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Oxygenate Analysis 2 V 30 August 1997 i The problem of identifying which oxgenates are present is further compounded because the oil refineries ship gasoline around the state and then trade gasoline between geographic areas. For instance, if gasoline is needed in the San Francisco Bay area by BogCo Oil, BogCo will obtain some gasoline from, say, Generic Oil in the Bay area and, in exchange, Generic will receive some BogCo gasoline in Southern California. The result is that we do not know what oxygenate compound is in the gasoline at a particular gas station. TAME may be used by Generic, but, because of this swapping, TAME, rather than MTBE, will end up in the ground water at a BogCo site. x Research recently completed by DuPont -Dow (http://www.dupont-dow.com/products/viton/lkprev.html) show that oxygenates may be incompatible with some elastomer seals used on underground tank piping. One test, using several concentrations of MTBE, were short term (168 hours) and showed swelling could occur with some elastomers at current gasoline mixture levels. Presumably, this will be true, to some extent, for all ether oxygenate additives, and, over a longer time, conceivably cause the failure of the seals; thereby, releasing the oxygenated gasoline into the environment. We are particularly concerned that older tank seals or material used to upgrade tanks may not be compatible with the oxygenates and may fail due to the high concentrations of oxygenates in the alternative fuel sources. On 14 August 1997, a workshop was conducted at the Sacramento office of this Regional Board, attended by representatives of Regional and State Boards, Local Implementing Agencies, analytical Laboratories and the petroleum industry. The objective was to provide guidance to the regulated community on how and where to analyze for the oxygenated compounds in gasoline until definitive protocol can be established in several months. The goal was to allow closure of underground tank sites with assurances that the interim methodology can detect and quantify oxygenates. The workshop attendees concurred that the methyl and ethyl alcohols cant be detected by EPA Method 8260 with certainty and that detection limits for methyl and ethyl alcohols are about two orders of magnitude higher than TBA and the ethers. Also, with the exception of one oil company and special, alternative fuel vehicles (including the State of California automobiles), ethanol and methanol are used infrequently in California, and can be isolated by station and the more accurate analytical methods used. Therefore, at this time, unless ethanol or methanol are specifically requested, we are requiring soil and water analysis only for TBA and the ether compounds by EPA Method 8260 in order to determine which oxygenated compound is present. Presence or absence of the oxygenate must be reported. However, because free product or high petroleum concentrations raise the detection limits of the oxygenates, the oxygenates cannot be detected with certainty. Therefore, at this time, we do not recommend sampling where product is present on groundwater.