never heard of it being carcinogenic through handling Emma

?? ,apart from reccommendations not to let come into contact with broken skin !!!! but no proof of any cases of any form of cancer from contact with it . There are reports

that it can harm the liver , but there is no conclusive proof anywhere that comfrey was the cause of any liver disease that I am aware of . All human cases (3 or 4 ) are very much debatable as to cause of the illness !!! In Lawrence D Hills book of Comfrey ( he being the definitive sage on all things comfrey !!) he says that it would take a fully grown man drinking many , many cups of comfrey tea every day , for 140 years to show any signs of liver disease due to drinking comfrey tea. This being based on the amount of Pyrrolizidine Alkaloids present in comfrey , ie very small amounts, but even this was only a maybe scenario !!. Almost anything taken in excess can be harmfull even water . One or two paracetamol or aspirin can ease pain or bring down temps...but take too many and you are in serious trouble !!
http://www.equineiridology.eu/herbs.php scroll down to the section on comfrey ....
So no conclusive evidence of any cases as far as I know

? I think the good seems to far outweigh the possible bad !!! All a matter of choice really .
cheers
Russ