A Norfolk village was brought to a standstill today when an agricultural worker walked into a medical practice after being contaminated with a toxic chemical.

Staff at a medical practice and the emergency services were praised for their quick actions after a farm worker triggered a major chemical alert.

The man walked into the East Harling Surgery, near Thetford, at about 11am today after coming into contact with a toxic pest-control substance.

Fears were raised that patients and staff at the practice had also been contaminated by the aluminium phosphide and 35 people were contained in the building.

The farm worker, who was complaining of respiratory problems and was taken to hospital for monitoring, was also isolated by medical staff.

Paramedics, fire crews from Thetford, East Harling, Attleborough, a chemical incident support unit from Sprowston and an NHS Hazardous Area Response Team from Cambridgeshire attended, which closed the main road through the village for more than two hours. The Norfolk and Norwich University Hospital was also placed on major incident standby.

However, the emergency services deemed that the 35 patients and practice staff did not need decontamination treatment after it emerged that the toxic chemical, used for controlling rodent numbers, had been spilled as a gas and not in its more dangerous powder form.

Paul Bassett, emergency operations general manager for the East of England Ambulance Service, said the chemical could cause death if ingested, but the incident was not as serious as first thought.

Jonathan Wilby, station manager at Thetford fire station, added: 'It may look over the top, but we were following procedure. People were not in immediate danger and we wanted to make sure people were reassured and were given the best advice from us and the emergency services. The doctors' surgery did exactly the right thing and isolated the man from the public and held him in a contained area.'

GP Andrew Hayward from the East Harling Surgery, which reopened at 1pm, said the incident was 'out of the blue' and their emergency procedures had worked well.