The department's Energy Information Administration said 9,000 barrels of oil per day was exported from the United States to China in January. That was the first time oil was sent to China since 2005.
The EIA states that 35,000 bpd of crude oil was exported from the United States, on average, from 2003-12. It said that 98 percent of that was sent to Canada.
The U.S. Commerce Department's Bureau of Industry and Security says the export of crude oil is limited to Canada, those designated for the Strategic Petroleum Reserve, California heavy crude and foreign crude oil imported but not used in domestic refiners.
The EIA said it doesn't collect data on crude oil exports, leaving that responsibility to the U.S. Census Bureau, which is restricted in what it publishes. Small amounts of oil have left the United States to markets other than Canada, however.
The Energy Department said that January exports to China were from an undisclosed company that bought foreign crude oil but couldn't use it in the United States.
"The 9,000 bpd of oil that the United States exported to China in January 2013 was a rare event," the EIA said.