A ‘BLEVE’ is a ‘Boiling Liquid Evaporating Vapor Explosion’ typical in a “Superfund Site.” But it seems the site in Asheville, North Carolina, was completely overplayed in consideration for a Superfund site.
The Asheville, North Carolina ‘CTS’ plant was closed recently. From 1959-1986, CTS operated an electroplating facility. The chemical trichloroethylene (TCE) was used by CTS to degrease metal objects prior to electroplating. In March (2012), the old CTS was officially named a Superfund Site, and placed on the NPL List.
In August of 1999, neighbors of the 10-acre CTS property discovered an oily substance in their spring. The EPA found TCE at 21,000 parts per billion (ppb) in some of the drinking water. By that time, the EPA Maximum Concentration Limit (MCL) for TCE was reduced to 5 ug/l (5 micrograms per liter, or ~5 ppb) in potable water.
This is a far cry from the 50 parts per million (ppm) for TCE in 1990. However, limits of ‘detectability’ improvement over the last 25 years doesn’t affect actual toxicity. That’s over an order of magnitude difference [>1000 ppm]. It seems a bizarre case of “chemophobia” [exaggerated fear of toxicity created by the widespread use of chemicals] is pandemic. Most notably in Asheville, less than one mile from the writer’s home. The EPA even razed the surrounding buildings to the ground to eliminate the ‘RCRA Hazardous Site’ notifications. Nearby communities demanded action-even 20 years after the site had shutdown-due to nearby complaints of TCE groundwater contamination.
When additional groundwater tests were done around 2000, the findings showed “[relatively] elevated levels of dichloroethene, trichloroethylene, vinyl chloride, and several unidentified organic compounds.” But, it was concluded CTS was not enough of a concern to warrant federal attention, and recommended no further action. The EPA determined the TCE was well within federal guidelines.
Similarly, in all U.S. locations (>100) where TCE was used, there was no evidence anyone had ever been harmed by TCE vapors-nor by drinking any allegedly contaminated water. The ACGIH listed TCE as: “Not suspected to be a human carcinogen.”
The Division of Waste Management found no contamination near any subdivision in 2000. A surface-water sample near CTS in May 2000 was positive with small amounts of TCE. In May 2001, a subsurface test revealed some TCE just beneath the CTS site.
A soil-vapor-extraction system was installed at CTS in July 2006, and per EPA David Dorian: “Under the Emergency Response Branch, our approach is to remove the exposure.” The system was a series of wells installed in a hexagonal grid pattern, and remained in operation as long as it extracted volatile organic compounds (VOCs). The system was shut down after 2010, because of the lack of further contamination.
On 1/8/08 Mountain Express (Hendersonville), said NC Department of Environmental and Natural Resources (NCDENR) sampled 66 wells, and only one active well showed 57 ppb-exceeding the 5 ppb MCL. Two months after the initial 66 wells, eight previously untested turned up one contaminated well-but it was far below the MCL. No other contaminants were detected.
Recently (9/29/11), EPA released a health assessment for TCE. For the first time, EPA classified TCE as “carcinogenic to humans.” Let’s forget in 50 years of usage by the populace, not one cancer case has been proven to have been caused by TCE, and EPA lowered TCE’s minimum safe level over 1000% because of improved ‘detectability’. Still no cancer deaths due to TCE usage by millions.
We forget TCE was used as a gas anesthetic for expectant mothers to relieve pain of childbirth difficulties in the 50’s-60’s. Millions have breathed 1% TCE through self-administered analgesia.
One must remember TCE was never produced for play. Of course, chemicals like “di-hydrogen oxide” [water] can cause breathing problems, global warming (sic), and even death with ingestion of 70 gal/day. It took 25 years for the EPA to call CTS a “Superfund Site,” and over $7 million in likely wasted expenditures. Darn, a Chemical Engineer can sometimes wreak havoc with some good info about ‘chemophobia’.
Four local papers, and a local TV station, incited panic about this purported TCE scare. Some likely still believe the hazards of ‘dihydrogen oxide’.