Today EPA took an important step towards protecting the public and wildlife from trichloroethylene (TCE), a very hazardous mutagenic cancer-causing chemical that pollutes the nation’s water and air. TCE is also the culprit involved in the Woburn, MA cancer cluster of childhood leukemia cases (and the subject of the movie, “A Civil Action” starring John Travolta). EPA’s press release is here.
This much-delayed action is a triumph of science over special interest politics. The public won today. Here I tell the history of science-manipulation for this chemical, but for the political shenanigans see today’s blog of my colleague Daniel Rosenberg.
TCE is a chlorinated solvent used primarily for metal degreasing—most notably for jet parts—and is a widespread drinking water contaminant that is leaching from military bases and industrial sites throughout the country. In addition to cancer, TCE causes harmful effects to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing fetus. The EPA has been trying to finalize its assessment of TCE for 22 years, making today’s announcement a long-overdue victory for health.
The last EPA assessment of TCE was 24 years ago, in 1987, classifying TCE as a “probable” human carcinogen (Group 2B). In 1989, the EPA started to update its TCE cancer assessment, but didn’t issue a draft for public and peer review for a dozen years, until 2001. The 2001 EPA draft for TCE calculated that the chemical was 5 to 65 times more toxic than previously estimated, and classified it as “highly likely” to cause human cancer. It identified children as a susceptible population, and noted that co-exposure to some other chemicals may augment the toxicity of TCE.
The 2001 draft also triggered a decade-long firestorm of criticism from the chemical industry, the Department of Defense (DOD) and the Department of Energy (DOE), which together are responsible for about 750 TCE-contaminated dump sites in the nation.
Dianne Saxe of envirolaw says this opens Canada to potential litigation as well:
Yes, TCE is a carcinogen
by DIANNE SAXE on OCTOBER 3, 2011
After 22 years of study, and intense political maneuvering, the US Environmental Protection Agency has formally classified TCE (trichloroethene, also called trichloroethylene) as a carcinogen, as well as a non-cancer hazard to human health. The assessment is now a formal part of the the Integrated Risk Information System (IRIS) database, a human health assessment program that evaluates the latest science on chemicals in the environment, and which has drawn considerable fire from industry. The new assessment may make it harder to cleanup TCE contaminated sites to acceptable levels, and may require changes in Canadian air, soil and water standards.
TCE is one of the most common man-made chemicals found in the environment. It is a volatile chemical and a widely used chlorinated solvent, especially from the 1930s to the 1970s. Frequently found at contaminated sites, TCE migrates easily from contaminated ground water and soil into the indoor air of overlying buildings. Since 1987, it has been classed as a “probable human carcinogen”, but it now turns out to have been dangerous at levels previously believed to be safe. In 2001, EPA calculated that the chemical was 5 to 65 times more toxic than previously estimated, and classified it as “highly likely” to cause human cancer, especially in children.This assessment has undergone several levels of peer review including, agency review, interagency review, public comment, external peer review by EPA’s Science Advisory Board in January 2011, and a scientific consultation review in 2006 by the National Academy of Sciences.
The new assessment may require regulators across Canada and the US to reassess generic criteria (for air, water and soil), risk assessments for sites contaminated with TCE, and limits on current industrial emissions. For example, until recently, Ontario allowed 50 ug/L of TCE in drinking water. According to the new assessment, that level was likely to cause cancer in about 1 in 10,000 people, possibly more in small children. Co-exposure to other chemicals can make TCE more dangerous to health.
The EPA plans to use the new TCE toxicity values in:
· Establishing cleanup methods at the 761 Superfund sites where TCE has been identified as a contaminant
· Understanding the risk from vapor intrusion as TCE vapors move from contaminated groundwater and soil into the indoor air of overlying buildings
· Revising EPA’s Maximum Contaminant Level for TCE as part of the carcinogenic volatile organic compounds group in drinking water
· Developing appropriate regulatory standards limiting the atmospheric emissions of TCE.
All of these changes will likely affect Canadian standards as well, since we typically follow the US lead.