On a sweltering spring day in South Carolina, a worker they call the “Burn Boss” stands by a house, holding a torch. The radio crackles with a countdown, “3, 2, 1!”

And the Burn Boss sets the house on fire.

Within minutes, flames breach the walls and enter the building. They set alight a sofa, a bed, a closet full of clothes and a kitchen stocked with cooking oil and potato chips — all fuels for an accelerating blaze. Moments later, the light and heat roar outward from shattered windows, forcing onlookers to step back.

This is a test.

A nonprofit in South Carolina is in the unusual business of intentionally burning down houses built for this purpose in order to learn how best to protect people and their property against catastrophic wildfires.

As climate change amplifies heat waves and droughts, it is priming wildfires to burn bigger and faster. At the same time, people continue to move into areas more vulnerable to fire. This one-two punch is driving record financial losses as homes and entire communities burn.

Controlled experiments like these are contributing to a growing body of evidence suggesting that losing entire communities to fire is not inevitable, if the right steps are taken when designing homes and neighborhoods. If you can “prevent this house from igniting, you’ve likely prevented the next one from igniting,” said Murray Morrison, the Managing Director of Research at the Insurance Institute for Business and Home Safety, or IBHS, the organization running the test.

Disastrous wildfires used to be thought of as relatively isolated events, but there’s been a significant change in their frequency, said Michael J. Gollner, the director of the fire research laboratory at the University of California at Berkeley. “We have to start recognizing that our communities are no longer safe,” he said.

Tests like the one in South Carolina are an acknowledgment that climate change is already affecting people’s lives in potentially devastating ways.

After the test house ignites, IBHS employees track the flames as they burrow under the roof, shatter windows and send a torrent of embers toward a second building downwind. While they’re studying the blaze, a wall of industrial turbines fan the flames with gusts up to 50 miles per hour — roughly the same wind speeds that helped to fuel the wildfires in 2018 that destroyed Paradise, Calif., one of the most devastating disasters in recent years.

By the end of the experiment, millions of data points will capture exactly how a fire might spread from house to house. This is precisely the kind of blaze that’s becoming more common as wildfires reach into dense neighborhoods.

Few organizations have the funding and facilities to study fire in this way. In a series of experiments, researchers have burned down 14 “test” homes. They tweak the building materials, wind speeds and other variables to mimic real-world conditions. The video above shows the downwind building, equipped with a half-million dollars of sensors and equipment, as it measured the danger posed by its fiery neighbor under one of these scenarios.

These and other experiments have taught valuable lessons. For example, use building materials and methods designed to withstand embers, heat and flames. Remove flammable things in the yard, particularly within five feet of a building, to lower the chance of fire reaching it at all.

An analysis found that communities combining these strategies were twice as likely to survive a major conflagration.

The insurance industry, which is the primary source of funding for IBHS, is using its research. California requires insurers to offer discounts if homeowners upgrade their properties to be more fire-resistant. Some of the biggest savings come from meeting a collection of standards that qualify for a certification under the IBHS Wildfire Prepared Home program, rather than making individual changes. California’s fifth-largest insurer, CSAA, now guarantees policies to anyone with the certification.

Studies also show that the distance between buildings is important. Ideally, according to IBHS research, homes would have 30 feet or more between them to minimize the chance that one becomes fuel to burn the other.

Of course, the distance between homes is impossible to modify once a neighborhood has been built. But “can we reduce the exposure enough that the hardened materials on the neighbor’s structure actually prevent your home from igniting?” asked Dr. Morrison. “What you’re trying to do is stop the catastrophe, not achieve perfection,” he said.

Even though California has some of the country’s strongest standards for new construction, it has struggled to keep pace with the wildfire threat. After devastating fire seasons in 2017 and 2018, private insurers began rapidly dropping customers, pushing more than 500,000 homeowners onto the state’s costly, bare-bones insurer of last resort. Many people have decided to forgo coverage altogether.

In an effort to lure insurance companies back into the state, California lawmakers have taken steps to require people to reduce their fire risk.

In 2020, the state legislature passed a bill requiring people in particularly fire-prone places to clear flammable materials from the first five feet around their house. However, some local officials and neighborhood organizations objected, and implementation of the plan has been delayed.

Unwilling to wait, the city of Berkeley, Calif., enacted its own local version of the rules. They took effect in January. “This is an area where there is a strong body of research,” said Colin Arnold, the assistant fire chief at Berkeley Fire.

As this map shows, homes in Berkeley with starkly different fire risks can exist on the very same street, depending on construction methods, vegetation nearby and proximity to other houses. By focusing on the blocks closest to the fire-prone hills to the east, Berkeley officials hope to lower the threat posed to the rest of the city.

To ease the transition, fire officials started with voluntary inspections and community groups are helping clear brush for neighbors at no cost. And local landscape architects are helping residents adapt their yards in ways that they still find attractive.

Wildfire isn’t a new threat; it’s been affecting humanity for millennia, said Roy Wright, the president of IBHS. “I don’t want us to ever assert that we can somehow design ourselves out of this risk,” he said. The goal, instead, is to put people in a place where “the risk doesn’t feel catastrophic.”

Thousands of people across 34 states are experiencing explosive and prolonged diarrhea due to a food and water-borne parasitic disease that has prompted experts to urge people to take extra precautions when preparing food.

A specific type of produce, grower or supplier has not been identified as the source of each state’s outbreak; officials say there could be multiple sources.

At the epicenter of the cyclosporiasis outbreak in Michigan, where more than 3,700 residents have been infected, public health experts say a possible culprit under investigation is leafy greens.

Some Taco Bell locations in Michigan are also being investigated after the chain voluntarily stopped selling lettuce, cilantro, onion, pico de gallo and guacamole, “due to a nationwide recall.”

Even though the clusters of outbreaks are concentrated in the Midwest and East Coast, epidemiological and infection prevention experts urge people in California and the rest of the U.S. to be cautious with their produce and take the necessary steps to reduce their risk of infection.

California has reported 41 cases of cyclosporiasis, between January and June, none of which are linked to the current outbreak. That is below the average of 100 cases reported annually in California, usually between May and August, said Robert Barsanti, spokesperson for the California Department of Public Health.

“It’s important to understand that California experiences cases of cyclosporiasis every year, with a majority of cases acquired internationally,” said Erica Pan, director of the state agency. “Cases for 2026 are well within expected ranges for California.”

Rising cyclosporiasis cases shouldn’t deter Californians from eating fruits and vegetables. Instead, experts say, it’s a call to take extra precautions to reduce the risk of contracting the parasitic disease.

Which produce are potential sources of cyclosporiasis

In the U.S., food-borne outbreaks of cyclosporiasis have been linked to various types of fresh produce imported from Latin America, including raspberries, cilantro, basil, snow peas and mixed salad, according to the California Department of Public Health.

One of the largest cyclosporiasis outbreaks in North America was linked to imported raspberries from Guatemalan farms in 1996, said Dana Mordue, associate professor of pathology, microbiology and immunology with New York Medical College.

At the time, more than 1,400 cases of the disease were reported in 20 states, the District of Columbia and Canada.

How to reduce your risk of contracting cyclosporiasis

The first step is to wash your hands with soap and water before handling produce.

Then, experts say:

• Wash all fruits and vegetables thoroughly under running water before eating, cutting or cooking.
• Remove and discard outer leaves from lettuce and leafy greens.
• Cook vegetables and herbs whenever practical, especially for vulnerable populations including young children, pregnant women and immunocompromised individuals.
• Prevent cross-contamination: Use clean cutting boards, utensils and food-contact surfaces. Keep ready-to-eat foods separate from raw produce during preparation.
• Refrigerate cut, peeled or cooked fruits and vegetables as soon as possible (within two hours).
• Avoid food or water that may be contaminated by human feces, especially when traveling to countries where tap water or food may be unsafe.

If your produce comes in a package that says “pre-rinsed,” experts say you should still take the time to rinse it yourself.

Will a simple rinse of all types of fruits and veggies reduce my risk?

Some fruits and vegetables should be rinsed and others scrubbed, depending on the type of produce, said Britanny Saunier, executive director with the Partnership for Food Safety Education, a nonprofit that develops and promotes food safety material to reduce food-borne illness.

All types of produce should be rinsed under running water, including those with skins or rinds that are not eaten.

“We recommend an extra step for those firm-skinned fruits and vegetables — such as a cucumber or melon — which should be rubbed by hand or scrubbed with a clean brush while rinsing under running tap water, Saunier said.

You should dry your cleaned produce with a clean cloth or paper towel.

Some supermarkets offer “produce washes,” usually provided in spray bottles, which claim to break down surface waxes and remove dirt, pesticide residues and harmful bacteria. But the U.S. Food and Drug Administration does not recommend them because the safety of their residues has not been evaluated, she said.

“Many types of fresh produce are porous and could absorb these products, potentially changing their safety and taste,” Saunier added.

Rinsing and scrubbing is the most effective method of lessening your risk of contracting the disease but it doesn’t eliminate it entirely, Mordue said.

That’s because the parasite has a tough outer shell, making it difficult to eliminate, said Dr. Norman Beatty, associate professor of medicine with the Division of Infectious Diseases & Global Medicine at the University of Florida College of Medicine.

The parasites’ cell walls are “highly resistant to adverse environmental pressures and traditional disinfectants,” Beatty said.

In general, the parasite has been found in soil and from there it sticks to produce, likely due to the use of contaminated water or inadequate hygiene among food handlers, she said.

“It is unclear how to safely remove these [parasites] from produce once they have contaminated soil or plant matter, but merely washing with water is likely not to remove them prior to eating,” Beatty said.

Are there any types of produce I should avoid entirely?

Because lettuce and bagged salad greens have been identified as potential sources of the outbreak in Michigan, Mordue said she would be cautious with bagged leafy greens.

As a resident of New York, one of the states currently reporting an outbreak, Mordue said she has a bag of packaged greens in her fridge that she plans to toss in the trash.

The advice for Californians might be slightly different since the state isn’t reporting an outbreak. Rinsing leafy greens before serving them is fine, Mordue said. But if you can do without them for the time being, she said, avoid them.

In the case of packaged spinach, cooking the leaves can reduce your risk of contracting cyclosporiasis.

How does this type of outbreak end?

It’s difficult to say when an outbreak might end until the source of the parasitic disease is identified.

When local and federal public health officials, “zero in on a specific causative agent, they can end it pretty quickly,” Mordue said.

Once a source is identified, she said, a recall notice will be issued for the contaminated produce and people will know exactly what they shouldn’t eat.

“The sooner they can figure it out, the sooner it’s going to end,” Mordue said. “That said, if they cannot figure out the source this could go on for a while.”

What are the symptoms and remedies for cyclosporiasis?

Someone who contracts the parasite might end up with week-long watery and explosive diarrhea, “which is bad enough,” she said.

Other symptoms include loss of appetite, weight loss, cramping, bloating, increased gas, nausea and fatigue.

If you start to have debilitating diarrhea and feel fatigue, experts urge you to seek medical care.

Medical providers will likely test a stool sample to determine whether you’ve contracted cyclosporiasis and treat you with an antibiotic called Bactrim, among other treatments.