The fire service was called to the home on Main Street, East Kilbride, just after 11.20am on Monday, May 3.
One 52 -year-old man who was injured in the suspected explosion has been taken to Glasgow Royal Infirmary.
Police originally said two people had been injured, however have now said this information was incorrect and it is only one man who has been injured.
The man’s condition is not yet known.
A Police Scotland spokesperson said: “Around 11.25am on Monday, 3 May, 2021, police received a report of a suspected gas explosion in Main Street, East Kilbride.
"One man, aged 52 was injured and has been taken to the Glasgow Royal Infirmary.
"A number of people have been evacuated as a precaution from the surrounding buildings.
"Emergency services remain on the scene.
"We initially confirmed two people had been injured but that information was incorrect. Our apologies for any inconvenience."
Surrounding buildings have been evacuated as a precaution and Main Street has been closed.
Emergency Services remain at the scene.
One witness said that the window of the flat was blown 50 foot onto a footpath following the explosion.
A Scottish Fire and Rescue Service spokeswoman said: “We were alerted at 11.23am on Monday, May 3 to reports of a building on fire at Main Street, East Kilbride.
“Operations Control immediately mobilised six appliances and additional specialist rescue equipment to the three-storey tenement block.
“On arrival firefighters found the scene of a suspected gas explosion at a third floor flat.”