How is the PEL calculated for shifts greater than 8 hours?

The correct choice states that the Permissible Exposure Limit (PEL) is calculated by taking 400 and dividing it by the number of hours worked. This method is applicable for shifts that exceed 8 hours.

The rationale behind this formula lies in the need to account for increased exposure over longer work hours. The standard PEL typically applies to an 8-hour workday. Therefore, when the work shift extends beyond this duration, the allowable exposure level must be recalibrated to prevent health risks associated with longer exposure times.

By dividing 400 by the number of hours worked, this calculation creates a proportional adjustment of the PEL based on the actual hours employees are exposed to lead. For example, if a worker is on duty for 10 hours, the new PEL would be 40, reflecting a reduced limit to ensure safety over that extended period. This method provides a safeguard by ensuring that workers are not exposed to lead levels that would be considered safe for an 8-hour shift.

Understanding this calculation is crucial for ensuring health and safety in environments where lead exposure is a concern, thus protecting workers from potential health effects.