Air ambulance lands in Grays (file picture)
The air ambulance was scrambled after a man was found unconscious and not breathing at the Thames Complex.
A spokesman for the ambulance service said: "The East of England Ambulance Service NHS Trust (EEAST) received a call just after 5pm today to Orsett Road, Grays, to a report of a man who was found unconscious and not breathing.
"A community first responder, three response cars, ambulance crew and air ambulance from Essex and Herts Air Ambulance were dispatched.
"They treated a man, believed to be in his 30s, who was in cardiac arrest.
"Following treatment at the scene he was resuscitated and taken by land ambulance to Basildon and Thurrock Hospital in a critical condition."
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