As floodwaters receded, poisonous mold flourished in NJ homes

By Michael Sol Warren (NJ Spotlight), John Upton (Climate Central)

Sept. 4, 2021: Volunteers removed debris from a house in Millburn after flash floods from the remnants of Hurricane Ida inundated the neighborhood.

This story was produced through a collaboration between NJ Spotlight News and Climate Central.

It wasn’t until last spring that Charlene Dionio’s father was hospitalized by poisonous after-effects of Hurricane Ida, which swept from Louisiana through New England the previous fall, killing more than 100 in the United States, including 29 in New Jersey.

“I underestimated the Ida storm,” Dionio said. She lives on a hill in Bergen County’s Dumont, with her daughter and dad and was surprised when her basement flooded. After an arduous cleanup, she began to notice spots in the basement carpet. “I opened the closet, and there’s black spots going up, and I said, ‘Oh my gosh.’ So now I know there’s mold,” said Dionio, who works as a nurse at New York-Presbyterian Columbia University Irving Medical Center.

As pollution traps heat, storms are growing more ferocious and the intensity of rainfall is increasing, fostering more mold.

Mold — or mildew — is a term describing forms of fungi that can flourish inside homes in damp conditions. Toxins released by mold can contaminate food. They can cause allergic reactions when inhaled and are most dangerous to children and the elderly, and to those with asthma and other lung conditions. Sometimes, the fungi themselves cause infections.

Dionio’s father suffers from COPD (chronic obstructive pulmonary disease), and after catching COVID-19 in 2020 his dementia worsened. “He’s not the same anymore,” Dionio said. Despite trying to prevent him from using the mold-infested bathroom in the basement, her father would forget and use it anyway, exposing him to the poisons secreted by the microorganisms.

While Dionio and her daughter experienced allergic reactions, she blames the mold for landing her father back in the hospital for three days, unable to breathe properly.

“We’re healthy and we started having symptoms,” Dionio said. “When he’s exposed, when he inhales it, with his age and his condition, it will just balloon or mushroom into something that he cannot tolerate.”

Mold and growing intensity of storms

Mold infestations can follow undetected leaks in seemingly safe homes, and they can also follow floods from disastrous storms. As pollution traps heat, storms are growing more ferocious and the intensity of rainfall is increasing, fostering more mold. For those living near shores and estuaries, coastal flooding is occurring more frequently as seas rise.

State authorities warned of this risk in 2020, when the Department of Environmental Protection released its “Scientific Report on Climate Change.” That report cites the aftermath of Superstorm Sandy as a prime example of how storm surges and heavy rains can set the stage for outbreaks of mold.

“The conditions the storm created were ideal for numerous molds and bacteria,” the report reads. “Power loss rendered heating, ventilation, and air conditioning systems useless, making it difficult for many buildings to maintain indoor temperature, humidity and keep up ventilation, filtration and circulation.”

Dionio’s Dumont home was within a roughly 25-mile band from southeastern Pennsylvania to the greater New York City area that experienced Ida’s most intense rainfall. The storm lifted warm Atlantic Ocean waters and dumped them inland as rain as it moved north past the Appalachians.

Mold infestations can be costly to remove, adding to domestic financial crises following disasters and causing health problems for those who can’t afford the high remediation costs — or whose landlords refuse to pay for fixes.

New Jersey State Climatologist David Robinson said that within that narrow band, 6 to 9 inches of rain fell within six hours, causing flash flooding so severe that people drowned in basement apartments and vehicles.

Although climate change is intensifying storms and escalating the intensity of rainfall, Robinson predominantly blames a confluence of meteorological and geographical factors for Ida’s destructiveness.

“It was a matter of that much rain in a six-hour interval that put a lot of water in places that wouldn’t have gotten it if it had fallen at a slower rate,” Robinson said. “And it happened to fall in a very inhabited area.”

Experts caution that dangers from mold are often underestimated by researchers and other experts, even as the effects of heat-trapping pollution give it a leg up in blooming inside homes.

“With climate change and the number of really devastating storms going up, we’re going to be seeing more and more flooding, more and more mold growth and more and more people getting sick,” said Joan Bennett, a distinguished professor in Rutgers University’s plant pathology department.

Hurricane Katrina connection

Bennett trained as a fungal geneticist and began studying chemicals known as volatile organic compounds that are released by indoor mold after her home in New Orleans was flooded by Hurricane Katrina. Mold grew on prized books and other possessions, destroying them.

“There’s a saying among those of us who work with mold — ‘just add water,’” Bennett said. “There are so many mold spores in the air that basically when things get wet — almost anything, paper, rugs, food — it’s likely that mold will grow.”

Mold infestations can be costly to remove, adding to domestic financial crises following disasters and causing health problems for those who can’t afford the high remediation costs — or whose landlords refuse to pay for fixes.

After Ida inundated the Bridgewater basement of Alyssa Geibel and her husband with 3 inches of water, they immediately tore out the carpet and threw away soggy documents, artwork and other possessions, but it wasn’t enough to head off a mold infestation.

The couple paid contractors roughly $6,000 to remediate the mold, a hefty bill that her parents helped pay.

“They did a fabulous job,” Geibel said. “Our basement now is fine, and safe to be in.”

Speedy cleanup is key

Mike Van Dyke, an industrial hygienist at the Colorado School of Public Health who has researched mold and its health effects, said removing water and soggy furniture and other items immediately after a flood can reduce the likelihood of a mold breakout.

“If we get the house dried out in 24 to 48 hours, there’s a lot less chance of a long-term problem,” Van Dyke said, noting that isn’t always possible. “You have these homes where people can’t get in them for a long time, so by the time they come back to the home, even three or four days later, that house is pretty well overgrown with mold.”

Van Dyke and Bennett both say research into the health effects of mold is lacking, even as climate pollution amplifies the dangers that it poses.

“Clearly, this is a climate issue,” Van Dyke said. “It gets a bit controversial, but I think what everybody can agree on is that mold can cause things like upper respiratory irritation; it could make asthma symptoms worse. It can cause breathing problems for those who have reduced lung function. And, in general, in those who are allergic, make allergies worse.”

Van Dyke said clues that mold has taken hold inside a home include telltale odors and the dark dots and stains it produces on surfaces.

“We’ve all been in a damp basement, we know what a damp basement smells like,” Van Dyke said. “When you go into a damp basement, you’re actually smelling mold, or, more specifically, the chemicals that mold produces.”

--Raina DeFonza of Climate Central contributed reporting to this story.