A CHEMICAL incident at Fieldways Hotel and Health Club began inside the men’s sauna after a mystery 'ammonia-based liquid' was poured onto hot coals.

The complex was evacuated and five people were treated at the scene by South Western Ambulance on Tuesday afternoon in an incident fire services described as 'thankfully relatively minor'.

Ambulance services checked over and discharged victims suffering from headaches caused by exposure to the evaporated liquid containing ammonia.

Fire services and hazardous materials experts discovered the chemical incident was a result a plume of vapour containing the chemical often found in cleaning products escaping into the changing rooms from the sauna.

The coals were taken outside by the emergency services and further testing confirmed that they were the source of the incident.

Jason Moncreiff, a hazardous materials and items (HAZMAT) expert for Dorset & Wiltshire Fire Service, was at the facility on Hilperton Road, Trowbridge, as part of the team investigating the suspected chemical incident.

He said: “Using a chlorine detector we found that the levels of chlorine were in the acceptable range. However we did see a high concentration of ammonia. Our investigations found that the gent’s sauna was the source of this.

"Through a process of elimination we narrowed it down to the coals in the sauna. The coals have a heating element on them which heat the coals and warm the sauna.

“A person had put a liquid containing ammonia onto the coals which immediately vaporised and was very hot. That was the source of the cloud. People in the changing rooms suddenly felt it.

“It was a relatively minor incident thankfully.

“Any ideas about what the liquid could have been is pure speculation.”

A representative from Fieldways Hotel said: “All the people involved were tested by ambulance crews and given the all clear.

"The pool and sauna was closed yesterday as a precautionary measure and is reopened today.”

The incident was attended by two fire crews as well as two rapid response vehicles, one ambulance and a Hazardous Area Response Team

The hotel and health facility is now fully reopened.