O'Lehane had been working at Cannocks in Limerick where several female shop workers living on the premises died in a major fire.
The union focused its campaigns on reducing working hours, creating a half-day holiday per week, and setting up agreements to cover overtime pay.
[2] O'Lehane stood down as secretary in 1919, being succeeded by several high-profile trade unionists, including Luke Duffy, Michael Drumgoole and Billy Fitzpatrick.
[4][5] The action made international headlines and at one stage a delegation of eight of the Dunnes Workers led by IDATU Official Brendan Archbold were expelled from South Africa where they had gone to meet Archbishop Desmond Tutu.
[7] In 1994, IDATU merged with the Irish National Union of Vintners', Grocers' and Allied Trades Assistants to form Mandate.