Andrew unfortunately caused his own demise by driving erratically. His careless driving could have caused the deaths of those in the Citroën he collided with. Thankfully they survived. While their injuries weren't life-threatening or life changing, we don't know how this accident has impacted on their mental health.
The point is that the crash investigators stated that the cause of death was the tank moving forward (tipping), breaking through the bulkhead, deforming the driver's seat and crushing him against the steering wheel. They referred to the way the tank was secured with those ratchet straps that they used as inappropriate. It's this that we should be taking note of.
We don't know what the outcome would have been if the tank was the right tank and secured properly. You are right @PC , these crash tested systems are only tested to 30mph. I would have hoped that with better securing of the tank, Andrew's injuries wouldn't have been fatal.
I don't think much is stopping a ibc tote tank in a crash if its full. It's a thing I've never seen used up here tbh. Driving about with an ibc tank in the back of a small van is madness.