Energy intelligence service Genscape reported Tuesday morning that the refinery's 70,000 (bpd) fluid catalytic cracker was shut, just days after it was restarted after planned work. Reuters has not independently confirmed the reported outage.
The US gasoline crack spread, a key indicator in refining margins, was up 3.09 percent at 12:57 GMT to $12.28 a barrel, as US gasoline futures were slightly leading the oil complex.
The FCC unit was restarted last week following a large turnaround at the refinery that began in late September.
The plant's 150,000 bpd crude unit, its largest, was shut down as part of the planned work and was expected to be restarted by the end of the month.
Meanwhile, Philadelphia Energy Solutions is still in the process of determining whether to advance planned work at its 330,000 bpd refinery complex in Philadelphia after a weekend fire in a unifiner and reformer unit, a source told Reuters Tuesday morning.
Traders said the uncertainty at the Philadelphia refinery is also boosting margins.