Are there Realistic Dry-Cleaning Alternatives to Perc?

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By Jennifer Manning

[May 12, 2006]

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Perc - the most common name for a chemical also referred to as percholorethylene, PCE, tetrachloroethylene, and tetrachloroethene - has been used by the dry cleaning industry since the mid-1930s, but has since been identified as a toxic contaminant and potential human carcinogen (see part 1 of "Looking Good, Feeling Bad"). In fact, many National Priorities List- (NPL-) sites - otherwise known as Superfund sites - are contaminated by perc. According to the Agency for Toxic Substances and Disease Registry (ATSDR), perc has been found in at least 771 of the nation's 1,430 NPL sites (ATSDR, 1997).

The Environmental Protection Agency's (EPA's) Design for the Environment states that "We all may be exposed to perc because it is found in the air and drinking water nationwide" (EPA, 2005). If this almost 200-year-old chemical is everywhere, and we still don't know the extent of the damage it has done and is doing, what's next? How do we reduce our dependence on it for something as uniquely human as dry cleaning our clothes?

Dry cleaners are the most significant source of perc emissions in the United States. Various estimates indicate that dry cleaning may be as much as a $10 billion industry. According to the National Institute for Occupational Health and Safety (NIOSH), "the commercial drycleaning industry in the United States consists of approximately 36,000 shops... Approximately 85% of drycleaning shops in the U.S. use perchloroethylene as their primary solvent" (NIOSH, 2003).

Once a compound, even a hazardous one, has become an established part of our infrastructure, it is hard to eliminate it; as an example, consider the long and complicated process the automotive industry is going through as it slowly moves away from gasoline-powered vehicles and toward those that use other fuel sources.

Despite the decades of science showing how harmful perc is, especially to industry workers and the environment, the move from perc to less toxic forms of cleaning is a gradual and difficult one. Perhaps part of the reason is that most of the human impacts are on garment industry workers; given that this is a relatively small and low-profile population of workers in unaffiliated shops, it may be that such workers do not attract the attention a larger, well-organized demographic would. However, the health risks are real and proven - studies by the National Cancer Institute and NIOSH show, for example, an "excess [of] bladder, esophageal, and cervical cancer deaths among groups of dry-cleaning workers" (NIOSH, 1996). Impacts to fertility, including reduced sperm count and increased incidence of miscarriage, have also been demonstrated among dry cleaning workers.

However, there are multiple alternatives to cleaning with perc, and most communities have at least one cleaning establishment proclaiming itself as green or organic. Most of these perc alternatives do have reduced health and environmental impacts, although they are still being studied. The three most common non-perc cleaning methods, and their pros and cons, are:

Carbon dioxide (CO2). Development of a market-ready CO2 method was announced in 1997 by Joseph DeSimone, a chemical engineer with North Carolina State and the University of North Carolina - Chapel Hill. This innovation was important in the chemical engineering world, as CO2 "had long been presumed the holy grail of environmentally sound solvents, but it had a seemingly insurmountable problem: its dissolving potential was like water to oil... industry had largely given up on it in the '80s" (North Carolina State University News Services, 1997). However, in the process of other CO2-related research he was conducting, DeSimone realized he could make the compound into a solvent, and with funding from the EPA, the National Science Foundation, and eight private chemical companies, DeSimone was able to do so. He co-founded MiCELL Technologies Inc. to market the product, and MiCELL is now parent company to Hangers Cleaners, which has a proprietary hold on the CO2 process.

CO2 cleaning may be difficult to convert to for some dry-cleaning shops as it is only available using MiCELL machines, which can only be obtained by operating a Hangers franchise. In addition, as of 2002, a state air quality office stated that while the use of CO2 pressurized to a liquid state is "completely non-toxic," the equipment, estimated at $90,000, "is too expensive at this time for widespread use" (South Coast Air Quality Management District [AQMD], 2002). Nonetheless, the safety and stability of CO2, as well as its cleaning power, make it a frontrunner for the cleaner of the future; for example, when the cleaning process is over, instead of putting fluids into the water or air, the CO2 is reused in the system and the surfactants are recycled. This sustainable and apparently harmless technology is winning fans in the environmental advocacy world.

Silicon. The silicon cleaning process has been shown to be environmentally friendly, as it "degrades to sand, water and carbon dioxide and is listed by EPA as a substitute for ozone-depleting chemicals" (EPA, 2006). However, with respect to human health, there are mixed reports on the safety of siloxanes (the name comes from silicon, oxygen, and alkane), which are a combination of organic and inorganic compounds. The form used in clothes cleaning, cosmetics, and personal health products is decamethylcyclopentasiloxane, also known as D5.

Like CO2, the silicon-based cleaning approach is proprietary, belonging to GreenEarth Cleaning, which licenses several franchises to use its technology. There has been positive feedback about the cleaning ability of the silicon cleaning process, and the GreenEarth technology is relatively available; this availability may be due, in part, to its corporate backing. "While CO2 dry cleaning has some big companies behind it, the silicone-based GreenEarth approach is backed by two of the corporate world's biggest names: General Electric and Procter & Gamble," says Chemical & Engineering News, which also notes that "GreenEarth literature describes D5 as nontoxic, nonirritating to skin, and nonregulated... [and] the compound is already used in personal care products such as roll-on deodorants, shampoos, and body lotions." Not enough data are yet available for the EPA to make a determination on whether D5 poses a cancer risk to humans; therefore, EPA is still assessing the research and expects that the decision for further studies will be made by the end of 2006.

Carbon dioxide (CO2). Development of a market-ready CO2 method was announced in 1997 by Joseph DeSimone, a chemical engineer with North Carolina State and the University of North Carolina - Chapel Hill. This innovation was important in the chemical engineering world, as CO2 "had long been presumed the holy grail of environmentally sound solvents, but it had a seemingly insurmountable problem: its dissolving potential was like water to oil... industry had largely given up on it in the '80s" (North Carolina State University News Services, 1997). However, in the process of other CO2-related research he was conducting, DeSimone realized he could make the compound into a solvent, and with funding from the EPA, the National Science Foundation, and eight private chemical companies, DeSimone was able to do so. He co-founded MiCELL Technologies Inc. to market the product, and MiCELL is now parent company to Hangers Cleaners, which has a proprietary hold on the CO2 process.

CO2 cleaning may be difficult to convert to for some dry-cleaning shops as it is only available using MiCELL machines, which can only be obtained by operating a Hangers franchise. In addition, as of 2002, a state air quality office stated that while the use of CO2 pressurized to a liquid state is "completely non-toxic," the equipment, estimated at $90,000, "is too expensive at this time for widespread use" (South Coast Air Quality Management District [AQMD], 2002). Nonetheless, the safety and stability of CO2, as well as its cleaning power, make it a frontrunner for the cleaner of the future; for example, when the cleaning process is over, instead of putting fluids into the water or air, the CO2 is reused in the system and the surfactants are recycled. This sustainable and apparently harmless technology is winning fans in the environmental advocacy world.

CONTINUED: More alternative dry-cleaning methods

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