A bill is being considered in the state Assembly to allow police to stop vehicles if a minor appears to be exposed to smoke from a pipe, cigar, cigarette, or "any other plant."

The bill has the support of the American Lung Association, which points to research showing secondhand smoke can cause cancer, respiratory infections and asthma.

Assemblyman Marco Firebaugh, a Democrat and author of the bill, has referred to a survey by state health officials that found 29 percent of youth in the state had been exposed to secondhand smoke in the prior week.

Opponents say the bill, which last week passed in the Transportation Committee and now heads to the Appropriations Committee, not only encroaches on Constitutional freedoms but demonstrates the intentions of some politicians to eventually ban smoking everywhere in California.

"If the ultimate goal is to ban smoking, then have the courage to come up and say that," said Assemblyman Dennis Mountjoy, a Republican in the Democratic-dominated legislative body.

"Show me good science that shows that secondhand smoke is a problem. I don't know that they've proved that," Mountjoy added.

California in 1995 became the first state in the nation to ban smoking in virtually all workplaces, said Paul Knepprath, the vice president of government relations at the American Lung Association of California.