Police in Pontefract have asked parents to speak to their children after receiving reports of up to 50 children playing in quicksand like slurry pits at the former Prince of Wales Colliery site near Pontefract.
Officers have said they cannot overstate how dangerous the pits are and it could only be a matter of time before a life will be lost, if children continue to play in them.
Aside from the substantial risk of drowning, the dirty water and unsanitary conditions in the pits can pose significant health risks for those who enter them.
Other risks include the temperature of open water which can often by very cold, often not over 12 degrees. People suddenly entering cold water are susceptible to hyperventilation which could result in the body going into seizure and a person drowning as a result.
Sgt Jeff Dulson of the Wakefield East Neighbourhood Policing Team, said: “There have been reports of up to 50 children/youths from the age of around 10 upwards playing and swimming in the slurry pit and this is something which is of huge concern for us.
“The area is extremely dangerous - the pit itself is approximately 100 feet deep and many of the surrounding areas are in fact a thin crust of solid of solid material over further liquid slurry which would be impossible to swim out of.
“We all know that open water sources can look inviting to youngsters in the summer heat and that playing in any open water source is of course dangerous.
“The quicksand like nature of these pits make them even more hazardous however and impossible to get out of, no matter how strong a swimmer the trapped person is.”
Insp Geoff Carter, added: “Aside from the obvious, immediate danger, there are also clear health risks to young people from playing in this unsanitary water.
“I would ask that parents speak with their children and look out for signs they have been swimming in the slurry pit.
“Anyone doing so would come out filthy although there are signs that some are taking baby wipes and towels to clean themselves up with. “
Ian Bitcon, Area Manager for Fire Safety for West Yorkshire Fire and Rescue Service, said: “We reinforce the message of West Yorkshire Police. Around the county there are a number of former collieries which might seem like a great place to play however they can be highly dangerous with unexpected risks and hazards.”