I assure you that you did not need an LLM to engage in, ahem, risky shenanigans, much before all this AI was ever a thing.
Sincerely, a former engineering student.
(Put another way - extracting for eg meth - or any such "dangerous"/illicit thing is stupidly easy for any engineering graduate who actually paid attention to their coursework. Hell, there are/were forums on one of the biggest red-colored, YC associated social media platforms that would tell you the steps for personal usage of these things.)
Do note that I'm not condoning lowering the bar. I'm merely pointing out that the bar was already quite low, and the current position of the bar is a small incremental change to anyone who actually knew where the bar truly lay to begin with.
I don't doubt it. Bleach + ammonia is something anyone can make.
But I rather suspect there are improvements to be made in the realm that are a lot easier than building a uranium enrichment centrifuge hall under a mountain.