Campaigns to scare the public about man-made chemicals usually focus on one chemical at a time.  But it’s the possible effects of lots of chemicals combined that is the target of a new scare campaign organized by a group called the Collaborative on Health and the Environment.   According to science writer Todd Seavey, this campaign has been timed to coincide with a new report by the CDC about trace levels of chemicals in our bodies.  But while that  report recognizes that our chemical exposure is extremely low, and is not linked to specific illnesses, this new campaign is another example of what experts call a disturbing pattern by activists to manipulate the public and promote legislation, litigation, and regulation.