Tetrachloroethylene is a manufactured chemical used for dry cleaning and metal degreasing. Exposure to very high concentrations of tetrachloroethylene can cause dizziness, headaches, sleepiness, confusion, nausea, difficulty in speaking and walking, unconsciousness, and death. Tetrachloroethylene has been found in at least 771 of the 1,430 National Priorities List sites identified by the Environmental Protection Agency (EPA).

These manmade chemicals have been heavily used as cleaning agents in the dry cleaning industry and as metal degreasers in many manufacturing industries and were used many years prior to any regulations established on their use, and disposal. Although they readily evaporate when released to soil, some will leach slowly to ground water. These chemicals are only slightly soluble in water, but their breakdown by microbes is also slow, so improper disposal prior to government regulations being established has caused considerable ground water contamination. The Maximum Contaminant Level (MCL) now allowed in public drinking water is 5 parts per billion for both chemicals. More information can be found on the chemicals from U.S. EPA at http://www.epa.gov/safewater/hfacts.html.

One way of testing for tetrachloroethylene exposure is to measure the amount of the chemical in the breath, much the same way breath-alcohol measurements are used to determine the amount of alcohol in the blood. Because it is stored in the body's fat and slowly released into the bloodstream, tetrachloroethylene can be detected in the breath for weeks following a heavy exposure. Tetrachloroethylene and trichloroacetic acid (TCA), a breakdown product of tetrachloroethylene, can be detected in the blood.

While these tests are relatively simple to perform, they aren't available at most doctors' offices, but can be performed at special laboratories that have the right equipment. Because exposure to other chemicals can produce the same breakdown products in the urine and blood, the tests for breakdown products cannot determine if you have been exposed to tetrachloroethylene or the other chemicals.