573. If a covered facility has analytical data indicating the concentration of a Section 313 chemical is below the limits of detection and the facility has no information on the probability of the chemical being present in that waste stream (e.g., Superfund waste), should the facility use half the detection limit? What documentation will EPA require if the facility asserts that it had no basis for expecting the Section 313 chemical to be present?
If the facility has no information to indicate that the chemical exists in the waste stream, it may assume that the concentration is zero. If the facility has reason to believe that the listed toxic chemical is present, it may use half of the detection limit. The facility should document that it looked at all readily available data in making this determination.