Oil prices began Monday where they ended last week, in a free fall along with other key global commodities as traders respond to China’s economic slowdown and an ongoing global oversupply that has knocked oil prices down nearly 60 percent over the past year. If Monday’s trading activity is any indication, U.S. oil prices are headed to a ninth straight weekly decline, the longest losing streak since before the oil glut of the early 1980s.

"We are in the midst of a full-blown growth scare," British investment bank JP Morgan Cazenove said in a research note on Monday.

BRENT Brent crude prices were trading at around $43 a barrel on Monday, near its lowest level since February 2009. Photo: Thomson Reuters

West Texas Intermediate crude, the benchmark for U.S. oil prices, fell 5.7 percent to $38.13 per barrel for October delivery on the New York Mercantile Exchange. On the London ICE Futures Exchange, Brent crude, the global benchmark for oil prices, dropped nearly 5.8 percent to $42.84 per barrel. Both benchmarks are at their lowest levels since February 2009 in the midst of the global economic downturn.

U.S. oil prices dipped briefly below $40 a barrel on Friday before edging back up. On Monday the price fell more firmly below that price, threatening S&P 500 listed energy and drilling companies. Energy stocks have already lost 35 percent over the past 12 months.

Energy stocks were deep in the red Monday. Houston-based driller Apache Corporation (NYSE:APA) was down more than 4 percent Monday morning, to $41.47, while Anadarko Petroleum (NYSE:APC) of Woodlands, Texas, plunged nearly 5 percent to $65.56. Spanish oil giant Repsol  SA (BME:REP) was leading losses among oil giants, with a 6.58 percent drop to 12.56 euros ($14.58).

Oil followed other key global commodities down to more than six-year lows. Copper, a weather vane of global industrial demand, dropped 3.3 percent to $4,888.50 a tonne on the London Metal Exchange on Monday.