Okay, so it will probably come as no surprise to those readers that know anything about perc (also known as PCE, short for perchloroethylene, another name for tetrachloroethylene – whew!) that, when the U.S. Environmental Protection Agency (EPA) released it’s final health assessment for the chemical this week, EPA essentially concluded “yep, it’s still bad stuff.” More specifically (and much more scientifically), the assessment characterized it as a “likely human carcinogen.” In addition, the assessment cited non-cancer long-term health effects including harm to the nervous system, kidney, liver, immune and hematologic systems.
Perc is best known for being the chemical solvent widely used in the dry-cleaning industry. Discharges of perc (mainly from dry-cleaning facilities) have contributed to contamination at many properties. According to EPA, hundreds of Superfund sites in the country have perc as a contaminant.
So why should you care about this assessment that seemed to tell us something we pretty much already knew?? Well, dear readers, I will tell you. Although the health effects were known, the specific toxicity values that are presented in the assessment will likely affect the current cleanup levels for perc-impacted soil and groundwater in some states, making remediation potentially more expensive than it would previously have been. (However, certain states, including California, have a more stringent standard for perc, therefore that standard will be the cleanup goal.)
The assessment will also be considered when EPA evaluates whether to propose additional limits on the emissions of perc into the atmosphere. Perc is considered a hazardous air pollutant (HAP) under the Clean Air Act. The CAA requires EPA to set standards to reduce HAPs, like perc, from various businesses. These standards are called National Emissions Standards for Hazardous Air Pollutants or NESHAPs. EPA issued a NESHAP for dry-cleaners using perc and revised it significantly in 2006. EPA is set to review the standard again in 2014 and the final assessment will be considered. This could mean tighter restrictions on emissions of perc by dry-cleaners. Typically such restrictions require the installation of certain new equipment or technology which means… you guessed, it… more money spent on such equipment. In California, the use of perc by dry-cleaners was banned almost five years ago, but the practice is still common in other states.
In addition, although we already knew it was “bad stuff”, perc’s classification as a “likely human carcinogen” is a change from its previous status in the gray area between “possible” and “probable” – this may increase the level of concern generally with regard to human exposure to the chemical. The impact that this elevated level of general concern may have on policy-making, if any, is hard to predict, but may play out in the court of public opinion.