Police have appealed for help finding three people are a gas canister was set of inside a branch of McDonald’s.
Police, fire crews and paramedics attended the scene following the incident at a restaurant in Eccleshall Road in Stafford on Monday evening.
Ambulance workers assessed 12 people at the scene, including three who were judged to be suffering minor breathing difficulties, while the McDonald's was temporarily evacuated.
An investigation by Staffordshire Police established no evidence of any noxious substances contained within the canister.
But police still wanted to speak to three people seen leaving the scene at around 8.30pm, after the incident saw at least two people taken to hospital.
Staffordshire Police said in a statement: “Colleagues from Staffordshire Fire and Rescue Service have completed their investigation into this incident and there are no noxious substances in the building or surrounding area.
“Officers from Staffordshire Police are now carrying out inquiries at the scene, including obtaining CCTV evidence, to establish the background to this incident.”
