President Biden directed the Occupational Safety and Health Administration on Thursday to release new guidance to employers on protecting workers from Covid-19.

In one of 10 executive orders that he signed Thursday, the president asked the agency to step up enforcement of existing rules to help stop the spread of the coronavirus in the workplace and to explore issuing a new rule requiring employers to take additional precautions.

The other executive orders also relate to the pandemic, including orders directing federal agencies to issue guidance for the reopening of schools and to use their powers to accelerate the production of protective equipment and expand access to testing.

Critics accused OSHA, which is part of the Labor Department, of weak oversight under former President Donald J. Trump, especially in the last year, when it relaxed record-keeping and reporting requirements related to Covid-19 cases.

Under Mr. Trump, the agency also announced that it would mostly refrain from inspecting workplaces outside of a few high-risk industries like health care and emergency response. And critics complained that its appetite for fining employers was limited. Mr. Biden’s executive order urges the agency to target “the worst violators,” according to a White House fact sheet.

Union officials and labor advocacy groups have long pleaded with the agency to issue a rule, known as an emergency temporary standard, laying out steps that employers must take to protect workers from the coronavirus. The agency declined to do so under Mr. Trump, but Mr. Biden supported the approach during the campaign.

“We talked about a national standardized strategy for working men and women in this country to function under this cloud of the pandemic,” Rory Gamble, the president of the United Automobile Workers union, said after a meeting with Mr. Biden in mid-November. “He indicated he would do whatever it took.”

OSHA’s oversight of the meatpacking industry under Mr. Trump attracted particular scrutiny from labor groups and scholars. A study published in the fall in the Proceedings of the National Academy of Sciences connected between 236,000 and 310,000 Covid-19 cases to livestock processing plants through late July, or between 6 percent and 8 percent of the national total at that point.

That figure is roughly 50 times the 0.15 percent of the U.S. population that works in meatpacking plants, according to the study, suggesting that the industry played an outsized role in spreading the illness.

The study found that a majority of the Covid-19 cases linked to meatpacking plants had likely originated in the plants and then spread through surrounding communities.

Despite the problems identified by the study, the Trump administration did not include meatpacking plants in the category of workplaces that OSHA should regularly inspect. Only a small fraction of the roughly $4 million in coronavirus-related penalties that the agency proposed under Mr. Trump targeted the industry. Fines for any given plant were generally below $30,000.

The Labor Department under Mr. Trump said it had assessed the maximum fines allowed under the law. But former OSHA officials have said that the agency can impose bigger fines by citing facilities for multiple violations, which could raise proposed penalties to over $100,000.

Even when it did inspect meatpacking plants and propose fines, OSHA rarely required these employers to place workers six feet apart, the distance recommended by its own guidance.

During a court case involving a plant in Pennsylvania whose workers complained last year that they were in imminent danger because of the risk of infection, OSHA wrote in a letter on Jan. 12 that it was OK with spacing at the plant, even though some workers were spaced less than six feet apart. Separately, union officials at two other plants where OSHA issued citations said workers continued to stand close to one another after the citations.

Debbie Berkowitz, a senior OSHA official during the Obama administration who is now at the National Employment Law Project, a worker advocacy group, said she expected the Biden administration to issue a rule requiring meatpacking facilities to space workers six feet apart and mandating other safety measures, such as providing high-quality masks and improving ventilation and sanitation at their facilities.

“OSHA had been sidelined under Trump,” said Ms. Berkowitz. “This is a signal they’re going to play a significant role in mitigating the spread of Covid-19,” she added, alluding to Mr. Biden’s executive order.

The Biden administration is likely to revisit a wide variety of labor and employment issues from the Trump era, including a rule that would make it harder for employees of franchises and contractors to recover wages that were improperly withheld from them, and another rule that would likely classify Uber drivers and other gig workers as contractors rather than employees.

On Wednesday, the new administration fired the general counsel of the National Labor Relations Board, a Senate-confirmed official who has wide latitude over which labor law violations the board pursues. The official, Peter B. Robb, was appointed by Mr. Trump and clashed frequently with unions.