A 15-year-old boy has died after being injured at a location in Woodhouses, Bishop Auckland.
He was treated for his injuries at Royal Victoria Infirmary, in Newcastle before he died.
Police are working alongside the Health and Safety Executive to establish the circumstances surrounding the incident.
A spokesperson for the North East Ambulance Service said they were called to the scene at 2:35pm on July 24 and dispatched an ambulance crew, a clinical team leader, and a rapid response paramedic.
They also requested support from the Great North Air Ambulance Service, and one patient was taken to hospital by road for further treatment.
Police are urging other parents to keep their children away from the area.
An investigation is ongoing to determine the cause of the incident.
