SAN FRANCISCO – A federal review says the U.S. Environmental Protection Agency is failing to protect drinking-water reserves from oilfield contamination.

The U.S. Government Accountability Office review follows disclosures that California allowed oil companies to dump wastewater into some federally protected supplies of drinking-water. The review looked at California’s problems and sampled how EPA offices in several states were doing on the same issue. Those states were Colorado, Kentucky, North Dakota, Ohio, Oklahoma, Pennsylvania and Texas.

Inspectors found EPA offices were failing to do the paperwork and on-site inspections needed to make sure states are enforcing safe-drinking water laws when it comes to oilfield waste.

In a statement, the EPA said it generally agreed with the GAO’s findings and was working to improve. California officials did not immediately respond to requests for comment.