Some Boston managers are concerned that banning smoking will create safety hazards as groups of smokers huddle outside bars and nightclubs .
Some Boston bar managers said they worry that banning smoking will create a hazard as groups of smokers huddle outside on sidewalks and in parking lots to smoke .
The broad Standard & Poor 's 500 Index .SPX gained 19.72 points , or 1.98 percent , to 1,015.69 .