Russell Hulstine, NewsOn6.com

KEYSTONE LAKE, Oklahoma -- Good news for swimmers and boaters on Keystone Lake. The U.S. Army Corps of Engineers says based on recent tests, all blue-green algae closures, warnings and advisories at Keystone Lake have been lifted.

The Corps of Engineers collected water samples at Keystone Lake on September 21, 2011 and after analysis, results show that blue-green algae levels have dropped below the advisory level at the lake.

A warning is still in effect for Burnt Cabin and Petit Bay on Tenkiller Lake and an advisory is still in effect for all of Eufaula Lake.