One man has died and another has been seriously injured in an explosion at a recycling plant.
South Yorkshire Police said the men were injured when a waste incinerator exploded at Sterecycle, in Rotherham at 2.40pm on Tuesday.
A 42-year-old Rotherham man was airlifted to Leeds General Hospital but died later, police said.
A 50-year-old Barnsley man was taken to Sheffield's Northern General Hospital with serious, "potentially life-changing", head and body injuries. He is said to be in a stable condition.
A police spokesman said: "Emergency services were called to Sterecycle - a business close to Magna Science Adventure Centre - at 2.40pm after a waste incinerator exploded creating a hole in the side of the factory and causing damage to parked cars across the road."
The site on Sheffield Road is just off the M1 and officers closed the route from its junction with Bessemer Way to the motorway for about four hours.
The spokesman added: "Investigators from South Yorkshire Police and the Health and Safety Executive are currently at the scene with inquiries ongoing into the cause of the explosion."
A spokesman for South Yorkshire Fire and Rescue said four crews were sent and at least one of the injured men was brought out by firefighters. He said the crews had been stood down.
According the Sterecycle website, the plant is the world's first commercial autoclave waste treatment facility.
The firm said autoclaving is a process which involves the steam processing of "black bag waste" to recover recyclable material and organic residue which can used to make a biofuel.