Comments on the Legal Admissibility of a Performance Assessment for a Radioactive Waste Disposal Facility

Abstract

We were invited by the Editor of Risk Analysis to comment on the legal admissibility of the performance assessment conducted for the Waste Isolation Pilot Plant (WIPP) in 1996.(1) This invitation was extended because of work we have conducted regarding the admissibility as evidence in legal proceedings of risk assessments and the results thereof.(2,3) With the advent of ‘‘risk-based’’ decision making and ‘‘risk-informed’’ decision making in environmental management, the legal admissibility of the underlying risk assessment becomes a key issue if the affected environmental decision is challenged within the legal framework. For that reason, we undertook the studies in Refs. 2 and 3. We have examined the tests and criteria to which a court of law may subject risk assessment and their results to determine whether or not they can be admitted as evidence. We have discovered that those tests and criteria are different, and generally stricter, that the standards of scientific acceptability to which we are accustomed. We have also found that, in general, risk assessment practitioners are seldom aware of the admissibility standards for technical and scientific data as evidence. Consequently, those standards are not usually factored in when designing and conducting risk assessments. We reviewed Ref. 1 from the point of view of the legal admissibility of the performance assessment methodology. We were not able to draw specific conclusions on the legal admissibility of the performance assessment methodology for two reasons. First, the level of detail in the information that would had to be examined is far more than could be reasonably included in a journal publication, and this is indeed