Paramedics confirmed 33 adults and six children were treated at Alton Towers after guests and staff complained about irritation to their eyes and throat.
Police, firefighters, the air ambulance, and West Midlands Ambulance Service crews raced to the North Staffordshire tourist attraction shortly before 2pm today (March 2).
The Waterpark had to close as a result of the incident.
“We sent a number of resources, including the Midlands Air Ambulance from Cosford, three paramedic officers and an ambulance to the scene. Crews assessed 39 patients (33 adults and 6 children) who were all later discharged at the scene.”
Alton Towers was forced to close the popular attraction as its guests sought medical attention.
A spokesman said: “At around 1 o’clock today we took the decision to close the Waterpark after a small number of people reported irritation of the eyes and throat.
“The Fire Brigade, WMAS and Staffordshire Police attended the resort, as is standard for any site where chemicals are used.
“Thirty-nine people, including 6 children, were assessed by medical staff but all have been discharged with no treatment required.
“We are helping the Fire Brigade with their ongoing investigation.”
Staffordshire Fire and Rescue Service confirmed crews from Leek, Cheadle, and Uttoxeter attended the scene.
A spokesman said: “Staffordshire Fire and Rescue Service were called to the waterpark at Alton Towers Resort at 1.50pm this afternoon (Monday 2 March) following reports of staff and guests with irritation to the eyes and throat.”
Police officers confirmed they remain at the scene.