3) May include naturally occurring contaminants or residual levels of halogen elements (e.g. from processing aides, ingredients, synthesis, etc.) that are not included in the material formulation. The defined concentration limits should be low enough to precludethe use of one or more halogen elements in the material formulation and high enough to account for naturally occurring contaminants or residual levels of halogen elements (e.g. from processing aides, ingredients, synthesis, etc.).