This, sadly, is a difficuly process as the chemicals are
used in the tanning process of
leather and in a lot of adhesives used in the shoe making process. I have treid vegan shoes and thanks to latex issues, they didn't work for me.
On a good note, I have found a shoe manufacturer that uses vegetable tanned leather and glues that have not caused any issues with me. I have 4 pairs of shoes from this company.