On January 28, 1975, the United States Court of Appeals for the District of Columbia ruled that the EPA regulation to reduce the level of tetraethyl lead in gasoline was arbitrary and capricious. Within only slightly more than one month, the Environmental Protection Agency itself reversed a previously held position concerning the schedule for clamping down on automotive exhaust emissions. The reversal was occasioned, it was said, because of the likelihood of sulfuric acid mist emissions from the catalytic devices necessary to meet the more restrictive standards.

Each of these decisions was inevitably seen in some quarters as a setback for the cause of preserving environmental integrity. There were other, and perhaps, more fundamental ramifications as well. These two moves—one by the judiciary and one by the executive—both reflected earlier decisions taken on the basis of exceedingly thin scientific fabric. Thus, these represented the latest (yet probably not the last) examples of bringing the scientific basis for a regulatory decision under more careful scrutiny than was exercised when the decision was originally made. In the case of tetraethyl lead, the majority opinion found that ". . . the evidence does not support the EPA's health concern and . . . the case against auto lead emissions is a speculative and inconclusive one at best."¹ In the case of automotive emissions, the Administrator of EPA declared that the Agency had ". . . made a mistake . . ." earlier in its initial decision to rely on the catalytic exhaust device.²