I am often told by real estate owners that they have a “drycleaner headache”. Dry cleaners can easily become a real estateheadache for a real estate owner and often, can develop into a realmigraine. What is this headache? The headache I am referring iscaused by a carcinogenic chemical known as PCE. PCE ortetrachloroethene (also known by at least 40 other names), isprimarily used in dry cleaning. Such operations can result in arelease of PCE at the site with entry to soil beneath the building. So what specifically is the issue, the migraine associatedwith a PCE release? It consists of two parts. Firstly, thepotential for exposure of PCE vapor to occupants of the building,and secondly the possibility of PCE entering water beneath the siteand therefore impacting local drinking water. What is the best method to address a PCE release? Find anexperienced PCE doctor: an experienced consultant with a backgroundin all aspects of PCE characteristics, release scenarios, migrationproperties, cost-effective cleanup options and applications, andexperience working with regulatory agencies and providinglitigation support and expert witness testimony. In upcoming blogs, I will take a look at how PCE can become amigraine to a real estate holder, what to do to diagnose and analyze the problem, and remediesto address the release in a timely and cost effective manner. What is PCE and what's an important persistent PCErelease?PCE was first formulated in 1821. It is a double-bonded carbonstructure with four chlorines. PCE is a colorless liquid that hasbeen used in dry cleaning since the late 1930s, replacing syntheticsolvents like carbon tetrachloride, with PCE demand increasingthrough 1981. In 1990, of the total amount of PCE used, 50% was used for drycleaning, 25% in chemical manufacturing, 15% in metalcleaning/degreasing and the remainder 10% for miscellaneous uses.In the mid 1990s, PCE use in dry cleaning declined primarily due tothe introduction of machines with closed loop systems. Prior tothis time, 30% of the units were a transfer machine and 70% adry-to-dry vented machine. In the transfer machine, clothing iswashed in one unit and transferred to another for drying, withemissions either uncontrolled or routed to a control device. In thedry-to-dry closed loop machine, the wash and dry cycles are in thesame unit with PCE either uncontrolled or vented to a controldevice. The probability of a PCE release from the earlier units issignificantly higher than from the later, closed loop system. A Persistent PCE Release An important persistent PCE release with respect to theenvironment is one that finds its way to soil beneath the building. Once beneath the building, PCE will volatilize into the voidsbetween soil particles and migrate horizontally and vertically,creating a PCE cloud or plume. Horizontal migration spreads the PCE, making the plumelarger. Vertical upward migration probably will result in vaporsentering a building and vertical downward migration will probablyresult in making the plume larger and a possible contribution tocontamination of groundwater. This kind of migration is known asVapor Intrusion. For simplicity, I have dividedPCE releases to soil into a small release, medium release and largerelease based on my experience:

• In general, a“small” release to soil results in minor soil contamination and thepresence of vapor beneath the building.
• A “medium”release to soil results in soil contamination to a depth of up toapproximately 20 feet beneath the building; has spread horizontallybeneath the building; and can generate vapors that result in aprobable significant vapor intrusion to an overlying building andpossible groundwater contamination.
• A “large”release to soil results in soil contamination of greater than tensof feet beneath a building, significant vapor intrusion to thebuilding and groundwater contamination that is probably aboveregulatory guidelines.

I will discuss specific problems associated with a release inan upcoming blog. In the meantime, to find out more about the realestate risks and rewards of dry cleaners, you can read my colleagueNicole Moore's blog here.