They have been told the Garda investigation into the explosion will be completed early next year.
Representatives for the families say they feel a step closer to a conclusion after meeting the Justice Minister yesterday.
Hugh Harper lost his daughter Leona in the 2022 blast.
He says they have waited far too long for answers already:
"We're coming to Halloween, one of Leona's favourite times of the year, and then come to Christmas where we'll have an empty chair again at the Christmas table. Where we'll go and spend nearly all day at her graveside. To leave her graveside, and then go home without her again. I can't put a measurement on that to make everybody understand how that feels."
