Origin of oil spill in Chicago River remains mystery

CHICAGO -- The EPA continues to investigate the cause of an oil spill on the South Branch of the Chicago River.

Crews have worked to clean it up and contain it since a black sheen was first spotted last week.

They are using booms and absorbent pads and pyrotechnics to try to scare birds away from this area. One dead Canada goose was recovered today.

Officials with the U.S. Fish and Wildlife service say they can see birds that have oil on their feathers but they're having a hard time catching them. They were only able to catch one goose and also a turtle that were covered in oil. They'll eventually be taken to Flint Creek Wildlife Rehab for decontamination.

The EPA believes this spill started on Wednesday stretchingaAbout a mile long through Bubbly Creek and west along the Chicago River to California Ave.

EPA officials say they sent out samples to try to determine what kind of oil it is.  They're not sure how much oil spilled.

The EPA also says they expect to be cleaning up for at least a week. In the meantime, Bubbly Creek is closed.