Biological Monitoring of Worker Exposure-February 2015

Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety

February 2015

IN THIS ISSUE: Biological Monitoring of Worker Exposure

Biological monitoring is a type of medical monitoring that assesses a worker’s exposure to a hazardous agent. For employees exposed to significant amounts of hazardous chemicals, medical monitoring is essential to care, and biological monitoring can be used to further assess an employee’s health. 

How Does Biological Monitoring Work?
Biological monitoring measures exposure through the use of a biomarker that results from contact with the hazardous agent. The biomarker typically is the agent or its metabolite in a biological specimen taken from the worker, usually from blood testing or urinalysis. The biomarker may also be an effect of the agent, such as elevated levels of zinc protoporphyrin in blood caused by lead exposure.
A worker can receive a dose of a chemical only if it is absorbed into the body. This can occur through inhalation, ingestion, penetration, or skin and eye contact. The extent and rate of absorption depends upon the concentration, the characteristics of the chemical, and the tissue into which it is absorbed. Very soluble chemicals may be distributed throughout the body while others may concentrate in the body fat or other lipid-rich tissues, such as the brain. Once in the body, the types and rates of metabolism and excretion can influence the chemical’s effect. These can be affected by age, diet, general health status, and other factors. Unlike air monitoring, biological monitoring has the potential to evaluate the effect of all routes of entry. ( See

Assessing Risk & Biological Monitoring
Biological monitoring can be used to assess the risk to workers from exposure hazards and to demonstrate the adequacy of controls that are in place. The American Conference of Governmental Industrial Hygienists (ACGIH) publishes Biological Exposure Indices (BEI), and OSHA specifies biological testing in a number of standards such as those for lead and hexavalent chromium. BEIs are an index of measurement of a worker’s uptake of a chemical while air monitoring indicates the potential of exposure to an individual. Most BEIs are correlated to Threshold Limit Values while others are directly related to an adverse health effect. They indicate a level below which nearly all workers should not experience adverse health effects.
Employees who regularly work with hazardous chemicals should participate in a medical monitoring program. Biological monitoring can be an important part of that program. Meet with your medical provider, discuss current information about the hazardous chemicals in the operation, and develop a medical monitoring program that can best protect employees.

For more information on this topic and to discuss your company’s safety and industrial hygiene needs call OccuSafe at (214) 662-6005 or contact us at

OccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health. OccuSafe services companies of all sizes in a range of industries.

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