What it is: The overexposure principle notes that every chemical has a safe and an unsafe level of exposure and you won’t be harmed unless you repeatedly exceed the safe level.
Why it occurs: Over-exposure is caused by prolonged and repeated exposure beyond levels specified as safe by the regulator/manufacturer. Prolonged and repeated exposure to a substance can cause an allergy, however, all chemical products are safe when used correctly. Sadly, once an allergic reaction occurs, it is for life.