it is costly to employ it in stoichiometric amounts
Ah..of course..thats the kicker!
I think it was listed in mine at ~$75/100g.
That envirotoxin bit sounds about right as I believe its used as 'defoulant' for boats.(for barnacles and such I suppose.)
Patent US5811586 (http://l2.espacenet.com/dips/viewer?PN=US5811586&CY=gb&LG=en&DB=EPD)
. Nevertheless it would be interesting to make the 4-tfm-amph.