Instead of returning to familiar hallways and classrooms, hundreds of students from John H. Kinzie Elementary School in Garfield Ridge began their first week of classes this year at the adjacent John F. Kennedy High School.
The students had been moved while the school underwent environmental testing and remediation after mold was discovered in several parts of the building at 5625 S. Mobile Ave. The Chicago Public Schools district began monitoring concerns at the South Side school in early August after receiving reports of musty odors, water damage, peeling paint and possible mold in some parts of the building, according to communications shared with families. On Aug. 31, one week after the first day of school, students safely returned to classes at Kinzie.
In recent weeks, mold has similarly derailed daily activities and operations across several public buildings in the area, including at least a handful of other schools in Chicago, multiple facilities in a southwest suburbs school district, two schools in Mount Prospect and a police station in Waukegan.
As greenhouse gas emissions from human activities like fossil fuel burning increase average global temperatures, summers in the Midwest are becoming more humid. When the atmosphere warms, it can hold more moisture, leading to heavier downpours and local flooding. This causes storm damage and damp conditions in buildings, which can support mold growth and expose humans to bad air quality and health issues.
Because school buildings operate differently in the summer, their air conditioning, ventilation and dehumidification systems remain mostly unused, and water damage likely goes unnoticed without occupants. This puts them at particular risk of developing mold. But the people they serve are also especially vulnerable because of their immature immune systems: Children exposed to mold can develop short- and long-term health issues such as mild allergic reactions, worsening asthma, respiratory infections and severe illness.
“The safety and well-being of students and staff is a top priority at Chicago Public Schools,” a spokesperson said in an emailed statement to the Tribune. “Every student and staff member deserves a safe, clean, and welcoming teaching and learning environment. As part of its ongoing commitment to maintaining safe and healthy learning environments, CPS proactively conducts regular environmental inspections and addresses any potential instances of mold promptly and thoroughly.”
Proactive monitoring and quick responsiveness have only become more imperative in recent decades.
Illinois had a 15% increase in rainfall between 1895 and 2019. From 1958 to 2016, the heaviest 1% of rainfall events in the Midwest became 42% wetter, according to the U.S. Global Change Research Program’s Fourth National Climate Assessment.
“Without a doubt, there (have) been many more calls in the last couple years, and this year in particular,” said Barton Robertson, who runs a Chicago-area mold remediation business, Above Board Indoor Environmental. “This year has been exceptionally challenging with the moisture management. We’ve got prolonged heat, high outdoor humidity, heavy rainfall. Buildings are under a lot of moisture pressure.”
And scientists do not expect the myriad problems — including a higher risk of mold exposure — posed by more intense rainfall to go away. With additional warming, the Midwest and Northeast are expected to see the largest future increases, of about 40% by the end of the century, in the extreme 1% of rainfall events.
Erica Washington, assistant research professor of molecular genetics and microbiology at Duke University, began studying the relationship between rising global temperatures and heat tolerance in fungi like mold after Hurricane Helene. Mold, she said, is an understudied problem, and its repercussions in the aftermath of natural disasters are widespread across different parts of the country, different weather patterns and even different levels of flooding intensity.
She said there’s a common understanding that, if a fungus can’t colonize and grow in humans, then it doesn’t pose a danger to public health.
“And I think it’s just not as simple as that,” she said. “There’s multiple ways that mold in a built environment can be a problem.”
For instance, some fungi can produce toxins or gases, such as volatile organic compounds, that can make people really sick, she said.
As part of their research, Washington and her team went to Black Mountain, a town east of Asheville in North Carolina, to collect mold samples from different sites after flooding from the 2024 hurricane. At a golf maintenance facility they visited, up to where the water had reached just above Washington’s head (she’s 5 feet, 3 inches tall), the walls were covered in different colors of fungi: white, yellow, pink, brown, black.
“It was really overwhelming, just seeing, visually, the different species that were there on that wall, on all of those walls,” Washington said. “It shows these are not all the same fungi. These are not all the same molds. They are doing different things and interacting with each other, even. And that’s something we haven’t figured out yet.”
Robertson said most area buildings are usually affected by species of penicillium and aspergillus, which are common molds; Stachybotrys, or black mold; and Chaetomium, known as “the other black mold,” which often grows alongside the former and tends to be the source of musty odors.
According to laboratory analyses from samples taken at Kinzie, the most commonly identified fungal spores in rooms at the school were aspergillus and penicillium, the also common Cladosporium, and Basidiospores, which come from some kinds of gilled and cap mushrooms, bracket or shelf fungi and plant pathogens like rusts and smuts.
After a storm, mold can quickly begin growing in absorbent materials like carpets, drywall, textiles and furniture. For instance, at the Waukegan police station, mold was found growing not only on walls, but also on U.S. and Illinois flags.
Robertson called cellulose-based products — made from a natural polymer found in plant cell walls — “mold’s favorite food.” Building materials containing cellulose include wood panels, planks and beams, some types of gypsum boards and some kinds of insulation.
The golf course building in Black Mountain was made out of wood, Washington said, “so it was just wet and damp and ready for fungal growth.”
However, even non-cellulosic materials can be susceptible to water damage and mold. For example, visible mold had grown on fiberglass pipe insulation at Kinzie, according to the third-party post-remediation report
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.“Concrete is pretty porous, and it absorbs moisture, and then it can collect dirt, you know, and dust settles on it,” said Brent Stephens, a civil and environmental engineer and professor at the Illinois Institute of Technology. “And then that becomes basically a food source.”
Stephens led a 2019 study that found wet building materials have higher rates of microbial growth. He leads IIT’s Built Environment Research Group, which, among other things, researches how climate change and weatherization might affect indoor air quality and chronic health issues in U.S. homes.
The easiest way to prevent mold from growing in buildings, regardless of their materials, is to ensure the indoor environment “stays dry enough,” Robertson said.
“Schools are particularly interesting because many of them spend part of the summer partially occupied or operating differently than they do during the school year,” Robertson said. “And if HVAC and dehumidification aren’t managing that moisture, you’ve also got roof leaks, plumbing problems, condensation — you can create conditions where mold develops before anyone even realizes there’s a problem.”
For instance, six rooms initially tested at Kinzie had relative humidity readings above the 65% upper limit recommended by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, according to the post-remediation report.
The ideal range for indoor humidity levels, however, is closer to 30%-50%, the U.S. Environmental Protection Agency says. Robertson said sticking to those is “significantly safer,” and anything closer to 60%-65% “creates a much smaller margin for error, especially if there are any temperature fluctuations or hidden moisture sources.”
According to CPS, controlling relative humidity levels, locating and repairing water leaks, routine building inspections and ensuring proper ventilation are all “crucial preventative measures” it takes to reduce mold growth.
Mold exposure can worsen preexisting asthma, which is one of the most common chronic diseases in children. Breathing in spores can also cause an immunologic reaction in humans, leading to scarring or inflammation of the lungs — a respiratory disease called hypersensitivity pneumonitis.
“You can get symptoms at any time” from this disease, said Traci Adams, director of the interstitial lung disease program at University of Texas Southwestern Medical Center. “So it can be a few days into the exposure, or even hours into a really heavy exposure, or it could be 25 years into having mold in your house, that you finally develop it.”
Symptoms from hypersensitivity pneumonitis include coughing, shortness of breath and wheezing, and are sometimes confused for the flu. It is reversible in its early stages if exposure to the allergen is cut off.
“Most people who are around mold don’t develop lung disease from it,” Adams said. “The number of people with mold in their house is a lot relative to the number of people who develop this. It is some combination of genetics and environment that explains why, (of) two people living in the same house, one will develop disease and one won’t.”
Breathing in spores can cause infections in weakened immune systems. While these so-called invasive mold infections are rare, they cause severe, life-threatening illness, according to the Centers for Disease Control and Prevention. But only a tiny fraction of fungi are pathogenic, and a smaller subset of these are molds. For a fungus to function as an infectious agent in humans, it needs to be able to survive and reproduce inside their bodies.
“Some of the fungi can grow at human body temperature, but not all of them,” Washington said. “When we think about … fungi adapting to warmer temperatures, one of the things that we’re really worried about as a field is if an environmental fungus can adapt to be able to survive in a human body.”
Her research team has found that some species of aspergillus mold previously thought harmless to people can, in fact, survive at 98.6 degrees in a lab environment, which is the average human body temperature.
To infect a person, however, a species of fungus also needs to get past the immune system.
“So we want to be careful to differentiate. Just because a fungus can grow at human body temperature doesn’t mean that it’s a pathogen yet,” she said. “That’s why it’s also important to think about immunocompromised patients, or the children or senior citizens that don’t have a fully, 100% functioning immune system, because in those patients it’s that much easier for the fungus to become a pathogen.”
According to the Chicago Teachers Union, the following six school buildings, plus Kinzie, have reportedly experienced mold since the beginning of the school year:
- Horace Greeley Elementary at 832 W. Sheridan Road
- Dr. Jorge Prieto Math and Science Academy at 2231 N. Central Ave.
- Irma C. Ruiz Elementary School at 2410 S. Leavitt St.
- Esmond Elementary School at 1865 W. Montvale Ave.
- Northside Learning Center at 3730 W. Bryn Mawr Ave.
- William Howard Taft High School at 6530 W. Bryn Mawr Ave.
Data from CPS indicates that the current pre-K to eighth grade population across these schools is over 2,000 children. The two high schools in the list account for more than 4,000 students. According to a CTU spokesperson, operations at the other schools were not as significantly affected as at Kinzie, but “learning was likely disrupted at some.”
For example, the spokesperson said, at Ruiz Elementary, teachers were told to run dehumidifiers during class time, but because of the noise they ultimately had to turn them off so students could hear the lesson. At Taft High School, the mold was addressed before students returned to the building. Northside Learning Center was the only school that, as of mid-October, was still reporting a moldy smell yet to be fixed.
Edgebrook Elementary School at 6525 N. Hiawatha Ave. has been the only CPS school to reportedly have damage from flooding this year.
“Unfortunately, not every school (was) ready to receive our students because natural disasters and climate change added to years of disinvestment,” said Diane Castro, CTU financial secretary, at a news conference before the August Board of Education meeting. “Students and educators did not have the sense of homecoming at Kinzie Elementary due to the mold that has been unaddressed.”
The union has said Gov. JB Pritzker should release disaster relief funds to the district for storm-caused issues.
“If anything showed why the state needs to keep the momentum up and deliver for students across Illinois, it was the first week of school,” Castro said at the news conference. “Our governor is sitting on a $2 billion rainy-day fund when it is raining so much in Chicago that our schools have mold. It doesn’t make sense.”
A spokesperson for the governor’s office told the Tribune they had not received any such formal request from CTU or CPS.
Castro also said that Illinois currently underfunds CPS by around $2 billion, a figure CTU often cites using the state’s own formula.
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The state’s evidence-based formula, a K-12 school finance system enacted in 2017, promised the Chicago district full funding in the second half of this school year, according to CTU. Currently, the state is funding CPS at 70% in the 2026-27 school year.
“Our kind of overall perspective is that, as we see more climate change and catastrophe and flooding, we’re going to see greater impacts on school facilities and increased harm to students if there isn’t full state funding to address the deferred maintenance in the district,” Jackson Potter, CTU vice president, told the Tribune. “We have schools that are … 85 years old on average, and already the state is behind its own funding formula.”
In an emailed statement to the Tribune, a Pritzker spokesperson said the governor has increased funding for public schools by more than $2.5 billion since 2019 “while investing hundreds of millions more in teachers and student supports.”
In addition, “the Governor and General Assembly have worked hard to rebuild Illinois’ rainy day fund to protect core essential services when revenues fall or the economy slows,” the spokesperson said.
While the state has grown its rainy-day fund from $48,000 in 2018 to $2.5 billion now, it is still way below other state averages.
“Drawing down those reserves would be one time money to cover ongoing expenses,” Pritzker’s spokesperson said of the state’s public school and rainy-day funds. “This … approach would leave Illinois less prepared for an economic downturn without providing the reliable, recurring funding schools need. The Governor remains committed to fully funding public education across the state responsibly and sustainably.”
The CPS capital budget for fiscal year 2027 — which began July 1 — is $600 million, of which $80 million is allocated for emergency repairs. CPS did not respond to the Tribune’s specific questions regarding how much has been used to address storm damage and mold so far in the 2026-27 school year.
A CPS spokesperson said the district oversees 799 buildings, across which it has identified over $16.3 billion in capital projects. This includes $3.7 billion in “immediate critical needs” concerning repairs to windows, roofs and heating and cooling systems. Noting the age and complexity of district buildings, the spokesperson said, capital needs compound faster than funding is available.
Potter said emergencies, like addressing asbestos and lead paint or roof collapses, mean the district is often “putting out fires — that’s not planning ahead.” But he called its mold remediation process and preventive measures “very expensive and thorough.”
“And they deserve a lot of credit for the effort and detail that they undertook to address the extent of the problem” at Kinzie, he said. “But, without additional resources, it means another Kinzie is just inevitable. When it happens, and if it happens — and if there’s more than one at the same time — students will get hurt and harmed, and there will be respiratory issues, and there will be asthma, and perhaps worse. And we can prevent it, but it’s going to require a coordinated strategy.”
baiduhai’s Kate Armanini contributed.