(Bloomberg) -- Trader Joe’s fired a New York City employee in retaliation for union activism, according to a complaint from a group organizing workers there, in the latest sign of labor tension at the grocery chain.

In a Friday filing with the National Labor Relations Board, the group called Trader Joe’s United accused the company of illegally firing a leader of an organizing campaign at a Brooklyn store, part of an effort to discourage involvement with the union.

The worker was fired around the same date that employees there petitioned to unionize in September, according to the filing, which accuses the company of violating federal law. Workers at the Brooklyn site are scheduled to vote next week on whether to make it the chain’s third unionized store, following recent victories for Trader Joe’s United in Massachusetts and Minnesota.

Trader Joe’s didn’t immediately respond to requests for comment. The company has said that it offers “industry-leading” benefits, and that it would negotiate with the union at the stores where it won.

“While we are concerned about how this new rigid legal relationship will impact Trader Joe’s culture, we are prepared to immediately begin discussions with their collective bargaining representative to negotiate a contract,” spokesperson Nakia Rohde said in an email following the Minnesota vote in August.

Trader Joe’s is one of several prominent US companies where organizers have secured new footholds over the past year, including Starbucks Corp., Amazon.com Inc. and Apple Inc. Employees at Home Depot Inc. and Lowe’s Cos. also have recently petitioned to unionize.

Like organizers at Amazon and Home Depot, the Trader Joe’s workers opted to create their own worker-run labor group, rather than affiliating with an existing union. And like their counterparts at Starbucks and Apple, they’ve framed their campaign in part as a way of advancing the same humane values that their brands already espouse.

In still-pending NLRB filings, the union has accused Trader Joe’s of breaking the law at the stores where it prevailed. In Hadley, Massachusetts, the union claimed management threatened to retaliate if workers supported organizing. In Minneapolis, the union alleged the company undertook anti-union surveillance and interrogation.

Sarah Beth Ryther, a Minneapolis union leader, said in an interview that after a co-worker posted a sign in the break room saying, “We need a living wage, not a pizza party,” management launched an investigation and questioned several employees about it.

The Trader Joe’s union has said that it’s been hearing from workers across the country interested in organizing their stores.

(Updates with employee’s comment in second-to-last paragraph.)

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