Two Tulsa parks were partially closed Wednesday night, because of potential problems with the mulch.
The playground at Hunter Park, which is near 91st and Sheridan, and the swing area of Helmerich Park along Riverside are closed.
The city says one of its contractors had problems with mulch it delivered to other cities.
It had plastic pieces or roofing materials mixed in it.
The Department of Environmental Quality is testing the mulch at Hunter and Helmerich Parks.
The city is keeping the areas with the new mulch closed until they get the DEQ's results.