The Tenth Circuit Court of Appeals has ruled that Colorado is preempted from taking enforcement action under the state’s hazardous waste law against the U.S. Army with respect to stored chemical weapons awaiting destruction within the state. Colorado Dep’t of Pub. Health & Env’t v. United States, No. 09–1554 (10th Cir. 9/5/2012). The stored materials included leaking weapons and contaminated materials that the Army agreed constituted hazardous wastes, as well as non-leaking weapons that the Army asserted were not wastes, although it had, as a matter of comity, obtained a hazardous waste storage permit for those materials under Colorado’s approved hazardous waste program.

In 1985, Congress mandated destruction of all chemical weapons, and in 1994, Congress forbade transport of any weapon from a chemical-weapons stockpile out of the state in which it then resided. The Army has attempted to determine how best to destroy the weapons, and those efforts continue. After undertaking a series of regulatory enforcement actions under a state law prohibiting the storage of wastes prohibited from land disposal, Colorado initiated a lawsuit against the Army, asserting that the Army was storing both the leaking and intact weapons illegally under the state program.

In the district court and before the Tenth Circuit, Colorado sought affirmation that it had the authority to regulate munitions as hazardous waste and confirmation of the state’s determination that the non-leaking weapons constituted solid wastes. Both courts declined to address the second issue, and both held that federal law preempted the state’s program. According to the Tenth Circuit, “Congress has required a measured pace in undertaking the destruction of these chemical weapons and, on at least six occasions, has extended the destruction deadline to accommodate that pace. This unmistakably indicates that Congress intended to reserve for itself the power and flexibility to establish and extend the destruction deadline, as well as to alter the process and timing by which these chemical weapons are destroyed.” The court held that, even assuming the weapons constituted hazardous waste, the federal weapons disposal provisions indicated a congressional intent to occupy the field and preempted the Colorado law.