There was an interesting article, "A Survey of Carbon Monoxide and Nitrogen Dioxide in Indoor Ice Arenas in Vermont," by Leonard J. Paulozzi et al. in the Dec. 1993 issue of the Journal of Environmental Health. (p. 23-25). The researchers tested carbon monoxide and nitrogen dioxide measurements in enclosed ice arenas in Vermont during high school hockey games. They tested 9 of the 11 indoor ice arenas in Vermont. They found that a significant number of the arenas had undesirable levels of either or both of these air contaminants. The authors recommend that electric ice resurfacing machines be used, especially if the air contamination problem can't be solved with ventilation. The bibliography lists a number of article about air quality problems in ice arenas, including several about carbon monoxide poisonings. Carol