ELIZABETH JACKSON: Professor Priyan Mendis is the head of Civil Engineering at the University of Melbourne. He's also written extensively about explosive devices and buildings.
I asked Professor Mendis whether he was surprised that the fertiliser plant in Texas was located so close to a residential area.
PRIYAN MENDIS: Yes, it is, but as long they are careful and they have analysed the effects - in this case we can clearly see that they haven't done that so yes, I was surprised.
ELIZABETH JACKSON: If this is an industrial accident, what do you think is the most likely cause?
PRIYAN MENDIS: Now actually in fact the reports are coming in. It looks like first of all there was a small fire, which triggered this explosion. Now all these ammonia based explosions needs triggers so looks like the fire is the trigger.
ELIZABETH JACKSON: What sort of safety regulations usually apply? Are buildings that house these types of chemicals built in a special way to withstand the pressure of an explosion?
PRIYAN MENDIS: That is a very good question and it's about because in a confined space these events get really magnified. We saw that in that explosion underground train stations in London so these confined blasts are really dangerous but these buildings can be designed for that.
These days we have the tools to design these buildings.
ELIZABETH JACKSON: So an open plan is what's needed?
PRIYAN MENDIS: Actually it is not the solution because it had to be stored inside but the building can be strengthened to really take these very large loads. It's not easy because we are talking about for example if the wind blowed, maybe pressure let's say a value of two, this could be thousands and thousands so it will be hard to design but it can be done.
ELIZABETH JACKSON: Does it look to you as though the buildings in Texas were especially designed to house these types of chemicals?
PRIYAN MENDIS: I'm really surprised, I don't think so. The reason is that of course there is a fire as well and big explosions but these days you can really restrict that damage and maybe these plants were built a long time back.
I know I did an interview today, we are talking about another fertiliser plant in Australian which had been built more than 50 years back so at that time maybe, I'm sure the rules would have been different.
ELIZABETH JACKSON: So do you think that the damage could have been minimised had the buildings been a better structure?
PRIYAN MENDIS: That is right but also we call it the stand-off distance. Once we do this analysis we can say right now locate the buildings further away. We can really predict some distances where the buildings could be located. Now the other point here is that we are talking about a very big blast. This is about, the first reports are saying about 2,500 tonnes of like material. This can be really dangerous but up to a certain extent it can be designed for.
ELIZABETH JACKSON: Now you mentioned plants in Australia a little earlier. Do we have similar plants to this one here in Australia?
PRIYAN MENDIS: My, in fact I haven't studied all of them but my thinking is that the storage may not be as large as this Texas plant, but we know that there are fertiliser plants in Australia close to residential areas so we have to be really carefully analyse all of them.
ELIZABETH JACKSON: Do you think that perhaps it would be timely to look at those plants and perhaps relocate some of them if necessary?
PRIYAN MENDIS: There is two sides. Now of course there is a risk in anything because this material even event could happen when they are transported. So relocation sometimes is essential but if they are carefully analysed then predict these stand-off distances, that is a distance, the safe distance then of course relocation may not be necessary.
ELIZABETH JACKSON: Are you satisfied that in Australia at the current time that our safety regulations make our fertiliser plants as safe as they can be?
PRIYAN MENDIS: Even I am not 100 per cent sure but I have a feeling. After Bali bombing in 2012 we basically did a lot of analysis. We analysed our critical infrastructure, we thought now what would happen if there's an event in cities but then of course, we are a bit complacent now. We are thinking that these events are not going to happen in Australia, but I wouldn't be surprised if we have not analysed all of those fertiliser plants and so on for possible explosions.
ELIZABETH JACKSON: So you think that perhaps it could be timely for some work to be done.
PRIYAN MENDIS: Correct, yes. I think it is essential and we need to really study very carefully.