WASHINGTON -- The Senate overwhelmingly passed historic legislation Thursday that puts the tobacco industry under the regulation of the Food and Drug Administration.

Companies are weighing the impact of the bill, which they say also puts severe, perhaps unconstitutional, restrictions on advertising and packaging. Those limits, they worry, could undo business plans based on smokeless tobacco products, which they have been developing in anticipation of this day -- even as they were fighting to derail the legislation.

Former...