Mica scandal
The Mica scandal began in 2011 in Ireland when defective concrete blocks used in the construction of homes and other buildings showed signs of cracking and decay. The blocks were found to contain more than the maximum permitted amount of the mineral mica. The majority of affected buildings were in County Donegal but other counties were also impacted. The scandal led to calls for, and then the establishment of, a scheme to fund affected homeowners of the fault to repair, or demolish and rebuild, their homes. A similar issue with the presence of pyrite was identified in 2007, originating with a quarry in the east of Ireland, and legislation was enacted to address both of the issues similarly. Issues Muscovite (also known as common mica) can be found in rocks used to make concrete blocks. It is estimated that a presence of 1% of muscovite in concrete reduces the strength of the internal bonding by 5%, and further that such blocks bond poorly with cement paste. Mica also absorbs water, and excess water can cause problems in cold winters as the process of freezing and thawing damages the blocks. More than five thousand houses and an unknown number of office