Several local labor unions began picketing at Ridgedale Mall on Wednesday, protesting non-union contractors who are working on the center's $100 million upgrade.

Members of Minneapolis-based Laborers International Union of North America Local 563, and other construction trade unions say they have pay and safety concerns about the project.

The renovation of the 1970s-era mall includes the addition of a Nordstrom store, the consolidation and upgrade of the Macy's store, as well as improvements to in-line shops.

Local 563 Business Agent Joe Fowler said the picket line will continue until issues are resolved. He said he attended the mall owner General Growth Properties' shareholder meeting on May 16 and was assured by company executives that the union's concerns would be investigated.

But so far, Fowler said, the alleged safety issues remain, including failure to lock electrical panels, improper disposal of potentially hazardous materials, and an unsecured demolition site that was accessible to the public.

Fowler also said contractors working on the project were not meeting "community standards for wages and benefits."

Ridgedale officials referred questions to General Growth's office in Chicago. Two messages left with the company's spokesman Wednesday were not returned.