(Adds BP no comment, background)
HOUSTON, Jan 12 (Reuters) - BP Plc's 413,500-barrel-per-day refinery in Whiting, Indiana, wasrestarting a 90,000 bpd crude distillation unit and a 60,000 bpdreformer on Monday morning, said sources familiar with theoperations.
BP on Friday began restarting the CDU, called Pipestill 11C,but was delayed by freezing weather much of the weekend. Thereformer, called Ultraformer 4, was shut by a power outage overthe weekend, the sources said.
The largest CDU of three at the Whiting refinery, the240,000 bpd Pipestill 12, briefly cut back production over theweekend, the sources said, but it was back to normal operationon Monday.
Energy industry intelligence service Genscape reported thedip in Pipestill 12 production and the reformer outage on Mondaymorning.
A BP spokesman declined to discuss operations at the Whitingrefinery.
Pipestill 11C was knocked out of production on Thursday byextremely cold weather. The U.S. National Weather Service saidwind chills were between 20 and 30 degrees below zero Fahrenheit(minus 29 and 34 Celsius) Thursday night along the shore of LakeMichigan, where the refinery is located.
The refinery's three CDUs do the initial refining of crudeoil coming into the refinery and provide feed stock for allother units.
A reformer converts low-octane refining by-products intooctane-boosting components for blending into gasoline.
(Reporting by Erwin Seba; Editing by Lisa Von Ahn and DanGrebler)