Natural Disasters, Severe Weather, and COVID-19

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Information for Clinicians Helping Patients with Asthma, Other Respiratory Conditions, and/or Allergies to Mold After a Hurricane or Other Tropical Storm

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A picture of a stethoscope and and asthma inhaler on a table

This information is intended to complement, not replace, standard, guidelines-based medical care (e.g., ensuring patients are taking the appropriate medications correctly).

  • Patients with asthma and other lung conditions should not enter buildings with indoor water leaks or mold growth that can be seen or smelled, even if they do not have an allergy to mold.
  • Patients with immune suppression (such as people with HIV infection, cancer patients taking chemotherapy, and people who have received an organ or stem cell transplant) should not enter buildings with indoor water leaks or mold growth that can be seen or smelled.
  • Children should not take part in disaster cleanup work.
How Exposure to Mold Can Affect Asthma, Other Respiratory Conditions, and Allergies
stethoscope
  • Patients with asthma, allergies, or other lung conditions may be more sensitive to mold. Exposure to mold can lead to asthma attacks, as well as eye, nose, and skin irritation.
  • Patients with asthma and other lung conditions should stay away from moldy sites, even if they do not have an allergy to mold. Patients with immune suppression (such as people with HIV infection, cancer patients taking chemotherapy, and people who have received an organ or stem cell transplant) should avoid buildings with mold damage or water leaks that can lead to mold. Children should not take part in disaster cleanup work.
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Is There Mold in a Home After a Hurricane or Other Tropical Storm?
Sheetrock covered in mold
  • If your patients’ homes were flooded or were wet indoors (including furniture, carpeting, and other household items) for more than 24–48 hours, then they should assume the presence of mold in their homes. Before re-occupying their homes, homeowners and renters need to completely dry everything, clean up the mold, and make sure they don’t still have moisture problems such as a damaged roof or other water leaks inside the home.
  • Your patients may see or smell mold on clothing, drywall, furniture, cardboard boxes, or books, but mold may also be hidden under or behind items like carpet, cushions, or walls.
Should Patients’ Homes Be Tested for the Presence of Mold or Types of Mold Present?

CDC recommends no matter what type of mold is present, it needs to be removed and not tested. Sampling for mold can be expensive, and there are no set standards to determine the different kinds of mold in a home or other building. The best thing to do is to safely remove the mold and prevent future mold growth.

If your patients’ homes were flooded or were wet indoors (including furniture, carpeting, and other household items) for more than 24–48 hours, then they should assume there is mold growth.

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Professional Mold Cleanup Resources

CDC recommends no matter what type of mold is present, it needs to be removed and not tested. Sampling for mold can be expensive, and there are no set standards to determine the different kinds of mold in a home or other building. The best thing to do is to safely remove the mold and prevent future mold growth.

If your patients’ homes were flooded or were wet indoors (including furniture, carpeting, and other household items) for more than 24–48 hours, then they should assume there is mold growth.

How Patients Can Protect Themselves and Their Loved Ones If They Must Enter a Moldy Site
cover of infographic - What to Wear before entering a Home or Building with Mold Damage
How Patients Can Protect Themselves and Their Loved Ones If They Must Cleanup Mold Themselves
  • Guidance from CDC, EPA, FEMA, HUD, and NIH on safe mold cleanup after a natural disaster is available in multiple languages: Homeowner’s and Renter’s Guide to Mold Cleanup After Disasters
thumbnail image of CDC infographic cover - Homeowner's and Renter's Guide to Mold Cleanup After Disasters
  • Patients with asthma and other lung conditions should not enter or clean up buildings with indoor water leaks or mold growth that can be seen or smelled, even if they do not have an allergy to mold.
  • Patients with immune suppression (such as people with HIV infection, cancer patients taking chemotherapy, and people who have received an organ or stem cell transplant) should not enter or clean up buildings with indoor water leaks or mold growth that can be seen or smelled.
  • Children should not take part in disaster cleanup work.
  • Mold growth can be removed from hard surfaces using commercial products, soap and water, or a bleach solution of no more than 1 cup of household laundry bleach in 1 gallon of water. Patients who can safely enter the building should follow the manufacturers’ instructions for use (see product label). Patients who can safely enter the building can use a stiff brush on rough surface materials such as concrete.
  • Bleach should never be mixed with ammonia or other household cleaners. Mixing bleach with ammonia or other cleaning products will produce dangerous, toxic fumes.
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Preventing Mold Growth in Patients’ Homes

To prevent mold growth in their homes, patients can:

  • Keep humidity levels in their homes as low as they can — no higher than 50 percent — all day long. An air conditioner or dehumidifier will help keep the humidity level low. Patients can buy meters (hygrometers) to check their homes’ humidity at home improvement stores. Humidity levels change over the course of a day so they will need to check the humidity levels more than once a day.
  • Be sure the air in their homes flows freely. Use exhaust fans that vent outside their homes in the kitchen and bathroom. Make sure their clothes dryers vent outside their homes.
  • Fix any leaks in their homes’ roofs, walls, or plumbing to help prevent mold growth.
  • Clean up and dry out their homes fully and quickly (within 24–48 hours) after a flood.
  • Add mold inhibitors to paints before painting. They can buy mold inhibitors at paint and home improvement stores.
  • Clean bathrooms with mold-killing products.
  • Remove or replace carpets and upholstery that have been soaked and cannot be dried right away. Avoid using carpet in places like bathrooms or basements that may have a lot of moisture.
  • To learn more about preventing mold in the home, patients can see the Environmental Protection Agency’s book A Brief Guide to Mold, Moisture, and Your Home at https://www.epa.gov/sites/production/files/2016-10/documents/moldguide12.pdf. [PDF – 1.38 MB]
Additional Resources
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Infographic: Be Ready! Hurricanes Ready: Prepare. Plan. Stay Informed. Social Media at CDC Emergency