Public health groups that had supported an earlier version of the bill pulled their backing today, saying that the legislation, Senate Bill 246, had become too watered down.
Sen. Stewart Greenleaf (R., Montgomery), who had championed a statewide ban for a decade, voted for the bill even though he opposed the exemptions.
"Without a vote, I think the process could be stumbled, stopped. and it's important for us to continue with this process," said Greenleaf, adding that he is hoping a stronger bill will emerge from the House.
The House is expected to consider a separate ban later this week, perhaps as early as Wednesday.
It has far fewer exemptions, allowing smoking in cigar bars, tobacco manufacturers and tobacco shops. Hotels and motels would be permitted to allow smoking in as many as a quarter of their rooms.
And, unlike the Senate version, the legislation would not replace stricter local smoking ordinances, such as Philadelphia's, said Rep. Mike Gerber (D., Montgomery), who sponsored the bill.
Gerber said the Senate bill has so many exemptions that "it's going to drown of its own weight."
"They have watered it down to the point that I don't think it's protecting public health."
Philadelphia's law, which has been in place since January, is stricter than the Senate bill in several respects.
The Senate bill would allow smoking in designated areas of nursing homes, mental hospitals and adult care facilities, while the city bans it in all those health settings.
Philadelphia's ordinance also bans smoking at gaming establishments - two slots casinos are planned for the city - but the Senate bill would allow smoking on 25 percent of a casino's floor.