On May 4, 2009, the U.S. Supreme Court handed down its decision in Burlington Northern & Santa Fe Railway Co. v. United States. The decision is of major significance with respect to two areas of Superfund jurisprudence--"arranger" liability, and divisibility or apportionment of harm. This Article is concerned only with the latter issue and, moreover, only with one specific element of that issue.

Much has already been written about this decision, but few of those writings have focused on the mathematical equation used by the Burlington court to assign a specific apportioned share of the liability for the Superfund site in question to the two defendant railroad companies. The focus of this Article is the court's arithmetic, which the author contends is fundamentally flawed.