Methanol burns with an almost invisible flame, which can be monitored using a thermal imaging camera. The risk of extinguishing the fire is that there will be vapours of methanol coming from the puddle and likely the top-hatch. These vapours could potentially reignite from a distance and cause a flashback or uncontained vapour cloud explosion. If there are no lives at risk, strong consideration should be given to allowing the fire coming from the tank to continue to burn while deploying ground monitors (unmanned, fixed position hoses) to spray cooling water on the tank’s exterior. This would reduce the tank’s temperature and lower the vapour pressure inside, in turn decreasing the risk of mechanical failure. Using monitors enables evacuation of all personnel to a safe location.
Tom Johnson is an emergency responder at the National Chemical Emergency Centre