GRANTS PASS, Ore. (AP) -- Another look at sediment behind dams on the Klamath River confirms earlier findings that there is not enough contamination to pose extra costs or a risk to public health if the dams are removed.

The U.S. Interior Department announced Thursday that a more thorough examination will be done.

But a preliminary analysis of samples from the river bottom show very low levels of contaminants left over from gold mining, farming and plywood manufacturing.

A 2006 study for the California State Coastal Conservancy found similar results.

The study was part of the Interior Department's assessment of whether it will be feasible to remove the dams as part of a landmark agreement to help salmon and end a century-old fight over water.

Copyright 2010 The AP.