Occurrence of MTBE in Heating Oil and Diesel Fuel in Connecticut

Abstract The objective of this study was to confirm if MTBE, which is not intentionally added to fuels other than gasoline, is a contaminant in heating oil and diesel fuel. The study entailed conducting a statewide sampling program of heating oil and diesel fuel in Connecticut. An analytical method was developed to conduct analyses of heating oil and diesel fuel for MTBE in the milligram per liter (mg/L) range. The method involved equilibrating product with water to extract MTBE followed by static head‐space analysis on aliquots of the water. Analyses were conducted using a gas chromatograph with a MTBE specific column. The statewide sampling program confirmed the widespread occurrence of MTBE in heating oil and diesel fuel. MTBE was detected in all samples collected during our sampling program at concentrations ranging from 9.7 to 906 mg/L in heating oil (26 samples), and from 74 to 120 mg/L in diesel fuel (five samples). Based on these ranges. MTBE concentrations in ground water in the vicinity of heating oil and diesel fuel releases could exceed thousands of micrograms per liter. Our analysis would suggest that the levels of heating oil and diesel fuel contamination observed could result from the commingling of only a few parts gasoline with thousands of parts of these fuels. The extent to which MTBE occurs in heating oil and diesel fuel nationwide is not known, but our data suggests that it may be widespread.