A sewage backflow into a home is a serious problem. Depending on volume and other factors, it may create severe sewage contamination in the indoor environment with potentially extreme health risks. Sewage contamination has the potential to be much more unsafe than even the most severely mold contaminated environment. Yet many homeowners and property managers are not aware of these facts and often underestimate the potential health and safety risks. This brief article on sewage contamination is intended to help address this disparity between perception and reality.
For more detailed discussion of potential health effects, see: http://www.oseh.umich.edu/pdf/guideline/fdrappe.pdf
Health Effects from Sewage Contamination
A variety of disease-causing microorganisms, including bacteria, parasites and viruses, can be found in buildings polluted from large quantities of raw sewage contamination (termed Category 3 or “black” water). These include pathogenic strains of Escherichia coli (E. coli), Salmonella, Campylobacter, Shigella, and Pseudomonas bacteria, Giardia and Cryptosporidium parasites, and enteric and hepatitis viruses. Exposure and infection from sewage contamination can occur through ingestion, inhalation or skin wounds.
In addition to the infectious disease risk of sewage contamination, gram-negative bacteria contain endotoxins that are released at the time of cell death or destruction. These can be aerosolized into the air during improper sewage remediation, such as during ineffective attempts to clean and dry sewage contamination from carpets or other materials. Endotoxin exposure can lead to a number of health symptoms.
Infants and young children, the elderly, convalescents, and people with compromised immune systems, such as organ transplant and post-surgery patients, are particularly susceptible to illness and symptoms, which can be contributed to exposure to microorganisms. For medical questions, please consult with your physician or your local health department.
Sewage Contamination Complexities
Sewage contamination poses specific health and restoration challenges. The use of air movers during the drying of sewage contamination in buildings, even initially, spreads bacteria and their spores and other contaminants that normally do not get aerosolized. Bacteria are not as aerodynamic as mold spores, and spreading through the air is not part of their normal life cycle. They normally remain in water unless disturbed by over aggressive and improperly contained remediation efforts. Therefore, it is inappropriate to use positive air movement as a drying tool during water extraction or drying until after decontamination has been successfully completed. The use of negative air pressure and dehumidification is acceptable.
An initial application of an approved biocide is recommended to reduce the contaminant load. This is not intended as a sanitizing process. Sanitization occurs after detail cleaning using an approved biocide with a minimum of 15 minutes contact time when applied to a clean, non-porous surface. Note: This is a general rule. Sanitizers vary.
All porous materials that come in contact with raw sewage (including drywall, carpet, pads etc.) must be replaced, per IICRC S500 Standard and Reference Guide for Professional Water Damage Restoration. Dealing effectively with sewage contamination health/safety challenges, as well as with those associated with the known or potential presence of mold and other contaminants, must be taken into consideration when developing a plan of action.
Indoor Environmental Technologies (IET) works with remediation contractors to ensure that work is handled in full compliance with IICRC’s S500 Standard and Reference Guide for Professional Water Damage Restoration. Contact us if you have any questions or to schedule an assessment.