Three teenage girls from Illinois suffered severe symptoms of carbon-monoxide poisoning yesterday afternoon driving through Janesville.
Their condition stabilized after they were taken to oxygen-rich chambers at a Milwaukee hospital.
Fire commander Tim Ehlers says the bus was carrying a girl's volleyball team from Schaumburg, Illinois, to Watertown. Nine people were on the bus.
He says the exhaust system on the ten-person bus apparently malfunctioned, sending the odorless gas seeping into the cabin.