EPA: Oil spill probe to begin after cleanup

The investigation into an oil spill in the Des Plaines River in suburban Chicago will begin later this week, after the mess is cleaned up, the U.S. Environmental Protection Agency said Monday.

About 65,000 gallons of waste oil overflowed from two holding pits at a Caterpillar plant in Rockdale, near Joliet, early Sunday after a pump failed. Most spilled onto the ground, but about 6,000 gallons ran down an embankment and into the river, where it moved for about three miles.

Although environmental damage appeared to be minimal, the U.S. Fish and Wildlife Service and state officials were conducting a comprehensive assessment of the riverbank to determine if waterfowl or aquatic life were harmed, said EPA spokesman Mick Hans.

Meanwhile, high-powered vacuum trucks collected oil from the ground and booms kept oil from moving farther down river. The cleanup was expected to last through Wednesday or Thursday, Hans said.

It was not immediately clear how long the pits overflowed before a security guard reported the accident Sunday morning, EPA and Caterpillar officials said. Caterpillar spokeswoman Kate Kenny said it began overnight Saturday.

The pits, about 100 feet from the river, were not surrounded by a backup containment system, such as an earthen berm, but it was not immediately clear if it was required, said Jim Mitchell, the EPA official managing the federal response and cleanup.

Once the cleanup and shoreline assessment are completed, "then the investigation will soon follow," Mitchell said. That will include determining if the company's spill-containment plan was adequate, he said.

The spill was relatively moderate, and no heavy pools of oil appeared to collect in the river, Mitchell said.

The river reopened to barge traffic Monday afternoon.

The Rockland plant makes hydraulic components for Caterpillar's earth movers, Kenny said.