In 2003 2 people died on a Shell offshore platform from exposure to butane and propane vapours from a flashing condensate. The formal cause of death was asphyxiation, however, there is evidence that at no point in time during the event the oxygen levels were below 19%, which should be survivable. Unknown to many in EP the vapours have an anesthetic effect through which people lose their judgment and after a short while become unconscious and stop breathing.
The attached presentation pack provides information on the above effect. Further guidance and an alert poster is under development by Shell EP.