In September 1993, children broke into a laboratory in an abandoned scrap metal recycling plant in Hamilton and removed mercury and other materials from the site. They began distribution of the mercury to their peers but this activity was halted once an emergency response was established. This paper focuses on the identification and assessment of children exposed to mercury and the use of Epi Info 6 in the analysis. Approximately 6,000 children were screened and 269 children identified as being exposed or at risk of exposure. We found that distribution of mercury within the school system was swift. Children exhibited a number of risky behaviours with mercury. There were no significant gender differences in these behaviours. The majority of children involved were 10 to 13 years of age. No child exhibited health effects from exposure.