Standard dry cleaning, despite its name, is neither a dry nor "clean” process. In the US, dry cleaners are the largest source of emissions from perchloroethylene (perc), which is used as the liquid solvent in their cleaning method. Perc, which is also known as tetrachloroethylene, has been classified as a carcinogen by the California Air Resources Board. Further, the organization estimates that one out of every 10 drinking wells in California has been contaminated by perc. The board approved a plan to phase out the use of perc in California by 2023. In the US, dry cleaners are the largest source of emissions from perc.
Professional equipment is designed to prevent leakage, and waste is disposed of by hazardous waste companies, however, improperly maintained equipment and filtration systems can emit perc into the air. Perc can also escape during the disposal process, contaminating the air, soil, and water.
Perc itself does not deplete the ozone, but when broken down it may combine with other chemicals and contribute to ozone depletion. All solvents, both industrial (e.g. dry cleaning) and non-industrial (e.g. paint thinners), release greenhouse gases. Dry cleaning solvents comprise approximately 6 percent of overall solvent-related hydrocarbon emissions and also contributes to carbon monoxide and nitrogen oxide emissions.
Commercial alternatives to perc dry cleaning do exist. Companies have developed solvents that are less toxic than perc, such as siloxane and hydrocarbons. But keep in mind that ‘less toxic’ still implies some level of toxicity. Siloxane is a likely carcinogen—the US Environmental Protection Agency (EPA) is still determining the health and environmental effects of this chemical.
Two nontoxic options are wetcleaning and liquid carbon dioxide (CO2) cleaning. Wetcleaning, which is safe for "Dry clean only" clothes, uses water and biodegradable soaps but is more rigorous than home laundering.
CO2 cleaning uses the same liquid found in carbonated soft drinks to remove stains from clothing. CO2 is a naturally occurring gas and its release does not produce any health safety hazards. Although CO2 gas is a major greenhouse gas, the liquid CO2 solvent is recycled back into the dry cleaning system to prevent CO2 emissions. However, the process does involve some volatile organic compounds (VOCs).
For dry cleaning, the term "green cleaning" is not regulated and does not indicate that a particular method is practiced. Therefore any cleaner can deem itself a green cleaner regardless of how environmentally friendly it may or may not be. Be sure to ask what methods are actually used, so you know exactly what is going into your clothing.
Related health issues
Perc has been known to cause short-term side effects, such as headaches, dizziness, and nausea. These symptoms are seen in customers who wear conventionally dry cleaned clothing that hasn't been properly aired out. Perc can enter the body through skin contact or inhalation, but the average person is only exposed to minimal levels of perc from residue left on dry cleaned clothing.
The greater risk is to dry cleaner employees and the environment. Prolonged inhalation exposure, common among dry cleaning employees, is linked to chronic kidney, liver, and reproductive damage, and may also increase the risk of cancer. An individual cleaning company only uses about 140 gallons of perc per year, but when this is multiplied by 30,000 businesses it amounts to approximately 4.2 million gallons of perc that are used annually.
- volatile organic compounds (VOCs): Organic solvents that easily evaporate into the air. VOCs are emitted by thousands of products, including paints, cleaning supplies, pesticides, building materials and furnishings, and may cause immediate and long-term health problems. VOCs are also considered a possible carcinogen, and can create ground-level ozone, the main component of smog.
- Illinois Environmental Protection Agency - Watch Your Perc!
- Coalition for Clean Air - Hung Out to Dry: Getting Toxics Out of Dry Cleaning
- US Department of Labor - Occupational Safety & Health Administration: Reducing Worker Exposure to Perchloroethylene (Perc) in Dry Cleaning
- US Environmental Protection Agency - Design for the Environment (DfE): Frequently Asked Questions About Drycleaning
- US Environmental Protection Agency - Inventory of US Greenhouse Gas Emissions and Sinks: 1990-2005, Chapter 5
- Green Guide - Wet Cleaning and Dry Cleaning Alternatives
- Cool Earth Technologies - CO2 Cleaning Process Fact Sheet
- Consumer Reports Greener Choices - Dry cleaning alternatives
- US Environmental Protection Agency - Technology Transfer Network Air Toxics Web Site: Tetrachloroethylene (Perchloroethylene)
- US Environmental Protection Agency - Compliance Assistance For Dry Cleaners