Board of Certified Safety Professionals (BCSP) Practice Exam

If a chemical has an 8-hour OEL of 0.5 ppm, what is the OEL for a 10-hour shift?

1. 0.45 ppm

2. 0.35 ppm

3. 0.50 ppm

4. 0.30 ppm

The correct answer is: 0.35 ppm

The occupational exposure limit (OEL) refers to the maximum allowable concentration of a hazardous substance in the workplace, typically based on an 8-hour workday. In this case, the given OEL is 0.5 ppm for an 8-hour shift. When extending the work period to 10 hours, it is important to consider the additive nature of exposure over time. Longer exposure shifts typically necessitate a reevaluation of the permissible concentration in order to keep the exposure within safe limits over the extended period. The calculation for the adjusted OEL involves taking into account the increased duration of exposure. This often employs the formula for 8-hour limits, which factors in the time-weighted average. The adjustment accounts for the risk increase associated with the extra 2 hours of work at the same concentration. In this case, reducing the OEL slightly to 0.35 ppm takes into consideration the additional exposure time and helps maintain overall safety by reducing the concentration slightly for the longer duration. As a result, the lower limit reflects a conservative approach to limit health risks associated with prolonged exposure to chemicals in the workplace. This method is critical in occupational health, as it emphasizes the importance of ensuring worker safety and complying with regulations for longer shifts