The Los Angeles County Metro Board of Directors on Thursday approved a COVID-19 vaccine requirement for law enforcement officers who are contracted to provide security.

The details of the requirement, which was included as an amendment proposed by Supervisor Janice Hahn, will be considered early next year, Hahn’s office said in a press release.

Hahn’s office added that it is possible that the vaccine mandate will not only apply to officers who work with Metro, but to entire organizations, which could put Metro in conflict with the Los Angeles County Sheriff’s Department, one of three law enforcement agencies that have contracts with Metro.

Los Angeles County Sheriff Alex Villanueva announced in October that he won’t enforce a vaccine mandate for his deputies, and Hahn’s office said that “just 53% of his department’s employees are currently vaccinated.”

“During this pandemic, public safety also means keeping the public safe from this virus,” Hahn said. “Metro staff and bus drivers are already required to be vaccinated and the law enforcement officers and deputies who are charged with keeping our riders safe need to be vaccinated as well.”

Villanueva, who has opposed the county’s mandate since it was approved in August and took effect in October, said requiring the vaccine would mean some of his deputies would resign or retire.

“I don’t want to be in a position to lose 5, 10% of my workforce overnight on a vaccine mandate,” Villanueva said in October.

Last month, Villanueva announced that the number of resignations and retirements has increased, and he blamed the vaccine mandate, according to the Los Angeles Daily News.