Emergency services were called to a McDonald’s restaurant in Crawley after an unknown substance was reportedly sprayed inside the premises.
Police and ambulance crews responded to the restaurant in Haslett Avenue West shortly after 1pm on Friday.
The area was initially cordoned off as a precaution while emergency services assessed the incident.
The cordon was quickly stood down after it was established that there were no significant health concerns and no serious injuries had been reported.
Two people were checked by ambulance staff but are not believed to have suffered any lasting injury.
Police rule out reported ‘acid attack’
Police have also moved to reassure the public following claims circulating on social media suggesting an acid attack had taken place.

Officers confirmed those reports were incorrect.
Police said: “We are aware of reports circulating on social media of a suspected ‘acid attack’ and we would like to reassure the public that this is not the case.”
The nature of the substance reportedly sprayed inside the restaurant has not been confirmed.