Cordon in place at back of building in Wimborne Road

Emergency services cordoned off the BT building, next to Poole Police Station, Wimborne Road, after the alarm was raised around 8am.

Casualties were treated by paramedics at the scene, and three workers - who complained of feeling unwell - were taken to hospital.

Picture by Daniel Cunningham

Ambulance workers said their conditions were “not thought to be serious.”

According to BT, the incident was sparked by a small reaction between two chemicals.

Subsequent investigations, by a Dorset & Wiltshire Fire and Rescue Service’s hazardous materials advisor found the cause to be testing gas.

A fire service spokesman said: “The ambulance service passed a call to fire control regarding the potential smell of gas at premises in Wimborne Road. A crew from Poole was mobilised to the scene to investigate. 

“Following a request from this crew, a second crew - Redhill who were on standby at Poole fire station - was then mobilised to assist. 

“A hazardous materials advisor was also sent to the incident. 

“Following a thorough investigation, the cause was found to be a testing gas. 

“The building was monitored and ventilated, and the ambulance service transported three casualties to hospital.”

BT workers on site declined to comment.

However, a BT spokesman thanked emergency services for attending the building.

They added: “The site is now open as normal and the incident closed.

"Three BT employees have been taken to hospital as a precaution after breathing in fumes from the hazardous substance but their condition is not thought to be serious.

“At no point were any phone or broadband services affected.”

Meanwhile, a South Western Ambulance Service spokesman confirmed: “We understand there was a release of a small volume of gas at this location. 

“We attended with two ambulances and an operations officer. Three patients were taken to Poole Hospital because of suspected exposure to gas.

“They were said not to be feeling too well, but their conditions were not thought to be serious.”

Iona Edgar, who lives opposite, said: “It was very busy with people checking things over and wandering around and there were firefighters with face masks on who had come out of the building.”