Ecolab Inc. and Ecolab USA Inc. v. IBA, Inc.

Background

Ecolab challenged Magistrate Judge David T. Schultz’s order requiring it to produce documents concerning interviews conducted by two Ecolab experts. Ecolab retained Frances McCloskey as a damages expert and Thomas Hemling, Ph.D., as a technical expert. Both interviewed Ecolab employees and referred to those interviews in their expert reports.

McCloskey’s report disclosed discussions with Jason Koerth, Greg Stumpf, and Charlie Adams and cited those discussions multiple times. Hemling’s report disclosed conversations with Dr. Joe Morelli and cited them to support his conclusions. The reports did not disclose any additional information the employees may have shared, including information that could undermine or contradict the experts’ conclusions.

McCloskey destroyed her own interview notes before the discovery dispute arose. An Ecolab attorney had attended her interviews and took notes. Hemling took and preserved notes from his interview with Dr. Morelli. Judge Schultz ordered Ecolab to produce the attorney’s notes and Hemling’s notes.

Legal Standard

Under Federal Rule of Civil Procedure 72(a), a district judge reviewing a magistrate judge’s ruling on a nondispositive issue must modify or set aside the ruling if it is clearly erroneous or contrary to law. A ruling is clearly erroneous when the reviewing court has a firm conviction that a mistake was made. A ruling is contrary to law when the court fails to apply or misapplies a relevant statute, case law, or procedural rule. The opinion described this review as extremely deferential.

Federal Rule of Civil Procedure 26(a)(2)(B)(ii) requires a retained expert’s report to include “the facts or data considered by the witness in forming” the witness’s opinions. The opinion explained that “facts or data” must be interpreted broadly to include any material containing factual information that the expert considered, regardless of its source and regardless of whether the expert relied on it.

Court’s Analysis

The court concluded that Rule 26(a)(2)(B)(ii) requires an expert to disclose all information a fact witness shared with the expert for consideration in forming an opinion. This includes information the expert did not rely on and information that conflicts with the expert’s conclusions.

Judge Tostrud reviewed the notes and agreed with Judge Schultz that McCloskey’s and Hemling’s reports omitted factual information from the interviews. The opinion gave as an example information about Ecolab’s damages that would be useful to IBA when cross-examining the damages expert. The court also agreed that Hemling’s notes contained factual information not disclosed in his report.

The court reasoned that unrecorded interviews create special disclosure concerns. Unlike a written treatise, which the opposing party can review in full, an unrecorded interview leaves the opposing party dependent largely on the expert’s memory of what the witness said. Those concerns supported requiring more complete disclosure of information obtained through such interviews.

The court noted that Judge Schultz could have required revised expert reports or additional depositions of the interviewed employees. Requiring Ecolab to produce the notes was another reasonable option and was not clearly erroneous or contrary to law.

Order

Judge Tostrud overruled Ecolab’s objections to Judge Schultz’s January 21, 2026 order and affirmed that order. The parties were directed to file a joint status update by May 15, 2026, stating whether they intended to submit several other motions on the existing briefing, with reply briefs to follow, or whether those motions needed to be fully re-briefed in light of this order.