CASPER, Wyo. (AP) — Federal regulators have withheld approval of Wyoming's plan to increase pollution limits in a 20-mile stream that flows into the Boysen Reservoir north of Riverton.

Kevin Frederick of the Wyoming Department of Environmental Quality says the federal agency has instructed the state to collect more data before changing pollution limits for Badwater Creek.

Badwater Creek is already polluted from a mixture of produced and treated water used in oil and gas production from wells in Aethon Energy's Moneta Divide gas field.

But with about 4,000 wells proposed in an expansion of that project, it's likely that Badwater would see much greater volumes of discharged water.