PHOTOS: 20 years of blue-green algae at lake

THERE are fears of a blue-green algae outbreak at Lake Ainsworth at Lennox Head, after dozens of people reported vomiting and illness after swimming at the lake over the weekend.

But it's not the first time this has happened.

In fact, Ballina Shire Council's 2002 management plan for the lake explains it has been a problem for more than 20 years.

"In January 1994, an outbreak of Oscillatoria occurred, and outbreaks of Anabaena and Microcystis occurred in the spring and summer of 1995-96," the report states.

"These latter blooms resulted in the erection of warning signs by council advising water users of the potential human health problems caused by algal blooms."