How does a facility count the amount of a release-toxic chemical present in a mixture?
Pursuant to ยง 27.204(a)(1), if a release-toxic chemical is present in a mixture, and the concentration of the chemical is equal to or greater than one percent (1%) by weight, the facility shall count the amount of the COI in the mixture toward the applicable STQ. For example, if a facility has 500 pounds of a toxic mixture containing five percent (5%) acrolein, the facility should count five percent (5%) of the wright of the mixture, or 25 pounds of acrolein, toward the STQ of 5,000 pounds. Except for oleum, if a facility can measure or estimate (and document) that the partial pressure of the regulated substance in the mixture is less than 10 mm Hg, the facility need not consider the mixture when determining the STQ. If a release-toxic COI is present in a mixture, and the concentration of the chemical is less than one percent (1%) by weight of the mixture, the facility need not count the amount of that chemical in the mixture in determining whether the facility possesses the STQ. Refer
