http://www.pbs.org/wgbh/pages/frontline/meth/etc/cron.html
(The gist is that large labs tend to spring up whenever they find a bulk source for either chemical and then go away when that bulk source is eliminated)
[0] "Give me some pseudoephedrine geez!!" http://forums.whirlpool.net.au/forum-replies.cfm?t=1488355
http://www.pbs.org/wgbh/pages/frontline/meth/etc/cron.html
(The gist is that large labs tend to spring up whenever they find a bulk source for either chemical and then go away when that bulk source is eliminated)