A waterpark was evacuated by police as two people were taken to hospital and dozens of others treated on site after reports visitors suffered irritated eyes and nausea.
Emergency services were called to Waterworld in Stoke on Trent before 110 people were evacuated, with 46 being treated at the scene and a further two needing hospital treatment.
West Midlands Ambulance Service said in a statement: "Two ambulances, Hazardous Area Response Team (HART) paramedics, four paramedic officers, a BASICS emergency doctor and the Midlands Air Ambulance from Cosford with a doctor and critical care paramedic on board attended the scene.
“Waterworld was evacuated after a number of people inside began displaying minor symptoms including watery eyes, a runny nose and nausea.
"A total of 110 people evacuated from the building who were displaying symptoms were rapidly triaged by the team of ambulance medics.
"Once triaged, 46 out of the 110 people received treatment by ambulance staff on scene before being discharged.
"A man and a woman were conveyed to hospital for further checks as a precaution.
“This was a well-managed tri-service response which saw the safe and speedy evacuation of a large number of people.
"Thankfully no one involved was in a serious condition. Investigations into the cause of the incident continue.”
A Staffordshire Police spokeswoman told the Mirror: "We were called at 2pm today (Wednesday 8 June) by colleagues from the ambulance service to a report of guests feeling unwell at a waterpark in Etruria.
"Officers are currently at the scene alongside colleagues from the West Midlands Ambulance Service and Staffordshire Fire and Rescue Service.
"The building has been evacuated as a precaution.
"A road closure has also been put in place on Festival Way to allow access for the emergency service response vehicles."
Staffordshire Fire and Rescue spokeswoman added: "We were called to the waterpark in Etruria at 2pm this afternoon (Wednesday 8 June) following reports of guests feeling unwell.
"A number of crews are currently in attendance and carrying out an assessment with support from the Detection, Identification and Monitoring Team."
Potteries buses tweeted: "Due to a spillage near Waterworld on Festival Park, services 4/4A avoiding Festival Park due to no suitable diversion.
"No stops served between Octagon Centre Etruria Rd & Forge Ln. Passengers waiting on Festival Park/Bet365 advised to wait at the stops on the A53 or Etruria Rd."
The water park, which opened in 1989, attracts around 400,000 visitors each year and boasts three pools and 20 slides.
