The explosion of imports from Asia has turned Southern California into the nation’s loading dock.

More than 40% of the goods that come to U.S. shores in truck-size cargo containers flow through the region’s twin ports to destinations in every state, and 28% of exports from around the country leave through the local harbors, a new study found, the Los Angeles Times reports.

The value of container trade through the ports of Los Angeles and Long Beach hit $256 billion in 2005, up 246% from $74 billion in 1994, according to a study commissioned by the ports and the Alameda Corridor Transportation Authority that will be released today.

State and local tax revenues generated nationwide by the country’s largest port complex rose 368% over the same period, to more than $28.1 billion from $6 billion. Trade through the two ports supported 3.3 million U.S. jobs, up 200% from the 1.1 million such jobs in 1994.

The report sketches a portrait of the neighboring ports as the focal point of a “floodtide of trade” and as a vibrant goods-moving, jobs-generating machine.

Come Monday, the study will be used by a small invasion of nearly 200 California business and government leaders who are heading to Washington to call for a bigger share of federal transportation funding, port security money and healthcare dollars for trade-related illnesses.

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