Crude oil prices slipped to nearly $90 per barrel Monday on the New York Mercantile Exchange, following a steady week of stock market losses. Tensions in the Middle East are adding support to crude oil prices but concern over struggling economies is pushing prices down. Markets are also skittish due to an upcoming election in which the outcome is far from clear. On Monday, West Texas Intermediate crude for November delivery lost $12.45 to $90.41 per barrel. Natural gas prices shed 1.34 cents to $3.477 per million British thermal units. Home heating oil lost 2.76 cents to $3.1963 per gallon. Reformulated blendstock gasoline dropped 4.81 cents to $2.8447 per gallon. At the pump, the average price for a gallon of regular unleaded gasoline was $3.787 per gallon, down from Sunday\'s $3.794, AAA reported.