A suspected chemical leak has left 45 people suffering the effects of carbon monoxide exposure.
Kent Fire and Rescue Service were called to a suspected chemical leak in Sutton Road, Langley, near Maidstone, at around 2.20pm.
South East Coast Ambulance Service, which also responded to the incident, said crews were treating 45 people for carbon monoxide exposure.
None are in a serious condition and one person was being taken to hospital for further assessment.
Five fire engines, hazardous material officers and a specialist chemical unit are in attendance.
More than 40 firefighters are at the scene. Emergency services say the suspected chemical leak is "contained to the site".
Earlier reports said 57 people were treated.
Fire crews wearing breathing apparatus, alongside hazardous material officers, are working to establish what the chemical is.
A Kent Fire and Rescue Service spokesman confirmed: "It is believed those being treated have experienced exposure to carbon monoxide."