Weaker earnings from Bank of America and other companies also pushed the market lower.
Crude dropped another $2 to $87 a barrel, the lowest price since December, as expectations for global demand weaken. Chevron dropped 2 per cent.
Bank of America fell 4 per cent after reporting earnings that fell short of analysts' expectations.
The Dow Jones Industrial average was down 144 points, or 1 per cent, to 14,610 as of noon Wednesday.
Other indexes fell even more.
The Standard & Poor's 500 dropped 24 points, or 1.5 per cent, to 1,550. The Nasdaq fell 63 points, or 1.9 per cent, to 3,201, weighed down by a 5 per cent slump in Apple.