“Claudia Miller has spent 30 years hammering out a theory to explain the contemporary surge in perplexing, multi-symptom illnesses—from autism to Gulf War Syndrome—which represent a Kuhnian shift in medicine. She calls her theory “TILT,” short for Toxicant Induced Loss of Tolerance. TILT posits that a surprising range of today’s most common chronic conditions are linked to daily exposure to very low doses of synthetic chemicals that have been in mass production since World War II. These include organophosphate pesticides, flame-retardants, formaldehyde, benzene, and tens of thousands of other chemicals. TILT, says Miller, is a two-step process. Genetically susceptible individuals get sick after a toxic exposure or series of exposures. Instead of recovering, their neurological and immune systems become “tilted.” Then, they lose tolerance to a wide range of chemicals commonly found at low doses in everyday life and develop ongoing illnesses. Along with Nicholas Ashford, professor of policy and technology at the Massachusetts Institute of Technology, Miller co-authored Chemical Exposures: Low Levels and High Stakes. In 2012, Miller and her colleagues published a study in the family practice journal Annals of Family Medicine. They reported that 20.3 percent of individuals with chronic health issues suffer from some degree of chemical intolerance. That’s one in five—and, says Miller, they become vulnerable to TILT if they endure too much toxic exposure.”