Some 10,000 grocery store workers across the greater Denver area went on strike Thursday, claiming unfair and illegal negotiating practices by King Soopers while their union has been negotiating a new contract with the store chain.

King Soopers, a chain owned by Kroger, with 121 stores in Colorado and Wyoming, has been negotiating a new contract with the union since October.

Negotiations on a new collective bargaining deal date back to October 2024, with the union's previous deal having expired in January 2025.