Amazon agreed to pay its workers at least $15 an hour last year, but that concession has not put an end to protests by employees, at least not at its fulfillment center in Shakopee, Minnesota, where a Prime Day 2019 work stoppage is planned for this year's expanded two-day sales event July 15 and 16.

Some workers at the warehouse say they want the retailer to soften productivity quotas that they claim makes their jobs unsafe and needlessly stressful. "They try to get someone to work as hard as you can under the threat of being fired," said Tyler Hamilton, a 22-year-old employed at the warehouse for nearly two years. "As much as they can, they figure out ways to collect data and measure work."

Trying to get Amazon to ease quotas and its reliance on temporary workers, Hamilton and others at the facility plan to walk off the job for three hours at the end of the day shift and three hours at the beginning of the night shift on July 15. That's the first day of the highly touted annual sales event used to entice and keep Amazon Prime subscribers who pay an annual fee for free shipping and other benefits. Workers also intend to rally outside the warehouse.

Get Breaking News Delivered to Your Inbox

"Amazon offers already what this outside organization is asking for," a company spokesperson stated in an email to CBS MoneyWatch, referring to the Awood Center, an advocacy group for the Amazon warehouse workers.

"We encourage anyone to compare our pay, benefits and workplace to other retailers and major employers in the Shakopee community and across the country," added the company spokesperson, who cited cited hourly pay ranging from $16.25 to $20.80 and benefits including health care.

Hamilton, however, refuted the notion that the Awood Center had stoked worker demands: "This is from within Amazon. It's not just an outside agitating force," he said. "We reached out to the Awood Center for advice, as many of us are recent immigrants in the U.S. and also this is not something they teach in high school."

A group of Amazon engineers reportedly intend to fly to Minnesota to join the demonstration, which will include demands that Amazon take steps to curb climate change, along with relaxing productivity quotas and making the company's corps of temp workers permanent employees.