I'm not surprised to learn such a pathway exists, but I was surprised it was around in the 70s. And then I realised what you were probably talking about.

For what it's worth, I think I know how to make a directed energy weapon that could cause 50% probabilty of lethal effects that are only noticable hours afterwards (you could probably get a lethal shot even if you power it with a potato battery, too); and I realised a few years ago that when I was 9 years old I already knew enough basic chemistry to make a chemical weapon that could kill everyone on a London underground station. I'm neither a chemist nor a physicist, these are both things other people invented and I just saw a way they could be abused.

Despite that, I don't fear terrorists. They're demonstrably idiots, because it took them how long to realise that guns are highly effective tools for killing lots of people quickly? And then they decided to switch from guns to mimicing Carmageddon?

Edit:

Just to add, yes, I agree, ban it. All it takes is one, so the risk outweighs any benefit from encouraging more biologists.