1. (a) To comply with the requirements of this chapter, the oxygen content of gasoline must be determined by

   1. (1) taking a representative sample of the gasoline to be tested, using the sampling methods specified in 40 C.F.R. 80, Appendix D, as amended through July 1, 1996, hereby adopted by reference;
   2. (2) testing the gasoline sampled to determine the mass concentration of each oxygenate, using the test method specified in ASTM D 4815-94a, as approved July 25, 1994, hereby adopted by reference; and

   3. (3) using the following oxygen content calculations, with volume measurements adjusted to 60° Fahrenheit:

      1. (A) for blends with only one oxygenate:
      2. (B) for blends with more than one oxygenate:

      W oxygen = V oxygenate x d oxygenate x W oxygen/oxygenate _________ (V gas x d gas) + (V oxygenate x d oxygenate)where:W= weight fraction (for percent, multiply by 100)oxygenate= oxygenate in the blendV= volume fractiond= specific gravitygas= gasoline

      W oxygen = S (V oxygen x d oxygenate x W oxygen/oxygenate) _________ (V gas x d gas) + S (V oxygenate x d oxygenate)where:W= weight fraction (for percent, multiply by 100)oxygenate= oxygenate in the blendV= volume fractiond= specific gravitygas= gasoline

2. (b) The oxygen molecular weight contributions of an oxygenate approved for use under this chapter are set out in the following table: OXYGEN MOLECULAR WEIGHT CONTRIBUTIONS Oxygen Molecular Weight Contribution Specific Gravity at 60° Fahrenheit Methanol0.49930.796Ethanol0.34730.794Propanols0.26620.789Butanols0.21580.810Pentanols0.18150.817Methyl Tertiary-Butyl Ether (MTBE)0.18150.744Hexanols0.15660.823Ethyl Tertiary-Butyl Ether (ETBE)0.15690.755Tertiary Amyl Methyl Ether (TAME)0.15660.770

(Eff. 9/25/92, Register 123; am 10/31/97, Register 144)