The small parcel of land beneath the Tobin Bridge just north of Boston is, to commuters, a blur of industrial sprawl. Mountains of road salt along Marginal Street wait to be hauled to nearby towns. Waterfront tanks of fuel go on to heat the region and refill planes at neighboring Logan International Airport. Tractor trailers trek in and out relentlessly.

Amid that commotion is Chelsea, Mass., a dense, 1.8-square-mile community of immigrants that powers Boston and its well-to-do suburbs. In normal times, tens of thousands of service industry workers span out across the metro area from their homes in Chelsea to clock shifts as grocery cashiers, landscapers and restaurant back-of-the-housers. While the physical weight of the economy has long fallen on the shoulders of communities like Chelsea, they are especially vulnerable during the coronavirus pandemic.

Now, Chelsea has the highest infection rate in Massachusetts, a state where more than 75,000 people have tested positive for the novel coronavirus, behind only New York and New Jersey for the number of confirmed cases.

More than 2,200 people in Chelsea, a city of 40,000, have tested positive for the coronavirus, and 124 have died. Many more have lost the minimum-wage jobs that sustained them.

The community was primed for an uneven assault as the coronavirus spread, said Damali Vidot, a city council member. In addition to high rates of asthma in the community, many service-sector employees in Chelsea live in crowded or multigenerational homes, conditions in which the virus flourishes. Because the city has a high number of “essential” workers, many families have continued to be exposed to the coronavirus even as members of the same household faced layoffs.

“One essential worker in a household poses a threat to everyone in that household,” Vidot said. “When a virus comes through that affects people that are breath-burdened, we’re going to be number one on the list.”

Local nonprofits mobilized rapidly to address the one-two punch of hunger and illness that suddenly took hold of the city.

But the extent to which Chelsea, where 67 percent of residents are Hispanic, was shouldering a disproportionate brunt of infections was not apparent until early April. At the time, the state was not publishing city-by-city data. Then, Tom Ambrosino, Chelsea’s city manager, received a spreadsheet of statewide case numbers from Brian Kyes, the city’s police chief. Kyes, who is also president of the Massachusetts Major City Chiefs of Police, had compiled city-by-city data and sent it around to city managers “just as an FYI,” Ambrosino said.

The spreadsheet contained a revelation: Chelsea, despite its small population, had the third most coronavirus cases in the state.

“We were the epicenter,” Ambrosino said.

By mid-March, layoffs caused by the pandemic had exacerbated deep-seated economic insecurity among Chelsea’s residents, 20 percent of whom live in poverty, according to the U.S. Census. Those who suddenly could not work — because they were sick or had been laid off — faced hunger and destitution. Those who could fill essential roles worried about catching the virus and infecting their family members.

“My husband has been taking food to students, leaving it on the doorstep where they live. He can’t work from home. His work is physical, it’s essential,” said Mayra, 42, in Spanish. “These are jobs that only people like us, immigrants, are daring to do right now.”

Mayra, who did not want her last name used because she is undocumented, lost her job making pupusas at a Salvadoran restaurant in March. She and her husband, Luis, have seen their limited savings quickly evaporate as his hours were cut.

When the restaurant where she worked recently reopened for takeout orders, Mayra did not think twice about returning despite being worried about contracting the coronavirus. On reduced hours, Mayra and Luis will still not be able to pay all of their bills, but they hope they can at least mitigate some of the financial damage.

Next will come decisions about which bills can wait.

“The people who live here are people who can’t afford to take a month off work. People who need that check because they don’t have savings; people who either go to work or they don’t eat,” said Roy Avellaneda, president of the Chelsea City Council and a local business owner, noting that the thousands of undocumented people in the city do not receive unemployment compensation.

“All of the assistance that was being offered on the federal level for stimulus checks was not going to happen here, was not going to our crowd,” he said.

The pandemic has also exacerbated the trade-offs between health and wealth that have long plagued Chelsea and communities like it, saddled disproportionately with illnesses caused by poor air quality and poverty, said María Belén Power, an activist and organizer in Chelsea.

“This community powers the entire region,” said Power, who helped found GreenRoots, an environmental justice nonprofit. “But when you look at the composition of our people, by race and class, and you look at the impact on the air quality and on public health, you also see the burdens that we carry.”

She added: “It’s funny that the governors are using the term ‘essential workers.’ I think about the essential role that Chelsea has always played, and yet it is never recognized, even by our neighbors who just don’t realize the impact and the significant role that Chelsea plays in their everyday lives.”

For more than a century, Chelsea has been a crucial repository for successive waves of immigrants arriving in the United States from across the globe. The city is a living storehouse of global history and migration; its decennial census can be read like a rock layer in demographic time, showing influxes of Jews, eastern Europeans, Puerto Ricans and Central Americans across the 20th century. In the 1990s, Chelsea became much more heavily Latino as waves of Central Americans arrived in the United States amid intense violence and economic turmoil in their countries of origin. Today, about 70 percent of families in Chelsea do not speak English at home, and about 60 percent speak Spanish instead.

“If there was any sort of strife somewhere in the world, civil unrest, war, I swear to God, within a week or two, you’d see that group of refugees coming here and living in Chelsea. Central Americans. Croatians. Somalis. Everyone,” Avellaneda said. “The running joke was that everyone landed at Logan Airport and with only five dollars in their pockets, and they could only get as far as Chelsea.”

That history has informed a dramatic community mobilization that sprang up as the illness was spreading in March alongside a second pandemic of unemployment. Avellaneda and others in the community want people to know that what is happening in Chelsea is not just a tragedy. It is also a testament to the community’s strength and resilience.

Gladys Vega, a longtime activist and executive director of the Chelsea Collaborative, a nonprofit, began to see in March how even minor disruptions in the economy would dramatically destabilize the community, especially among day laborers whose hours were suddenly being cut. Food scarcity was already a problem in Chelsea, but the coronavirus sparked a wave of hunger.

Vega began to distribute food on her porch — which she called a “pop-up food pantry” — and the effort has grown into an operation that pulls donations from local businesses and distributes 750 boxes of food twice a week.

An informal pandemic response force has been meeting by phone to coordinate efforts across official city channels, nonprofits and community volunteers. Vega said she knows “I have to play nice” even though she has a reputation for being headstrong.

Avellaneda offered the cafe he owns to Vega so she could have more space to run the pop-up.

“There were lines all the way down the block full of people who were desperate,” he said.

One of those people was Mirna Rivera, 39, who planned to return to work at a frozen fish distribution center after an unpaid maternity leave but has been told that job no longer exists. When her husband, Jose, lost his job at a restaurant, they were suddenly left with no income. Some days, she stands in line for nearly four hours to receive a box of food to take back to her family of four.

“If we don’t go to the line, we don’t have food to eat. Thank God that they’ve been helping us. Thank God,” she said.

The spreadsheet Ambrosino received in April allowed him and nonprofit community groups to make the case that Massachusetts should mount an aggressive response effort in Chelsea. It opened up a floodgate of resources from the government and bolstered the philanthropic efforts that kept thousands of families afloat.

Ambrosino estimates that the city is now delivering about 800 30-pound boxes of food a day, which should last two people about a week. The goal is to distribute 1,500 boxes each day of the week, with the intention of feeding about 40 percent of the population.

The city has also set up temporary housing for recovering coronavirus patients who have nowhere to recover safely, including people whose roommates or family members have asked them to move out after becoming infected, which Vega said she has encountered several times. About half of the 50 rooms secured by the city at a local hotel are occupied.

The city council has allocated $2.1 million to finance the food and housing efforts.

That money is supplemented by donations from the Salvation Army and the Greater Boston Food Bank. About 40 members of the National Guard have been dispatched by the governor to assist with distribution and transportation since April 16. The state has also promised to deliver three meals a day to the sick staying at the hotel.

On a recent afternoon, Rep. Joe Kennedy (D-Mass.) visited the office of the Chelsea Collaborative during one of its food distribution days, the latest in a long line of political visitors that recently included Sen. Edward J. Markey (D-Mass.).

But for all the emergency resources being distributed in the community by nonprofits, organizers and the government, people in the city stressed that the structural inequities that made Chelsea vulnerable will persist long after the pandemic is over. They are clear even now.

“Many of the people that are deemed essential workers aren’t even getting paid wages that allow them to live well. They’re getting paid $12 an hour to work in service jobs,” Vidot said. “We put people in the predicament where they’re forced to pick between their livelihoods or their lives. Fine, let them be essential workers, but let them get essential pay.”

In the meantime, the community’s efforts remain trained on responding to its most immediate crises: sickness and hunger.

On a recent night, Vega had just finished delivering about 300 boxes of food to families quarantined at home with active cases of covid-19, the disease the virus causes. She followed a strict ritual before interacting with anyone in her family. She took off her shoes on the porch. She sprayed herself all over with Lysol, which she called “my new Chanel.” She discreetly undressed and went upstairs to take a shower.

“No disrespect to people who are at home, but they should have a taste of the pain these community members are going through,” she said. “We cry, we laugh, we cry again.”