Necessitea does not carry any decaffeinated "tea". In that none of the teas from the Camillia Sinensis plant are ordered in decaf. The only decaf teas we have are the herbal teas which are all caffeine free. Including Rooibos.
Most tea suppliers use organic chemical solvents (methylene chloride or ethyl acetate) or carbon dioxide or the water method (also known as the Swiss Water method). Ethyl acetate is derived from fruit. However, introducing chemicals changes the tea.
It's not the process or whether or not there are risks with consuming decaf versus regular tea. It's that every tea that is in stock is hand picked for a variety of reasons. Every tea has a relationship with it's consumer. And all teas have been discovered by the tea lady to be acceptable to her fellow tea aficionados.
However, wikihow has an 8 step process to decaffeinate your own tea. No teas are truly 100% decaffeinated, so this is the next best thing.