CASPER, Wyo. (AP) — Wyoming regulators have approved tougher bonding requirements for oil and gas wells in response to a bust that has littered the Powder River Basin with thousands of abandoned coal-bed methane wells.

The rules approved Tuesday by the Wyoming Oil and Gas Conservation Commission include suggestions from the petroleum industry. Among them is allowing petroleum developers to submit a plan to address their idle wells in lieu of having to post additional bond.

State Oil and Gas Supervisor Mark Watson says Wyoming has plugged some 1,000 coal-bed methane wells over a year and a half at a cost of $4.7 million. The commission originally estimated the effort would take twice as long at several times the cost.

Watson says coal-bed methane wells are cheaper to plug than conventional gas wells.