The residential Building Regulations focus on thermal performance requirements, rather than being prescriptive in relation to particular materials. Fibrous materials have been commonly used for insulation of attic spaces over many years.
The Building Regulations Part L were substantially revised in 2007 and Sustainable Energy Ireland (SEI) advise that the stringent thermal insulation standards now required of new homes are likely to see the industry increasingly using materials with the lowest thermal conductivities, for reasons of practicality in relation to construction dimensions. These materials tend to be of rigid foam type structure, rather than fibrous. The use of glass fibre insulation may be expected to diminish over time, but I am not aware of any proposals to exclude it from the list of choices available to the industry.
Insulation materials are not generally designed for direct exposure to an inhabited space. An attic space is generally designed as a ventilated and unoccupied space. I am further advised by SEI that any trace levels of gaseous emissions arising from the installation of insulation materials in such an attic space would be expected to dissipate quickly and would be ventilated out in any case. However, in the case of a converted or occupied attic space, insulation materials should normally be sealed behind a suitable barrier such as plasterboard.