The indoor mask mandate, which applies to the vaccinated and takes effect before midnight Saturday, was reinstated in Los Angeles County Thursday in response to surging COVID-19 cases.
The sheriff's office said that forcing vaccinated people and those who already contracted COVID-19 to wear masks indoors "is not backed by science."
Under current Centers for Disease Control and Prevention guidance, people who are fully vaccinated do not need to wear a mask indoors or practice social distancing.
The "underfunded/defunded" sheriff's department "will not expend our limited resources and instead ask for voluntary compliance," Sheriff Alex Villanueva said in a news release Friday.
He noted that the Los Angeles County Department of Public Health has the authority to enforce the order and encouraged the department to "work collaboratively with the Board of Supervisors and law enforcement to establish mandates that are both achievable and supported by science."
California has seen a startling spike in virus infections since fully reopening on June 15. Before the reopening, cases had declined and the virus outlook seemed optimistic.
Dr. Muntu Davis, the public health officer for the county, said that handing out citations to people who refuse to comply with the rule is "not something we really want to have to do."
The county reported 1,902 new COVID-19 cases Friday and six deaths. Officlas warned that cases are surging among young adults, with 71% of the new virus cases reported Friday among adults 18 to 49-years-old, public health officials said in a release.
On Friday, a test positivity rate of 3.8% was reported, a major jump from the 0.4% rate reported in early June. Currently, there are 452 people hospitalized with the virus, double the 216 hospitalized one month ago.
So far 61% of residents 16 and older are fully vaccinated, according to county data.
Cases are highest and rising the fastest in adults age 18 to 49 years old. Of the new cases reported by Public Health Saturday, 71% are among adults 18 to 49 years old.
"Over 99% of the COVID-19 cases, hospitalizations and deaths we are seeing are among unvaccinated individuals," Barbara Ferrer, Los Angeles County's director of public health, said in a statement Monday.
Officials noted that breakthrough infections -- where a person who has been vaccinated and still contracts COVID-19 -- are low, but still pose a risk. Of the more than 4 million vaccinated people in the county, there have been 4,122 confirmed virus cases as of Tuesday, the release stated.
The release stated the county has a "current substantial and increasing community transmission" and "masking by all indoors can reduce everyone's risk of infection and the risk of transmission to others if infected."
LA County isn't the only one cracking down on rising cases, at least seven California counties issued mask recommndations this week, including San Francisco and Alameda.