Arkansas Attorney General Dustin McDaniel requested that Exxon preserve documents related to the incident "for any future litigation" by Wednesday.
"The people of Arkansas deserve a full explanation from Exxon about how this incident occurred and the extent of damages to private property and to our state's natural resource," he said last week.
Exxon's 60-year old Pegasus oil pipeline ruptured in late March in Mayflower, Ark. The pipeline can carry Canadian crude oil, a type considered more toxic to the environment than conventional crude oil.
Around 5,000 barrels of oil were spilled from the pipeline, though Exxon said a final volume would be determined once the pipeline was repaired and refilled. The company is working to get the damaged section of the pipeline out of the ground for federal inspectors.
Exxon said 23 ducks, five turtles and a nutria, or river rat, died as a result of the spill. Fish in nearby waters weren't affected by the spill. The company said it was working on clean-up operations in a marsh area near the region's Lake Conway.
The cause of the rupture is under investigation.