Mr. Aidan O'Connell:

Currently, under the existing IS 465 scheme we are concentrating on properties that have been damaged with muscovite mica and also with pyrite within the concrete blocks. It has been brought to our attention that there is a potential new causation, which is pyrrhotite, which may be a contributory factor or may be a primary proximate cause. However, there is another one as well which has not been getting as much daylight or publicity, and that is what we call weak concrete blocks in themselves and where they then undergo wetting and drying cycles during the course of their life. Over time those weak concrete blocks break down and they effectively mirror the damage that one would see by pyrite or with mica, but there is no smoking gun. One cannot put one's finger on it and say there is mica, there is pyrrhotite or there is pyrite on its own.

Ultimately, as Mr. Forde said, it is going to be the NSAI that will drive the research and drive the relevant checking. We are looking for research to be carried out on the wetting and drying cycles and we are looking for some research proposals in respect of the potential impact that pyrrhotite has on the concrete blocks. Pyrrhotite in itself is not a new issue. We knew about pyrrhotite when we were dealing with the IS 398 problems. The difference is that pyrrhotite within the infill material was reacting so fast, because of the type of lithology and the type of geology we were dealing with, that we were not really finding any damage resulting from that pyrrhotite. All I can say is that one will not find Engineers Ireland, NSAI or any of the consulting engineers dealing with this problem lacking in their enthusiasm to try to categorically come down and find the cause of the damage.