Businesses in California are voicing their opposition to a plan by the state to end distinctions for vaccinated and unvaccinated workers that they say will make it harder to maintain a robust labor force.

On Thursday, California's Occupational Safety and Health Standards Board revised a temporary rule that would erase current distinctions that exist between vaccinated and unvaccinated workers.

Under these rules, both would be barred from the workplace if they come in close contact with someone with the virus. If they report contact with an infected person but are asymptomatic, they would have to stay home for 14 days even if they test negative or, if they return to work, wear masks and stay 6 feet from anyone else during those two weeks.

The California Chamber of Commerce, the largest association of businesses in the state, opposed the measure. Leading a coalition of 60 business groups, they authored a letter to state authorities that touted the benefits of available COVID-19 vaccines as enough to thwart serious illness or death.

They argued that the regulation for asymptomatic workers would strain the availability of rapid tests and increase costs on employers across sectors of the California economy.

“Treating vaccinated and unvaccinated people similarly really denies the scientific value of the vaccine and disincentivizes vaccination,” Rob Moutrie, a policy advocate for the California Chamber of Commerce, told the Associated Press.

The businesses said that the social distancing requirements would also be difficult to enforce in some fields. For instance, the Motion Pictures Association protested that these restrictions would make filming much more difficult.

Concern has been mounting in the United States about the spread of the Omicron variant of COVID-19. The Biden administration has encouraged Americans to get vaccinated as their first line of defense against the virus and urged the fully vaccinated to get their boosters. President Joe Biden himself said that he saw no need for restrictions, including a lockdown, if higher numbers of Americans are vaccinated.

California was where the first case of an Omicron infection was detected by the Centers for Disease Control and Prevention (CDC) on Dec. 1. A total of 85.1% of Californians have received at least one dose of a COVID-19 vaccination to date, but some counties are reporting higher caseloads and hospitalizations in the weeks since Omicron was detected.