U.S. crude oil tumbled to a more than four-month low under $100 a barrel on Thursday, on news of a potentially lengthy shutdown at a key oil refinery in Kansas, while Brent also slipped amid signs of robust OPEC oil production.
Oil futures in New York abruptly extended losses at midday after CVR Refining said its 115,000-barrel-per-day refinery in Coffeyville, Kansas - a major consumer of benchmark West Texas Intermediate crude - might be shut for as long as four weeks after a fire in a gasoline-related unit on Tuesday.
Prices fell earlier in the day following a Reuters survey that showed OPEC pumped more oil in July than in June, adding to signs of a well-supplied global oil market and further tempering concerns that unrest in North Africa and the Middle East could hurt supplies.
Brent crude for September delivery fell nearly $1 to under $106 a barrel. Brent has fallen more than 6 percent in July and is on track for its biggest monthly loss since April 2013.
U.S. crude futures for September delivery swooned by $2.10 to settle at $98.17 a barrel, its lowest settlement since March 17.That puts the contract on course for a drop of more than 6.4 percent on the month - the biggest since May 2012.
This week's fire at the isomerization unit of the Coffeyville refinery could temper immediate demand for WTI crude, which traders say should help rebuild inventories in the Cushing, Oklahoma, delivery hub that have fallen this summer to six-year lows.
Rising gasoline stockpiles in the United States, even during the peak summer driving season, have raised concerns about the demand outlook in the world's largest oil consumer.
Oil prices have steadily eased after hitting multi-month highs in June on world political tensions.
--By Reuters. For more information on commodities, please click here.