What is Biological Exposure Index (BEI) and when is it used?

• A. Biological Exposure Index; used to interpret biomonitoring results against reference values for health risk assessment.
• B. Biological Exposure Index; used to set indoor air quality standards.
• C. Basic Environmental Indicator; used to measure air concentrations.
• D. Biological Exposure Information; used to monitor work hours.

Answer: (A)

Biological Exposure Index is a reference value used to interpret biomonitoring results by comparing the measured levels of a chemical or its metabolite in a worker’s biological specimen (like blood or urine) to a level associated with health risk. It reflects internal dose and helps translate what’s measured in the body into an assessment of exposure relative to known health-based thresholds. When biomonitoring results are below the BEI, the internal dose is generally considered not to pose a health risk based on available data; when results exceed the BEI, it suggests potential overexposure and may prompt further investigation, controls, or medical surveillance. BEIs, typically developed by professional organizations, are interpretive reference values—not regulatory air standards—and they’re used to inform risk assessment and workplace health decisions rather than to set indoor air quality limits or measure air concentrations.