Redefining what is normal has become a game that special interests play. But the rules of this game are changing faster than anyone wants to acknowledge. Take the most basic assumption in chemical-risk assessment—an assumption used in connection with all products produced—that there is a certain safe level of contamination below which no effects are caused. That reassuring idea was dealt a serious blow in 1999 with the publication, in Environmental Health Perspectives, of a study showing that endocrine disrupter chemicals can cause health effects at extremely low dosages. Some low levels of exposure actually create more negative health effects in either humans or animals than higher doses do.
Fitzgerald, Randall. The Hundred-Year Lie: How to Protect Yourself from the Chemicals That Are Destroying Your Health (p. 160). Plume. Kindle Edition.