43 CFR 11.37: Must the trustee confirm exposure before implementing the Type B Assessment Plan?

(a) Before including any Type B methodologies in the Assessment Plan, the trustee must confirm that at least one of the natural resources identified as potentially injured in the preassessment screen has in fact been exposed to the released substance.

(b) Whenever possible, exposure shall be confirmed by using existing data, such as those collected for response actions by the On-Scene Coordinator, or other available studies or surveys of the assessment area.

(c) Where sampling has been done before the completion of the preassessment screen, chemical analyses of such samples may be performed to confirm that exposure has occurred.

(d) Where existing data are unavailable or insufficient to confirm exposure, one or more of the analytical methodologies provided in the Injury Determination phase subpart E of this part may be used.

(e) Type B assessment methodologies shall be included in the Assessment Plan only upon meeting the requirements of this section.