Part 5: Conclusions

Gasoline quality standards prevalent in PADD 5 are diverse. The independence given to California in developing its own air quality (and, by extension, fuel quality) regulations, the flexibility afforded to states in managing their own nonattainment areas via air quality implementation plans (with the EPA’s imprimatur, to be sure), the statutory limitations placed on the EPA’s ability to regulate only parameters most closely associated with pollution (i.e. the “cause and contribute” doctrine), as well as climactic and topographical diversity all contribute to this outcome.

While the ASTM D4814 standard, as currently written, often captures this diversity, there are key parameters where state regulations can, and sometimes do, diverge with the ASTM standard. These include