Professor Paul Dunlop:

As a professional researcher at Ulster University, I was very concerned about the lack of research into this issue so I brought a team of people together. Dr. Leemann is one of these and another is Mr. Nick Scaglione from the USA. We have looked at the concrete issue independently without being restricted to the IS 465 protocols. We presented our research at the European Parliament on 23 March. We invited Engineers Ireland, the National Standards Authority of Ireland, NSAI, and people from the Department to join us and to look at the findings. It is absolutely clear from the research we have done that pyrrhotite is oxidising and releasing sulphur, which is turning into sulphuric acid and attacking the cement hydrates. We have found the process connected to the cracking of concrete blocks in Donegal. It is a real thing and cannot be ignored.

Mr. Doherty has already said that many of these homes were built during the Celtic tiger years. The regulations that were in place at that time, the European standards on aggregates for concrete, EN 12620:2002, specified very clearly that, if pyrrhotite is present in the aggregate, then 0.1% of sulphur can be released, which is a very low level. That was published by the NSAI in 2004. Its regulation was called SR 16:2004 and used the exact same wording. The NSAI updated that standard in 2008 which was then called IS EN 12620:2002+A1:2008. I know that is quite a long title but I mention it for the record. This standard said the same thing, that special attention must be given to aggregates that contain pyrrhotite and that you cannot have more than 0.1% sulphur being released into concrete.

Analysis that we have done with Dr. Leemann and Mr. Scaglione has clearly identified that in areas where there is this cracking, you find pyrrhotite being oxidised and sulphur being released. Dr. Leemann presented really good results that show sulphur being released in situin the blocks in Donegal today. We have also shown the process whereby these secondary minerals, ettringite and thaumasite, form and expand, causing cracking. It is a really serious problem because, in Donegal, those involved in the IS 456 process have decided that the problem is mica and mica alone. People involved in the setting up of that protocol are holding on to those old ideas. We need the science to move forward.