According to a post by PreventDisease.com on EatLocalGrown.com's blog, most countries permit three food additives for decaffeination of tea and coffee: carbon dioxide, ethyl acetate and methylene chloride. The last two are chemical solvents that strip the caffeine from green coffee beans or tea leaves.
Green tea labeled as “naturally decaffeinated” may have been decaffeinated using carbon dioxide, whereas methylene chloride is more often used to remove caffeine from black tea or coffee.
Methylene chloride, or dichloromethane is recognized as possibly carcinogenic, and for this reason, many manufacturers have switched to using carbon dioxide or the Swiss Water process instead. Of course, the methylene chloride is removed from the coffee or tea before it is packaged and sold, but knowing your tea or coffee has been processed using a carcinogenic solvent may influence your shopping choices.
Bottom line is if you're going to drink coffee, make it caffeinated.
