By Ben Geman - 06/15/11 03:03 PM EDT
Alexander also questioned whether EPA has the legal authority to make needed changes to a key portion of the rule, and whether the agency has the time to fix the rule, which was long delayed and promulgated under a court order.
Alexander is seen as a centrist on several Clean Air Act issues, but for months has expressed major concerns about constraints facing EPA on the rule.
A number of industry groups and House Republicans are also targeting the rule, one of several they argue should be softened, delayed or scuttled.
This post was updated at 11:11 a.m.