NEBRASKA CITY, Neb. (AP) — Authorities in eastern Nebraska say they are searching for whoever stole grease from a Burger King and accidentally spilled it across 16 city blocks.

Nebraska City Public Properties Director Dan Giittinger tells the Lincoln Journal Star (http://bit.ly/1v6qGwM ) the theft happened early Monday. He says someone pumped grease left over from cooking fried foods from a tap on the side of the building but forgot to close a valve on the tank.

Giittinger says city workers laid down a claylike material to soak up the grease. He says the cleanup cost the city about $1,000 and 14 hours of labor.

Nebraska City Police are reviewing surveillance footage.

Authorities believe the thief planned to sell the used oil to companies making biodiesel fuel or livestock feed.