Dry cleaning using chlorinated solvents such as perchloroethylene can cause significant soil and groundwater contamination that is extremely problematic to remediate. With increasing environmental awareness and regulation, dry cleaning has become “cleaner” with the use of hydrocarbon-based solvents and “dry to dry” machines. Also, the volume of solvent used in the process has dramatically been reduced, from many drums to perhaps a small drum. Nevertheless, an environmental site assessment will need to address many angles to avoid calling this kind of site activity anything but a REC.
One easy way to get into the clear is to establish, without a doubt, that dry cleaner is and has always been a “drop off” only store, meaning a centralized plant is used, and the clothes are shipped back and forth. Still these “drop off” stores will have “perc” on hand for spot cleaning, but certainly not at a material level.
Why are chlorinated solvents so evil? The layman’s explanation is that they are heavier than water, and they sink rather than float on the surface of the groundwater water. As such, they can penetrate through concrete surfaces and any conduit in a floor (e.g. seams, bolts, etc.) and the base materials below. From there it will normally proceed straight down until it meets resistance such as clay or rock. Over time it will dissolve into the groundwater, but it can stay in its non-liquid state for a long time. If it penetrates lower into the rock containing the drinking water aquifer, it can contaminate that too, and can be present in two aquifers at one time, flowing in different directions. Therefore, its incumbent upon the assessor to do his or her homework.
In Florida, dry cleaner registration commenced in the 1990s, and applications were made into the state’s dry cleaning solvent cleanup program. Eligibility into the program was based on confirmed contamination, soil or groundwater, usually determined by performing soil and groundwater sampling and chemical testing inside the structure next to the dry cleaning machine and outside the building next to the back door of the facility. In 1998 this popular program closed. The state is slowly cleaning up these facilities on a priority basis. There are many considerations to taking title to or lending against a cleaner in the program even if eligible for state cleanup, i.e. future marketability of site.
Generally, the presence of a dry cleaner, or the past presence of a facility, requires serious assessment and research to determine if the cleaner was indeed a plant, if it operated at a time when a “wet” process was used to change from washing to drying machines, if perc was used in the process, if it operated at a time when significant volumes of solvent were required on the premises, if non-chlorinated solvents were used such as Stoddard chemicals requiring an expansion of testing parameters, and/or if the facility is in a cleanup program and stands a chance of ever being cleaned up based on its priority ranking. Regardless, you’ll end up needing to perform the same kind of soil and groundwater testing that you’d have to perform to get into the cleanup program (inside and outside) in days gone by, using EPA methods 8260 and 8270.
Practically and realistically, during the “due diligence” phase of a transaction, don’t count on the owner wanting to be invaded for a core through his or her concrete floor. You may have to find a location outside near the dry cleaning machines. In this case, any faint detection of a chlorination solvent should be considered material, since the solvent normally migrates straight down and only a limited amount of dissolution has occurred.
In your drilling, certainly do not drill into or through rock. This will enable the solvents to penetrate even deeper. This is obviously not good.
There are many exotic remediation methods to address chlorinated solvent contamination, but the simplest and sometimes the most effective is to remove the source, i.e. excavate. Again this may be problematic with a viable business in place.
It’s also important to understand that chlorinated solvents are used in other applications with the same ramifications. For example, a printing business will likely use the solvent to wipe down its machines.