From 1948 to 1950, Charles Sternhagen sprayed crops using the herbicide 2,4-D. In 1982, Sternhagen was diagnosed with cancer and died. Sternhagen’s wife, Marlene Sternhagen (plaintiff) sued Dow Company (defendant), the maker of 2,4-D, alleging that the herbicide caused Sternhagen’s cancer. Dow argued that from 1948 to 1950 it neither knew nor had reason to know that 2,4-D might cause cancer. Dow sought to prove that it had no knowledge of 2,4-D’s danger by submitting state-of-the-art evidence. Marlene argued that there was no state-of-the-art defense under strict product liability. The trial court certified to the supreme court the question of whether, in a strict-liability case, state-of-the-art evidence is admissible to show that a manufacturer knew or should have known of an inherently unsafe product.