I'd love to ban it, because...

I'd stock up (like 5 railcars' worth) just before the ban. It's actually pretty cheap, ya'know...

After about 48 hrs or so, all those dihydrogen monoxide addicts (they'd die without, ya know) will be jonesing, big time...probably turn a 10,000% profit.

And the cops? Can't touch me, or I'll cut 'em off! (They're just as bad as the rest, surprisingly.)

Incidentally, dihydrogen monoxide is a "precursor" substance, as it is necessary for the production of alcohol, among other drugs...