On the long thread about the history of climbing gear and clothes...
http://www.ukclimbing.com/forums/t.php?t=241927&v=1#3558749
... people were talking about Fires, the history of Boreal rubber, where it came from, what it was made of.
Some had heard it was the same as racing car tyre rubber, some that it was made from recycled tyres. A poster who worked in a gear shop when Fires first arrived remembered being informed that it had to be made in Spain because it had cyanide in it, and Spain was the only place where health and safety laws were lax enough to allow the addition of cyanide to open vats.
So, I emailed Boreal to find out the truth. They say:
"Thank-you for your interst on rock shoe story and BOREAL. I think stories told to you were not exactly right. I have no information about where our rubber came from. It has been made in Spain, but not for the given reasons to you.
I am sorry not being able offering further information."
So, are the origins of Boreal rubber lost for ever in the mists of time?
ps Dear mods, have not posted this under gear, because I reckoned history of gear goes on Rocktalk. Hope that's ok.