Dry cleaning is a method of cleaning clothes and textiles using a chemical solvent instead of water. This process is necessary for delicate fabrics that traditional washing machines might damage. The use of industrial solvents has historically led to public concern regarding the safety of the chemicals involved. Solvents employed in dry cleaning have been linked to health issues, prompting a significant shift in industry practices over time. Understanding the scientific classification of the primary chemical used helps clarify the potential risks.
Perchloroethylene The Main Concern
For many decades, the standard solvent used by the dry cleaning industry was Perchloroethylene (PCE), also known as “Perc.” This chemical was widely adopted because it is highly effective at dissolving grease and stains while remaining non-flammable. PCE is a volatile liquid that easily turns into a vapor at room temperature, allowing it to enter the body through inhalation.
Exposure occurs in two distinct ways, each with different risk levels. Occupational exposure affects dry cleaning workers who handle the chemical daily, leading to prolonged, high-volume contact through breathing and direct skin contact. Consumer exposure is far lower, occurring when residual solvent vapors linger on cleaned garments brought into the home. These residual chemicals can off-gas, slightly elevating toxin levels in the immediate environment.
Understanding the Scientific Classification of Risk
The question of whether dry cleaning causes cancer is addressed by the scientific classification of Perchloroethylene. Major public health bodies have evaluated the evidence. The International Agency for Research on Cancer (IARC) classifies PCE as a Group 2A carcinogen, meaning it is probably carcinogenic to humans. This classification is based on sufficient evidence of cancer in experimental animals and limited evidence of an association in humans.
The United States Environmental Protection Agency (EPA) similarly classifies PCE as likely to be carcinogenic to humans. Studies of highly exposed dry cleaning workers have shown associations with increased risks for certain cancers, including non-Hodgkin lymphoma, bladder, and kidney cancers. This evidence primarily comes from individuals with years of high-level occupational exposure, not from the low-level residual exposure experienced by customers. The greatest risk is to the worker, not the consumer who occasionally wears a dry-cleaned garment.
Safer Practices and Modern Cleaning Methods
In response to health concerns, the dry cleaning industry is transitioning away from PCE. The EPA has issued rules to prohibit its use in new dry cleaning machines, spurring the adoption of several modern, safer alternatives.
One prominent method is professional wet cleaning, which utilizes water and specialized, biodegradable detergents and conditioners with computer-controlled machinery. Another alternative is liquid carbon dioxide (\(\text{CO}_2\)) cleaning, which uses pressurized, recycled carbon dioxide as the solvent. This process leaves no chemical residue and is considered environmentally sound. Additionally, many cleaners now use silicone-based solvents, such as GreenEarth, which are non-toxic, odorless, and break down into natural elements.
For consumers concerned about residual exposure, a simple step is to immediately remove the plastic garment bag upon returning home. The item should then air out in a well-ventilated area before being put away.