A very in-depth article about the history of meth and how it is currently a scourge for the homeless, and soon to be homeless. Definitely worth a read. It is the Atlantic, and you are limited on articles, unless you are a subscriber.

Hundreds of those bags contained a substance neither Bozenko nor Toske had ever thought could be used to make P2P. Bozenko often consulted a book that outlined chemicals that might serve as precursors to making methamphetamine, but this particular substance wasn’t in it. Well-trained organic chemists were clearly improvising new ways to make the ingredients, expanding potential supply even further.

Working through all the chemicals in the plant, by Bozenko’s estimation, the lab could have produced 900 metric tons of methamphetamine. Against a wall stood three 1,000-liter reactors, two stories tall.
Nothing like this had been achieved with ephedrine, nor could it have been; no one could have imagined the accumulation of 900 metric tons of the chemical. Later, Mexican investigators would report that of the 16 workers arrested at the Querétaro lab, 14 died over the next six months from liver failure—presumably caused by exposure to chemicals at the lab.

Methamphetamine was having a cultural moment in the U.S.—“meth mouth” had become an object of can’t-look-away fascination on the internet, and Breaking Bad was big. The switch from ephedrine-based labs to ones using the P2P method was even a plot point in the series. But few people outside the DEA really understood the consequences of this shift. Soon, tons of P2P meth were moving north, without any letup, and the price of meth collapsed. But there was more to the story than higher volume. Ephedrine meth tended to damage people gradually, over years. With the switchover to P2P meth, that damage seemed to accelerate, especially damage to the brain.

update: I am still reading the article, but what stands out is that the new meth is even more toxic to the brain, and instead of wasting away usually over a period of months or years, not weeks. That current meth use goes hand in hand with the increase use of fentanyl. Scary stuff.
and lastly:

The spread of P2P meth is part of a larger narrative—a shift in drug supply from plant-based drugs such as marijuana, cocaine, and heroin to synthetic drugs, which can be made anywhere, quickly, cheaply, and year-round. Underground chemists are continually seeking to develop more potent and addictive varieties of them. The use of mind-altering substances by humans is age-old, but we have entered a new era.