A suspected chemical leak at the Co-Operative in Raynes Park saw the area cordoned off by police to members of the public.
A fridge in the store in Grand Drive is believed to have leaked chemicals into the air on Sunday, July 20, when the shop was closed.
Crews from London Fire Brigade (LFB) and the police attended the scene where people gathered to see what the commotion was.
The building did not need to be evacuated and there were no reported injuries during the incident on Sunday, July 20 just after 4.30pm.
An LFB spokesperson said: "We were called to a shop in Grand Drive at the junction with Queen Mary Avenue at 4.37 on Sunday, July 20, to a suspected leak of chemicals from a fridge in the shop.
"The police put a cordon around the area.
"LFB stayed on the scene for half an hour."
A police spokesperson said they attended at 4.53pm to reports of a leak of refrigeration gas.
The area around the leak was cordoned off and the site was assessed to be safe, the spokesman said.
Police left the scene at 6.02pm.
The Co-Operative store has now re-opened.
A manager at the store declined to comment.