Firefighters were called to a report of a smell of chemicals on an Elizabeth Line platform at Farringdon Station.
Crews attended and carried out a sweep of the area to check for no elevated readings of any chemical substances. No elevated readings were detected.
Fourteen people were treated at the scene with two of those people taken to hospital by London Ambulance Service as a precaution.
The Brigade was called at 0941 and Control Officers mobilised two fire engines, two fire rescue units and specialist officers to the scene. The scene was declared safe by 1135.