This article has all cyclists and hikers concerned. The U.S. government is expected to release a report on the safety of certain plastic water bottles containing the chemical compound bisphenol-A or BPA, which some scientists consider a health concern. Recent lab tests indicate that exposure to BPA may raise the risk of certain cancers, effect both male and female fertility and possibly enhance the risk of developing Type II diabetes at certain exposure levels. Look for a small triangle on the bottom of your bottles. The number inside the triangle indicates the category of plastic that is used to manufacture the bottle. Bottles that contain the number 3, 6, or 7 have either BPA or other chemicals that should be avoided. Most cycling bottles are made with No. 4 plastic.