The Long Beach harbor commission on Monday unanimously approved a fee system, expected to generate $1.6 billion, which will fund a long-delayed clean air program backed by the local ports.

Under the tariff, which goes into effect June 1, all trucks loaded with cargo will be charged a $35 fee when they enter or leave the port

The estimated 16,000 dirty diesel trucks in San Pedro Bay are the first target of the ports’ jointly-adopted Clean Air Action Plan, which calls for the replacement of nearly all of the rigs with newer, less-polluting models.

The ports recently approved a schedule for the phase-out of the oldest truck models starting in October. But they have yet to vote on the most controversial element of the program, which would require all motor carriers to replace their independent drivers with employees.

The Port of Los Angeles’ harbor commission is expected to approve an identical fee on Thursday.