Gov. Arnold Schwarzenegger declared a state of emergency Saturday in Barstow after samples of the city’s water supply were found to be contaminated with a chemical used in rocket fuel and defense manufacturing. A statement on the city’s website says the Golden State Water Co. was notified Thursday that water samples showed levels of perchlorate above the maximum contaminant level of 6 parts per billion. Golden State Water identified and shut down three wells out of 20 that show elevated levels of the chemical, reported the Desert Dispatch newspaper in Barstow. One of the wells was located near the Marine Corps Logistics Base in Barstow.