Oil plunged almost $3 a barrel on Tuesday to its lowest since mid-April, extending the previous day's rout on initial signs that a weakened Hurricane Gustav spared major Gulf oil facilities.Early checks by some US refiners reported no damage from Gustav, which weakened to Category 2 before roaring ashore near Port Fourchon, Louisiana, on Monday. At least two others were expected to dip into the US Strategic Petroleum Reserve, helping ensure steady gasoline and diesel supplies.US crude fell to $1   read more »