GreenEarth Cleaning is a patented process for drycleaning using liquid silicone (decamethylcyclopentasiloxane, or D5), a clear, odorless, non-toxic solvent solution in a closed loop system. D5 degrades into silica (SiO2) and trace amounts of water and carbon dioxide within days if spilled or disposed of. There are currently more than 1,600 drycleaners using D5 worldwide.
D5 solvent properties
The International Fabricare Institute (a trade association for garment care and dry cleaning) conducted an independent, comprehensive study of the GreenEarth Cleaning system in 2002 to assess its effectiveness in comparison with tetrachloroethene (a commonly used solvent in dry cleaning commonly known as PERC). Perc and GreenEarth were concluded to be “virtually identical in terms of the ability to remove stains completely” except in the cases of ballpoint pen and shoe polish stains.
The IFI also tested common materials that pose problems for regular drycleaners, such as leather, sequined and beaded garments. Specialty fabrics and decorative trims withstood the GreenEarth process much better than the perc process, which can remove paint on sequins, and dissolve some plastic beads, and such items need to be tested before cleaning.
A separate evaluation of alternative solvents by the IFI in 2007 using the same criteria rated GreenEarth as "good" in the areas of capital costs and health, and “excellent” in the categories of cleaning, environmental safety, ability to handle fabrics and trims and labor/operating efficiency. Perc received a “poor” rating in the areas of health and environmental safety and excellent in all other areas.
- Has been specifically exempt from VOC regulation by U.S. EPA.
- Does not pose an adverse health risk to the public.
- Not regulated by the Environmental Protection Agency (EPA), Resource Conservation and Recovery Act (RCRA) or Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)
- Listed by the EPA as a “SNAP” (Significant New Alternatives Policy) material, a good substance to use in place of ozone-depleting chemicals
- Degrades to silica and trace amounts of water and CO2
- Requires no special permit
- Not listed on California Proposition 65
- Is highly lipophilic and has been found to persist in animal tissues and aquatic species
Health and safety
D5 has many commercial and industrial applications beyond dry cleaning, and is the base ingredient in many personal care products such as body lotions, soaps, underarm deodorants, and shampoos. It may be listed as dimethicone, polydimethylsiloxane, cyclosiloxane, siloxane or other abbreviations as an ingredient. It is non-toxic, non-irritating to skin, non-sensitizing and has no immunosuppressant effects. More than 30 studies on D5, performed at a cost in excess of $30 million, have been conducted and the data support the safe use of D5 in all of its many applications, including dry cleaning. No other alternative dry cleaning solvent has been subjected to independent health and safety testing to this degree.
GreenEarth was given excellent ratings for health and safety by the IFI in its 2007 Alternative Solvent Evaluation. Independent waste stream and air exposure testing, conducted by Severn Trent Laboratories and California Industrial Hygiene Services, confirmed that D5 as used in daily dry cleaning operation exceeds all federal, state and local requirements for water and air safety.
In February 2012, Canada's Environment Minister,Peter Kent, declared that D5 is not harmful to humans or the environment. After extensive research and analysis, Environment Canada has concluded that D5 does not require regulation.
The city of San Francisco on its environmental website warns that "effects of D5 include impacts to the nervous system, fat tissue, the liver (bile formation), and the immune system. Exposure to D5 is known to aggravate liver disorders and cause liver weight changes in rats exposed to it. Should this combustible solvent ignite and start a fire, one of the resulting products is formaldehyde, an acute respiratory and nervous system toxicant and cancer hazard." Also, because D5 is an environmental contaminant, humans could be exposed to it by consuming wildlife and fish that ingested it.
A two-year bioassay study was commissioned by Dow Corning, a manufacturer of D5, to study the effects of inhalation of D5 at the highest concentration possible (160 ppm, total air saturation) on lab rats. The rats were exposed to fumes six hours a day, five days a week, for two years. The results, submitted to the EPA under the Toxic Substances Control Act (TSCA) section 8(e) in 2003, showed an increased risk of uterine tumors and increased liver weight in female rats. No effects were seen in male rats. Based on the observed effects, follow up research was conducted by the Silicones Environmental, Health and Safety Council (SEHSC) and concluded that the effects observed in the Dow Corning study were rat-specific, not relevant to humans, and did not pose a health risk to humans. The SEHSC report also pointed out that the concentration of D5 that the rats were exposed far exceeded workplace or consumer exposure from dry cleaning applications; the workers' average exposure to silicone in a drycleaning plant is less than 3 ppm. The Dow Corning study was a risk assessment of the chemical D5, not its application in a dry cleaning operation. The federal EPA has not moved to conduct a risk assessment of D5 in dry cleaning or other applications. However, the California Air Resources Board (CARB) conducted an 18-month study of D5 as it is used in dry cleaning. In February 2008, CARB concluded that D5 does not pose a health risk to the public, and does not see a need to regulate its use in dry cleaning.
- International Fabricare Institute Fellowship Report (2002) No. F-47.
- CARB letter to local air districts, 8 February 2008. Accessed 13 May 2008.
- "Compare Dry Cleaning Solvents | sfenvironment.org". Retrieved 17 December 2014.
- Sarah, Hoover. "OEHHA. Comments on Human Health and Environmental Hazards for GreenEarth".
- Riesenman, Stephanie. “Alternative Dry Cleaning Method May Be Unsafe.” February 17, 2005. Accessed 2007-08-01.
- Silicones Environmental, Health and Safety Council. “Fact Sheet: D5 in Dry Cleaning.” December 2004. Accessed 2007-07-30.
- GreenEarth Cleaning official website
- California EPA Dry Cleaning Alternative Solvents Fact Sheet