(CNN) -- Arkansas is opening an investigation into what caused last week's pipeline rupture that allowed thousands of barrels of heavy crude oil to flow into a community in the middle of the state.
Attorney General Dustin McDaniel said Tuesday he asked Exxon Mobil, the owner of the 60-year-old Pegasus pipeline, to preserve all documents and information related to the spill and cleanup efforts.
"This incident has damaged private property and Arkansas's natural resources. Homeowners have been forced from their homes as a result of this spill," McDaniel said in a news release Tuesday. "Requesting that Exxon secure these documents and data is the first step in determining what happened and preserving evidence for any future litigation."
About two dozen homes in Mayflower, Arkansas, were evacuated last week as the crude oil, which originated in Canada and was bound for Gulf Coast refineries, crawled through yards and down streets. The evacuation could last for several more days as crews work to clean the spill.
The oil began spilling Friday from a 2- or 3-inch gash in the Pegasus pipeline, which carries Canadian crude from Illinois to Texas, a state transportation engineer said.
Exxon Mobil, which owns the 60-year-old pipeline, met with displaced residents over the weekend to explain how they can make claims for losses. "If you have been harmed by this spill then we're going to look at how to make that right," Exxon Mobil Pipeline Co. President Gary Pruessing told them.
Resident Darren Hale complained to CNN affiliate KHTV on Saturday that being forced to leave his home was frustrating.
"I've heard three contradictory answers as to when I will be able to go back home," Hale said. He was first told it would be two days, but later that it would be up to two weeks, he said.
An around-the-clock cleanup operation began Saturday, with workers scrubbing streets and driveways in the Northwood subdivision, CNN affiliate KATV reported.
None of the estimated 12,000 barrels of oil that spilled has made it to nearby Lake Conway, a local drinking water source, Faulkner County Judge Allen Dodson told KATV Sunday said.
The Pegasus pipeline, which could carry up to 90,000 barrels of crude each day, was built more than 60 years ago, an Exxon Mobil spokesman said. Leaks are not uncommon, but the company's recent inspections showed no red flags for this section, he told KARK.