HADLEY — Sixteen months after the Hadley store became the first Trader Joe’s in the nation to unionize, a group of workers is calling it a failed experiment and pushing for decertification.

Crew members at the grocery store are accusing the union of spreading misinformation and trying to drive a wedge between workers and management.

“The constant defamation against our captain, our mates, and our employer has become tiresome and unjust,” the group stated in a release Friday announcing the push for decertification.

“It’s just getting progressively worse,” Les Stratford, a 10-year employee, said Monday. “We’re losing people who can’t handle the stress.”

He said the union has a habit of “shading stuff with media,” which he called disconcerting.

“A lot of stuff they’ve done to make the workplace look bad,” he said.

Maeg Yosef, spokeswoman for the independent Trader Joe’s United union, said the decertification effort was not a surprise because there has been a “vocal minority” of union opponents all along.

“Since before the election, we’ve had majority support in the store, and we continue to have majority support,” Yosef said. “Most crew members want a contract for better pay and better protections.”

Yosef, a 19-year employee of the Hadley store, said she could not respond to general accusations of spreading misinformation, though she said such a charge has been leveled at the union over the complaints of unfair labor practices it has filed. She said the National Labor Relations Board has found merit in most of those complaints. It has scheduled a hearing on them for Jan. 16.

In July, crew members walked out to protest what they said was the unfair firing of a colleague.

The union and management have been negotiating for about a year and have reached some tentative agreements, Yosef said, but progress has been slow. She said the company has refused to engage on some key issues, and the sides are still far apart on wages, retirement and health benefits.

As in a union vote, if 30% of crew members call for decertification, supporters can call on the NLRB to hold an up-or-down vote on the union. If 51% of the bargaining unit sign the decertification petition, according to Stratford, the petitioners can ask the company to no longer recognize the union.

Decertification elections cannot be held until one year following the union’s certification by the NLRB, which has passed, and for three years after a collective bargaining agreement has been reached.

Decertification supporters stated they had taken “this monumental step ... after careful consideration and consensus among us, without any interference from management or corporate.”

Stratford said the crew members want to ensure the process is conducted openly, and they encourage any employees with questions to bring them forward. He described Trader Joe’s as a great workplace.

“We’re not anti-union,” he said. “They have a place in most workplaces. We just don’t believe Trader Joe’s is one of them.”

After the Hadley store unionized — the vote was 45-31 — Trader Joe’s stores in Minneapolis and Oakland, Calif., also organized under the independent Trader Joe’s United banner. The Louisville, Ky., store did, too, although that election has not yet been certified. Union votes at two Trader Joe’s stores in New York have failed.

Yosef said workers at the other unionized stores face potentially the same issues, so coordination among the locals is important.

The company, headquartered in Monrovia, Calif., had 564 stores across the U.S. at last count.