SANTA FE, N.M. (AP) — A top state regulator of the petroleum industry in New Mexico who helped implement new restrictions on methane pollution and waste is leaving her post at year’s end, the governor’s office announced Thursday.

Sarah Cottrell Propst is ending her five-year tenure as secretary of the Energy, Minerals and Natural Resources Department — a period that saw an unprecedented expansion of oil and natural gas production. New Mexico is the nation’s No. 2 oil producer.

Advanced oil-drilling techniques have unlocked massive amounts of natural gas from New Mexico’s portion of the Permian Basin, which extends into Texas, while producers sometimes struggle to fully gather and transport the gas.

State oil and gas regulators recently updated regulations to limit methane venting and flaring at petroleum production sites to rein in releases and unmonitored burning of the potent climate warming gas, with some allowances for emergencies and mandatory reporting.

In a statement, Gov. Michelle Lujan Grisham praised Cottrell Propst for responsible stewardship of natural resources that limited local climate pollution.

She also highlighted Cottrell Propst’s role in negotiating 2019 legislation that set benchmarks for modernizing the state’s electrical grid with the integration of more electricity production from solar and wind installations.

Cottrell Propst has led an agency with more than 550 employees with responsibilities ranging from forest health to oversight of 35 state parks.