A Southern California regulatory agency slapped the Los Angeles Department of Water & Power with a notice of violation over equipment identified as the source of a multi-year methane gas leak at a Sun Valley power plant.

Responding to South Coast Air Quality Management District’s notice, LADWP said in a statement that repairs to a pair of compressors at the natural gas-powered Valley Generating Plant were completed in December, adding that the “the leak has been completely stopped.”

Research drones from NASA’s Jet Propulsion Lab in Pasadena detected the leaks beginning in mid-July, the Daily News reported. LADWP General Manager Marty Adams notified the public — and the utility’s board of commissioners — about the leak in late August.

A staffer told the Times that the 67-year-old plant’s compressor units had been leaking gas “for the last couple years.”

Read the full story on LATimes.com.