Trichloroethene (TCE) has been produced commercially since the
1920s and was commonly used by manufacturing companies as a metal
degreaser. TCE was historically considered environmentally
harmless. Because of TCE's widespread use prior to the
enactment of environmental regulations, it is a fairly common
contaminant at former manufacturing facilities, and often a risk
driver for remediation. Many manufacturing companies in the
automotive sector have facilities with legacy environmental
liabilities related to past use of TCE for metal parts
degreasing.
On September 28, 2011 the USEPA issued a long-awaited final
health assessment for TCE. Since then, updated toxicity values were
published in the Integrated Risk Information System (IRIS) database
for use in risk assessment. The toxicity values for TCE will result
in lower (more conservative) screening levels for vapor intrusion
assessment, and States are evaluating how to incorporate the
toxicity data into state-specific
