Two thugs may have blinded a man after hurling a noxious substance at him.
Police said the unprovoked attack happened near a woodland in St Helens, Merseyside, at around 9.20pm last night.
The yobs remain on the loose, Merseyside Police added.
It is suspected substance may have been acid, Radio City News says.
They are described as being in their mid 20s and white. They were both wearing bubble jackets.
A spokesman for the police force said: "We are appealing for information after a man had a substance thrown at him as he stood by his car in St Helens yesterday evening.
"At around 9.20pm, the man was stood by his car on Milton Street, Sutton Manor when two males in bubble jackets threw a substance in his face.
"The man suffered breathing difficulties and extreme irritation to his eyes and he has been taken to hospital where he was treated.
"Early indications from medical staff are that the victim could potentially lose his sight."
House-to-house enquiries are being carried out in the area.
CCTV footage is being examined to try to snag the offenders.
Detective Inspector Lisa Ryan said: "This was an unprovoked attack and enquiries are ongoing to establish the full circumstances in relation to the incident.
"The investigation is in the very early stages and we are working to determine what was thrown at the victim.
"I would appeal to anyone who was in the area of Milton Street who may have witnessed the incident, or two men in bubble jackets acting suspiciously in the area before or after the incident to get in touch @MerPolCC quoting 19100174832."
