Important Advice Post-Flooding, to Avoid Mold-Related Health Hazards

Mold at Home

Story at-a-glance -

  • Mold, fungi and disease-causing bacteria thrive in water-logged environments, so any building affected by flooding or water damage need to be remediated as quickly as possible, ideally within 24-36 hours
  • Exposure to mold can cause significant and wide-ranging health problems, both acute and long-term
  • Five professional mold remediation organizations are listed, where you locate a licensed professional. Proper remediation is critical to avoid health problems related to hidden mold
  • The non-profit organization National Center for Healthy Housing has issued a free cleanup guide called Creating a Healthy Home: A Field Guide for Clean-Up of Flooded Homes, which offers advice on how to quickly address water damage caused by flooding to minimize further damage
  • Recommendations for what items may be safely cleaned and restored following a flood, and what items are best to toss, are included, along with guidelines for how to clean up small areas affected by minor water damage

By Dr. Mercola

In the wake of Hurricane Sandy, which battered large portions of the East coast of the United States last week, mold remediation will top the list of many people's cleanup efforts.

Our hearts go out to all who were affected by this tremendous storm.

Unfortunately, as with virtually every hurricane battering land, the water damage is extensive. It's important to act quickly, as mold, fungi and disease-causing bacteria thrive in water-logged environments. This also applies in cases where your home was not completely inundated with water. Indications that your home may be conducive to mold growth due to hurricane damage include:

Obvious water damage Condensation on windows
Musty odor Water stains
New or increased allergy symptoms Cracked or peeling paint, or loose drywall tape/wall paper
Rusty metal (as it's a sign of high humidity) Drawers or doors that stick


The problem with mold contamination goes far beyond cosmetics. It's important to be aware that exposure to mold can cause significant health problems, both acute and long-term. According to mycotoxin expert Dr. Harriet Ammann1, indoor molds can damage the systems of your body in the following ways:

Vascular: blood vessel fragility, hemorrhage from tissues or lungs Digestive: diarrhea, vomiting, hemorrhage, liver damage, fibrosis and necrosis
Respiratory: trouble breathing, bleeding from lungs Neurological: tremors, loss of coordination, headaches, depression2, multiple sclerosis
Skin: rashes, burning, sloughing, photosensitivity Urinary: kidney toxicity
Reproductive: infertility, changes in reproductive cycles Immune: Immunosuppression

Hazardous Bacteria—Another Threat From Flooding

Mold isn't the only threat from flooding. Raw sewage may have contaminated certain flooded areas, which can cause dangerous gastrointestinal and skin infections. Avoid wading around unprotected in such areas, and do not drink potentially contaminated water. Water damage itself can also spawn pathogenic bacteria unrelated to sewage contamination.

The key in any flooding situation is to act fast.

According to Rebecca Morley, executive director of the National Center for Healthy Housing, a nonprofit organization that created a helpful cleanup guide after Hurricane Katrina called Creating a Healthy Home: A Field Guide for Clean-Up of Flooded Homes3, you really want to address the problem within 24-36 hours4.

The faster you act, the more you may be able to save. The longer you leave the water damage unattended, the more dangerous the area becomes, as both mold and bacteria start to fester and multiply.

In any area damaged by water, growing right along with mold are what's called 'gram negative' and 'gram positive' bacteria. Just like mold, they require moisture and organic material to thrive, and the synergistic action between mold and bacteria further increase and worsen inflammatory health conditions. The positive gram bacteria consist of several different varieties: bacilli, cocci, streptomyces, and actinomycetes. The actinomycetes contain several different groups of bacteria, including mycobacterium tuberculosis, which can cause very serious lung infection.

Gram negative bacteria are also extremely harmful. When they die, they release their cell walls, which are referred to as lipopolysaccharide, or endotoxins. These endotoxins can severely exacerbate asthma and other conditions because they are highly inflammatory. Research indicates the inflammation they cause can also affect your brain and other organs.

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Should You Call in a Professional?

If your home was flooded, you'd be well advised to hire a pro. Especially if it smells like sewage may be involved. Common sense advice for cleaning out your home includes:

  • Have the area cleared by emergency workers if you have standing water in an area where fuse boxes and/or electrical circuitry is submerged before attempting to pump out the water
  • Turn off your gas line
  • Wear an N95 or N100 respirator mask, available at most hardware- and medical supply stores
  • Wear rubber boots and puncture-resistant gloves. Ideally, don a polypropylene coverall
  • Be sure to carefully dry any belongings you want to try to save

For more detailed instructions on cleanup and restoration of your belongings, please see the National Center for Healthy Housing's cleanup guide5. Morley recommends getting rid of the following items if they've been underwater:

  • Carpet, carpet padding, and rugs
  • Upholstered furniture
  • Computers, microwaves, window A/C units, or any appliances that have fans
  • Papers and books
  • Food items, including canned foods if they were in contact with flood waters

If you want to keep clothes and textiles soaked by flood waters, make sure to wash them in a washing machine (not by hand), and add two tablespoons of liquid chlorine bleach to each load.

Other items that can usually be cleaned and salvaged include:

  • Hard, non-porous items like jewelry, china and dishes, glass, porcelain, and metal
  • Wood furniture (as long as you follow proper cleanup and drying guidelines)
  • Some electronics and small appliances, depending on flooding conditions
  • Photographs, books, and valuable legal documents as long as they only have minor mold damage
  • Artwork that has little or no mold damage

Choosing a Professional Remediator

When scams within the mold remediation industry became a problem, an official professional mold remediation standard and reference guide was written, which is certified by the American National Standards Institute6 (ANSI). This document describes the correct way to address molds, so make sure any remediator you hire follows these standards.

I strongly recommend hiring a qualified expert certified by one of the agencies below, to make sure the job is done right. I would also suggest getting several bids for the work. You can find contractor or professional listings on the following sites. Both the IICRC and NORMI are certifying organizations for mold remediation, but the IICRC certification is perhaps the most widely used:

  • IICRC (Institute of Inspection, Cleaning and Restoration Certification)
  • ACAC (American Council for Accredited Certification)—a certifying body that is third-party accredited.
  • The IAQA (Indoor Air Quality Association)—a membership organization with no certification program (the ACAC handles this by agreement)
  • RIA (Restoration Industry Association)
  • NORMI (National Organization of Remediators and Mold Inspectors) 

Keep in mind that a mere certification or listing may not be enough. Also evaluate the remediator's qualifications and insurance (liability as well as workman's comp). With the ACAC, there are a few different levels.

What Does Mold Remediation Entail?

Naturally, in the case of flooding, step number one is to pump out any standing water and remove all personal belongings, which also need to be carefully cleaned and dried if you're going to try to salvage them.  Standard mold remediation includes:

1.  Setting up containments and sucking the air out with negative air pressure. (This is similar to turning on your bathroom vent fan.)
2.  Next, they clear the air using a HEPA filtered air purifier or scrubber. The air must be cleaned because once they start working on the mold, the spores will begin to fly everywhere like light dust.
3.  Wearing protective gear, such as HEPA filtered respirators, goggles, protective suits and latex gloves, the remediator begins taking the affected area apart. Removed parts, such as drywall, are slowly and carefully placed into a bag.
4.  Once the affected pieces are bagged, every inch of the area is carefully HEPA vacuumed again.
5.  Once the source of the mold has been located, it's carefully removed using hot soapy water, scrub brush, HEPA filtered sanders, chisels, or any other tool that will remove the mold.
6.  Professional remediators will typically treat the area with a disinfectant, as bacteria accompany mold growth.
7.  Next, the area is force dried. Once thoroughly dry, repairs can be made.

How to Clean Up Minor Surface Mold

If your home was spared from major flood damage, still take the time to carefully inspect your home for any minor leaks and signs of water intrusion. If you find you have a small area of water damage and/or surface mold, you probably don't have to call in an expert. However, only attempt to clean it if it's limited to the surface of a small area.

Do NOT try to "kill off mold" with ammonia or bleach. It will kill the mold, but toxic spores can still be released into the air, so you've really just exchanged surface mold for airborne mold.

For minor visible surface mold on say a baseboard, or on a piece of furniture, Dr. Jack Thrasher, an expert on the impact of mold on human health, recommends wiping the area using a little bit of vinegar (straight). Then, mix a couple of tablespoons of baking soda to a quart of water and wipe the area again with the baking soda solution. Dry thoroughly.