LOS ANGELES, Sept. 15 (Xinhua) -- The Board of Supervisors voted on Tuesday to prohibit smoking in parks in the Los Angeles County, with some exceptions.

    Citing secondhand smoke as the third leading cause of preventable death in the United States, the board voted 4-1 in favor of the ban proposed by the Department of Parks and Recreation (DPR).

    Smoking will be allowed in designated areas of recreational facilities run by outside contractors or lessees, such as golf courses and tennis courts.

    Special exceptions will also be made for actors in productions under permit or for models in permitted photography sessions.

    Several advocates, including representatives from the American Lung and American Heart associations, appeared before the board in favor of the proposal.

    According to the DPR's report to the board, 52,000 non-smokers die of exposure to secondhand smoke in the United States each year. The medical and other costs to U.S. non-smokers suffering from lung cancer or heart disease total nearly six billion dollars annually, according to the report.

    Some contractors expressed concern that a complete smoking ban would hurt attendance and revenues. The department was unable to quantify the economic impact of a total ban, but suggested designated smoking areas in a compromise move.

    The city of Los Angeles already has a similar smoking ban in place.

    Supervisor Don Knabe cast the lone vote against the ban.