The household hazard behind RFK Jr.'s latest warning

Some say the roots of America’s mold problem go back to 1973, when Arab oil producers embargoed the United States. The resulting energy crisis pushed Americans to insulate and seal their homes more tightly to save energy. Without adequate ventilation, those homes trap moisture, giving mold the conditions it needs to thrive. Today, Secretary Kennedy is sounding the alarm, calling for answers about what he described at a recent HHS roundtable as an explosion in mold-related illness.

He cited about 7,300 deaths a year and a $19.4 billion annual cost from fungal disease, figures a 2025 CDC study in Medical Mycology built from 2021 through 2023 records. Those totals cover every fungal illness, not mold in houses. About 9 million of the 13 million outpatient visits in that tally are ringworm and other skin infections. Read the cost study.

Mold feeds on a wet home

Mold is a type of fungus. It spreads through tiny spores that float through the air and settle on surfaces.

Give those spores moisture and something to feed on, and they grow. Paper, wood, and drywall all make suitable homes. A dripping pipe or a damp ceiling keeps the patch fed.

You breathe in spores and fragments. They can irritate your airways, trigger an allergic response, and aflatoxins can cause whole body inflammation.

Damp homes come with more asthma

In 2012, researchers at Finland's University of Oulu pooled 16 studies of homes and new asthma. Visible mold came with a 29% higher relative risk, roughly 1.3 times the risk in the comparison groups. Musty odor showed a stronger link. Read the review.

A 2025 study led by Lille University Hospital in France looked at 424 children with wheeze or asthma. Among the children whose parents reported dampness or mold, 45% had poorly controlled asthma, against 33% in the other group. Read the study.

Sick building syndrome

Headaches at your desk. Burning eyes. Fatigue that lifts when you leave. Public-health researchers have studied this pattern for decades under the name “sick building syndrome.” It describes symptoms linked to time in a building when no specific illness or cause has been identified. Symptoms often ease within minutes to hours of leaving.

Mold can contribute, but so can fumes from furnishings and cleaning products, poorly maintained ventilation, and other indoor pollutants. Feeling better outside is a clue worth investigating, but it doesn’t identify the culprit. The EPA recommends checking pollution sources and ventilation alongside moisture problems.

Indoor carbon dioxide can offer another clue. CO₂ from our breath builds up when a room gets too little outdoor air. Higher readings have been associated with more sick-building symptoms, though other pollutants accumulating alongside CO₂ may help explain the connection. A CO₂ monitor can flag poor ventilation, but it cannot detect mold or certify that the air is healthy. Britain’s workplace-safety agency recommends improving ventilation when readings consistently exceed 1,500 parts per million in an occupied room.

Taking action

• Control moisture first. Keep indoor humidity around 30% to 50%, vent bathroom and kitchen fans outdoors, and dry wet materials within 24 to 48 hours. Fix the leak feeding the problem. If you rent, photograph the damage and report it in writing. EPA’s prevention guide.

• Investigate hidden damage. A past leak, persistent musty smell, or stained wall deserves attention even if an air test comes back negative. An experienced inspector can check moisture levels and, when warranted, investigate behind drywall. Have a professional handle opening suspect cavities, which can release spores and dust. CDC explains testing limitations.

• Understand ERMI before buying it. The Environmental Relative Moldiness Index analyzes DNA from 36 types of mold in settled dust. It can characterize the mold in that sample, but it does not measure toxins or establish whether your home is making you sick. EPA developed it for research and does not recommend routine consumer use. Read EPA’s explanation.

• Be selective about blood testing. Blood and urine mycotoxin panels are sold commercially, but they are not validated to diagnose illness from household mold or identify the building responsible. Mycotoxin-antibody blood tests are also unvalidated for assessing exposure. A clinician may instead use mold-specific IgE blood tests or skin testing to investigate an allergy. Those assess allergic sensitization, not a “toxin load.” Read the clinical guideline and medical toxicologists’ guidance.

• Act on visible growth. You usually do not need a species identification before addressing it. Get experienced help for sewage contamination, extensive water damage, or growth covering more than about 10 square feet. For small jobs, EPA recommends gloves, goggles, and an N95 respirator. People with asthma, lung disease, or weakened immunity should have someone else handle cleanup. EPA’s cleanup guide.

Did you like this newsletter?
Loved it! ❤️ 
It could be better. 👎 

Seed Oil Scout subscriptions keep this newsletter afloat! Get unlimited access to clean dining globally for a deep discount of $19.99 when you join here