WE ADD UP tees are made with 100 percent certified organic cotton that is grown and manufactured in the United States under strict fair labor practices. While organic cotton is grown without the use of synthetic pesticides or herbicides, non-organic cotton is the most pesticide-intensive crop on earth. Although cotton is grown on only about three percent of the farmland in the world, 25 percent of the world's pesticides are used on cotton fields. National Academy of Sciences researchers have classified more than 80 percent of the most commonly used pesticides as potentially carcinogenic. Each tee helps prevent about one-third of a pound of pesticides from getting into topsoil and groundwater, and helps farm workers avoid dangerous chemical exposure. Organic agriculture also helps create fertile soil that is more resistant to degradation from droughts and floods, thus limiting some of the long-term effects of global warming. All in all, choosing organic cotton has a positive impact on the planet.