Tanning Leather

http://en.wikipedia.org/wiki/Tanning
http://www.motherearthnews.com/homesteading-and-livestock/how-to-tan-a-hide.aspx#axzz2gqKwm6Br
http://www.alpharubicon.com/primitive/tanningdragoona.htm
http://www.epa.gov/ttnchie1/ap42/ch09/final/c9s15.pdf
http://www.kemira.com/en/industries-applications/leather/leather-tanning/Pages/default.aspx

Bangladesh
http://world.time.com/2013/09/03/hell-for-leather-bangladeshs-toxic-tanneries-ravage-lives-and-environment/
http://www.hrw.org/news/2012/10/08/bangladesh-tanneries-harm-workers-poison-communities
http://www.irinnews.org/report/98182/atrocious-conditions-in-bangladesh-tanneries
http://www.chainamag.com/1211/articles/bangladesh-leather-tarnished-by-toxic-tanneries
http://globalvoicesonline.org/2010/05/20/bangladesh-colours-of-water-leather-tanneries/
http://www.theecologist.org/trial_investigations/314208/hell_for_leather.html

Videos
http://www.youtube.com/watch?v=kT3xjfxMmoc