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Mr.Nuel Henderson ~ Re: 102 S. Wilson Way—Petition for Closure Page 3 Methanol Methanol is used as a component in the chemical formation of biodiesel fuel. In the 1990s, large amounts of methanol were also used to produce MTBE. MTBE is manufactured by the chemical reaction of methanol and isobutylene. As explained above,there was never an unauthorized release of fuel containing MTBE at the site. In addition,there was never an underground storage tank on the site containing any type of diesel or biodiesel fuel. Since these are the two most prevalent sources of methanol, evidence suggests that the methanol contaminants did not result from an unauthorized release at 102 S. Wilson Way. Ethanol In 2004, California banned the use of MTBE as a gasoline additive,generally replacing it with ethanol. Although ethanol contaminants are not likely a result of an unauthorized release at the site,the most recent monitoring data shows that the level of ethanol contamination is well within the water quality objectives established by the Central Valley Regional Water Quality Control Board.3 TBA Tert-butyl alcohol(TBA)is both a trace component found in fuel-grade MTBE and is also a metabolite of MTBE biodegradation. This is supported by a report issued by the federal MTBE Blue Ribbon Panel.4 As a bi-product of MTBE, it is unreasonable to conclude that the presence of TBA is in any way attributable to an unauthorized release on the site. Since monitoring on the site began (17 years after the removal of underground storage tanks), data shows that 96 percent of the wells registered increases of at least 100 times greater for the presence of TBA contaminants. ETBE/TAME In 1997,the California Department of Health Services issued a Final Statement of Reasons for its proposed regulatory action to add ETBE and TAME to the Unregulated Chemical Monitoring List(contained in Title 22, Section 64450 of the California Code of Regulations). In this document, DHS notes the following(emphasis added: ' Central Valley RWQCB memo;dated April 1,2004;titled"Beneficial Use—Protective Water Quality Limits or Components of Petroleum-based Fuels." 4 The following is an excerpt from the panel's report,available at http://www.epa.gov/otaq/consumer/fuels/oxypaneVr99021.pdf(emphasis added): Tertiary butyl alchohol(TBA)is another oxygenate that has been found at oxygenated gasoline release sites. Becaues TBA is a byprodcut of some MTBE production processes, TBA is found in some fuel-grade MTBE. TBA is also a metabolite of the biodegradation of MTBE. Because TBA is infinitely soluble in water... The presence of TBA will further limit the usefulness of the above described tehcnologies[air stripping,activated carbon treatment,and advanced oxidation]and increase treatment costs. http://www.dhs.ca.gov/ps/ddwem/chemicals/MTBE/PDFs/SecondaryMCLMTBE.PDF