Quantitative risk estimates often utilize specific metrics to express risk levels:
No-Observed-Adverse-Effect Level (NOAEL): The highest dose at which no adverse effects are observed in a study. Lowest-Observed-Adverse-Effect Level (LOAEL): The lowest dose at which adverse effects are observed. Reference Dose (RfD): An estimate of a daily exposure level that is likely to be without appreciable risk over a lifetime. Carcinogenic Risk: Often expressed as a probability (e.g., one in a million) of developing cancer over a lifetime of exposure.
