Update: 1600 hrs
Three ambulances, a rapid response vehicle and Essex and Herts Air Ambulance were called to an address in Grays to attend a report of a man in cardiac arrest.
One patient was transported to Basildon and Thurrock Hospital by road ambulance in a serious condition.
AN AIR ambulance has landed on Kilverts Field in Grays.
There are also a number of other emergency vehicles in the area.
YT has contacted the relevant media services for more information.