http://prattdrn.files.wordpress.com/2012/11/flood-health-hazards-from-sewage-1112.pdf
Catastrophic flooding, like that caused by Hurricane Sandy, can introduce sewage from external sources into the indoor environment. This sewage can pose serious health threats to building occupants and to cleanup and restoration workers.
Sewage is untreated water that contains raw animal or human body fluids or fecal matter or other organic contaminants. During and after Hurricane Sandy, untreated sewage mixed with storm water may have overwhelmed sewers and sewage treatment plants. It then saturated soil and entered flooded buildings and vehicles.
Sewage-contaminated floodwater may remain in a building for hours or days. During this time,
extensive penetration and contamination of wood, gypsum, concrete, and other materials may occur.
If sewage is present, it should be assumed that pathogens are present. Pathogens are disease-causing agents, which can be in the form of bacteria (such as e. coli), viruses, mold spores, or protozoans, and which are normally present in large numbers in sewage wastes. In any flood cleanup project, regardless of the
source, assume that pathogens are present and take appropriate precautions.
CHEMICAL DISINFECTION
Sewage-affected areas should be washed with a detergent solution, then disinfected and allowed to dry. Cleaning and disinfection are two different processes. Cleaning removes dirt. Disinfection eliminates the pathogens and organisms that were in the sewage or that grew during the period of contamination. Even concrete can be colonized and broken down by microorganisms if it is allowed to remain wet and contaminated by organic matter. If a commercial disinfectant is used, directions must be strictly followed so as to not endanger workers, occupants, or the indoor environment. A household bleach solution is also an effective disinfection agent. It can be made by combining one quarter cup of household bleach to one gallon of water. Bleach should never be used in concentrated form because it can cause severe skin and respiratory harm. Bleach should also never be used with any product that contains ammonia.
PERSONAL PROTECTIVE EQUIPMENT (PPE)
Assume anything touched by sewage is contaminated. In so far as possible, avoid direct skin contact with floodwaters to minimize the chance for infection. Be especially careful of the face and eyes. Protect all cuts, scrapes, and sores. Immediately wash and disinfect any wound that comes in contact with sewage.Cleanup workers should be trained and equipped with appropriate personal protective equipment, including rubber boots or equivalent, rubber gloves, splash-proof goggles, full-body protective clothing, and, if conditions warrant, respirators. An N95 respirator may be adequate. A half face air purifying respirator with hybrid organic vapor/HEPA cartridges may be more appropriate in some circumstances.
HEALTH-BASED RECOMMENDATIONS FOR RESTORATION
The goal is to restore the contaminated area to a condition that eliminates any additional risk of pathogen-caused disease, using methods that protect the health of cleanup workers.
1. Remediation should begin as soon as possible. The longer the contamination is allowed to persist, the greater the potential for microbial growth.
2. Unprotected occupants and workers should be evacuated from the affected areas during the initial stages of decontamination, cleaning, and disinfection (until sewage has been removed and disinfectants applied).
3. During the initial stages of sewage decontamination, cleaning, and disinfection, cleanup workers should be equipped with at least a half face air purifying respirator with hybrid organic vapor/HEPA cartridges, rubber gloves, splash-proof goggles, rubber boots, protective suits, and hard hats as appropriate.
4. Rapid evacuation of water and rapid drying of impacted materials is essential. Wet extraction systems should be used to remove sewage and water. Dampness and humidity should be Using a respirator, even the right respirator, probably will not provide proper protection unless you have been fit-tested, trained, and qualified to use a respirator. If you are an employee and are required to use a respirator, your employer must provide you with a respirator at no cost, along with annual training, fit-testing, and medical clearance.reduced as much as possible by using the existing mechanical ventilation system, auxiliary fans, and dehumidifiers. Where possible, evaporation of indoor water should be sped up by introducing outside air. Where flooding is extensive, the drying process may require several days or longer to be effective. Drying should be evaluated with a moisture meter and a humidity meter.
5. After water removal, affected materials should be decontaminated by spraying with a disinfectant solution.
6. Highly porous materials with low cost or replacement value should be removed and discarded as soon as possible. High value highly porous materials, such as some rugs, upholstery, and other textiles, should be removed and restored off site.
7. Semi-porous materials such as linoleum, hardboard furniture, and construction materials such as wood and plaster, should be replaced or cleaned and disinfected. If these materials are not removed or properly disinfected, they can become reservoirs for growth of microorganisms.
8. Heavy organic matter such as raw sewage and silt must be physically removed in a manner that protects both workers and the indoor environment. This may include the use of shovels, squeegees, septic pump trucks, wet vacuums, and moisture-extraction machines. All tools and machines, especially recovery tanks, wands, and hoses, must be cleaned and disinfected after use.
9. More than one round of moisture removal, cleaning, and/or disinfection may be warranted.
10. Environmental monitoring should consist of moisture measurements, rather than surface or air sampling for microorganisms. After the restoration process, surveillance of occupants for illness, allergy, and sensitivity may also be used to assess cleanup adequacy.
11. Outdoor areas might need cleanup. Most biological contaminants from sewage on lawns and paved areas will be inactivated within several days from exposure to UV radiation from sunlight. A disinfectant can be used on paved areas. Contamination on grass may be left to degrade naturally. Typically, bacterial numbers on turf are reduced to background levels within 2 to 3 weeks. Depending on the type and amount of chemical contamination present in sewage, soil removal may be warranted in some circumstances.
