Valero Energy (VLO -1.1%) leads a retreat across much of the oil sector as Hurricane Isaac leaves behind less damage to the Gulf Coast's energy industry than first feared. Among refiners: COP -0.2%, TSO -1%. Big E&Ps: XOM -0.2%, CVX -0.5%, MRO -1.1%. Oilfield services: RIG -1.5%, HAL -1.2%, SLB -0.7%. Explorers: APA -0.3%, APC -0.3%.