NEW YORK (NYTIMES) - A group of gravediggers in Columbus, Ohio, who just negotiated a 3 per cent raise. The poultry plant that processes chicken nuggets for McDonald's. The workers who make Cap'n Crunch in Iowa. The women's shoe department at Saks Fifth Avenue in Manhattan.

The Retail, Wholesale and Department Store Union (RWDSU) is not the largest labour union in the United States, but it may be one of the most eclectic. Its membership, totaling about 100,000 workers, seems to reach into every conceivable corner of the US economy, stretching from the cradle (they make Gerber baby food) to the grave (those cemetery workers in Columbus).

And now it is potentially on the cusp of breaking into Amazon, one of the world's most dominant companies, which since its founding has beaten back every attempt to organise any part of its massive US workforce.

This month, a group of 5,800 workers at an Amazon warehouse in Bessemer, Alabama, are voting whether to join the RWDSU. It is the first large-scale union vote in Amazon's history, and a decision by the workers to organise would have implications for the labour movement across the country, especially as retail giants like Amazon and Walmart have gained power - and added workers - during the pandemic.

The Amazon campaign, said Stuart Appelbaum, the union's president, "is about the future of work and how working people are going to be treated in the new economy."

For some labour activists, the union and its early success at the Bessemer warehouse represent the vanguard of the modern organising campaigns. It is outspoken on social issues and savvy on social media - posting a TikTok video of support from the rapper Killer Mike and tweeting an endorsement from the National Football League Players Association during the Super Bowl.

"It's a bit of an odd-duck union," said Joshua Freeman, a professor emeritus of labour history at Queens College at the City University of New York. "They keep morphing over the years and have been very inventive in their tactics."

The union is also racially, geographically and politically diverse. Founded during a heyday of organized labour in New York City in 1937 - and perhaps best known for representing workers at Macy's and Bloomingdale's - most of its members are now employed in right-to-work states, across the South and rural Midwest.

While the union's overall membership has stagnated over the past decade, the number of members in its Mid-South office, which includes Alabama, Tennessee and Louisiana, has nearly doubled, to about 9,000 from 4,700 in 2011, driven by aggressive recruitment efforts in the poultry, warehouse and health care industries. More than half of its members across the country are workers of colour.

Over the years, the union has faced some powerful enemies. In the 1960s, its Black organizers were threatened - one was even shot at - while trying to sign up food industry workers across the South.

Johnny Whitaker, a former dairy worker who started as a union organiser in the 1970s, said he had grown up in a white family in Hanceville, Alabama, without much money. Still, he was shocked by the working conditions and racism he witnessed when he started organising in the poultry plants years ago.

Black workers were classified differently from their white counterparts and paid much less. Women were expected to engage in sexual acts with managers in exchange for more hours, he said. Many workers could not read or write.

Despite threats that they would lose their jobs if they organised, thousands of poultry workers have joined the RWDSU over the past three decades, though the industry still is predominantly non-union.

When a small group of Amazon workers contacted the union in late August about their interest in organising the Bessemer warehouse, Mr Whitaker acknowledged, "there was a lot of doubt" internally about the idea.

The RWDSU had tried to lay the groundwork for organising Amazon's warehouse in Staten Island, New York, in 2019, but the effort failed when the company pulled the plug on its plans to build a second headquarters in New York, known as HQ2, partly because of political pressure to allow organising at its facilities.

"What we learned from HQ2 was that Amazon was going to do anything it possibly could to avoid having a union at any of its workplaces," Mr Appelbaum said.

At the time, Amazon said it canceled its plans after "a number of state and local politicians have made it clear that they oppose our presence and will not work with us to build the type of relationships that are required to go forward with the project."

But the more the workers in Alabama kept talking to the union about their working conditions, the more Mr Appelbaum and others believed the warehouse was fertile ground for organising.

The workers described the control that Amazon exerts over their work lives, including tracking their time in the restroom or other time spent away from their primary task in the warehouse. Some workers have said they can be penalized for taking too much time away from their specific assignments.

"We are talking about bathroom breaks," said Mr Whitaker, an executive vice president at the union. "It's the year 2021 and workers are being penalized for taking a pee."

In an email, an Amazon spokeswoman said the company does not penalize workers for taking bathroom breaks.

"Those are not our policies," she said. "People can take bathroom breaks."