Drug Rehabilitation that works

I’m doing a project on methamphetamine, and I need to know why the household labs potentially explode. What is the chemical reaction(s) that are the cause of the explosion?

The way I see it, drinking alcohol is a choice because you are voluntarily putting it into your body and you have the choice NOT to do it. Being predisposed to it does not make it an involuntary act. I am predisposed to gaining weight and eating, I do what I can to eat right.

Out of curiosity.
The way I see it, genetics may predispose a person to drink as much at it predisposes some people to over eat like myself. Yet I choose to limit my food intake and the same for a person to drink. I feel it’s about responsibility and choice. I don’t understand having a lack of responsibility and the choice of making the wrong decision is considered a full blown disease.