An independent inquiry into a botched green energy scheme which sparked a major political row in Northern Ireland will hear final submissions next week.
The probe is examining how costs in the Renewable Heat Incentive (RHI) scheme spiralled.
The RHI Inquiry led by retired judge Sir Patrick Coghlin has exposed many of the failings at the heart of the scheme.
It was designed to encourage businesses to shift from fossil fuels to renewable sources like wood but ended up paying out more than it cost to fuel the burners – earning it the moniker “Cash for Ash”.
The fiasco led to a political row, the resignation of Northern Ireland’s then deputy First Minister Martin McGuinness and the collapse of the powersharing government in January 2017.
Stormont has since remained in suspension, leaving the region without devolved government and senior civil servants left to lead their departments.
Mrs Foster told the DUP’s annual conference last month that its handling of the RHI scheme had been painful for its members.
She reiterated her apology and said she was deeply sorry for the mistakes.
The inquiry is set to hear closing submissions on Wednesday December 12.
Oral submissions will also be heard from some of the 27 individuals and organisations who were granted enhanced participatory rights.
These include Mrs Foster, former Democratic Unionist minister Jonathan Bell, a number of the party’s special advisers and some senior civil servants.