EPA has taken another step in developing its scientific basis for assessing risk posed by vapor intrusion of trichloroethylene (TCE), a solvent commonly used in dry cleaning and industrial operations. EPA issued its Draft IRIS Toxicological Review of TCE in Nov. 2009, concluding that TCE is a human carcinogen by all routes of exposure. EPA is seeking public comment on the document, which calculates an inhalation unit risk value for TCE that is twice the value EPA used in developing a regional screening level value for TCE. Comments are due by February 1, 2010. EPA also announced a listening session to be held on Jan. 26, 2010. Parties interested in participating can register with EPA online by Jan. 19.