Get the support you need
Lululemon's Breathe Bra ($42; lululemon.com) is lightweight and made with pesticide-free organic cotton yarn. Regular cotton uses 1/3 of a pound of chemicals to make a t-shirt.
Another great option is Go Lite's Siss Boom Bra ($40; golite.com), made of recycled polyester, which reduces the amount of petroleum used.
Top it off
Danskin offers a Y-Back Jersey Tank-Top ($38; danskin.com) that's made with 95% organic cotton. It's free from harmful dyes, and even the handtags are partially made with post-consumer waste.