Ammonia when in liquid form is confined (trapped) and heat is applied to the chemical it will build pressures at least 100 PSI per degree of F exposure, thus creating hydraulic pressure. Relief protection can stop the hazard, unfortunately it doesn’t look like this facility consider this engineering solution.
Below is a picture link to short video of the aftermath of the accident
[youtube]https://www.youtube.com/watch?v=VRlxKCiikL4[/youtube]
