Dry cleaning is a process of cleaning clothes and fabrics with solutions that do not contain water. The practice has been traced back to France where around 1825 turpentine was used in the cleaning this process. According to Albert R. Martin and George P. Fulton in Dry cleaning, Technology and Theory, published in 1958, the tradition passed down regarding the origins of dry cleaning states that the process was discovered when "a can of 'camphene,' a fuel for oil lamps, was accidentally spilled on a gown and found to clean it, and this discovery led to the first dry cleaning establishment." Because of this, dry cleaning was referred to as "French cleaning" even into the second half of the twentieth century. By the late 1800s, naphtha, gasoline , benzene , and benzol—the most common solvent—were being used for dry cleaning. Fire hazards associated with using gasoline for dry cleaning prompted the United States Department of Commerce in March 1928 to issue a standard for dry cleaning specifying that a dry cleaning solvent derived from petroleum must have a minimum flash point (the temperature at which it combusts) of 100°F (38°C). This was known as the Stoddard solvent. The first chlorinated solvent used in dry cleaning was carbon tetrachloride. It continued to be used until the 1950s when its toxicity and corrosiveness were determined to be hazardous. By the 1930s, the use of trichloroethylene became common. In the 1990s the chemical was still being used in industrial cleaning plants and on a limited basis in Europe. This chemical's incompatibility with acetate dyes used in the United States brought about the end of its use in the United States. Tetrachloroethylene replaced other dry cleaning solvents almost completely by the 1940s and 1950s. In 1990 about 53% of worldwide demand for tetrachloroethylene was for dry cleaning, and approximately 75% of all dry cleaners used it. However, in Japan petroleum-based solvents continued in use through the 1990s. By the late 1990s, perchloroethylene (perc or PCE) replaced tetrachloroethylene as the predominant cleaning solvent. When the United States Environmental Protection Agency (EPA) issued national regulations to control air emissions of perc from dry cleaners in September 1993, environmental groups and consumers began to pay closer attention to the possible negative impact this chemical could have on human health. In July 2001, the American Council on Science and Health issued a report concluding that perc was not hazardous to humans at the levels most commonly used in dry cleaning. The report noted that, "Perchloroethylene has been the subject of close government and public scrutiny for more than 20 years. But government agencies in the United States and around the world have not agreed about the potential of environmental exposure to PCE to cause adverse health effects, including cancer , in humans."Inhalation of high levels of PCE and chemically similar solvents can cause neurological effects such as nausea, headache, and dizziness.
High inhaled doses have been linked to changes in blood chemistry indicating that the liver and kidneys have been affected. These effects have been seen almost exclusively in workers, particularly in the dry-cleaning and chemical industries. There have been claims that reproductive difficulties are associated with occupational exposure to PCE. The claim that PCE is a carcinogen (cancer-causing substance) has received the most public and governmental attention. Concern has been expressed that environmental exposures to PCE in outdoor or indoor air and in drinking water can cause cancer in humans. Results of some epidemiological studies of dry cleaning and chemical workers exposed to PCE have been interpreted to suggest a relationship between occupational exposure and various types of cancer. Careful examination of the way in which these studies were conducted reveals serious problems including uncertainties about the amount of PCE to which people were exposed, failure to take into account exposure to other chemicals at the same time, and failure to take into account known confounders. Due to these deficiencies, these studies do not support a link between PCE and cancer or other adverse effects in humans. The differences between humans and rodents in the metabolism and mechanisms of action of PCE make it unlikely that the carcinogenic effects seen in mice and rats administered high levels of PCE will occur in humans exposed at environmentally relevant levels. The environmental activist association Greenpeace also issued a report in July 2001, entitled, Out of Fashion Moving Beyond Toxic Cleaners. This report urged the EPA to classify perc as a probable human carcinogen. The report claimed that up to 266 workers' cancer deaths in New York, Chicago, Detroit, and San Francisco were linked to perc. As of 2002, the dry cleaning industry estimates that approximately 36,000 dry cleaning establishments exist across the United States, with about 200,000 people employed in the industry. Perc is used in at least 85% of dry cleaning shops as the primary solvent. This means that if perc is found to be a cancer causing chemical, many people, including both workers in and people who live near dry cleaning facilities, may be adversely affected