What is PERC? Is it safe for health?

This report is fully cited from American Cancer Society. You can read full report at (http://www.cancer.org/cancer/cancercauses/othercarcinogens/intheworkplace/tetrachlorethylene-perchloroethylene) Tetrachlorethylene (Perchloroethylene) What is tetrachlorethylene? Tetrachlorethylene, also known as tetrachloroethylene, perchloroethylene, PCE, or "perc," is a commonly used solvent (a substance, usually a liquid, capable of dissolving another substance). It has been in commercial use since the early 1900s. A common use of tetrachlorethylene is to dry clean fabrics. It dissolves greases, oils, and waxes without affecting fabrics, which makes it useful for this purpose. Tetrachlorethylene is also used to clean and degrease metals. Oil and wax are used to shape and polish metal during the manufacturing process. Removing oil, wax, and related substances from the finished products is known as degreasing. It has also been used in water repellants, paint removers, printing inks, glues, sealants, polishes, and lubricants. Tetrachlorethylene is also used to make other chemicals. How are people exposed to tetrachlorethylene? Tetrachlorethylene is a liquid at room temperature but evaporates easily into air. When it is in the air it can condense again and get into soil and water. It can also be washed out of the air with rain. It can also get into soil and water during waste disposal, or by leaking from underground storage tanks. In the past, in certain areas, it also could get in the water by leaching out of the vinyl lining of the pipes in the water system. This is less of a concern now, because the pipes have been treated in areas where this has happened. Tetrachlorethylene is present in very tiny amounts in the air we breathe and in the water we drink. It can also be present in very tiny amounts in soil, and less often, in food. Using a consumer product, such as a water repellent, that contains tetrachlorethylene, could also expose you to a small amount of this chemical. People can be exposed to tetrachlorethylene by breathing it in, by direct contact with the skin, or by ingesting contaminated water or food. No matter how you are exposed to tetrachlorethylene, most of it leaves your body when you exhale. A small amount may stay behind. Some of this is changed by the body into other chemicals and then removed from the body in urine. Some stays in the body for a time. People who live near dry cleaning or metal degreasing operations, people using coin-operated laundries where dry cleaning machines are present, and people who live in buildings where dry cleaning shops are located are exposed to higher amounts of tetrachlorethylene in the air. The highest exposures to tetrachlorethylene tend to occur in the workplace, especially among dry cleaning and degreasing workers. Workers in some other industries may also be exposed to tetrachlorethylene. Does tetrachlorethylene cause cancer? Tetrachlorethylene has been suspected of causing some types of cancer, based on both human and animal evidence.
Studies in people
Studies have looked at people exposed at work and people in communities with contaminated drinking water. Some studies of people exposed to tetrachlorethylene at work (dry cleaning workers, workers at a chemical company, and workers in aircraft maintenance) found more cases than expected of certain cancers, including cancers of the esophagus, kidney, cervix, and bladder, as well as lymphomas. However, the results of these studies did not always agree, and there were so few cases of cancer that the increased risk often may have been due to chance. Many of these studies also weren't able to account for other factors that might affect cancer risk, such as cigarette smoking or alcohol use. Other studies have looked for a link between tetrachlorethylene in drinking water and cancer. A few studies have looked at areas of Massachusetts where some drinking water supplies were accidentally contaminated with high levels of tetrachlorethylene. (Levels in some of these areas were hundreds of times the current Environmental Protection Agency [EPA] standard of 0.005 milligrams of tetrachlorethylene per liter of water [0.005 mg/L]). These studies found evidence of an increased risk of leukemia as well as lung and bladder cancer among residents with the highest exposure to tetrachlorethylene. However, these studies often weren’t able to take other risk factors for cancer into account, so it isn’t clear how much the increased risk was from the chemical.
Studies done in the lab
Laboratory studies have found that ingesting or inhaling tetrachlorethylene increased the risk of liver cancer in mice. In rats, inhaling tetrachloethylene was linked to kidney cancer and a rare type of leukemia.
What expert agencies say
Several agencies (national and international) study different substances in the environment to determine if they can cause cancer. (A substance that causes cancer or helps cancer grow is called a carcinogen.) The American Cancer Society looks to these organizations to evaluate the risks based on evidence from laboratory, animal, and human research studies. A few expert agencies have looked at whether tetrachlorethylene can cause cancer. The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. Based on the data from studies in people and lab animals, IARC classifies tetrachlorethylene as “probably carcinogenic to humans.” The National Toxicology Program (NTP) is formed from parts of several different US government agencies, including the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). The NTP has classified tetrachlorethylene as “reasonably anticipated to be a human carcinogen.” The US Environmental Protection Agency (EPA) maintains the Integrated Risk Information System (IRIS), an electronic database that contains information on human health effects from exposure to various substances in the environment. The EPA has classified tetrachlorethylene “likely to be carcinogenic in humans by all routes of exposure.” (For more information on the classification systems used by these agencies, see our document Known and Probable Human Carcinogens.) Does tetrachlorethylene cause any other health problems? Tetrachlorethylene is not absorbed well through the skin, but skin contact can cause irritation. The low levels of tetrachlorethylene that most people are exposed to in air, water, and food don’t seem to cause any symptoms. Higher levels of tetrachlorethylene in the air can lead to irritation of the eyes, skin, nose, throat, and/or respiratory system. Other effects may include nausea, headache, dizziness, vision problems, and trouble speaking and walking. There can also be facial flushing and abnormal heartbeat. Kidney and liver damage can occur over the long term. Very high concentrations of tetrachlorethylene (such as in a closed and poorly ventilated area) can cause worse neurologic symptoms such as confusion, drowsiness, loss of consciousness (passing out), and even coma and death.
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