Professor Paul Dunlop:

I thank the committee for letting me in again. I would like to bring Mr. Leemann into the discussion as well. The main issue we are worried about in Donegal is not so much pyrite as pyrrhotite, which is another form of unstable iron sulphite. It is more highly reactive than pyrite and it is well known internationally, in the United States - in Massachusetts and Connecticut - and also in Quebec in Canada. Mr. Leemann has presented work that he has done in Switzerland where very high-strength concrete used in foundations and megastructures like dams fails because of oxidisation of pyrrhotite.

To date, from what I can see publicly, Engineers Ireland has been fairly quiet, but I heard its representatives speak on the radio. Dr. Martina Cleary organised an excellent conference a few weeks ago. All I can say at the moment is that there is a denial of the problem in Donegal that pyrrhotite is widespread. Mr. Campbell can speak about this as well. Some 86% of the homes in Donegal that he has sampled have appreciable levels of pyrrhotite in them. It is a major issue. People from Engineers Ireland or the NSAI, who are wedded to this old idea that mica is a problem in Donegal need to shift. There is a serious pyrrhotite issue. Pyrrhotite is classed as a geohazard. Other types of geohazards are hurricanes, earthquakes and tsunamis. This is a real problem. I accept we need more research to try to understand it, but evidence is there to show that it is a widespread issue. I will hand over to Mr. Leemann, who may have other comments to add.