In a recent decision, a federal appeals court for the first time relied on the statutory act of war defense to dismiss a CERCLA claim, one that sought recovery of the costs of remediating asbestos and other hazardous substances that were released by the September 11, 2001, attack on the World Trade Center. This Comment explores CERCLA's three statutory defenses, the difficulties CERCLA defendants have faced in trying to assert them, and whether In re September 11 will result in more successful assertions of these defenses in the future.