The Samuels, O’Connors, Rueger, Vroman, and Grandinetti were the representatives of three classes of plaintiffs (plaintiffs) who claimed that they or their properties were exposed to radioactive and toxic chemical substances wrongfully discharged by Boeing North American, Inc. and others (defendants) from four of its facilities. The plaintiffs claimed that the exposure to these substances increased their risk for serious illness and sought a medical-monitoring program. The plaintiffs also sought damages for expenses and lost property value from the alleged property contaminations. The plaintiffs served interrogatories on the defendants largely related to the types of substances used at Boeing’s facilities and test results for the substances on surrounding properties. The defendants objected but responded either with narrative answers or by pointing the plaintiffs to the voluminous business records already provided. The defendants then served interrogatories to the class representatives, seeking information about the plaintiffs’ exposure to toxic substances and the contamination of their properties. The class representatives responded with general answers indicating that they or their properties had been contaminated by airborne, soil, or water contamination by the defendants. The plaintiffs and the defendants each moved the magistrate judge to compel the other to provide more complete answers to the interrogatories.