The Iowa Supreme Court permitted the certification of a two-tier class action in a nuisance suit filed against the owner of a corn milling plant by nearby residents. See Freeman v. Grain Processing Corp., 895 N.W.2d 105 (Iowa, 2017).

An Iowa district court first granted class certification in 2015, dividing the class into two subclasses: one for members living in close proximity to the corn milling plant and one for those in peripheral proximity to the plant. On appeal, the plant owner argued that there was insufficient commonality between the plaintiffs’ claims, and that alleged common questions of law or fact did not “predominate” over individual issues that may have existed.

The Iowa Supreme Court agreed with the trial court that “[t]he central factual basis for all of Plaintiff’s claims… is [the defendant’s] course of conduct and knowledge of its potential hazards.” The court also held that by dividing the class into two subclasses, the trial court resolved issues arising from potential disparities in the alleged harm suffered by the plaintiffs.

The court also held that these common issues predominated over any individual questions of law or fact. Noting that the test for predominance is a pragmatic one, the court rejected the notion that the mere existence of any individual issues is fatal to class certification. Accordingly, the court held that individual issues, such as potential contamination from other sources or the precise extent of contamination on plaintiffs’ property, were nevertheless outweighed by common questions regarding the defendant’s course of conduct, its knowledge of emissions, and the level at which emissions would interfere with a normal person’s enjoyment of his or her property.