OLYMPIA, Wash. (AP) — The hedging practices of natural gas companies in Washington state have cost ratepayers hundreds of millions of dollars in recent years, and officials said Thursday they are recommending a moratorium on new hedging arrangements.

The state attorney general’s office said it wants the Washington Utilities and Transportation Commission to continue investigating the purchasing strategies used by utilities. Lisa W. Gafken, an assistant attorney general, said companies have no real incentive to improve their investment efforts — something that is evident in the losses during recent years.