The move comes shortly after Amazon agreed to raise its minimum wage to $15 an hour earlier this month, following a campaign by Sanders and organizers to shame the company over low pay.
“We write to express our alarm at recent reports that your company is distributing anti-union materials to Whole Foods managers that directs and encourages potentially illegal interference with the rights of thousands of workers,” Sanders and Warren write. “It is important to recognize that workers' rights do not stop at the minimum wage, and raising the pay of your lowest-paid workers, while important, does not give you a free pass to engage in potentially illegal anti-union behavior.”
Amazon said in a statement that their existing labor arrangement provided “the most effective way to understand and respond to the needs of our workforce.”
In late September, the tech news site Gizmodo published a story detailing a video produced by Amazon and sent to managers of the grocery chain Whole Foods Market, which was acquired by Amazon last year. The video, which has also been obtained by The Washington Post, lists “Warning Signs” of union organizing, such as using words like “living wage” and “steward,” handing out fliers, and wearing union T-shirts.
“We do not believe unions are in the best interest of our customers, our shareholders, or most importantly, our associates," the video says. "When we lose sight of those critical focus areas we jeopardize everyone’s job security: yours, mine, and the associates.”
At another point, the video states: “Ultimately, it’s up to the employees to decide whether to participate” in a union.
Legal experts said it was not clear if the video represents a violation of the law. Under federal labor law, management is allowed to make predictions about what could happen should workers unionize. Management is not allowed to make threats about the consequences of doing so, said Benjamin Sachs, a labor law expert at Harvard University.
“The law draws an ambiguous line between threats and predictions,” Sachs said. “It seems to me a reasonable employee might understand ‘we jeopardize everyone’s job security’ as a threat.”
In the letter, Sanders and Warren ask Bezos for a copy of the video and details about its distribution as well as about reports of retaliation against workers. Gizmodo also reported that an Amazon worker at the company’s Floridian Fulfillment Center lost his job because he sent complaints about low-pay to Bezos' email account.
Amazon “respects the individual rights of employees and has an open-door policy that encourages employees to bring their comments, questions, and concerns directly to their management team,” a spokesperson said in an email. The company previously pointed to a "full benefits package" for workers including health care, vision care, and dental insurance, as well as parental leave.
The pay hikes announced earlier this month will affect 250,000 Amazon employees and 100,000 seasonal employees hired at Amazon sites during the holiday season. But without a union, Amazon could rescind the pay hike unilaterally, or neuter it with loopholes and cuts to stock options and benefit packages, labor experts said.
“There’s a really big difference between getting one raise and having a long-term voice in the company,” said Kate Andrias, a professor of labor law at the University of Michigan. “The stakes for the workers here may be just as significant.”
Earlier this year, Sanders and Rep. Ro Khanna (D-Calif.) introduced the “Stop BEZOS Act,” which proposed taxing Amazon over the public benefits its employees receive. With Warren, Sanders earlier this year also released a bill to boost worker rights, protect those in the gig economy, and make it easier to organize across the American economy.
“This is part of a larger effort to restore workers' rights,” said Josh Miller-Lewis, Sanders' spokesman. “Amazon must not contribute to the ongoing attacks on the trade union movement and workers’ constitutional rights to organize."