What Is “Green” Dry Cleaning… and Is It Safe?

Dry cleaning is defined as a cleaning process for clothing which uses a chemical solvent other than water. Recognizing the environmental risk posed by dry cleaners is an essential task for an Environmental Professional conducting an assessment of a property. However, as the green drycleaners become more popular what are the key environmental considerations and is the green drycleaner still a cause for concern?

Dry cleaners have a substantial history of using chlorinated solvents.  Perchloroethylene (PERC or PCE), was first introduced to dry cleaning in 1931 with a substantial increase throughout the 1980s and peaked in the 1990s when closed loop machines were introduced. However, PERC and its associated daughter products are not the only solvent to be concerned with at dry cleaning locations.

Chemicals known to have been utilized as dry-cleaning solvents include: camphor oil, turpentine spirits, benzene, kerosene, white gasoline, petroleum solvents (primarily petroleum naphtha blends), chloroform, carbon tetrachloride (first use in dry cleaning in 1898), perchloroethylene (PERC), trichloroethylene (TCE), 1,1,2-trichlorotrifluoroethane, glycol ethers, 1,1,1-trichloroethane, decamethylcylcopentasiloxane, n-propyl bromide and liquid carbon dioxide.

What Is Petroleum Solvent for Dry Cleaning?

Petroleum-based cleaners were the most widely used solvents in dry cleaning; however, due to the risk of fires and explosions many cities banned dry cleaning within the city limits.  In addition, the business was not able to obtain insurance if white gasoline or another petroleum-based solvent was to be utilized.  This is what led William Joseph Stoddard to develop a less volatile petroleum dry cleaning solvent in 1924, which is commonly referred to as Stoddard solvent and has been in use since at least 1928.  Stoddard was the predominant dry-cleaning chemical used from the late 20s until at least the late 1950s.  It should be noted that not all petroleum solvents are Stoddard, despite that they are generally referred to as such.

PERC is still probably the most universally used dry cleaning solvent, at the present time. It presents and enormous headache for property owners, tenants and nearby businesses. PERC has been recognized as  a highly toxic carcinogen and, because it is heavier than water and highly mobile, can contaminate drinking water supplies near the site and spread through nearby soil. Additionally, it can take the form of vapors and travel vertically, which is dangerous to both the primary and neighboring properties. In addition to alternative hydrocarbons and tricholorethylene, there has been a big push towards phasing out the use of environmentally-liable chemicals to use green processes for dry cleaning.

But what are “green” dry cleaners, exactly, and how do they factor into environmental due diligence needs? As an Environmental Professional this question comes up more often than not, especially with recent changes to the U.S. Small Business Administration (SBA) due diligence approach to drycleaners. The SBA’s recent change has gone from specifically stating chlorinated solvents to now including petroleum-based solvents. The SBA now requires a Phase I Environmental Site Assessment and a Phase II Environmental Site Assessment for all properties currently or historically operating a dry-cleaning business, without consideration of a time frame or exceptions.

In general, a green drycleaner is referred to as any alternative drycleaner NOT USING PERC.  This can include a very wide net of chemicals and cleaning agents. So, what constitutes “Green”?  Well it truly depends on perception and ultimately understanding.  Scientists could argue that if it has a carbon chain, then it is organic; therefore, can be construed as natural and marketed as “green.”  If you take that approach, even cleaning your clothes in gasoline is green.  Of course, this is just an absurd analogy because who would really wash their laundry in gasoline? So, how can you truly determine is a drycleaner is green or not?

Approximately 80 percent of drycleaners still use PERC (in one form of another) to this day.  In the 1990s, the USEPA began regulating dry cleaning chemicals under RCRA which in turn encouraged the use of safer and more environmentally friendly products.  This is where the term “Green” dry cleaning truly came from.

Currently, four methods of alternative cleaning are offered. One is wet cleaning which is a gentler version of home laundering. Three other green cleaning methods use traditional solvents, carbon dioxide, hydrocarbon, or silicon-based cleaners instead of percholoethylene.

Wet Cleaning:
Wet cleaning uses water and specialized detergents that are milder than home laundry products to clean clothes. The EPA considers it one of the safest professional cleaning methods because there is “no hazardous chemical use, no hazardous waste generation, no air pollution, and reduced potential for water and soil contamination.”
Liquid Carbon Dioxide (CO2) Cleaning:
Carbon dioxide (CO2) cleaning uses a mixture of liquid CO2 along with detergent as the cleaning substance. The liquid CO2 is formed by placing the nonflammable and nontoxic gas under high pressure. Liquid CO2 is non-toxic and is used in many foods, drinks and other household products. The process uses less energy than traditional dry cleaning because there is no solvent to heat and less than 3% of the CO2 used for cleaning is lost into the air with each load. Unfortunately, the dry-cleaning machines used for liquid CO2 cost around $40,000 each, making them potentially cost prohibitive for many small businesses.
DF-2000 Hydrocarbon Solvent:
Some promote being green by using an “organic” solvent called DF-2000, which is a hydrocarbon that is produced from petroleum. Production of these chemicals raises environmental concerns over greenhouse gas emissions.
Silicon Based Solvent:
Some cleaners use the GreenEarth cleaning method (liquified sand, silicon dioxide) to replace perc. GreenEarth functions as a silicone based solvent called siloxane or D-5. Siloxane is similar to some of the base ingredients used in shaving creams and deodorant. When GreenEarth is discarded, it breaks down into sand, water, and carbon dioxide. The upside to silicon-based solvents is that no chemicals touch your clothes. However, the manufacture of siloxane uses chlorine, which releases carcinogenic dioxin during the manufacturing process.

Of the four “green” methods described above, wet cleaning and liquid carbon dioxide cleaning are the only methods that can reliably be considered environmentally safe.

California is forging ahead on environmental legislation by being the first state to phase out use of perchloroethylene in 2007, with legislation enacting a full ban by the year 2023. As scientists and environmental professionals learn more about the liabilities of using solvents like PERC or TCE, and as technology provides more gentle alternatives with equal cleaning ability, there will be an even greater demand for these green alternatives by business owners and customers alike.

For current and future owners of dry cleaning establishments, sound environmental practices are the best advice for minimizing future risk. While the aforementioned alternative dry-cleaning methodologies result in less environmental risk and potential remediation, your Environmental Professional would still need to ask and investigate what method is used when conducting the assessment of the property to verify. Beware that some older sites will still use PERC for spotting, while newer sites may have historical use of PERC or petroleum-based making careful due diligence assessments in any transaction critical. Regardless of which solvents are used on site and whether the site is currently or has always been a “green” dry cleaner, it is best practice to get an annual audit of the facility from a consultant to assure environmental compliance