578. If a facility monitors for a toxic chemical and the measurement is below the limit of detection of the method, can they report zero releases?
The facility must use reasonable judgment as to the presence and amount of the listed toxic chemical based on the best readily available information. An indication that a reportable chemical is below detection is not equivalent to stating that the chemical is not present. If the reportable Section 313 chemical is known to be present, a concentration equivalent to half the detection limit should be used. The facility should not estimate releases based solely on monitoring devices, but the facility should also rely on its knowledge of specific conditions at the plant.