By Sebastian Herrera

Amazon.com Inc. employees in Alabama voted not to unionize, handing the tech giant a victory in its biggest battle yet against labor-organizing efforts that fueled national debate over working conditions at one of the nation's largest employers.

Workers at the Bessemer warehouse overwhelmingly rejected unionization, with 71% casting ballots not to join the Retail, Wholesale and Department Store Union, according to the National Labor Relations Board. Some who voted no said they didn't see how a union would substantially improve their pay and benefits.

"Amazon didn't win -- our employees made the choice to vote against joining a union," the company said Friday.

The rejection is a blow to efforts to increase union membership in the private sector nationally, which has experienced a decades-long decline. The Amazon facility represented an opportunity to organize workers at the second-largest U.S. employer, in a fast-growing industry and in an environment where labor unions have thrived in the past -- a large blue-collar site where many employees do similar jobs.

"It's much harder to organize big groups. Large employers like Amazon and Walmart have been the holy grail," said Jonathan Spitz, co-leader of the labor relations practice at Jackson Lewis, a management-side law firm.

President Biden had endorsed the union movement, and he has pledged to create more union jobs. The White House said Friday that it would wait until the NLRB completes its analysis of the results before making a comment. "We know it's very difficult for workers to make the choice to form a union," White House Press Secretary Jen Psaki said.

In a news conference organized by Amazon, workers from the Bessemer facility who sided against organizing said the union ultimately didn't offer a convincing argument. The workers called for changes at the facility, such as added training for managers, but said they could resolve issues with the company without a third party.

"A lot of us are in agreement that we don't need anybody there to speak for us and take our money," said Cori Jennings, 40 years old, who works there and voted against unionizing. Ms. Jennings, who talked to The Wall Street Journal before the results were final, said she and many of her colleagues were also eager for the national attention to fade: "We want our lives to go back to normal."

The outcome underscores unions' difficulties in boosting their ranks in the U.S. private sector, where they represent just 6.3% of workers, down from 24.2% in 1973, according to the earliest available data from Georgia State University's union stats database. Of total U.S. workers, 10.8% were union members last year, according to the Labor Department.

Unions are a much larger presence in the public sector, where they represent 34.8% of government workers, according to the Labor Department.

Shares of Amazon rose 2.2% Friday to $3,372.20, closing at its highest level in two months. The company's win will mean continued flexibility as it adds workers at a record pace and expands into new industries. Last year, Amazon hired 500,000 workers globally and extended its reach further into healthcare, grocery and other markets.

The NLRB on Friday finished counting all the votes that weren't challenged. The federal agency has yet to certify the results, which could happen in about a week, but it has noted that the challenged ballots aren't enough to exceed the vote margin against unionization. The Bessemer facility employs fewer than 1% of the roughly 950,000 Amazon employees in the U.S.

The union said it would appeal the vote, accusing Amazon of violating legal restrictions governing unionization campaigns. Amazon has said it followed the law in communicating with employees before and during the election.

The appeal would seek to overturn results of the election or have it held again. The union is expected to take issue with meetings Amazon held with Bessemer employees and a mailbox the company pushed to install outside the facility.

"We won't rest until workers' voices are heard fairly under the law. When they are, we believe they will be victorious in this historic and critical fight to unionize the first Amazon warehouse in the United States," RWDSU President Stuart Appelbaum said.

Amazon, in a blog post, said, "It's easy to predict the union will say that Amazon won this election because we intimidated employees, but that's not true. Our employees heard far more anti-Amazon messages from the union, policymakers, and media outlets than they heard from us."

Fewer than 16% of the employees at the fulfillment center voted to join the union, the company said. Amazon said it has "worked hard to listen to them, take their feedback, make continuous improvements" and would keep working "to get better every day."

Previous unionization efforts at Amazon also failed. In 2018, an effort by Whole Foods Market employees to unionize failed to gain traction, and four years earlier a small group of Amazon workers in Middletown, Del., rejected a union push.

Politicians in both parties and celebrities had rallied for pro-union employees. Supporters painted the election as a battle that transcended traditional workplace disputes over pay and benefits. They contrasted Amazon's reputation for growth, profit and innovation with the working conditions for rank-and-file employees.

Some employees in Bessemer had said they wanted to unionize to negotiate over issues including their compensation, the pace of their work and the amount of break time they have per shift. One worker in Bessemer said he is expected to pick roughly 300 items per hour and at times doesn't have enough time to take a bathroom break without potentially getting in trouble. Amazon has said employees can take bathroom breaks when needed.

Amazon told its workers in Alabama that unionizing isn't necessary, saying it pays double the state's minimum wage of $7.25 an hour, which is also the federal minimum. The company warned of the cost of union dues and highlighted what it says are the generous healthcare benefits it offers employees.

The tech giant has grown rapidly in the past year as consumers and companies leaned on its services during the pandemic. Amazon had $386.1 billion in sales in 2020 and saw its share price rise about 76%.

Guru Hariharan, a former Amazon manager who runs the e-commerce analytics company CommerceIQ, said the company would continue to grow no matter how its labor battles play out. Amazon's advantage "is based on its technology, and that will continue to be the case regardless of incremental productivity-level shifts in fulfillment center workers."

Eric Morath, Lauren Weber and Inti Pacheco contributed to this article.

Write to Sebastian Herrera at Sebastian.Herrera@wsj.com

(END) Dow Jones Newswires

04-09-21 1801ET