Dr. Michaels said in an interview that OSHA might understandably focus inspections on certain high-risk industries during a crisis that is straining its resources. But he said this made it even more important for the agency to tell employers how to keep workers safe and clarify their responsibilities for doing so.

Instead, “they’re doing the opposite,” he said. “It’s really disheartening.”

A Labor Department spokeswoman said that notwithstanding the new enforcement approach, “if OSHA were to find flagrant violations of the law, the agency would use all enforcement tools available.” The spokeswoman said that OSHA had received about 2,400 coronavirus-related complaints by Tuesday and that it had resolved about 1,400. She said that the agency had yet to issue a citation to an employer but that it had six months to complete its investigations.

Mr. Ryan, the Target employee in Virginia, has not filed a complaint with OSHA about his concerns. Target cited a policy of limiting the number of shoppers when necessary. It said that it invited workers to raise concerns and had a process in place for addressing them, but that workers had not typically complained about the difficulty of social distancing at that location.

Some workplace-safety experts expressed concern that OSHA had largely exempted Covid-19 cases from a general requirement that employers determine whether a worker became seriously ill on the job, and that they report such cases to the agency and keep records of them.

In guidance issued on April 10, the agency said it would not enforce the record-keeping requirement for Covid cases until further notice, except when the employer could obtain clear evidence that the infection was work related, a substantially higher bar than before. Only employers in health care, emergency response or prisons must apply the standard record-keeping procedure in Covid cases.

The government relies on such reporting in several ways, like deciding which industries and workplaces to inspect in the future. Record-keeping also allows employers to figure out where their problems are and how to address them, making it particularly important when the agency is directing most employers to investigate coronavirus outbreaks on their own, experts said.

“First and foremost, they’re supposed to record so they themselves have the information necessary to determine where there are problems and when to do something about them,” said Jordan Barab, a top OSHA appointee during the Obama administration.