Billing Aquadrome bosses have launched an investigation over claims three holiday park residents had to be taken to hospital with suspected carbon monoxide poisoning.
East Midlands Ambulance Service was called to the caravan park off Crow Lane on Monday night.
A spokeswoman said: "We received a call at 23.38 on Monday to Billing Aquadrome where the caller reported three patients who required emergency treatment. We sent a paramedic in a car and an ambulance."
The condition of the three patients is not yet known.
Director of corporate affairs at Pure Leisure Group, which runs Billing Aquadrome, Trevor White, said: "We will investigate the claims that have been made fully and acsertain whether or not there was a problem."