R.I.S
I am sure the difference is volatility. On a good day a large pool of Jet A will just sit and smell, AVGAS will be a serious danger. I wouldn't want to be anywhere near a 300 litre spillage. I once walked into a mist spray of JetA without thinking to turn off a petrol driven pump after a hose split. If that had been AVGAS I would be toast!!!!!