The U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration issued a corrective action order to Exxon after a spill from its Pegasus oil pipeline in Mayflower, Ark.
The order prevents the company from restarting the pipeline until safety concerns are addressed. Exxon acknowledged the order and said it was developing an excavation and removal plan for the affected portion of the pipeline.
The PHMSA estimated at least 3,500 barrels of crude oil spilled from the pipeline. Exxon said more than 10,000 barrels of an oil and water mixture have been removed the site of the spill.
"Residual oil is being cleaned up through a combination of pressure washing, use of absorbent pads and removal of contaminated soil and vegetation," the company said.
Exxon said regional waterways remain oil-free and drinking water supplies are secure. A spokesman for Arkansas Central Water told local broadcaster KTHV that the pipeline runs within 600 feet of Lake Maumelle, a drinking water source. He said the only way to eliminate the risk of oil contamination is to get rid of the pipeline.