Western neighbors beginning to feel effects of California energy crisis.(Knight Ridder Newspapers)

WALNUT CREEK, Calif. _ California's energy crisis is spilling across state lines, spurring threats of record rate hikes, plant closures and layoffs from the Arizona desert to the Pacific Northwest.

While the Golden State's neighbors have yet to see their lights turned off, officials across the west fear California's power woes could become increasingly contagious.

Utility companies in five western states have warned their customers of possible rate hikes_some as high as 300 percent.

Skyrocketing energy costs have idled assembly lines and shut down plants in the northwest, leaving hundreds out of work.

In Las Vegas, where Californians account for 30 percent of all visitors, officials fear their neighbors' energy uncertainty might curb a booming economy.

"This isn't just a California problem," said David Danner, a top energy adviser to Washington Gov. Gary Locke. "This is also Washington state's problem. It's the whole region's problem."

With that in mind, California Gov. Gray Davis and his counterparts from nine western states participated Thursday in a two-day summit with federal regulators, utility company executives and members of the Bush Administration.