The Environment Agency has confirmed that a suspected blue green algae outbreak at a village pond is toxic.
Visitors to the nature reserve in Ashby Ville, North Lincolnshire, must not go in or near the water, or let their dogs go in the water.
Since the outbreak was identified, council officers have put up warning signs and have been on site every day speaking to visitors about the dangers of going in the water.
There is now a warden on site, seven days a week, to speak to visitors about the dangers of swimming in the pond and the blue green algae.
Thankfully, the algae has been reducing at the pond but visitors are warned to stay vigilant and stay clear of the water.
Councillor Ralph Ogg, cabinet member for safer, greener and cleaner places, said: “As soon as we were made aware of what looks to be blue green algae in Ashby Ville pond we contacted the Environment Agency to investigate. Now that they have confirmed the strain is toxic, it is important that people and animals don’t come into contact with the water or enter the pond.
“Despite the warning signs and our officers on site speaking to visitors, we have still had people swimming in the pond at Ashby Ville. It is important that visitors do not go in the water.”