Pentane and Butane Blending

In its proposal, the EPA introduces the notion of unified grades of “certified butane” and “certified pentane” for blending with other gasoline blendstocks. Currently there are two sets of standards (“commercial and “non-commercial” grades of each of the two respective blendstocks); these grades entail separate sampling and testing requirements.

The EPA proposes introducing standards of 95% purity for certified pentane and 92% purity for certified butane (versus its prior, draft standard of 95%, which was lowered to 92% after consultation with the industry). Likewise, the EPA proposes introducing a common sampling and testing standard for the two blendstocks entailing similar sample frequencies (i.e. every 500,000 gallons or every three months, whichever is more