Oil prices fell below US$106 a barrel Tuesday - US$10 below Friday's close before the U.S. Labor Day weekend - as investors shifted their focus to slowing global demand after worries about Hurricane Gustav subsided.
"If you are bullish, you should be concerned," said the Schork Report, edited by U.S. trader and analyst Stephen Schork.
By midday in Europe, light, sweet crude for October delivery had rebounded somewhat and was trading at US$108.24 a barrel in electronic trading on the New York Mercantile Exchange. Earlier in the session it had dropped as low as US$105.46.
On Monday, when U.S. trading was closed for Labor Day, the contract had plunged US$4.34 to US$111.12 a barrel in late electronic trading. On Friday, the contract settled at US$115.46 a barrel.
In London, October Brent crude was down US$2.38 to US$107.03 a barrel on the ICE Futures exchange.
Traders were relieved that Gustav weakened as it approached the offshore oil rigs and Louisiana refineries, and appeared to have caused less damage than expected in New Orleans and surrounding areas.
But they quickly turned their attention to slowing global economic growth, speculating that will dampen demand for crude oil, even in developing countries such as China and India.
"The market continues to be weighed down by worries of a global economic downturn and slowing oil demand in developing markets," said Victor Shum, an energy analyst with consultancy Purvin & Gertz in Singapore. "Action by OPEC and supply side concerns should put a backstop to any sharp price drop."
The Organization of Petroleum Exporting Countries is scheduled to meet Sept. 9 in Vienna and has indicated it may take action to defend the US$100 a barrel level.
Ahead of Gustav, there was some disruption to oil supplies as oil companies shut down production and evacuated facilities. Altogether, about 2.4 million barrels of refining capacity was halted, roughly 15 percent of the U.S. total, according to figures from Platts, the energy information arm of McGraw-Hill Cos. The Gulf Coast is home to nearly half of the nation's refining capacity.
It could be a day or more before oil and natural gas companies can assess the damage to their drilling and refining installations. Louisiana Gov. Bobby Jindal said as much as 20 percent of oil and gas production that was stopped because of Gustav could be restored by this weekend, stressing that it was a rough estimate.
Traders are also keeping an eye on other storms brewing in the region.
Hurricane Hanna was predicted to come ashore in Georgia and South Carolina late in the week, and Tropical Storm Ike formed late Monday in the Atlantic Ocean and may become a hurricane in the next 36 hours as it approaches the Bahamas.
"September is the peak of the Atlantic hurricane season. After Gustav, there are two more now on the radar screen. The storms are likely to provide some upside risks to the oil futures market," Shum said.
In other Nymex trading, heating oil futures fell 20.8 cents to US$3.9839 a gallon, while gasoline prices lost 21.63 cents to US$2.6379 a gallon. Natural gas for October delivery fell 68.7 cents to US$7.256 per 1,000 cubic feet.
Both Russia and Ukraine have been increasing their military presence on the border between the two countries lately. Russia warned Ukraine against any military scenarios