Legal experts say employers are waiting for the Occupational Safety and Health Administration to provide better guidance on whether workers should wear masks, weeks after the Centers for Disease Control and Prevention announced that vaccinated individuals can forgo mask-wearing indoors.

Meanwhile, workplace safety regulators in at least two states — Washington and Nevada — have issued guidance that they will follow the CDC guidelines. California regulators said they will consider changes in June. Meanwhile, safety organizations are calling for more federal guidance for workers.

Following the CDC’s May 13 announcement, OSHA updated its COVID-19 webpage Protecting Workers: Guidance on Mitigating and Preventing the Spread of COVID-19 in the Workplace with a disclaimer that it is reviewing the CDC guidelines; it intends to update its own guidance; and that employers should follow the current CDC rules.

“It’s a nightmare” for employers, said Fiona W. Ong, a Baltimore-based partner with Shawe Rosenthal LLP and general counsel for the Maryland Chamber of Commerce. “I have a lot of clients calling about what the CDC is saying.”

In light of conflicting federal, state and local guidance, and as more states abandoned mask-wearing altogether, legal experts had been telling frustrated employers to follow the CDC — a fallback option that became problematic with that federal agency’s recent announcement.

Kelley Barnett, Cleveland-based vice president, corporate counsel for labor and employment, at AmTrust Financial Services Inc., said she’s urging clients to consider new workplace policies carefully.

“It depends on the workplace setting and the type of workforce you have and what kind of company you have, and what is your risk tolerance,” she said of any decision to allow workers to go mask-less.

Several large employers have announced that they will follow the CDC’s new guidance on masks for vaccinated workers and customers: Target Corp., Costco Wholesale Corp. and Home Depot Inc. among them.

Ms. Barnett said most employers are waiting for more guidance from OSHA. The pending emergency temporary standard for COVID-19 safety was submitted on April 27 to the White House’s Office of Information and Regulatory Affairs for review. That ETS was in response to an executive order by President Joe Biden, who called on OSHA to develop it by March 15. Four states have created their own emergency safety standards, all of which call for mask-wearing in the workplace.

“I really wonder if that text (of the federal ETS) is going to change based on what the CDC has done,” Ms. Barnett said. “I think if anything it is going to make the process take longer. … It’s an unprecedented time, and we are really relying on our federal and local agencies to give us guidance.”

Adding to the frustration for employers is that OSHA hasn’t been forthcoming about changes to policies, said Brent Clark, partner in the Chicago office of Seyfarth Shaw LLP.

Mr. Clark, commenting on a change on OSHA’s website that stated the agency will not enforce the recordability of adverse reactions to vaccinations that are made mandatory by employers, said “This is now twice, within a week, that OSHA has made an important change and done so without any fanfare.”

“They adopted the CDC guidance that fully vaccinated employees no longer need to mask or social distance and did it just by changing the website,” he said. “They did it again here, embedded in an FAQ without a press release.”

OSHA did not respond to a request for comment.

Angela Childers contributed to this report.  

More insurance and workers compensation news on the coronavirus crisis here.