The Environmental Protection Agency isn’t doing enough to prevent methane leaks from natural gas pipelines that deliver energy to customers, according to a report from its internal watchdog.

The report suggested setting goals that can be reached voluntarily to determine whether additional regulations are necessary. It also said the EPA needs to keep more thorough, long-term accounting of methane leaks from the natural gas distribution system, rather than combining such data with other sectors, and to create a performance metric to track progress. It said rules for the distribution system, which the EPA does not currently regulate for methane emissions, also might be necessary.