The ambulance service has confirmed four people were taken to hospital last night following a chemical leak in Maidstone. Police are still at the scene this morning.

Almost 50 people were assessed and treated for carbon monoxide poisioning after emergency services were called to an industrial estate near Rumwood Green Farm off Sutton Road, Langley just before 3pm.

Three people were taken to Maidstone Hospital and one was taken to Tunbridge Wells Hospital at Pembury.

More than 40 firefighters were at the scene and worked into the night working with hazardous material officers to make the site safe. They cleared the scene at around 2am.

Earlier two minibuses ferried staff from Charltons Farm, wrapped in foil blankets, to a temporary rest centre set up by Maidstone council at Maidstone Leisure Centre. The council said it gave shelter to 45 people, but they were all allowed home later that night.

Kent Fire and Rescue have confirmed all those treated were staff at Charltons Farm and the leak did not affect any other businesses in the area.

Chris Stamp, the strategic commander overseeing the ambulance service's response said: “This has been a protracted incident, involving large numbers of patients. To date, four patients have been transported by our crews to hospital – one to Tunbridge Wells Hospital at Pembury and more recently, three to Maidstone Hospital.

“I would like to offer my sympathy to those affected and to reassure the public that the trust implemented well-rehearsed plans in response to this incident.

“We are continuing to work with our emergency service and local authority partners to care for patients who have now been transferred to a rest centre, which includes a significant welfare and treatment plan for those unfortunately affected.

“I would like to extend my thanks and praise to all of the staff involved for their hard work and commitment during this incident.”

The fire service confirmed the incident had been contained to the site.

A spokesman for Maidstone and Tunbridge Wells NHS Trust said: “As a precautionary measure a hazardous materials tent has been erected outside the emergency department to help us manage patients.

“While our Emergency Departments are open as normal, we would encourage people to only use our EDs for emergency and life-threatening situations during this period to help us focus our resources on those who need it most.”

This morning a spokesman for Kent Fire and Rescue said: “Initial indications suggested those experiencing breathing difficulties may have been exposed to carbon monoxide, and symptoms displayed were conducive with exposure to this gas. Paramedics treated patients accordingly in line with this and the condition of those affected improved as a result of treatment.

“Fire and Rescue Service operations concluded at the site just before 2am today, and a Health and Safety Executive investigation will now begin.”

This morning a spokesperson for Maidstone and Tunbridge Wells NHS Trust said that the three patients it had treated had all been discharged overnight."

“Following further assessments all three patients were discharged later that night.”

A spokeswoman from the Health and Safety Executive said they are still making initial inquiries and liasing with police.

Sean Charlton, the owner of Charlton Farms, a fruit packing business, said he was expecting a visit from the Health and Safety Executive this morning and declined to comment until after they had been.

Read more: All the latest news from Maidstone