A 55-gallon drum of nuclear waste, buried in a salt shaft 2,150 feet under the New Mexico desert, violently erupted late on Feb. 14 and spewed mounds of radioactive white foam. The flowing mass, looking like whipped cream but laced with plutonium, went airborne, traveled up a ventilation duct to the surface and delivered low-level radiation doses to 21 workers. The accident contaminated the nation's only dump for nuclear weapons waste — previously a focus of pride for the Energy Department — and gave the nation's elite ranks of nuclear chemists a mystery they still cannot unravel. Six months after...
