BARSTOW, Calif. (AP) — Gov. Arnold Schwarzenegger declared a state of emergency Saturday in Barstow, where excessive levels of a chemical found in rocket fuel has left the water contaminated for more than 40,000 customers of the local supplier.

The governor’s office said in a statement that the declaration — which releases otherwise unavailable state resources — came because dealing with the water shortage was beyond the control of city and county officials.

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Many local businesses, including hotels, restaurants and cafes, have been forced to close temporarily, the statement said.

Golden State Water Company — which provides water for most of Barstow and some of its surrounding areas — said in a statement that tests performed Thursday and Friday showed three of the 20 wells used to serve the area showed levels of the chemical perchlorate above the maximum contaminant level of six parts per billion. Only one of the three wells had been in service, the statement said.

The company said it was conducting “an aggressive investigation of its water system to determine the source of contamination,” and on Saturday began flushing its distribution system to remove the chemical-tainted water.

Fresh samples would be taken when that process was finished, but the company offered no estimate of when the water supply might be declared safe.

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The company was providing more than 100,000 bottles of free water at least through Monday to customers who came to one of four distribution centers.

Perchlorate has been shown to interfere with the uptake of iodide by the thyroid gland, reducing the production of thyroid hormones which could lead to adverse effects associated with inadequate hormone levels.

Boiling, freezing, filtering or letting water stand does not reduce the perchlorate level.

The statement said customers could wash dishes and shower in the water, because the chemical is not readily absorbed through the skin.

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