More than three decades after the mysterious deaths of 12 infants in Cleveland’s low-income neighborhoods shocked the United States, mold-related health concerns remain a source of confusion and concern. While toxic black mold was suspected in the 1990s tragedy, experts now caution that color alone is not an indicator of danger — and that the health risks associated with mold exposure are more complex than many people assume.
“Mold comes in many species and colors, and the color doesn’t necessarily determine its toxicity,” said Karen Dannemiller, associate professor of engineering and public health at Ohio State University. “What really matters is the presence of excess moisture that allows mold to grow and produce compounds that can impact health.”
Mold thrives in damp environments and is a common feature of most homes. Under normal conditions, indoor bacteria and fungi aren’t inherently harmful. However, when water damage or persistent leaks occur, mold can flourish, producing allergens and irritants that trigger respiratory issues.
According to the Centers for Disease Control and Prevention (CDC), mold exposure has been strongly linked to asthma attacks and chronic asthma, particularly in children. Other respiratory issues, including hypersensitivity pneumonitis and allergic rhinitis, have also been associated with certain molds.
Remote work has increased exposure risks, simply because people are spending more time indoors. “We know mold exposure can cause immune system disturbances and increase sensitivity to other allergens,” said David Miller, a professor at Carleton University who specializes in fungal toxins.
Despite public anxiety, experts say there is little evidence linking airborne mycotoxins — compounds produced by some molds — to illness in most home settings. “Inhaling mycotoxins is not a proven pathway for illness,” said CDC epidemiologist Ginger Chew, noting that dietary exposure to these compounds poses a more substantiated risk.
Testing for mold allergies remains imprecise. Allergy tests can sometimes yield false positives due to cross-reactions between different fungi. “The best test is often your senses,” said Dannemiller. “If you see mold or smell a musty, damp odor, that’s reason enough to take action.”
Visible mold may appear black, green, or orange and often looks fuzzy or powdery. Scientists have yet to define a “safe” level of mold exposure, as individual reactions vary widely.
Experts recommend professional inspections if mold is suspected. While tests can detect airborne spores, the most critical indicators are signs of dampness or water damage. “The presence of mold and moisture is enough to warrant cleanup,” Dannemiller said.
In the absence of conclusive data on long-term cognitive effects or fatigue, researchers continue to investigate potential links between mold exposure and neurological symptoms. “There are still more questions than answers,” Miller added, “but what’s clear is that mold should never be ignored.”