The Arizona Corporation Commission is one of the lesser-known agencies of state government, yet its actions decide how much we pay for gas, electricity and water. The Corporation Commission is a quasi-judicial panel that regulates utility companies. Because its members can and should be consumer advocates, it is important to be diligent about those we elect. This year, three of the five commissioners - Mike Gleason, Jeff Hatch-Miller and Bill Mundell, all Republicans - are seeking re-election to four-year terms. The Star endorses Hatch-Miller and Mundell, both of whom are from Phoenix. We also endorse Democratic challenger Nina Trasoff, the only Tucson candidate in this race. A fourth member of the commission, Kris Mayes, was appointed to her post last fall to replace Jim Irvin, who had resigned. Mayes, a Republican now running to complete Irvin's unexpired term, is opposed by Libertarian Rick Fowlkes. The Star endorses Mayes in her race. Along with Mundell, Mayes has been a strong proponent for environmental responsibility; the commission also plays a role in monitoring the safety of gas pipelines. The Star rejects Gleason for his casual attitude toward environmental hazards. The gasoline spill on Tucson's West Side by a break in the Kinder-Morgan pipeline was not that big a deal, Gleason suggested in an interview with the Star's editorial board, because it was a small percentage of the total fuel in the line. Tell that to the those who saw their houses torn down afterward. Mundell and Mayes have acted responsibly in raising detailed questions about an investment firm's plans to purchase UniSource Energy Services, the parent company of Tucson Electric Power. The impact of the UniSource deal, as Trasoff pointed out, is far from clear. The commission expects to make a decision on the sale by the end of this year, and incumbents, noting their judicial-like role in the outcome, were reluctant to discuss their concerns in detail. Mayes noted in an article in the Star, however, that she and Mundell "have been asking to see the rate of return projections made by the proposed buyers." She said "these projections - and what they may say about the proposed buyout of the state's second-largest regulated utility - are relevant." Hatch-Miller, who lives in Paradise Valley, has brought to the commission an intimate knowledge of rural Arizona. From 1990 to 1996, he worked for the University of Arizona assisting rural communities with economic development plans. A former member of the Arizona House of Representatives, he served as chairman of the House Energy, Utilities and Technology Committee. In that role, he sponsored legislation on behalf of the Corporation Commission that required Arizona's electric utilities to demonstrate the future reliability of transmission systems. Fowlkes, the lone Libertarian in this race, is an engineer whose chief interest is in reducing the role of government. It is difficult to see how he might fulfill the statutory requirements of the Corporation Commission while being philosophically opposed to what the commission does. Democrat Mark Manoil of Phoenix, who also seeks one of the four-year terms, is a lawyer seeking public office for the first time. Like Trasoff, Manoil is a critic of the commission for approving nearly two dozen gas-fired power plants since 1998. Manoil said many of those plants are producing energy not needed in Arizona. They says the plants exist mainly to sell power to California, a contention disputed by the incumbents - and one that fails to recognize that Arizona needs to build now for its future energy needs. The Star recommends that voters elect Hatch-Miller, Mundell, and Trasoff.