Amazon employees start their shifts passing through turnstiles and a sign reminding them what they can't bring with them as they report for work alongside robots.
Cell phones, belts, keys, and loose change must be stored away in one of hundreds of lockers by the break area at the West Deptford fulfillment center. Inside, 7.75-inch-tall robots that can carry up to 1,250 pounds and have no resemblance to the humanoid robots of science fiction help them do their jobs.
The robots -- effectively shelves on wheels -- zip around at 5 feet per second inside a large cage on the second and third floors of a warehouse the size of almost 30 football fields.
While Amazon hires tens of thousands of people in the process to staff warehouses like the one opened in September in Gloucester County, the Seattle-based company is also embracing automation and deploying robots to do work once done by humans. Critics and labor advocates worry that automation could replace human workers and that the machinery-rich Amazon warehouses are an unsafe working environment.
"It's not humans vs. machines at all," Tye Brady, the chief technologist at Amazon Robotics, told the BBC this month. "It's humans and machines working together to achieve a task."
Amazon has grown rapidly, from 20,700 employees in 2008 to 647,500 full-time and part-time employees last year. In West Deptford, the company said it has more than 1,500 full-time employees and uses more than 3,000 robots.
Amazon's net sales increased 31% last year to $232.9 billion and its net income more than tripled to $10.1 billion.
"Despite these vast resources," a report from the National Council for Occupational Safety and Health states, "there is little evidence the company has made a significant effort to address worker complaints about stress, overwork, and other conditions which can lead to illness, injuries and even fatalities."
Six workers have died at U.S. Amazon facilities or operations since November 2018, and 13 workers overall have died since 2013, according to the report.
Amazon insists that its facilities are safe and that increasing automation does not mean it will hire fewer people.