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a The problem of idea 'toying which oxo*gates are present is further compounded because the oil refineries ship gasoline around the state and than trade gasoline between geographic areas. For instance,if gasoline s needed in the San Francisco Bay area by BogCo Oil,Boa-Co will obtain some gasoline from,say,Generic Oil in the Bay area and,in exc�uange,Ge* is 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. TANS may be used by Generic, but, because of this swapping,TALK,rather than NITBE,will end up in the ground water at a BogCo site- Research recently completed by DuPont-Dow(hila.//40ww.dupont-dOw-c=/Pmdu=/Y't=/TcFre9hc31) show that oxygenates may be incompatible with some elastomer seals used on underground tank piping. One test,using several concentrations of y1TBE,were short term(168 hours).and showed swelling could occur with some eastomers at c irre*ut gasoline In 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 e*ivironment We are particularly concerned that older tank seals or material used to u-Carade tanks may not be compatible with the oxygenates and may fail due to the high concentrations of oxygenates in the alternative fuel sources- On 11 August 1997, a workshop was conducted at the Sacramento office of this Reg=ion— al attended by representatives or Regional and State Boards,Local Implemetting Age_*tcies, ana iytcaJ Laborator es and the petroleum industry. The objecyve 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 quantity oxygenates. True wor-ksh= attendees concuaed that the methyl and ethyl alcohols ca be dete�-ted by E'T'A tilefhod 8260 with certainty and that detection limits for methyl and ethyl alcohols are about two orders o£magnitude higi er than TBA and the ethers. Also,with the e-creption of one oil company and special,alternative fuel vehicles (including the State of C'a ifo=iia automobu es),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 specifica ly requested,we are requiring soil and water analysis only for TBA and the ether comvounds 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.