Ohio Oil Co. v. Conway

Background

An oil company that produces crude oil in North Louisiana fields sued to stop enforcement of a 1928 Louisiana law that imposed a per-barrel severance tax graded by oil gravity. The company’s main fields were Haynesville, Cotton Valley, Pine Island and Urania, and over ninety percent of its output came from the first three fields. The law set rates from four cents to eleven cents per 42-gallon barrel.

Reasoning

The central question was whether classifying oils by Baumé gravity and taxing by the barrel violated the Louisiana constitution or the federal equal-protection guarantee (which bars arbitrary discrimination). The Court explained that States have wide discretion in taxation but must proceed on a rational basis. The record showed the oil industry uses gravity as a rough index of gasoline content and that the company itself sold most of its oil on a gravity basis. For oils used to make lubricating oil, gravity was less important but those oils were taxed uniformly. The Court concluded that the gravity schedule was not a palpably arbitrary classification and declined to hold the tax unconstitutional.

Real world impact

The practical effect is that Louisiana may continue to collect the graduated per-barrel tax, and oil producers in different fields may face different effective tax burdens depending on gravity and local prices. Differences in wellhead prices, including possible transportation costs, do not by themselves make the tax unconstitutional. The Court affirmed the trial court’s dismissal and upheld the law.