They were arrested for alleged offences contrary to the Non-Fatal Offences Against the Person Act 1997.
Four men, three women and three young people, ranging in ages from five to 59, died in the Creeslough explosion.
Donegal has a large diaspora in West Dunbartonshire, particularly in Clydebank and Dumbarton.
They were Robert Garwe and his five-year-old daughter Shauna Flanagan Garwe, Catherine O’Donnell and her 13-year-old son James Monaghan, Jessica Gallagher, Martin McGill, James O’Flaherty, Martina Martin, Hugh Kelly and 14-year-old Leona Harper.