IDYLLWILD (CBSLA.com) — The Mountain Fire, which has burned 27,531 acres near Idyllwild since it broke out July 15, was 99 percent contained Monday afternoon.

Fire officials expected the remaining personnel still battling the fire to finish by Tuesday, the U.S. Forest Service reported.

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Investigators have determined that the cause of the blaze, which destroyed 23 structures, including seven residences, was due to an electrical equipment failure on private property.

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The cost of the fire effort was estimated to be more than $25.6 million.

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