Via Yahoo, the Chicago Tribune has this article discussing the use of corporate bankruptcies to avoid health-care obligations, highlighted by the Horizon coal case.
Following the bankruptcies of Continental Airlines and others, in 1984, Congress passes 11 U.S.C. 1113 to prevent the use of bankruptcies to rid companies of collective bargaining agreements; in 11 U.S.C. 1114, Congress dealt with benefits for retirees. Nevertheless, the Trib article notes that "Many, including Democratic U.S. Senate candidate Barack Obama, say federal bankruptcy laws need to be changed to prevent companies from declaring bankruptcy, dumping union obligations and then re-forming."