The Los Angeles County board of supervisors unanimously voted to prohibit new oil wells and evaluate existing ones, taking a big step towards ending oil extraction in the US’ largest county.

Currently, oil wells cannot be shuttered in the county until companies recoup the costs of drilling. Under the new measure, the county will evaluate if costs have been recouped on each well and designate extraction as “nonconforming” use, allowing the county to revoke permits.

Although oil drilling may not be the first thing that comes to mind when you think of Los Angeles, the county is actually home to thousands of wells. This new measure could potentially shut down 1,600 of them, most of which sit in the Inglewood Oil Field, a region that produces up to three million barrels of oil a year.

More than one million people live within a five-mile radius of the field, exposing them to dangerous air pollution which has been linked to cancer, preterm births, and respiratory illnesses. This would be particularly beneficial for communities of color as 73 percent of the tens of thousands of residents who live near oil wells in the county are people of color.

Supervisor Holly J. Mitchell, who led the motion, said, “We have an opportunity and responsibility as the home of the largest urban oil field in the nation to lead by example in creating an equitable path for phasing out oil drilling.”