The ports of Los Angeles and Long Beach on Wednesday unveiled a sweeping 10-year clean air plan for the nation’s busiest port complex.

The plan, estimated to cost $2 billion over the next five years, is intended to address rising concerns from environmental and community groups over cancer-causing and toxic air emissions from port operations. Taken together, the two ports are by far the single biggest polluter in Southern California; emissions from the ports have been blamed for dozens of cancer deaths each year.

Officials from the two ports say that when the plan is fully implemented, it would reduce diesel particulate emissions by 1,200 tons per year and nitrogen oxide emissions by 12,000 tons per year from current levels. In order to minimize disruptions to port operations and the region’s good movement economy, the steps outlined in joint plan from the two ports are to be phased in over the next 10 years.

Under the plan, all major container cargo and cruise ship terminals must be equipped with onshore electric power hookups so that ships can turn off their diesel engines while docked at port. Ships would also be required to use low-sulfur fuels and to reduce their speeds when entering or leaving the harbor area.

On the land side, all diesel trucks operating at the ports would have to be retrofitted or replaced within five years; the South Coast Air Quality Management District would kick in $200 million over five years to help terminal operators and truck owners offset the conversion cost.

Also, all locomotives entering or leaving the port region would have to meet strict Environmental Protection Agency emission standards, which means shifting to cleaner fuels and installing exhaust control equipment.

A series of public hearings on the plan will be held over the next 30 days. Revisions to the plan are expected to be completed this summer; a fully revised plan is expected to be brought to the commissions of both ports in late September.