Are “Green” Dry Cleaning Solvents Bad for Our Health?

by Diana Ceballos and Marcy Franck


Sometimes chemicals we call “green” are better for the environment, but not always good for our health. Dr. Diana Ceballos, our Visiting Scientist with the Hoffman Program on Chemicals and Health, and some of her research colleagues, set out to better understand how chemicals commonly used in the dry cleaning industry impact health, especially as many shops are making the switch to products thought to be better for the environment.

There are about 36,000 commercial dry cleaning shops in the United States. These shops are usually small businesses that are marginally profitable and owned and staffed by individuals with limited English proficiency. Due to these economic and logistical factors, they can have challenges maintaining a safe and healthy workplace.

To inform safe work practices that would better protect workers’ health, Dr. Diana Ceballos and her colleagues evaluated four dry cleaning shops, each using two new “green” dry cleaning solvents. They published their results in the Journal of Occupational and Environmental Hygiene (JOEH), in their article “Occupational Exposures to New Drycleaning Solvents: High-flashpoint Hydrocarbon and Butylal”.

Out with the old, in with the new

The dry cleaning industry is moving away from using the solvent perchloroethylene (PERC), because it is believed to cause cancer and can harm the nervous system, liver, and kidneys. Some of the PERC alternatives are promoted as safe and environmentally friendly, although their effects on human health and the environment are not well characterized.

Due to limited research studies, we know little about the potential human health impacts of the new alternative dry cleaning solvents Dr. Ceballos and her colleagues studied—butylal and high-flashpoint hydrocarbon solvents. Of them, we know that butylal does not suggest toxicity when exposed in the short term, but there’s no research telling us how this chemical might impact health with repeated exposures over time. The high-flashpoint hydrocarbon is a known irritant and, at high levels, can cause headaches, dizziness, drowsiness, unconsciousness, and other central nervous system effects, including death. While it’s unlikely for high-flashpoint hydrocarbons to appear at these levels in dry cleaning shops, the study seeks to better understand typical exposures of those working in close proximity to them on a regular basis.

What chemicals are in workers’ breathing zones?

Dr. Ceballos and her research colleagues collected air samples from workers’ breathing zones. They were looking for evidence of butylal and high-flashpoint hydrocarbons, and also formaldehyde, and butanol because they are potential by-products of butylal. Both are known irritants and formaldehyde is a probable carcinogen.

Air levels in all dry cleaning shops tested highest for the dry cleaning solvents when workers loaded and unloaded the dry cleaning machines and pressed dry cleaned fabrics.

The first two dry cleaning shops in the study used butylal as the cleaning solvent. Test results for these shops found butylal, formaldehyde, and butanol in workers’ breathing zones. The levels of formaldehyde and butanol measured were not of concern for worker’s health. The researchers could not determine if the levels of butylal were harmful, because there is insufficient research about the health impacts of this solvent.

The remaining two shops, each using the high-flashpoint hydrocarbon as the cleaning solvent, found high-flashpoint hydrocarbon solvents in the area where workers breathe, but they were found at levels of no concern for worker’s health.

Innovative new methods for measuring chemicals in the air

This study was important beyond assessing workers health. This is the first time that scientists measure the new dry cleaning solvents butylal and high-flashpoint hydrocarbons in dry cleaning shops. To do so, Dr. Ceballos team worked with chemists to develop a new analysis method to be able to measure butylal in air and adapted an existing method for hydrocarbons to be able to tease out the high-flashpoint hydrocarbon mixture. These methods can be used by other scientist as we learn more about these new solvents. Further, to assess the safety of butylal, Dr. Ceballos team used risk assessment tools as no occupational guidelines exists. The tools results suggested that dry cleaning workers should take precautions to avoid exposures; however, limited information on this new solvent makes the conclusions from the risk assessment tools also limited.

Understanding potential effects on human health of chemicals being used as dry cleaners is important to prevent workers’ health problems. However, there is insufficient toxicological and health information to determine confidently the safety of butylal on human health.

This lack of information can translate into uncertainty about the safety of people who wear clothes washed in these chemicals. As we support businesses using “green” chemicals because they may help the environment, it is important to acknowledge that these chemicals may be harmful. Until future research studies can measure their health impacts, we can’t be sure.