Crude oil futures ended lower on Tuesday as Wall Street declined on economic concers led crude oil for October delivery down 1.91 dollars, down 2.7 percent, to settle at 68.05 dollars a barrel on the New York Mercantile Exchange.Brent Crude for October delivery was down 1.92 dollars, to 67.73 dollars a barrel on the ICE Futures exchange.Rise in the dollar also pushed prices down.Dollar considered "safe haven" investment gained against the euro and other major currencies.Heating oil was down 2.7 percent dowm 4.96 cents to settle at $1.7589 a gallon.