Word around the North Cascades Institute is that there was a small spill of transmission fluid into Diablo Lake, way up the Skagit River.

The spill apparently occurred on June 18. Seattle City Light closed the lake to swimmers and boaters for a few days while cleanup crews worked.

Anacortes' drinking water comes from the Skagit River, miles downriver from Diablo Lake.

Then, Seattle City Light closed it again this weekend, telling the Institute, which operates an Environmental Learning Center at the lake that they had found new pockets of the spill and needed to close the lake again. Crews from NRC Environmental Services were working on the lake this weekend.

Update: The National Park Service issued a warning: "The oil from this leak contains low-level of PCBs.  While the risk is minimal, visitors to the area are advised to avoid contact with any oil sheen and the containment booms that are in place."

While the lake remained closed to the Institute students, guests and staff, Seattle City Light apparently continued to operate their summer boat tours and the Ross Lake Resort shuttle boat operated.

There were rumors around the Institute that an employee resigned over the spill, but I haven't been able to confirm that.

 The Institute operates environmental-oriented classes and sessions. I was there taking part in a regular weekend session.