HOUSTON: Royal Dutch Shell Plc cut production to minimum rates on Monday at its 227,400 barrel-per-day (bpd) Norco, Louisiana, refinery, including idling the refinery's crude distillation unit, said sources familiar with plant operations.

The 240,000-bpd DU-5 CDU was placed on warm circulation along with a alkylation unit because of the threat from Tropical Storm Sally, the sources said. A reformer at the refinery was shut last week for repairs.

Shell spokesman Curtis Smith declined on Monday to comment on operations at the refinery.

Units on warm circulation can restart quickly because they remain at operating temperatures.

Shell told contractors at the Norco refinery to leave work at 2 p.m. CDT on Monday ahead of the storm. Only essential personnel will be working at the refinery while Sally passes on shore on Tuesday.