The decision means the company will have to use alternatives to the traditional diesel to fuel the required emergency generators for its new Methodist Stone Oak Hospital, which is 20 months from completion. The authority, charged with regulating and protecting the aquifer, five years ago approved rules that forbid new liquid fuel storage tanks with a capacity of more than 600 gallons on the recharge zone. Methodist had requested a 4,400-gallon diesel tank. The rules were passed to try to protect the region's primary water source from accidental leaks and spills. Out-of-state engineers who designed the hospital weren't aware of the prohibition. Dean Alexander, chief executive officer for the new hospital, told the board that engineers have found another way to provide the on-site fuel for 24 hours of emergency generator operation required by the Texas Department of Health. But, he said, the combination system of 600 gallons of diesel plus natural gas is not widely used and is more expensive to install and use. Annalisa Peace, executive director of the Greater Edwards Aquifer Alliance, a coalition of 39 member groups, said, "While we realize that the Methodist Hospital is a leader in health care for our community, we ask that they respect the health and safety of the citizens of our community by complying with rules that were enacted to protect the same." Alexander said the technology for the proposed system is not really proven to the point he'd like it to be for critical care needs. Bruce Gilleland, a board member from Medina County, said he thought the directors might be going overboard in denying the exemption when fuel trucks cross the recharge zone every day. Susan Hughes, a Bexar County board member, said the recharge zone "is really not that much of San Antonio. There's lots of land everywhere else. I don't mean to be hard-core, but when it comes to aquifer protection, I am." The measure, the most controversial in a package of proposed rules changes, was denied in what appeared to be an 11-3 voice vote. jneedham@express-news.net