DENVER (AP) â¿¿ A Colorado coal-industry group says two public utilities commissioners should recuse themselves from considering a plan by Xcel Energy Inc. to switch some power plants to run on natural gas instead of coal. A new state law aimed at meeting federal clean air standards required Xcel to file a plan to cut emissions. The three-member Colorado Public Utilities Commission must accept, deny or modify that plan by Dec. 15. The Colorado Mining Association said in a filing with the commission that PUC Chairman Ronald Binz and Commissioner Matt Baker were involved in negotiations with Xcel on the new law and can't be considered impartial as they review Xcel's plan. A commission spokesman wasn't immediately available for comment Wednesday.