Carbon monoxide poisoning in ice rinks

I saw a piece in the news recently about a law that is being passed in Minnesota regarding setting indoor air quality standards for ice rinks.  There was an incident there similar to the Glen Ellyn ice rink carbon monoxide poisoning incident of this past winter where a number of youth hockey players were made ill by carbon monoxide poisoning.The source of the carbon monoxide in the Minnesota incident was the Zamboni and other ice grooming equipment.  The new law requires ice rinks to equip the ice making equipment with pollution emissions equipment and the rink with air monitoring equipment.The law is a sensible approach to addressing the dangers of carbon monoxide poisoning.  We all know that you do not leave the car engine running in a closed garage.  While an ice rink is obviously a much larger building, that only helps diminish the concentration of the carbon monoxide, not eliminate it.