If you use a hard plastic bottle to carry fluids when you hike, or for that matter at any time, you should read this.
http://www.cnn.com/2007/HEALTH/12/24/polycarbonate.worries.ap/index.html
Guy
http://www.cnn.com/2007/HEALTH/12/24/polycarbonate.worries.ap/index.html
Guy