In the summer of 2021, the Environmental Directory attempted to survey or otherwise determine the cleaning solvents that dry cleaners in the Austin/Central Texas region use. Click to see the summarized results in what is believed to be the first map of Central Texas dry cleaners detailing this information.
The Dangers of Dry Cleaning Chemicals
Taking the Environment to the Cleaners
Paul Robbins © 2021
Since at least the 17th century, history has recorded use of various natural and synthetic solvents (benzene, camphor oil, turpentine, gasoline, kerosene, naphtha) to clean delicate and specialty fabrics without water, and sometimes better than water.
The earliest recorded example in the U.S. dates to 1821 by Thomas L. Jennings, a Black freeman and abolitionist, who was an expert tailor. He perfected a chemical cleaning method that became the first recorded patent by a Black person in the country. Due to a fire in the patent office, the exact chemical he employed is unknown.
A later discovery by Frenchman John Baptiste Jolly led to the establishment of the first European dry cleaner in Paris in the 1840s at a time when the country had become obsessed with fashion. “French cleaning” swept Europe.
In that era, chemical dangers were not as acknowledged as they are today. Air and water pollution from dry cleaning solvents did not come under government regulation until the late 20th century. However, a more blatant danger was widely known – fire. These solvents were so flammable that dry cleaners often had to locate their operations outside of cities.
In the 1930s, dry cleaners began to use chlorinated solvents that were less flammable or nonflammable. Eventually, perchloroethylene (more commonly known as “perc”) became the most widely-used of these solvents. It cleaned well and was nonflammable. Its stability also allowed it to be recycled. This chemical, combined with smaller machines that were invented to use it after W.W.II, allowed for a smaller footprint that enabled urban dry cleaners to proliferate. For most of a century, perc was the industry standard.
However, as its use grew, its effects on dry cleaning workers, people living close to the dry cleaning shops, and the general environment, became apparent.
Documented Health Problems
Perc is an organochlorine, in the same chemical family as DDT. It biodegrades in the environment very slowly. It is a carcinogen, neurotoxicant, liver and kidney toxicant, reproductive and developmental toxicant, and respiratory and skin irritant. In addition, human exposure to perc has been associated with deficits in color vision and neuropsychological function in both occupational and community exposure studies. Sometimes harmful exposure that produced this effect took only a matter of months.
In 2017, there were about 20,600 dry cleaning shops in the U.S., with about 160,000 total employees, many of whom are directly exposed to chemicals used in the process.
Perc is also persistent in the general environment, contaminating air, water, soil, and adversely affecting wildlife. In 2014, there were 150 “Superfund” sites contaminated with perc that required government funding for remediation.
A 2019 study of 5,369 St. Louis, MO dry cleaning workers over a 22-year period (1993-2014) found incredibly high association of disease. Employees exposed to perc had a 4.2 times higher chance of contracting bladder cancer than a non-exposed person compared to the control group, and high-exposure employees showed a hazard ratio of 9.2. Employees showed a 1.6 hazard ratio for kidney cancer. High exposure carried a heart disease hazard ratio of 1.6, and a lymphatic/hematopoietic malignancy hazard ratio of 4.3. While regulations for perc have tightened a great deal since these observations began, this does show the harm from exposure to this chemical if left unchecked.
A 2011 study tracked 1,704 dry cleaning workers in 4 cities for 8 years of mortality and disease follow-up. Overall cancer deaths were in significant excess, with a 1.22 increased chance of mortality. Esophageal, lung and tongue cancers were correlated with excess deaths. Deaths from non-malignant underlying diseases of the stomach and duodenum were also in significant excess.
Perc has proven to be harmful to human fertility and reproduction. A 1989 study of female dry cleaning workers in Sweden observed an odds ratio for spontaneous abortion of 3.6.
A 2006 Israeli study discovered that children of dry cleaners had 3.4 times the risk of schizophrenia as children without this risk factor.
Perc’s dangers are not confined to dry cleaning workers. Air samples in these employees’ homes were found to be 132 times that of homes in control groups. A 2009 study of perc emissions in New York City showed a 10 to 27% elevated rate of kidney cancer in zip codes with a high density of dry cleaners in their geographic area. Interestingly, zip codes with the highest exposure rates had the most elevated risk of kidney cancer in higher income groups. The study’s authors speculated that this result could be due to more dry-cleaned clothes being worn by wealthier people.
Consumers who take dry-cleaned clothes back to their homes are also exposed. A 2011 study reported that clothing made of wool, cotton, and polyester retained low levels of perc, which were slowly emitted to the surrounding air as Volatile Organic Compounds (VOCs). While perc concentrations were reduced by half in a week’s time, concentrations also increased with successive cleanings. The unvolatalized chemical can also be absorbed through skin contact by wearing the clothes themselves. While low levels of the chemical in the air and on clothes are not considered acutely toxic, they can trigger chemical sensitivity, and add to the overall body burden of toxic chemicals to which the public is exposed.
Because of long-acknowledged chemical hazards, regulation at various levels of government has been enacted to reduce and sometimes eliminate harm from perc. At least partially because of this regulation, volumes of perc consumed by successive generations of cleaning machines fell from 300-500 gram-perc/kg of cleaned fabric to less than 10 grams.
The U.S. Environmental Protection Agency began regulating perc used for dry cleaning as long ago as 1993. Originally, regulations addressed emissions control, operations and maintenance, and record keeping. Its revised 2008 standards required the elimination or retrofit of old equipment. Monthly leak inspections were required.
At the end of 2020, the U.S. banned perc dry cleaners from co-locating in buildings that include residences (such as multistory apartment units).
California prohibited new perc machines from being installed as long ago as 2008, and will prohibit all use of perc for dry cleaning by the end of 2022. The region of Southern California (South Coast Air Quality Management District) banned new machines even earlier, by the end of 2002, and prohibited perc entirely at the end of 2020.
Minnesota has banned perc dry cleaning by 2026. The City of Minneapolis, MN, banned perc dry cleaning in 2019.
California, Maine, and New York require weekly leak inspections with an electronic gas analyzer, and will shut down operations if the leaks are not repaired in a specified time period.
New York City has enforceable standards for perc emissions from units co-located in the same building or adjacent premises. Usually inspections are complaint-driven, though sometimes they are proactive. Depending on the severity of the violations, dry cleaners can be given orders for corrective action, fines, and even shut down until a professional remediation plan has been approved and completed.
Certain local governments have used zoning ordinances to prohibit use of perc in dry cleaning businesses, including Albemarle County, VA, Naples, FL, and Doraville, GA.
Other state and local governments prohibit dry cleaners from being located near vulnerable populations. Maine bans co-location in buildings with child care centers. New Jersey prohibits child care centers being located near dry cleaners or in buildings formerly occupied by dry cleaners. New York state requires that day care facilities certify they are free of environmental hazards. New York City will not allow child care centers to co-locate in a building with dry cleaners.
New York state also requires all dry cleaners to post notices informing the public of the chemicals that they use, including but not limited to perc.
As evidence of health problems caused by perc have mounted, and stricter regulations have come into play to mitigate this harm, the dry cleaning industry has largely adopted alternatives. The relative harm of these alternatives to people and the general environment ranges.
The worst of these alternatives is n Propyl Bromide, a bromated hydrocarbon that is carcinogenic, highly neurotoxic, and a reproductive/developmental toxin. It is persistent in water and air, and emits VOCs. It is highly toxic in aquatic environments. The chemical is the only drop-in alternative that can be used in machines that use perc. However, it is a regrettable substitute, not a solution. Trade named products in this class used by dry cleaners include Drysolv® and Fabrisolv XL™.
Only slightly less concerning is siloxane, an odorless, colorless liquid that has some links to cancer and reproductive/developmental toxicity. It is persistent in the environment, moderately bioaccumulative, and highly toxic to aquatic life. One of the more popular trade named siloxane dry cleaning solvents is Green Earth®. This siloxane process requires electric use roughly twice as high as dry cleaning with perc, and higher than any other alternative process.
There are several classes of chemical solvents that are more benign.
High-flashpoint hydrocarbons (flammable, but ignitable at relatively high temperatures) are not known to cause cancer or be toxic to aquatic life. They are, however, neurotoxic, and emit VOCs. Trade names in this class include DF-2000™ and Ecosolv®, which are in common use in the Austin area.
Several products using high-flashpoint, biodegradable glycol ether solvents are also available. While neurotoxic, they are not believed to cause reproductive/developmental problems, and there are no dangers to the aquatic environment associated with them. However, of the three main chemicals in this class, one of them (PGtBE) is listed with California’s Prop 65 database as a potential carcinogen. This solvent class also emits VOCs. Trade names include Gen-X®, Impress®, and Rynex®.
Glycol ether solvents were not used by any of the Austin establishments interviewed by the Directory in its regional survey of dry cleaners (discussed below). However, it is possible that they are used by local shops who did not respond to the Directory’s request for information. Also worrisome is that 2 of the 3 specific trade named products listed above did not disclose all of their specific ingredients in their Safety Data Sheets.
Butylal, also known as acetal, is the high-flashpoint solvent used in Kreussler’s Solvon K4™ proprietary cleaning process. Its health effects are not well studied. It is moderately neurotoxic, and emits VOCs, but is not currently believed to be carcinogenic,. Its aquatic toxicity is less than 1/10th that of perc, though it is still dangerous enough that unused product would be classified as a Dangerous Waste in Washington State.
Using liquid carbon dioxide (CO2) in combination with special detergents under high pressure is considered environmentally preferable to any other solvent-based systems. CO2 is not directly toxic or flammable. Nor does it directly contribute to global warming emissions, as the chemical is recaptured as a waste product from chemical reactions in various industrial processes. However, the machinery cost is relatively high, so this limits the number of stores who use this alternative. In the summer of 2021, there were no Austin-area dry cleaners that used CO2.
Professional wet cleaning is considered the most environmental of all professional cleaning methods. It uses highly-specialized water-filled washing machines that are computerized to adjust for various sensitive fabrics that are typically dry cleaned. Specialized dryers with moisture sensors are also employed to prevent the excessive shrinking of fabrics. The detergents and spot cleaners are usually more benign compared to perc, siloxane, and hydrocarbon solvents.
Hazardous Waste in Dry Cleaning
Wastewater from conventional laundry is scarcely given a second thought (unless the bill is high). People assume that if the sewage is processed correctly at treatment plants, there is little reason for environmental concern. What happens to impurities removed from clothes by dry cleaning solvents? Alternative solvents may be less toxic to workers and the environment, but similar to perc, they can produce hazardous waste.
Used solvents are typically purified for reuse. Dirt, detergents, fats, oils, and grease are removed from clothing through filtration and distillation. The impurities are often solidified as “still bottoms,” which must be periodically emptied, usually every 1 to 2 weeks. These solids are contaminated with traces of solvent.
Since dry-cleaned clothes are often “spotted” with special chemicals to remove visible stains prior to insertion into a dry cleaning machine, traces of these spotting chemicals also end up in still bottoms. While some of these spotters are fairly benign, some products contain hazardous chemicals such as perc and trichloroethylene (TCE).
The purification process also removes water from solvent (known as “separator water”), which can be hazardous to the degree that certain chemicals taint it.
And solvent purification filters may end up contaminated with enough chemicals to also be considered hazardous waste.
A 2013 study by the King County, WA Local Hazardous Waste Management Program attempted to assess hazardous waste production from hydrocarbon and Solvon K4 solvent processes by sampling 25 companies that used them. The study determined that though almost none of the companies exhibited water contamination, many still bottom samples exceeded federal waste standards for flammability. Many of these samples also exceeded Washington State’s (but not federal) standards for fish toxicity and halogenated organic compound content.
There may have been improvements in alternative-solvent processes and spotting products since this assessment was conducted. However, the study underscores caution. Alternative solvents still have many environmental concerns, just not as many as perc.
Think Globally – Clean Locally
About the Austin Survey
In the summer of 2021, the Environmental Directory attempted to survey or otherwise determine the cleaning solvents that dry cleaners in the Austin/Central Texas region use. The results are summarized in what is believed to be the first map of Central Texas dry cleaners detailing this information.
Only a few establishments still used perc, and only a few others used siloxane.
Most of the balance of establishments used hydrocarbon solvents generally considered safer: DF-2000™; EcoSolv®, and SolvonK4™.
No dry cleaners in the Austin region used carbon dioxide as a solvent.
However, one company, EcoClean, offered professional wet cleaning.
About a quarter of establishments could not or would not identify what they used as solvents, or at least provide much information about what is in them. The manager of Reid’s Cleaning stated it used a hydrocarbon alternative to perc, but would not identify it for competitive reasons. Several others stated or guessed that they used Dri Rite, a solvent supplied by Dixie Oil of Texas. However, this supplier would not make its product Safety Data Sheet public, so transparency is limited. And some cleaners were so distracted or disinterested that they would not disclose the name of the solvent at all.
Safety Data Sheets
 Matchar, Emily, The First African-American to Hold a Patent Invented ‘Dry Scouring,’ Smithsonian Magazine, February 27, 2019. Online at https://www.smithsonianmag.com/innovation/first-african-american-hold-patent-invented-dry-scouring-180971394/
 “The History of Textile Cleaning,” Ophemert, The Netherlands: CINET Professional Textile Care, Online at https://www.cinet-online.com/historical-developments-in-textile-cleaning/
 Ceballos, Diana, Katie M. Fellows, Ashley E. Evans, Patricia A. Janulewicz, Eun Gyung Lee, and Stephen G. Whittaker, “Perchloroethylene and Dry Cleaning: It’s Time to Move the Industry to Safer Alternatives.” Frontiers in Public Health, March 5, 2021. Online at https://www.frontiersin.org/articles/10.3389/fpubh.2021.638082/full
 Scian, Paul, Environmental Evaluation of Dry-Cleaning Industry, Cincinatti, OH: Great American Insurance Group, 2020. Online at https://www.greatamericaninsurancegroup.com/docs/default-source/environmental/5704-env-whitepaper-drycleaning-011420.pdf
 Callahan, Catherine, Patricia A Stewart, Aaron Blair, Mark P Purdue, “Extended Mortality Follow-up of a Cohort of Dry Cleaners,” Epidemiology, March 2019, pp. 285-290. Online at https://pubmed.ncbi.nlm.nih.gov/30721169/
 Calvert, Geoffrey, Avima M Ruder, Martin R Petersen, “Mortality and end-stage renal disease incidence among dry cleaning workers,” Occupational & Environmental Medicine, December 16, 2010. Online at https://pubmed.ncbi.nlm.nih.gov/21172794/
 Kyyrönen, P, H Taskinen, M L Lindbohm, K Hemminki, O P Heinonen, “Spontaneous abortions and congenital malformations among women exposed to tetrachloroethylene in dry cleaning,” Journal of Epidemiology and Community Health, December 1989, pp. 346-21. Online at https://pubmed.ncbi.nlm.nih.gov/2614324/
 Perrin, Mary, Mark G. Oplera, Susan Harlap, Jill Harkavy-Friedman, Karine Kleinhaus, Daniella Nahon, MS, Shmuel Fennig, MD, Ezra S. Susser, MD, DrPH, and Dolores Malaspina, MD, MPH, “TETRACHLOROETHYLENE EXPOSURE AND RISK OF SCHIZOPHRENIA: OFFSPRING OF DRY CLEANERS IN A POPULATION BIRTH COHORT, PRELIMINARY FINDINGS,” Schizophrenia Research, February 2007, pp. 251-254. Online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2739584/pdf/nihms19720.pdf
 Aggazzotti, G, G Fantuzzi, G Predieri, E Righi, S Moscardelli, “Indoor exposure to perchloroethylene (PCE) in individuals living with dry-cleaning workers,” Science of the Total Environment, November 25, 1994, pp. 133-7. Online at https://pubmed.ncbi.nlm.nih.gov/7992032/
 Ma, Jing, Lawrence Lessner, Judith Schreiber, David O Carpenter, “Association between Residential Proximity to PERC Dry Cleaning Establishments and Kidney Cancer in New York City,” Journal of Environment and Public Health, Published on Web January 24, 2010. Online at https://pubmed.ncbi.nlm.nih.gov/20169137/
 Environmental Working Group, “Dry cleaning chemicals hang around – on your clothes,” 2011. Online at https://www.ewg.org/news-insights/news/dry-cleaning-chemicals-hang-around-your-clothes
Sherlach, Katy, Alexander P. Gorka, Alexa Dantzler, Paul D. Roepe, “Quantification of perchloroethylene residues in dry-cleaned fabrics,” Environmental Toxicology and Chemistry, August 26, 2011. Online at https://setac.onlinelibrary.wiley.com/doi/abs/10.1002/etc.665
 Facts for perc regulation from Environmental Law Center, Federal, State, and Local Policies Addressing Chemical Emissions from Dry Cleaners, July 20, 2020. Online at https://www.eli.org/sites/default/files/eli-pubs/dry-cleaner-report-complete-july-2020.pdf
 Op. cit., Ceballos, D., et al.
 Whittaker, Stephen, Evaluation of Solvon K4 in an Acute Fish Toxicity Test, Seattle, WA: Local Hazardous Waste Management Program in King County, 2013. Online at https://kingcountyhazwastewa.gov/-/media/lhwmp-documents/technical-reports/alternatives-to-dry-cleaning-with-perc/rsh-evaluation-of-solvon-k4-in-acute-fish-toxicity-test.pdf
 Whittaker, Stephen, Jessie Taylor, Linda M. Van Hooser, Characterizing Alternative Solvent Dry Cleaning Processes, Final Report, Seattle. WA: Local Hazardous Waste Management Program, LHWMP–1055, August 2013, p. 36. Online at https://kingcountyhazwastewa.gov/-/media/lhwmp-documents/technical-reports/alternatives-to-dry-cleaning-with-perc/rsh-characterizing-alternative-solvent-dry-cleaning-processes.pdf