Amazon warehouse workers in Minnesota are planning to strike during Prime Day on July 15, one of the company’s biggest sales events. Bloomberg reports that about 100 employees are expected to walk out for a total of six hours to demand changes in labor practices, including converting more temporary workers to employees and relaxing productivity quotas that they say create unsafe working conditions.

Striking workers at Amazon’s warehouse in Shakopee, Minn. will be joined by several engineers in a show of solidarity. The activism is being led by the Awood Center, a workers’ rights advocacy group, and backed by the Service Employees International Union, the Teamsters and the Minnesota chapter of the Council on American-Islamic Relations.

In a statement to Bloomberg, Amazon claimed that it “offers already what this outside organization is asking for,” including hourly rates from $16.25 to $20.80 with benefits. It also said that “on average” 90% of workers at the Shakopee warehouse are full-time Amazon employees and it provides coaching for people who are not reaching their productivity quotas.

Amazon announced last October that it was raising minimum wage for all workers to $15 an hour, but many workers said that increase was not enough, especially since it was also getting rid of incentive pay and restricted stock unit grants (the company claimed that its new wage hike compensated for the new wage structure).

There are more than 100 Amazon warehouses in the United States and the walkout will probably not affect logistics on Prime Day, but it is notable as the latest example of activism against the company’s labor practices, which are also under scrutiny from lawmakers. Democratic candidates Bernie Sanders and Elizabeth Warren have made Amazon’s practices a key part of their platforms. For example, Sanders introduced legislation aimed at forcing Amazon, Walmart and other large companies to pay higher wages, while Amazon is one of the tech companies Warren wants to break up.

According to the Bloomberg report, stronger unions in Europe mean Amazon employees there often stage walkouts on important sales days like Prime Day and Black Friday, but this is the first time American employees have walked out during a major sales events. The Minnesota strike follows other activism by Amazon warehouse workers in Minnesota, including a three-hour strike in March for better working conditions and calls last year for more prayer time and reduced workloads during fasting for Ramadan led by East African Muslim immigrants.