As Amazon continues its quest to shrink delivery times and add warehouses in Illinois, the e-commerce behemoth is eyeing technology that could track the movements of its workers' hands as they fulfill orders.

The company recently won patents for wristbands that could be used as part of an inventory system, communicating with equipment in warehouses and nudging employees via vibrations if, for example, they were about to place items in the wrong bins. But in a world where the legal limits on gathering and using people's data remain largely undefined, use of such devices could quickly turn nefarious, some experts said.

It's unclear if it ever plans on deploying the technology in its warehouses. The company said it does not track or intend to track its employees' locations.

Instead, it said the wristband technology could improve the work of warehouse employees and make them safer.

"Every day at companies around the world, employees use handheld scanners to check inventory and fulfill orders," spokeswoman Angie Quennell said in an e-mail. "This idea, if implemented in the future, would improve this process for our fulfillment associates."

But the concerns tied to such a device range from the potential for discrimination to data security risks for the company's employees, which number more than 8,000 in the Chicago area.

"Employers are increasingly treating their employees like robots," said Lori Andrews, a professor at the Illinois Institute of Technology's Chicago-Kent College of Law. Part of the problem is that workers rarely realize it, she said.

Some companies hand out Fitbits as part of wellness programs, but those are collecting data on employees, Andrews said. A vending machine company in Wisconsin offered last summer to implant microchips in its employees' hands to ease daily tasks like buying snacks or using the copy machine.

If an employer is hacked, information on workers' movements or other habits could be stolen, Andrews said. The data gleaned from a company-issued device also could end up in insurers' hands and could be viewed negatively, she said.