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pxygewte ,���isz 2 30 August 1997 <br /> i <br /> The problem of identifying which oxgenates are present is further compounded because the oil <br /> refineries ship gasoline around the state and then trade gasoline between geographic areas. <br /> For instance, if gasoline is needed in the San Francisco Bay area by BogCo Oil, BogCo will <br /> obtain same gasoline from,say, Generic Oil in the Bay area and, in exchange,Generic will <br /> receive some BogCo gasoline in Southern California. The result is that we do not know what <br /> oxygenate compound is in the gasoline at a particular gas station. TAME may be used by <br /> Generic;but, because of this swapping,TAME,rather than MTBE,will end up in the ground <br /> water ata BogCo site. <br /> Research recently icompleted by DuPont-Dow (h;p://'www.dupont-dow-corn/products/v ton/gp�ev.hti1) <br /> show that oxygenates may be incompatible with some elastomer seals used on underground <br /> tank piping. One test,using several concentrations of MTBE, was short term (168 hours) and <br /> showedI welling could occur with some elastomers at current gasoline mixture levels. <br /> Presumably, this will be true, to some extent,for all ether oxygenate additives, and,over a <br /> longer 'time, conceivably cause the failure of the seals; thereby,releasing the oxygenated <br /> asoline <br /> ginto the environment. We are particularly concerned that older tank seals or material <br /> used to upgrade tanks may not be compatible with the oxygenates and may fail due to the <br /> 11 <br /> high concentrations of oxygenates in the alternative fuel sources. <br /> Qn 14 August 1997, a workshop was conducted at the Sacramento office of this Regional <br /> Board, attended by representatives of Regional and State Boards,Local Implementing <br /> Agencies, analytical Laboratories and the petroleum industry. The objective was to provide <br /> guidance to the regulated community on how and where to analyze for the oxygenated <br /> compounds in gasoline until definitive protocol can be established in several months. The goal <br /> was to allow closure of underground tank sites with assurances that the interim methodology <br /> can detest and quantify oxygenates. <br /> The woLop attendees concurred that the methyl and ethyl alcohols can't be detected b <br /> Y Y - . Y <br /> EPA Method 8260 with certainty--and-that detection limits for methyl and ethyl alcohols are <br /> about two orders of magnitude higher than TBA and the ethers. Also,with the exception of <br /> one oil company and special, alternative fuel vehicles (including the State of California <br /> automobiles),ethanol and methanol are used infrequently in California, and can be isolated by <br /> station and the more accurate analytical methods used. Therefore, at this time,unless ethanol <br /> or methanol are specifically requested,we are requiring soil and water analysis only for TBA <br /> and the ether compounds by EPA Method 8260 in order to determine which oxygenated <br /> compound is present. 1 <br /> Presence or absence of the oxygenate must be reported whenever gasoline range hydrocarbons <br /> are present. However,because free product or high petroleum concentrations raise the <br /> detection limits of the oxygenates,the oxygenates cannot be detected with certainty. <br /> Therefore, at this time,we do not recommend sampling where product is present on l <br /> groundwater. <br /> f ' I <br />