Abstract: There is a good argument that the foundations of modern administrative law were laid in 1980, with the disparate opinions of a sharply divided Court in Industrial Union Department v. American Petroleum Institute (commonly referred to as “the Benzene Case”). Consider four points. (1) The Benzene Case is now understood to be the first contemporary appearance of the Major Questions Doctrine. (2) The Benzene Case marked the return of the nondelegation doctrine, signaled most plainly by Justice William Rehnquist’s elaborate concurring opinion, but also by a favorable reference in the plurality opinion by Justice John Paul Stevens and an open-minded sentence from Justice Lewis Powell. (3) The Benzene Case is the origin of contemporary cost-benefit default principles, permitting or requiring agencies to exempt de minimis risks, to consider costs, and to engage in some form of cost-benefit balancing, unless Congress has squarely said otherwise. (4) The Benzene Case essentially defined “significant risk,” with a precise numerical definition (one in one thousand) that persists at the Department of Labor to this day. At the same time, a close analysis of the plurality opinion in the Benzene Case shows that it is best understood as a specification, above all, of the Absurdity Canon – a Church of the Holy Trinity v. United States for the modern administrative state. So understood, the Benzene Case had, and continues to have, an important and salutary effect on regulatory programs. Its significant current role, more than four decades after the opinions were issued, is an intriguing case study in doctrinal development, and in particular in how Supreme Court decisions can plant small seeds that become big trees.