STAFF at a pharmaceutical company have been evacuated after an unidentified substance leaked fumes in a laboratory

Fire crews from Brentwood, Orsett and Grays were called to Martindale Pharmaceuticals Ltd, in Hubert Road, Brentwood, at 11.40am today, Friday.

Three people are being treated by ambulance crews and the the East of England Ambulance Service' hazardous area response teem (HART).

Ambulance service spokesman Gary Sanderson said: "At present our crews are treating and assessing three patients who are all suffering with headaches after it is believed they have inhaled unknown fumes."

Martyn Hodder, incident commander, said firefighters wearing breathing apparatus and protective gloves are standing by awaiting confirmation of the chemical involved.

"Casualties are reporting dizziness and nausea," he said.