For most people, dry cleaners don’t always jump to the top of the list when it comes to environmental red flags, but occasionally dry cleaning operations have been responsible for widespread soil and groundwater contamination. Initially the dry cleaning industry experimented with petroleum based products (including distillates like kerosene, benzene and gasoline) to clean clothes or remove stains. Not only are these materials harmful to the environment, but they are volatile due to their extremely low flash points. They created a multitude of general workplace hazards. After losing so many dry cleaning plants to fires, the industry tried nonflammable chlorinated solvents which were more efficient at removing stains. Carbon tetrachloride and trichloroethylene were used during the early stages of this process change, but acute health issues made these chemicals an unsuitable replacement. Around the turn of the 20th century, the industry made the switch to perchloroethylene (PCE), a chlorinated hydrocarbon solvent that was highly efficient at removing stains. PCE was stable and economical. It was win-win situation for the dry cleaning industry. It took a little longer for scientists to understand the full health and environmental impacts of these new chemicals.
PCE is a highly mobile solvent that easily migrates through concrete or asphalt parking lots impacting a site’s underlying soil and groundwater. PCE is considered a volatile organic compound (VOC) as it quickly evaporates into the air creating vapor intrusion issues. It must be noted that while PCE may be the primary culprit for contamination surrounding dry cleaner facilities, PCE’s breakdown products, from Trichloroethene (TCE) to vinyl chloride, share the blame as well. PCE and TCE are two of the most commonly found contaminants at Superfund Sites identified by the EPA.
Exposure to PCE has been associated with chronic, long term health effects including liver, kidney, and neurological damage. PCE has also been identified as a potential human carcinogen by the EPA’s Science Advisory Board. Acute exposure symptoms include loss of coordination, confusion, headache, drowsiness and eye, nose and throat irritation. The most common exposure routes for PCE are inhalation and absorption through the skin.
Historical Releases from Former Dry Cleaner Operations
Improvements in technology and hazardous waste handling have greatly reduced the potential for releases over the last several decades. However, PCE is still the dominant solvent used in dry cleaning today. It is a stable, noncorrosive solvent that removes stains without shrinking fabrics, or causing dyes to bleed (EPA). PCE can be reprocessed making it an economical and efficient solvent for dry cleaning clothes. Today, dry cleaning operations typically deliver the solvents through a closed loop system, virtually eliminating the potential release of PCE. Nonetheless, in the past there were multiple stages in the dry cleaning process in which the solvent had the opportunity to be released into the environment. Transfer machines were the primary method for dry cleaning for much of the 20th century. Transfer machines were comprised of three different machines to include a washer, extractor and tumbler to dry the garments. Before the process even began there was a potential for a PCE release associated with storage and delivery of the solvent. Then an additional opportunity for a release of the solvent and vapors between each machine as the clothes were transferred from one machine to the next. Over time minor spills and leaks that occurred during product transfer could result in a significant amount of PCE released into the environment.
A Need for Regulatory Action
In 1991, the Clean Air Act Amendments identified PCE as an air pollutant, forcing the industry to develop and use machines with engineering controls that reduce or recover the vapors. Dry cleaning machines have evolved, eliminating the need to transfer the clothes from one machine to the next. This reduced the amount of potential releases and protected employees from toxic vapors. Dry cleaning machines utilize a dry-to-dry method that includes a vapor recovery systems and does not produce contaminated separator water. Technology advancements have reduced the amount of PCE required for dry cleaning and as well as PCE emissions. Most releases today occur because of faulty equipment or between transfer of PCE from delivery to the machine.
Prior to the publication of Resource Conservation Recovery Act (RCRA) hazardous waste regulations in the 1980s waste generated at dry cleaners remained completely unchecked. Operators may have intentionally dumped PCE waste into storm drains, sanitary sewer lines or out the back door. Many releases may have occurred inadvertently through leaking sewer lines before making it to the wastewater treatment plant. Of course, PCE should have never been discharged to the sewer lines in the first place. Unfortunately this was common practice prior to the mid-1980s. Undoubtedly, leaking underground storage tanks (USTs) containing PCE have contributed to widespread PCE contamination as well.
How to Reduce Your Environmental Risk
Although dry cleaning operations and hazardous waste management at dry cleaning facilities have come a long way since the end of the 20th Century we are still dealing with the environmental impact of legacy dry cleaners today. Should a former dry cleaning plant be identified during an initial Phase I Environmental Site Assessment, a closer look is warranted. All information regarding the dry cleaning facility should be gathered to determine if the site has been impacted or previously remediated. Questions concerning how long and when the site operated as a dry cleaner should be answered. If no releases were reported or no regulatory action conducted, it doesn’t mean that the site is not an environmental risk. A thorough site characterization should be conducted to evaluate the potential environmental impact. This will help to determine the level of environmental risk associated with the site. Element has successfully investigated, characterized and remediated former dry cleaning sites. We understand the complexities surrounding PCE contamination and the value of returning these contaminated properties back to productive use.
This is the first post in our Brownfield series where we’ll take a closer look at general sites uses that have been associated with contaminated Brownfields. We’ll take a broad look at the type of operations, chemicals associated with these sites, health impacts and how to minimize risks associated with these sites. If you have questions, or would like to learn more, please contact Element.