Dr. Ken Murphy:

I suppose the original standard did set out the two types of deleterious materials. That was primarily based on the information given in the report of the expert panel. As was alluded to earlier, the testing and sampling that was carried out to support the original scheme did start to identify other deleterious materials, principally the pyrrhotite. That came to the attention of the TC63 working group in the summer of 2002, approximately.