Crude oil dips under $91 WASHINGTON, Oct. 15 (UPI) -- Crude oil prices fell under $91 per barrel Monday on the New York Mercantile Exchange, following last week's stock market losses. Tensions in the Middle East are adding support to crude oil prices, but concern over struggling economies is pushing prices down. On Monday, equity markets started with gains. But market uncertainty is bound to be an overriding theme at least until the Nov. 6 national election. West Texas Intermediate crude for November delivery in New York gave up $1.07, sagging to $90.79 per barrel. Natural gas prices shed 1.28 cents to $3.483 per million British thermal units. Home heating oil lost 3.1 cents to $3.1929 per gallon. Reformulated blendstock gasoline dropped 2.28 cents to $2.87 per gallon.