NBCNews.com | Oil Prices Dive Again, Crossing Briefly Below $30 a Barrel Threshold NBCNews.com NEW YORK - Oil fell briefly below $30 a barrel on Tuesday, extending a relentless selloff that has wiped almost 20 percent off prices this year amid deepening concerns about fragile Chinese demand and the absence of output restraint. Wall Street closes strong; oil dips below $30 Banks Slash Oil-Price Forecasts Again Oil crashes to $30 a barrel |