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

• A. A threshold for chemical exposure that triggers immediate shutdown.
• B. A policy requiring vaccination for workers.
• C. A reference value for interpreting biological monitoring results to assess internal dose when no established exposure limit exists.
• D. A tool for measuring environmental concentrations of contaminants.

Answer: (C)

Biological Exposure Index is a reference value used to interpret biomonitoring results and gauge the internal dose of a chemical in a worker when there is no established exposure limit. It provides a benchmark for the amount of chemical or its metabolite in a biological specimen (like blood or urine) that corresponds to an exposure level considered acceptable, helping determine whether additional controls or medical follow-up are needed. It isn’t an environmental concentration limit or a policy, and it isn’t used to trigger immediate shutdown. It guides interpretation of measured internal dose when regulatory limits don’t exist for that substance.