An investigation is under way after a chemical spill at a Dartford industrial estate.

Seventeen people were admitted to hospital after breathing in ammonia fumes on Friday at courier company Yodel in Bridge Close.

Firefighters from Dartford's station, two crews from Thames-side and two from Medway were called to Crossways Business Park at about 7.45am.

It is thought two litres of ammonia were spilt at courier company Yodel, in Bridge Close.

Ambulance crews and a hazardous area response team were called to the scene by firefighters amid concerns people were suffering from chemical inhalation.

Twenty employees were checked at the scene, with 17 of them taken to hospital for further checks.

Seven people were treated at Darent Valley Hospital, Dartford, five went to Medway Maritime Hospital and five to the Princess Royal in Bromley.

Yodel spokeswoman Teresa Bianchi said: "Two people stayed in hospital over night but they went home on Saturday.

"An investigation is taking place and we are absolutely looking into it.

"We are working with the local authorities to prevent it happening again.

"It is too early to say what happened and it is too early to say what action has been taken."

Darent Valley Hospital spokesman Glyn Oakley said the hospital's emergency tent was set up outside the entrance so the workers could be decontaminated first before heading into A&E.

Speaking shortly after the incident, he added: "The indications are that their conditions are not life threatening, but the exposure has caused chest and respiratory complaints.

The hospital got the first call about the incident at 8.30am and was immediately put on alert for a major incident, although this was later cancelled.

Mr Oakley added: "Once the seven got into the emergency tent they were able to wash themselves down and remove any traces of the chemical.

"The tent is really a precaution to de-contaminate, so that other patients don't get exposed to chemicals in A&E."

Exposure to ammonia in the air can cause eye and skin irritation to severe injury, burns and blindness depending on its strength. It can cause people to have problems breathing.

A South East Coast Ambulance Service spokesman said: "Approximately 20 people have been checked and treated by SECAmb at the scene and people have been taken to hospital for further checks.

"None of the patients were believed to be in a life-threatening condition."

A spokesman for Yodel added: "We are working closely with local fire crews to deal with an incident at our Dartford site.

"We take this matter very seriously and are doing everything we can to ensure the health and safety of our employees and local residents."

Are you or is anyone you know affected? Leave your comments below or phone the newsroom on 01474 564327.