The case landed before the Denver-based 10th U.S. Circuit Court of Appeals after a Utah magistrate judge ruled in January that the plaintiffs could review scores of documents held by the Cooper Rubber & Tire Company in their lawsuit against the tire maker.

Attorneys for both sides were peppered with questions by the three-judge panel during the one-hour hearing.

Attorneys for Cooper argued in legal briefs that the discovery order was "unprecedented" in its scope, and will force the company to reveal proprietary information, including data on tires that are not at issue in the lawsuit.

Cooper attorney Malcolm Wheeler told the judges Tuesday allowing an open-ended review of company documents entails producing thousands, if not millions of documents from the company's 89-year history.

The families' lawyers countered that they need wide access to the documents to prove that Cooper either knew or should have known that there were design flaws in the tire, and other similar models manufactured by the company.

The victims' lawyer, Brad Bearnson, told the judges Cooper is trying to "confuse everybody" by implying that the plaintiffs want the company's entire files.

"It [the discovery request] is much narrower; not back any earlier than the 1980s," Bearnson said.

Appellate Judge Michael McConnell said his reading of the record "looks like a request for all their tires."

U.S. District Judge Tena Campbell, who will preside over the trial scheduled to begin in late July, upheld the magistate's ruling. Cooper appealed the discovery order, setting the stage for the appeals court judge to review the case.

The injured students and the families of all but one of the dead students and the instructor's family sued Copper and the van's manufacturer, DaimlerChrysler Corp. Last December, Chrysler reached an out-of-court settlement with the families for an undisclosed amount, although the deal is awaiting a judge's approval.

In their lawsuit, the families claim that the tire was defective, causing the tread to separate from the tire, resulting in the fatal wreck. The case has attracted nationwide attention because in other similar product liability lawsuits courts have typically sided with Cooper to restrict access to the company's product information documents.

Cooper denies any wrongdoing in the manufacture of its tires. "When consumers buy a Cooper Tire, they are choosing a safe reliable and quality-engineered product," Cooper Vice President Patricia Brown told the Tribune in a January email.

The appeals court typically takes several months before issuing its written decision.