Not New
http://www.wfaa.com/sharedcontent/dws/wfaa/latestnews/stories/wfaa091029_mo_drilling.2669d39e4.html
WFAA (Dallas/Fort Worth)
30 October 2009
Air monitoring found potentially dangerous levels of benzene leaking from natural gas wells. One researcher said, "What I don't think anybody really knows yet is are the levels of these compounds...high enough and have they been in the air long enough to be a potential cancer risk?"