could be for our team," Kelly Nantel, an Amazon spokeswoman, told NYT.