On 12 May 2006, a fire occurred within the alkylation unit of the Wynnewood Refinery. An acid settler unit containing hydrofluoric acid (HF) was affected. By 26 May 2006, the fires had been extinguished and HF vapors were no longer emitted. Emergency response activities conducted by the responsible party ceased on 26 May 2006.
EPA responded to the fire upon notification (NRC#797020).