UPDATED THURSDAY — A blue-green algae warning in effect since June 4 for Marion Reservoir was extended for another week Thursday.

A similar alert for Marion County Lake, which had been under a warning for the past week, was downgraded to a less-serious watch.

The new advisories, which are likely to close swimming beaches at the reservoir, will remain in effect until June 24.

Contact with lake and reservoir water should be avoided, the Kansas Department of Health and Environment said in announcing the alerts. Visitors whose skin contacts the water should rinse with fresh water as soon as possible afterward.

Humans and pets should not drink lake water nor eat dried algae. Fish taken remain safe to eat but only after being rinsed with fresh water and all but the filet portion is discarded.

Swimming and skiing are discouraged, especially near algae blooms. Some boaters may experience difficulty if they inhale spray.

When they are crushed or die, blue-green algae release invisible toxins that can cause anything from mild skin irritation to potentially fatal neurological damage.

Municipal water supplies remain safe. Treatment plants in Marion and Hillsboro have special equipment, not always available at other water treatment plants, that neutralize algae toxins.

Current advisories are scheduled to be updated July 1.