The independent and self-described socialist from Vermont, a former presidential candidate, told his Twitter followers that Amazon employees were working under risky conditions, leaving them susceptible to the coronavirus, while being denied paid sick leave and hazard pay.
At the same time, Sanders claimed that Jeff Bezos – the wealthiest man in the world, with a fortune amounting to $187 billion – became $83 billion richer during the pandemic and that his company "made record profits."
"This ugly corporate greed must end," Sanders tweeted.
Amazon, the second-biggest private employer in the nation behind Walmart, flatly denied the claims.
"Everyone makes at least $15/hr *double the federal minimum wage* and we’ve created more than 275,000 new jobs in the US since the pandemic began," Amazon's policy team replied to Sanders via Twitter.
Amazon also noted that it has provided paid sick leave and comprehensive benefits for all its full-time employees, equivalent to the benefits its "most senior executives get."
While the globe has grappled with lockdown measures to stem the spread of COVID-19 during the past nine months, shoppers have become ever more reliant on the world’s largest online retailer, benefiting its sales.
In response, the company has grown its workforce throughout the year. Including seasonal hires, Amazon has added 1,400 jobs per day in 2020.
Employee complaints have crescendoed at the same time, however, particularly from workers who fear contracting the virus while on the job.
Small groups have staged walkouts at Amazon warehouses in New York, Chicago and Detroit, demanding that the facilities be closed for deep cleaning after workers there tested positive for the virus. Others argued the company had not been transparent enough with the public or its employees on how many workers have tested positive for the virus.
Earlier this month, protesters gathered outside the Amazon chief executive's multimillion-dollar Fifth Avenue residence to call attention to Bezos and other CEOs who they claim have made billions during the global health crisis while putting workers' lives at risk.
They called for stricter workplace safety standards and asked state lawmakers to pass the New York Health and Essential Rights Act, otherwise known as the NY HERO Act, which would implement minimum standards for workplace safety, enforceable through significant fines.
ALIGN NY pointed to the more than 19,000 Amazon frontline U.S. employees – or 1.44% of its total workforce, including Whole Foods workers – who have either tested positive or have been presumed positive for the virus.
At the time, Amazon called the claims a "series of misleading assertions by misinformed or self-interested groups who are using Amazon’s profile to further their individual causes."
In November, the company released a full state-by-state chart of case rates among its frontline employees in a blog post, along with plans to boost daily tests in an effort to keep frontline employees safe.
Infections were 42% lower than Amazon's earlier estimate of 33,952 cases, the company said at the time, a figure based on infection rates among the general population.
Amazon says it has made over 150 process updates, including enhanced cleaning and social distancing measures, distribution of personal protective gear and temperature checks across its global operations.
The Associated Press contributed to this report.