News Health Unit advises residents of blue-green algae SHARE ON: Smith Autumn, contributor, Tuesday, Jul. 8th, 2014 Reports of blue-green algae in Central Ontario waterways are becoming more common, according to the Haliburton Kawartha Pine Ridge District Health Unit. With hotter weather, the health unit is reminding people that algae will collect in fresh water lakes, bays and inlets. Many forms of blue-green algae are harmless, but some do produce toxins that can be harmful especially to children. To learn more about it and how to identify it, click here.