In a bad day for oil producers, prices fell by around 5% to fall below $50.
The Organization of the Petroleum Exporting Countries (OPEC) agreed to cut oil production late last year, in an attempt to shore up prices.
They are due to meet again later this month and are expected to extend the production cuts for a further six months.
However, with US shale and oil from non-OPEC nations now forming the most important elements of the market, the slide in the oil price could readily continue.
"It is dangerous to try and pick a bottom in this type of market, it is like trying to catch a falling knife," said Dean Rogers, senior technical analyst at Kase & Company.