Police and firefighters are on the scene at a hospital in Doncaster following an alarm over a mystery substance this afternoon.
A witness described hearing a car window smash, followed by loud screams, near the entrance to the Women's Hospital at Doncaster Royal Infirmary at around 1.20pm.
She said two victims were taken into the hospital for treatment and armed police and the fire brigade had sealed off the area, where there was a 'funny smell'.
She added that spillages could be seen all over the car park for the Women's Hospital, surrounding the car which she said was parked only about two metres from the entrance.
It is understood the incident happened away from the hospital and the patients were driven there, with the commotion in the car park due to their haste to get out of the car.
The incident was initially feared by shocked witnesses to be an acid attack but a spokesman for the fire brigade said three people who presented themselves at the hospital had been tested and no traces of a harmful substance were found.
"It all happened really fast. I heard a car window smash and heard a lot of loud screams," said one woman who witnessed the car arrive at the hospital but asked not to be named.
"There was a funny smell for a while and it all people kept saying was that two people were injured because acid was poured all over them and was spilled all over the car park.
"The two victims were rushed straight into A&E and the fire brigade were almost straight on scene followed by the police."
David Purdue, chief operating officer at Doncaster and Bassetlaw Hospitals NHS Foundation Trust, said: "We are currently caring for patients who have presented to Doncaster Royal Infirmary’s Emergency Department following an incident with an unknown substance.
"As a precautionary measure we are working with our partners at South Yorkshire Fire and Rescue to follow correct decontamination procedures to ensure the safety of our patients, visitors and staff."
A spokesman for South Yorkshire Fire and Rescue said it was called to Doncaster Royal Infirmary at about 1.45pm to reports of people coming into contact with an unknown substance.
"We sent a crew with decontamination equipment but they found no chemical residue on the three people who presented themselves at the hospital. It appears to have been a false alarm," he added.
South Yorkshire Police have been contacted, and we will bring you more details as we get them.