The Washington Department of Natural Resources has turned down a request by the Pacific Northwest National Laboratory to drill a well to inject carbon dioxide in Wallula for an experiment in carbon sequestration.

A June 5 letter to the lab says public outcry from residents in Walla Walla County and a potential threat of litigation kept the department from approving the project.

The proposed experiment would have helped scientists verify laboratory tests that show basalt can help mineralize carbon dioxide into calcium carbonate.