CHEYENNE, Wyo. (AP) — The Wyoming Oil and Gas Conservation Commission is poised to require companies drilling for oil and gas to first test nearby water wells for pollution.

The purpose is to document the condition of the water and help state regulators determine the source of any contamination that turns up later.

State officials posted the latest version of the proposed rules on the commission website Thursday. The commission will discuss and possibly vote on adopting the rules Tuesday.

John Robitaille with the Petroleum Association of Wyoming says the new rules aren't a problem for petroleum companies. He says many of them already are doing such tests.

The Wyoming Outdoor Council also supports the rules. Spokesman Chris Merrill calls it a "first line of defense" against groundwater contamination.