574. Is it appropriate for a covered TSD facility to develop an average concentration for a Section 313 chemical contained in thousands of different waste streams managed by the facility, and then use that average as a basis for threshold determinations? If so, does EPA have a recommended approach for developing such an average?
EPCRA allows covered facilities to use the best readily available data to provide information required under EPCRA section 313. When data are not readily available, EPCRA allows facilities to use reasonable estimates of the amounts involved. A facility must use its best judgment to determine whether data are readily available. Thus, with regard to use of average concentration levels, a facility must use its best judgment to decide whether the raw data from which it might base any average concentration level are readily available. In any event, a facility should carefully document its decision making. For example, if a facility decides to use average concentration levels, it should document why the raw data from which the averages are based are not readily available, how it arrived at any average concentration level used, and why the average concentration level is a reasonable estimate of the amount of the toxic chemical in the waste stream. EPA does not have a recommended approach for determining average concentration levels.