Leaking gas sent four people to the hospital Sunday morning and forced the evacuation of 30 to 40 people from a downtown commercial building. Firefighters traced the leak to the Koko Sushi Bar & Lounge, on the first floor at 301 N. Adams St. Steve Sellin, a Green Bay Metro Fire Department battalion chief, said the gas supply to a grill was on, but the pilot light was out. "When we pulled up, there was a strong smell of gas, and people were evacuating," Sellin said. "We turned off the gas (supply) right away, but it took a while to find the source" of the leak.