The federal agency responsible for making sure states effectively oversee the safety of natural gas and other pipelines is failing to do its job, a government watchdog said in a report released Friday.

The federal effort is so riddled with weaknesses that it’s not possible to ensure states are enforcing pipeline safety, the report by the Transportation Department’s Office of Inspector General said. The federal Pipeline and Hazardous Materials Safety Administration, or PHMSA, isn’t ensuring key state inspectors are properly trained, inspections are being conducted frequently enough and inspections target the most risky pipelines, it said.