Areas were defined in the 1989 Trail Lead Study Report (authored by UBC) by reviewing the distribution of blood lead levels at the time relative to the level of no concern (a term from the U.S.). Area 3 had a higher proportion of kids exceeding the ‘safe’ level and included Tadanac, East and West Trail, and Rivervale. Area 2 had a similar number of children above and below the safe level and included Glenmerry, Shavers Bench, Miral Heights and Sunningdale. Area 1 had a greater proportion of children at lower levels and included Warfield (including Annable), Waneta, Casino and Oasis.