Safety Tidbit #21 – Exposure Assessment

This week I’d like to discuss exposure assessment.  Assessment enables the client to determine their risk management strategy.  As an industrial hygienist, I help clients assess their workplaces by anticipating, recognizing, evaluating, and controlling workplace hazards.  The assessment addresses the third part of what the industrial hygienist (IH) does and can take a large portion of the time.  Mainly because this part involves both the art and the science of industrial hygiene.

 

First, the art portion, understanding the process in question.  The IH must profile the workplace to learn how often they perform the process, how many perform the process, the duration of the process, the work practices, and engineering control employed, as well as, any personal protective equipment worn.  Additionally, the IH should ascertain the level of training of the employee, how long they have been on the job, as well as the level of production. 

Now for the science portion, sampling, quantifying workplace exposures requires developing a body of knowledge of the exposures during a given set of circumstances.  The IH must learn if a method exists to capture the necessary information to assess the exposure. In other words, is there a means to capture the contaminant from the workplace and second can we reliably analyze the sample?

For instance, you know that Chemical X is present in the workplace, and you wish to evaluate how much of it is in the air.  As the consultant, you must determine what sampling method will yield the most reliable results and is most feasible to perform given the workplace circumstances.  Second, what analytical method do you want to employ?  Often the analytical method dictates how the IH samples for the chemical. The method may place limitations on or confounders that the IH must anticipate during sampling operations.  Furthermore, either the method of sampling or the analytical method may place special handling requirements for the sampling media (e.g., placing media in a fixing solution, refrigeration, avoid sunlight, etc.).  Improper handling can destroy the integrity of the sample, and any assessment desired, therefore, wasting the time spent obtaining the sample.

What I explained above is just a very rudimentary explanation of quantifying workplace exposures. Ultimately, the employer must evaluate all exposures, to all employees, on any given day during any work shift. Therefore, the employer needs several samples to be able to understand what truly are the exposure levels in their workplace.