The Invisible Dangers of Floodwaters

In September 1999, Hurricane Floyd devastated much of the East Coast of the United States. Massive flooding ensued in several states. No greater was the damage than in a few regions in North Carolina and New Jersey, where high floodwaters contaminated water supplies and left hundreds of residents homeless.

Flooding is by far the most common type of natural disaster in this country – and the most costly. In fact, flooding is so common and its devastation so awesome that nearly nine of every ten presidential disaster declarations are related to flooding. These directives are most often aimed at helping communities rebuild after facing widespread property damage. The total for such damage in the U.S. is more than $1 billion every year.

Waterborne Illness

When the flood waters recede, residents return home to try and rebuild their homes. From a public health perspective, the flood cleanup is a critical exercise in disease control. Floodwaters often carry numerous waterborne disease agents including viruses, protozoa and bacteria. Further, basements and other areas that are more likely to be exposed to floodwaters also can be a breeding ground for molds and spores that can have life-threatening impact. Floodwaters can become contaminated in a number of ways. The high waters can overwhelm water utilities and industrial plants, allowing disease agents to enter the water. If waste disposal systems are inundated with floodwater, sewage can be discharged into the water. In farming communities, floodwaters exposed to cattle and other livestock wastes can present a number of public health challenges. According to the American Red Cross, these waterborne disease agents typically cause symptoms such as fever, gastro-intestinal difficulties, diarrhea and stomach aches. They can also cause diseases such as dysentery and hepatitis. A 1998 study conducted by the American Academy of Pediatrics (AAP) addressed the potential danger resulting from flood-related molds. Occurring in household areas that have accumulated water deposits, mold spores can travel by air and deposit on people and animals, making ordinary objects such as clothing, shoes, and bags common carriers of potentially dangerous molds. The spores from these molds have proven to be life threatening to children. The AAP and the American Red Cross strongly suggest cleaning and disinfecting everything that may have been contaminated, including walls, floors, counters, dishes, glassware, utensils, clothing, outdoor and indoor furniture, patios, decks and playground equipment. A chlorine bleach disinfecting solution (3/4 cup of household liquid bleach to one gallon of water) will help cleanse any walls, floors, or other surfaces touched by floodwaters.

The CDC warns that "the physical devastation that accompanies a flood is enormous [but] as the floodwaters recede, there may be more threats to …personal health and safety." Both during and after a flood, it is of vital importance to keep the public informed about the more subtle threats posed by the stagnant and contaminated waters.

For more information on the invisible dangers of floodwaters, visit the CDC online at
http://www.cdc.gov/nceh/emergency/flood.htm or the Federal Emergency Management Agency’s web site at www.fema.gov/library/floodf.htm.