Chemicals used in Apple Watch leather band

Dear community,

I would like to know what chemicals Apple uses in the process of tanning the leather in order to make the leather Apple Watch bands. I am highly allergic to Chromium(III) sulfate and Sodium dichromate which are commonly used in the tanning process of the leather. I would like to know what chemicals are used to tan the leather of the bands to ensure I will not have an allergic reaction to it. Thanks in advance for your help!

With kind regards,

Valentijn