Government and Institutional Sites
In 1982 in Illinois, ethylene glycol back siphoned from an air conditioning system ’s water holding tank into a group of dialysis machines, contributing to the death of several” (number not given) patients (AWWA PNWS, 1995)
During shut-down of a water main to repair a valve in 1984, the backflow of water from a nursing home’s boiler caused burns to a water department employee’s hands in Washington State (AWWA PNWS, 1995).
In 1994, during repairs to a nursing home air conditioning unit in Franklin, Nebraska, a hole left in the
cooling coils allowed Freon to backflow into the city water main, affecting the city’s 1,100 residents.
Customers complained about the taste of the water, but no illnesses were reported (AWWA PNWS,
Schools, Universities, and Children’s Camps
In 1990, six staff members of an Indiana middle school reported becoming ill after drinking water containing ethylene glycol that backflowed from the school’s cooling system into the potable water system (AWWA PNWS, 1995).
In 1987, copper sediment contamination in a beverage mixing tank resulted in four cases of illness in a
residence hall at Michigan university (AWWA PNWS, 1995).
In 1995, three people became ill at a California school after drinking water from a system with a double-
check backflow prevention valve that did not meet industry standards and had badly deteriorated rubber
gaskets (Craunand Calderon, 2001).
Public Water Systems
In 1984, creosote was backsiphoned through a three-quarter inch hose used to prim e a pump, contaminating a section of a Georgia community water system. No illnesses were reported (AWWA PNWS, 1995).
In 1970 in Mattoon, Illinois, hot wash water from an asphalt plant backpressured into mains during flow
testing of fire hydrants (USC FCCCHR, 1993).
Other Government/ Institutional Sites (e.g.,public buildings, churches)
In 1976, water fountains at the State Capitol building in Salem, Oregon, were contaminated with freon
gas from a ruptured heat exchanger. The gas combined with the fluoride in the water supply, forming an
acid compound that caused a bitter, burning taste (AWWA PNWS, 1995).
In 1991, two check valves froze open at a Texas Air Force base, resulting in a back flow from a water
chiller; pathogenic bacteria were detected in the water. The specific contaminant was not identified.
Approximately 2,000 workers and residents were without water during system flushing (AWWA PNWS,
In 1994, the water system at a Tennessee prison was cross-contaminated by the facility’s wastewater
pump station, resulting in 304 cases of giardiasis (Craun and Calderon, 2001).
Purified drinking water lines at the Oak Ridge Reservation’s K-25 atomic bomb fuel plant were
interconnected for an unknown length of time (possibly on the order of decades) with lines carrying
impure creek water. The creek water contained poisons generated from nuclear fuel production, possibly
including contaminant s such as strontium -90 and arsenic (Nashville Tennessean, 2000).
Other Commercial Sites
In 1974 backsiphonage of a chromium compound from the chiller water of an air conditioning system
contaminated the drinking water system in the auditorium hosting the 94th annual AWWA conference
and exhibition in Massachusetts, involving thousands of people (AWWA PNWS, 1995).
In 1990, 1,100 guests of a Tennessee racquet and country club became ill with an intestinal disorder
after consuming the club 's contaminated water supplied from an unauthorized and unprotected auxiliary
well in close proximity to a malfunctioning sewage pumping station (AWWA PNWS, 1995).
In 1994, a number of individuals attending an Ohio convention got sick with giardiasis, spread by an ice
machine contaminated by a cross-connection to a sewage drain (AWWA PNWS, 1995).
In 1986 in Springfield, MO, failure of a single check valve on a soft drink dispensing machine at a local
fair resulted in the backflow of carbon dioxide that created levels of 2.7 mg/L of copper and 2.2 mg/L of
zinc. Three people experienced vomiting and abdominal pain (AWWA PNWS, 1995).
In 2000, contaminated water lines at an Ohio fairground resulted in an outbreak of E. co li, resulting in 30 cases of illness (Cleveland Plain Dealer, 2001).