Spills releasing PCE, the cancer-causing chemical used in dry cleaning and metal degreasing, have produced at least 86 underground plumes across Colorado that are poisoning soil and water and fouling air inside buildings.
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| The dry cleaning chemical PCE has been linked to cancer and other health effects. |
Cleaning up this chemical is a nightmare — a lesson in the limits of repairing environmental harm. The best that Colorado health enforcers and responsible parties have been able to do is keep the PCE they know about from reaching people.
But based on a review of Colorado Department of Public Health and Environment case files, people likely have been exposed.
For years, PCE (perchloroethylene or perc) penetrated homes and a church in Denver's Cole neighborhood, forcing installation of ventilators. It contaminated municipal drinking water wells near Colorado Springs. It reached rooms where toddlers play at an Aurora day care. And PCE is spreading under a central Denver Safeway at levels far exceeding health standards.
The required cleanups drag out for decades because of costs. But even if funds were sufficient, PCE is proving so pernicious — able to eat through concrete, staying volatile decades after spills — that experts increasingly question whether full cleanup to meet health standards is feasible.
Probable carcinogen
Federal authorities long have recognized sharp, sweet-sour-smelling PCE among the most dangerous chemicals contaminating U.S. cities.
A 2012 Environmental Protection Agency reassessment concluded that PCE is a probable carcinogen that also attacks nervous systems.
While occasionally inhaling PCE on dry-cleaned clothes isn't considered harmful, regular exposure is risky enough that the EPA has ordered a phase-out of dry cleaners using PCE in residential buildings by 2020.
Yet PCE remains legal. EPA data show there are 28,000 dry cleaners using it nationwide. About 350 cleaners use it in Colorado.
Dry cleaners favor PCE over other chemicals. The same penetrating properties that make it a nightmare when spilled also make it a wondrous obliterator of blotches on dresses and suits.
Identifying risks
Four to 18 new plumes due to PCE spills in Colorado are identified each year. The list has been growing. Cleanups last for years, and CDPHE could not say how many have been completed.
State law requires intervention when PCE contaminates groundwater at concentrations exceeding 17 parts per billion. In 2010, state water commissioners relaxed that standard from the EPA drinking-water standard of 5 ppb.
For PCE vapors in air, Colorado's limit is 41 micrograms per cubic meter in homes and 175 at work sites. The home limit was relaxed in 2012 from 4 micrograms .
An estimated 1,000 former dry-cleaner sites exist around Colorado — the majority not tested for PCE contamination.
Nationwide, EPA officials track an estimated 3,800 toxic chemical cleanups, many involving PCE. The Superfund list of major environmental disasters includes at least 50 sites where PCE and related chemicals are present.
These include PCE plume spreading from dry-cleaning facilities in a Veterans Affairs hospital in Salt Lake City that has contaminated springs, aquifers and creeks, forcing city officials to shut down a municipal well.
PCE likely will be found at 50 to 70 percent of the untested dry-cleaner sites in Colorado, said Denver lawyer Kemper Will, a former EPA employee who has represented industry, property owners and dry cleaners in numerous cases.
PCE contamination of indoor air is a serious concern, and businesses often aren't as careful handling chemicals as they should be, Will said. But it's not feasible to conduct full cleanups to meet today's highly protective health standards. "We cannot afford, as a nation, to purify all old mistakes."
Will lobbied for the policy giving state officials greater flexibility in deciding how much cleanup must be done. Reducing PCE levels in groundwater to 17 ppb isn't always necessary, he said. A smarter approach would focus on indoor air.
"I want to apply sound, rational judgment," he said.
This article has been edited for length.
Source: Denver Post
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