Toledo firefighters said they ended the Rumble Racing Series early Saturday when carbon monoxide levels rose too high inside the SeaGate Convention Centre.
Fire Capt. Bryce Blair said exhaust fumes from the powerful miniature race cars raised the carbon monoxide level to 350 parts per million, and the decision was made to end the last race early, open all of the exterior doors at the downtown hall, and evacuate the 1,500 spectators.
"If we go to someone's house and they have 10 parts per million, that's enough to red-flag it," Captain Blair said. "The cars were putting out a significant amount of exhaust and carbon monoxide. That can cause respiratory problems."
However, Tony Barhorst, the owner of the race, said the race was nearly done when the firefighters who had been monitoring the event took their action.
"Toledo's fire marshals [sic] are very strict and to the letter. We didn't have any complaints," Mr. Barhorst said.
Mark Smyth, a midget racer mechanic at the event, said, "The air wasn't bad until the very end. When it's real bad, you can get almost dopey. I've been here all day and it wasn't at that level at all."
The Rumble Series' indoor events feature national midget cars, winged modified midgets, go-karts, and quarter midgets. The vehicles burn methanol fuel, Mr. Smyth said.
The event was staged at SeaGate Friday and Saturday.