The links between our health and our environment were the focus of an environmental conference Friday in Des Moines. Carolyn Raffensburger of the Science and Environmental Health Network was one of the speakers. Raffensburger advocates what she calls the “precautionary principle” when it comes to making environmental decisions.She says the principle says if there’s some doubt that something might cause harm, you should be cautious about using it. Raffensburger uses the impact of farm chemicals on humans as an example.There’s a lot of information about the chemicals’ link to cancer, but not as much to other diseases, so we should be cautious about the chemical use. Americans are often bombarded with information and studies about what is safe and what isn’t. Raffensburger says there’s a way to cut through all the information.She says the length and breadth of the impact needs to be studied. Raffensburger, who is from Ames, spoke at the Iowa Environmental Council’s annual conference.