Indeed, different rules in different places for a common herb. The problems of PAs are real, plenty of evidence to show the effects, the long-term effects are especially worrying (cancerous potential when the liver fails to process the PAs, so it seems to linger in the liver). I helped out in a local herb shop last year and they had a form we were supposed to get customers to sign when they purchased any loose comfrey root – to say they would only use it externally. I believe it is now out of the tea products here, but certainly, the root is available in the pure herb suppliers. Best to grow it anyway and just use it for creams and salves – it is quite magical.