§ 626.12 - Maximum credible event (MCE).

(a) Because of the complexity of the RDTE conducted in the BDP, the range of potential consequences that could be associated with a mishap must be considered. MCE is a risk analysis technique which provides a useful tool for estimating the effectiveness of existing safeguards. The potential for events must be carefully analyzed to determine the MCE that could occur and cause a mishap. All hazard analysis and general construction plans mentioned in § 626.11 will include a consideration of an MCE.

(b) The term MCE, as used herein, is analogous to a realistic worst-case analysis. The best available credible information will be applied to estimate the results of various MCEs. Those assumptions that yield the potential for more severe consequences, as opposed to assumptions that operational and safety controls will always perform as designed, will be used. The rule of reason will be applied to confine the MCE to realistic or believable occurrences.

(c) When considering an MCE, consider the redundancy of safety systems engineered into the facilities and the equipment used, depending on containment level required to make them as fail-safe as practical. The MCE for containment laboratories must be considered in terms of physical containment for both toxins and biological organisms. Therefore, both toxin and biological MCEs will be considered.

(d) Because aerosols of etiologic agents represent the most significant potential hazard for exposure of workers or the environment, a hazard analysis (to include MCE) of proposed BDP RDTE activities will be performed to determine the procedures, engineering controls, and facility design required to mitigate potential significant hazards.