At the Bath Iron Works on Maine’s Kennebec River, workers are showing up by the hundreds to build ships for the Navy. At Mike Doherty’s auto repair shop in Everett, Wash., three mechanics continue to fix faulty transmissions and leaky radiators. And while the McDonald’s in Kansas City is closed to sit-down customers, the drive-through window still needs tending, as does the french fryer.

While many people across the country are hunkered down at home to prevent the spread of the coronavirus, armed with laptops and WiFi connections, millions more are required to show up at factories, hospitals and grocery stores to do their jobs. The coronavirus pandemic has highlighted yet another fault line in America’s racial and socioeconomic divisions — those who can do their jobs from home and those who can’t.

As new communities go into lockdown in hopes of slowing the spread of the virus, the people most at risk for getting sick, because they must venture out, are largely people of color, those with only a high school education and those whose incomes are likely to suffer during the ongoing crisis.

The concern came to a head last week as the big three auto manufacturers, GM, Ford and Chrysler, gave in to demands by the United Auto Workers union and took the extraordinary measure of shutting their plants for two weeks amid fears of the pandemic. In New York, Gov. Andrew M. Cuomo said all nonessential businesses in the state had to keep their workforces at home, saying: “This is not life as usual. Accept it, realize it and deal with it.”

Despite those attempts to limit contact in the workplace, many industries — from aerospace and defense to the service sector — remain open, renewing calls to protect workers’ health and shield them from the financial fallout of the pandemic.

During the past few decades, the growth of the digital economy has made it possible for an expanding number of people to work remotely — nearly 30 percent of American workers, 41.6 million people, can do that, according to a survey from 2017-2018 by the Bureau of Labor Statistics. But workers who make cars and airplanes, cook french fries, clean hospital rooms, and rely on wrenches and brooms, not Internet connections, for their jobs cannot.

The divide is stark within industries. About 60 percent of people who said they work in “management, business and financial operations” told the BLS that they could work from home. But fewer than 10 percent of workers said they could do so in categories described as “services,” “construction and extraction,” “installation, maintenance and repair,” “production” and “transportation and material moving.”

There are also divisions along race and class lines. Thirty-seven percent of Asian Americans and 30 percent of whites said they could work remotely. But only 20 percent of African Americans and 16 percent of Hispanics said they had that ability. Almost 52 percent of those with a college education or higher said they could work from home, but only 4 percent of those with less than a high school diploma said they could.

“It is really shedding light on some inequalities in a new way,” said Heidi Shierholz, former chief economist for the Labor Department, now at the Economic Policy Institute. “A lot of people who have highly paid, white-collar jobs that are computer-focused can adjust to this crisis without a lot of pain. And then there’s a much larger group that can’t adjust without a lot of pain to themselves and their families.”

Social media is full of photos of quarantined families gathered around the dining room table, parents with their laptops out, children with their schoolwork spread around them. For those who have the flexibility to work in their pajamas, the coronavirus might become a fun anecdote for the future, if life returns to normal in a few weeks or months.

“We’ll have stories to tell about how we had a little more time together with our family,” said David Wilcox, an economist at the Peterson Institute for International Economics. “That’s not the case for a line worker at a manufacturing plant. They need to show up at a specific physical location regardless of whether that’s convenient for them or not. And that presents a personal health risk to themselves, and a public health challenge because it also presents a risk to their co-workers.”

In many cases, manufacturing and service-sector workers don’t have paid sick leave, and can’t afford to miss work. That makes life particularly difficult for those who have to scramble to care for elderly parents susceptible to serious illness and look after children home from school.

“A lot of people are living paycheck to paycheck,” said Chris Wiers, president of Local S6 of the Machinists Union that represents many of the nearly 7,000 workers at the Bath Iron Works shipbuilding factory in Maine. “You go two weeks without pay or more and you risk losing your house, your car, and a lot of people have those concerns.”

Terrence Wise, a 40-year-old father of three teenage girls, was sent home 2½ hours before the end of his shift Tuesday night as a manager at a McDonald’s in Kansas City, Mo. The restaurant was serving only drive-through customers, sales were way down, and so the owner started sending people home.

“I make $13 an hour, so to lose 2½ hours, that’s over $25,” he said. “That’s a meal on the table for my girls. That’s one-fourth of my lighting bill.”

With no paid sick leave or health insurance, he fears things are only going to get worse — more lost hours, possibly layoffs and the difficulty of coming up with the $1,200 a month he needs for rent.

“To say I’m concerned is an understatement,” he said. “I’m scared to death.”

Even some older workers, who are at a heightened risk of dying from the virus should they contract it, are still actively reporting to work.

One is Karla Wagoner, 71, who depends on her $12-an-hour income as a nonmedical home health-care aide to meet the $1,750 monthly rent she splits with her son in Fort Collins, Colo. Recently she had to cash out her retirement account to buy a new car after her old one became too expensive to maintain.

Lately, her clients are fearful of an outsider coming into their home, she said, and many have canceled. She has only nine hours booked for the coming week and is worried about what comes next.

“Without the hours, I don’t know what’s going to happen,” Wagoner said.

Several unions said they were struggling to get employers to create safe work environments.

“There’s a lot of things that aren’t available — masks, hand sanitizer, gloves, things to specifically cut down on the rate of passing the virus on to other co-workers,” said Jon Holden, president of Machinists Union District 751, which represents 32,000 Boeing workers in Washington state.

Boeing, which has had about a dozen of its employees in the area test positive, said in a statement that the “health and safety of our employees is our top priority, and we’re partnering closely with public health officials to monitor and prevent the spread of COVID-19,” the disease caused by the coronavirus. The company is “taking extra precautions to ensure cleanliness in our factories and offices. This includes more frequent cleaning of high-touch surfaces and common areas,” it said. And if an employee does test positive, “we are taking swift action to ensure the affected employee is provided with the immediate medical care and guidance they need.”

Holden, however, said the company could be doing more.

“We need to ensure people have the proper personal protective equipment,” he said. “And in some instances we’re requesting there be special training. There’s a lot of concern. Our members work in and around each other in close quarters.”

At Bath Iron Works, the shipyard run by defense contractor General Dynamics, where some workers make $15.97 an hour, union officials have called for the factory to be shut down. They were also concerned when the company that provides bus service to the factory from employee parking lots discontinued operation as a precaution to prevent the spread of the virus. Instead of standing down, company officials asked employees to take over the bus service so work could continue, Wiers said.

“The company seems to be taking every advantage not to do the right thing,” he said. “I know people who have those licenses who said, ‘Are you crazy? No way I’m doing that.’ It obviously sends the message that we don’t care, we need you in the shipyard and we need you to be productive.”

In a statement to The Washington Post, the company said it has “implemented CDC-recommended measures to protect our workers in the labor intensive, heavy manufacturing shipyard environment.” And in a statement posted on the company website, it added, “neither the Department of Defense nor the Navy has directed us to stop work or otherwise relieved us from our contract or schedule requirements. This is no different for us than it is for other major U.S. defense manufacturers.”

The company “has taken measures to slow the spread of COVID-19” and “to ensure the employment security of our employees should they be unable to work or choose not to work.”

On Friday, Ellen Lord, the undersecretary of defense for acquisition and sustainment, issued a memo saying defense industry workers, such as those in Bath, were performing duties vital to national defense and are “expected to maintain their normal work schedules.”

At the Kohler factories in Sheboygan, Wis., the stark divide between who can work from home and who cannot is readily apparent, said Tim Tayloe, the president of United Auto Workers union Local 833, which represents about 1,900 workers at several factories run by Kohler.

Workers who must remain at their posts are sitting one foot from one another in one factory, a facility that makes engines for tractors and generators, while many on the administrative side are working from home.

Tayloe said the union and the company are “working hard to keep everybody safe on the floor.” That includes extra efforts to sanitize tools and surfaces and moving shifts around so there are fewer people in one place.

Still, some in the factory have acknowledged an uncomfortable divide between the company’s office employees who can work from home and those who have to be on-site.

“What are we, second-class citizens to the people that work in the office?” Tayloe asked.

In Ottumwa, Iowa, pretty much everything is shut down — the schools, the churches. But not the John Deere factory, which has stayed open, humming along. And the workers are in close quarters, whether they like it or not.

“Social distancing kind of seems like a joke in a factory setting,” said Julia McFarland, 42, who works a robotic welding machine there.

She thinks the plant should be temporarily closed. And with a 66-year-old mother, she’s concerned workers will spread the virus without knowing they have it, and bring it home to more vulnerable family members.

“It almost feels like they’re playing God with your health,” McFarland said. “They don’t seem to really care whether we’re exposed to this or not. We have office people that have been sent to work from home. And here we are in the factory. You’re just kind of at a loss for what to do.”

John Deere did not respond to a request for comment.

Mike Doherty, the owner of M&N Absolute Auto, an auto repair shop in Everett, Wash., said business was down last week. But customers were still bringing in cars for repair, and his mechanics are there to help.

“We can’t fix people’s cars from home,” he said. “And we need to help people get to work.”

CORRECTION: An earlier version of this story gave an incorrect figure for the number of workers who told the Bureau of Labor Statistics they could work remotely. The number is 41.6 million people, nearly 30 percent of the workforce.