Philadelphia Energy Solutions began the precautionary closure of key units at its Philadelphia refinery, the region’s biggest.\n“Many of the process units have been shut down, others are in ‘standby,’ and the remainder have been brought to their minimum safe operating levels,” said spokeswoman Cherice Corley.\nHurricane Sandy comes as low inventories of refined products have stirred concerns of potential price spikes during the heating season this winter.\nThe precautionary refinery closures are even more widespread than during Hurricane Irene in August 2011. During Hurricane Irene only the Bayway plant shut down completely.\nWhile refiners escaped any serious damage during that Irene, many fear Sandy’s massive storm surge. Sandy’s storm surge is forecasted to be as high as 11 feet. This could breach plant defenses and cause damaging flooding, which can sometimes take weeks to repair. The anticipated abrupt power outages also damage refinery equipment.