UPDATE 1-Valero plans Corpus Christi heavy oil cracker work

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HOUSTON, June 30 (Reuters) - Valero Energy Corp (VLO.N) plans maintenance on a heavy oil cracker in the west plant of its 315,000-barrel-per-day (bpd) Corpus Christi, Texas, refinery, according to a notice filed on Tuesday with state pollution regulators.

Work on HOC unit No. 21 was scheduled to begin Tuesday night and last at least through Thursday, according to the notice filed with the Texas Commission on Environmental Quality.

Valero is restarting the crude unit in the refinery's West Plant on Tuesday, which shut for repairs last one day, the company has said. (Reporting by Erwin Seba; Editing by David Gregorio)