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Dry Cleaning 

Alternative Solvents: Health and Environmental Impacts 

In January, 2007, the California Air Resources Board (ARB) amended its regulations addressing 

perchloroethlylene (Perc) emissions from dry cleaning operations. These amendments are effective as of 

December 27, 2007, and include: 

• January 1, 2008: No new sale or lease of Perc machines; 

• July 1, 2010: All Perc machines at co-residential facilities must be removed; 

• July 1, 2010: Perc machines 15 years and older may no longer be used; 

• January 1, 2023: Perc machines may no longer be used. 

 

The ARB determined that the benefits from dry cleaning alternatives outweigh the negative health and 

environmental impacts from the use of Perc. 

Questions have been raised about potential health impacts of alternatives to Perc. We offer this fact sheet 

to describe the available alternative solvents and provide current information on their health and 

environmental impacts. 

The alternative solvents listed are either already in use or are being considered for use in California. This 

information is not meant to be exhaustive as other solvents may also be available. 

Approved Non-toxic and Non-smog-forming Dry Cleaning Technologies

These systems qualify for grant money under California’s Non-Toxic Dry Cleaning Incentive Program, 

established by Assembly Bill (AB) 998. 

Water-Based Cleaning

Water-based cleaning systems use water and detergents to clean garments. Currently, there are three 

types available: 1) professional wet cleaning systems; 2) cold water cleaning systems; and, 3) Green Jet

dry-wet cleaning

 systems. 

• Health and Environmental Impacts 

Most detergents used in wet cleaning are a complex mixture of water and chemicals. Because there 

are a wide variety of formulations, it can be difficult to determine the toxicity of specific products. In 

general, detergents are approved for disposal into sewer systems by local sanitation districts. The 

United States Environmental Protection Agency examined the human health and environmental 

hazards of the primary components of detergents and found no expected health risks to the general 

public. 

Carbon Dioxide (CO2)

The CO2 process, developed by commercial and retail dry cleaners, is a high pressure system using liquid 

CO2 as the cleaning solvent. 

Fact Sheet Fact Sheet 

March 2008 
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• Health and Environmental Impacts 

CO2 is a non-flammable, non-toxic, naturally-occurring gas that becomes a liquid solvent when 

subjected to pressure. There is no expected health risk to the general public from these processes. 

Questions have been raised because CO2 is a greenhouse gas which contributes to global warming. 

Although the amount of emissions from dry cleaning processes have not been studied, the CO2 used 

in the dry cleaning processes is a by-product from industrial operations and therefore does not 

contribute to the greenhouse gas inventory. 

Financial Assistance 

Financial assistance is available for water-based and CO2 cleaning systems through the AB 998 Non-Toxic 

Dry Cleaning Incentive Program. This program provides $10,000 grants to dry cleaners that choose to 

replace their Perc dry cleaning system with a non-toxic and non-smog forming system. Currently, only 

water-based and CO2 cleaning systems qualify as approved technologies. A statewide demonstration 

program was also established to showcase these qualifying technologies, and to provide an opportunity to 

educate business owners of the benefits, costs, and effectiveness of these alternatives. More information 

can be found at http://www.arb.ca.gov/toxics/dryclean/ab998.htm. 

In addition to ARB’s Non-Toxic Dry Cleaning Incentive Program, some local air districts offer incentives for 

water-base and CO2 cleaning systems. A list of the local air districts’ contact information can be found on 

the following website: http://www.arb.ca.gov/capcoa/roster.htm. 

 

Other Available Dry Cleaning Technologies

The following systems are currently being used or being considered for use in California as alternatives to 

Perc machines. 

Hydrocarbon Solvents 

Currently, the types of hydrocarbon solvent technologies available are: 1) DF-2000 Fluid; 2) PureDry; 

3) EcoSolv; 4) Shell Sol 140 HT; and, 5) Stoddard solvent. The machines predominately used for 

hydrocarbon solvents are closed-loop machines equipped with primary controls. Detailed information on

each of the hydrocarbons is available in the Air Resources Board staff report available at 

http://www.arb.ca.gov/regact/2007/perc07/perc07.htm . 

• Health and Environmental Impacts 

There is limited health information on these hydrocarbon mixtures with the exception of the Stoddard 

solvent. None of the hydrocarbon solvents have undergone formal evaluation by California for 

identification as toxic air contaminants (TAC). A two-year inhalation study of Stoddard solvent 

conducted by the National Toxicology Program (NTP) concluded that there was some evidence of 

carcinogenic activity in male rats. Additionally, Stoddard solvent can be irritating to the eyes, nose, 

throat, and can also have effects on the nervous system. A detrimental and secondary health effect 

of the alternative solvents is that all hydrocarbon solvents are considered volatile organic 

compounds (VOC). VOCs contribute to the formation of ozone which is linked to many ill-health 

effects including respiratory irritation, asthma, and premature death. 

GreenEarth®

 (Volatile Methyl Siloxane) 

Decamethylcyclopentasiloxane (D5) or volatile methyl siloxane is an odorless, colorless liquid that has many 

consumer and industrial applications. D5 is the ingredient present in the GreenEarth

 dry cleaning solvent 

used in multi-solvent machines. The ARB does not consider D5 to be a VOC. 
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• Health and Environmental Impacts 

California’s Office of Environmental Health Hazard Assessment (OEHHA) recently conducted an 

evaluation of the available D5 information and concluded that exposures of D5 at the highest 

achievable vapor concentrations cause uterine tumors in rats. OEHHA is also concerned about the 

potential non-carcinogenic effects associated with D5 and its apparent persistence in the 

environment and animal and human tissues. However, available exposure information indicates that 

the use of D5 as an alternative dry cleaning solvent will not pose a risk to the public living near 

businesses using D5. D5 has not undergone formal evaluation for identification as a TAC. 

Rynex (Rynex 3 or Propylene Glycol Ether) 

Rynex (Rynex 3) is an organic and biodegradable solvent with low volatility and a high flash point. It is 

considered a VOC. Rynex 3 can be used in most hydrocarbon machines with some temperature and timing 

adjustments. 

• Health and Environmental Impacts 

Rynex 3 consists of a mixture of glycol ethers. This solvent brand has changed formulation since its 

inception. Based on a recent study by NTP on the glycol ether ingredient of a previous formulation 

for Rynex

, propylene glycol t-butyl ether (PGtBE), OEHHA has expressed concerns over its toxicity 

and carcinogenic potential. Of particular concern, was the presence of tumors in mice. More 

detailed information on the toxicological studies for the previous formulation of Rynexcan be found 

in the Technical Assessment Report. Rynex 3 represents the current formulation for Rynex, which 

does not contain PGtBE but instead contains dipropylene glycol tert-butyl ether (DPTB). Currently, 

there is limited toxicity data available for DPTB. It has not undergone formal evaluation for 

identification as a TAC. 

Limited Use Dry Cleaning Technologies 

1-Bromopropane (n-propyl bromide) 

1-Bromopropane (n-propyl bromide or n-PB or DrySolv) is an emerging technology which is currently being 

used outside of California. It is considered a VOC. Although this solvent is being used in modified 

perchloroethlylene-dry-cleaning machines with secondary control, industry representatives are concerned 

that n-propyl bromide’s inherent properties may lead to more leaks and emissions in such machines. 

• Health and Environmental Impacts 

According to the California Department of Health Services, this solvent is a neurotoxicant and 

reproductive toxicant and is listed under Proposition 65 as a reproductive toxicant. It causes sterility 

in both male and female test animals, and harms developing fetuses. It can damage nerves, 

causing weakness, pain, numbness, and paralysis. 1-Bromopropane has a strong odor and is a 

more volatile compound than Perc, thus increasing its potential for nuisance problems and exposure 

to near-by residents. This compound has not undergone formal evaluation for identification as a 

TAC. 

SolvairTM (dipropylene glycol normal butyl ether/ CO2) 

Solvair is a recently available commercial dry cleaning technology. The Solvair equipment uses a closed 

loop process in which dipropylene glycol n-butyl ether (DPNB) is used as the base cleaning and liquid CO2

is used to rinse out the solvent and dry the garments. 
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• Health and Environmental Impacts 

DPNB is a type of propylene glycol ether. Currently, there is limited toxicity information available for 

DPNB. It has not undergone formal evaluation for identification as a TAC. There is no expected 

health risk from the exposure to the CO2 used in the Solvair technology. 

Fire Hazard Considerations

The alternative dry cleaning technologies listed in this fact sheet, with the exception of water-based and 

CO2 cleaning technologies use solvents that may be regulated by local Certified Unified Program Agencies 

(CUPA) because of their flammability and/or combustibility. CUPA contact information may be found on the 

following website: http://www.calepa.ca.gov/CUPA/Directory/default.aspx. 

More information

More information on the alternative technologies may also be obtained from the following website: 

www.arb.ca.gov/toxics/dryclean/dryclean.htm. This website contains regulatory information and formal 

rulemaking documents. For more information on the status and requirements of the amended Dry Cleaning

Air Toxic Control Measure, please contact one of the following Air Resources Board staff. 

 Mei Fong Sonia Villalobos Hafizur Chowdhury (AB 998 Program) 

 Phone: (916) 324-2570 Phone: (916) 327-5983 Phone: (916) 322-2275 

Alternately, you may email questions to dryclean@arb.ca.gov.