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Flood Waters Bring Lasting Health Hazards


Hurricane Harvey and extensive subsequent flooding have brought significant health hazards to the Gulf Region. Public health nurses and everyone involved in disaster relief efforts must spread the word about the long-term health hazards associated with flood water.

Specializes in Family Nurse Practitioner. Has 8 years experience.

Flood Waters Bring Lasting Health Hazards

Whether you are volunteering your services on-site or providing other forms of support in the aftermath of Hurricane Harvey, public health professionals including nurses of all specialties owe it to themselves and to those they care for to recognize the long-term effects of floods and spread the word about the insidious health hazards they pose. Beyond the obvious and immediate dangers of drowning and acute injury, flood waters spread chemical and microbial contaminants, allow diseases to proliferate, and trigger other stresses that can adversely affect the local residents' health for weeks, months, and even years to come.

The health hazards brought by flood water extend far beyond drowning and acute injury. These hazards are not always immediately obvious or visible, and have longer lasting effects. Nurses and other health professionals have a duty to remind themselves and everyone they care for in the aftermath of a flood to raise awareness of these longer-term health hazards by incorporating them into patient education and public outreach efforts.

Here are some of the long-term health hazards associated with floods, and what you can do about them whether you are a resident in the affected area, a relief worker, or a remote supporter of recovery efforts:

Lingering Contamination

Chemicals, sewage, and microbes, oh my! Flood water is easily contaminated with household and industrial chemicals, sewage, microbes, agricultural runoff, and other contaminants. Flood water expands to contact everything in its path and when it finally recedes, it leaves residues behind. In other words, contamination does not automatically subside when the flood water recedes. The effects are lasting for months until cleanup can be executed.

Be especially aware of previously flooded outdoor areas like playgrounds, ballfields, and picnic areas. According to the CDC, most guidance on returning flood-water-contaminated outdoor areas to use regards microbial contamination not chemical contamination. Once flood waters recede, experts say it can take 2-3 months and even longer, depending on local weather, soil, and contamination circumstances, for microbial contaminants to dissipate.

What you can do: Awareness is foremost, closely followed by consistently practicing good personal hygiene [consider inserting link to previously posted allnurses article on disaster hand hygiene]. Make arrangements for sand, mulch, gravel to be disposed of and replaced.

Vector-borne diseases

Residents can expect a spike in mosquito populations in the aftermath of Harvey and health officials will be watching for an increase in West Nile and other vector-borne disease cases. It is worth noting that while experts have anticipated that local breeding sites of the Aedes aegypti mosquito (which spreads Zika, chikungunya, dengue and yellow fever) would be washed out by Harvey's flooding, the standing water left in Harvey's wake will likely trigger a surge in the Culex mosquito species (which spreads West Nile).

What you can do: Stay alert to local advisories and precautions regarding avoidance of mosquito-borne illness. In general, be sure to include removal of potential breeding grounds in cleanup activities, and use DEET containing repellant to reduce bites. It also pays to be aware of the widely varying signs and symptoms of West Nile virus infection, which can include mild fever, headache, nausea, and diarrhea-symptoms which are easily attributable to other medical conditions such as gastroenteritis that are common in the aftermath of flooding. Severe headaches, a stiff neck, confusion or seizures would indicate a serious West Nile infection that requires medical attention.


Like vector-borne illness, mold is expected to proliferate in the flooded areas in the weeks and months to come. The CDC recommends cleanup/dryout of buildings within 24-48 hours, which is may not be possible in the aftermath of Harvey, due to the sheer magnitude of the event. Those most at risk from exposure to mold are people with asthma, allergies, or other respiratory conditions and those who are immunosuppressed--specifically, people with HIV infections, people currently or recently on chemotherapy, and those who have had organ transplants.

What you can do: Response workers, residents and cleanup crews must be aware of the likely presence of mold. Observe for visual discolorations and evidence of water damage, and remember that bad odors are a bad sign. Additionally, the CDC recommends that those who must be in the presence of mold wear an N95 mask because it filters out particulate matter. The CDC also recommends that if the area to be cleaned is larger than 10 square feet, cleanup crews should follow the EPA's protocols for Mold Remediation in Schools and Commercial Buildings [see link below].

Stress, Bereavement, and Trauma

Those affected by any type of disaster, whether natural or human-caused, deal with catastrophic loss, disturbing memories, and permanent change. Young children and teens, older adults, first responders and recovery workers are at particular risk of suffering long term mental health consequences. Healthy coping strategies must allow for emotional expression and processing.

What you can do: In addition to local contacts and resources for mental health and counseling, SAMHSA's national Disaster Distress Helpline provides assistance. When electricity and utilities are back on line, those in need can call 1-800-985-5990 or text TalkWithUs to 66746 to connect with a trained crisis counselor.

The effects of recent flooding from Hurricane Harvey will continue to be felt long after the flood waters have receded. Public health nurses and everyone involved in disaster relief efforts must spread the word about the long term health hazards associated with flood water.

Questions for discussion

If you have friends and loved ones affected by Harvey, or if you are a disaster response nurse assisting with the aftermath of Harvey, did this information help?

Sources and Resources

Dangers of the Culex Mosquito

Disaster Distress Helpline | SAMHSA - Substance Abuse and Mental Health Services Administration

Floods| Water, Sanitation, & Hygiene-related Emergencies & and Outbreaks | Healthy Water | CDC

Food and Water Safety During Power Outages and Floods

Guidance on Microbial Contamination in Previously Flooded Outdoor Areas | EHS | CDC

Harvey health risks: Officials on alert amid massive flooding | Fox News

Household Cleaning & Sanitizing| Water, Sanitation, & Hygiene-related Emergencies & and Outbreaks | Healthy Water | CDC

Hurricanes and Tropical Storms | SAMHSA - Substance Abuse and Mental Health Services Administration

Tiny Mosquito: Understanding the Mosquito

Mold|Natural Disasters and Severe Weather

Mold Remediation in Schools and Commercial Buildings

NIOSH -Approved N95 Particulate Filtering Facepiece Respirators

Stay Safe After Hurricanes, Flooding

West Nile Virus Symptoms and Causes

Lane Therrell is a family nurse practitioner and health empowerment coach in California. She is an adjunct instructor in the nurse practitioner program at Samuel Merritt University. She blogs at www.BestHealthInterest.com

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1 Comment(s)

FranEMTnurse, CNA, LPN, EMT-I

Specializes in LTC, CPR instructor, First aid instructor.. Has 24 years experience.

Very informative for the sav=fety of others. Thank you.