I've looked at several newspaper articles and seen warning signs about the blue green algae. However scientific advice is somewhat varied and the BBC came up with this one recently: Toxic algae has been discovered at a fishing lake in Wrexham. Natural Resources Wales detected the blue-green algae following tests at Acton Park lake. Wrexham council has advised people to stay clear of the water as it can be harmful to humans and animals if swallowed or if it comes into contact with the skin. The algae is naturally occurring, usually during periods of calm, warm weather. Toxins produced by blue-green algae can cause skin rashes, nausea, vomiting, stomach pains, fever and headaches. But nowhere does it say that these problems can occur almost instantly. Being an old gravel pit the water could be very deep and still possibly cold enough in the middle to cause these fatalities? Whatever, this was indeed a tragedy and our feelings and sympathy go out to the two families concerned. What a brave and heroic girl she was to try to help her younger cousin.