The Foundation of a Great Industrial Hygiene Program

The Foundation of a Great Industrial Hygiene Program

How do we evaluate workplace exposures and ensure the health of all workers while making the most efficient use of our time and resources? SEGs are the answer.

Numerous OSHA Standards and other workplace exposure standards require companies to evaluate the health risks of their workers, and ensure they are controlled to a safe level. These evaluations are commonly performed through qualitative risk assessments (QEAs), or through quantitative measures such as sampling and monitoring of individual worker exposures.

But there’s a problem—how can a company expect to accurately evaluate and manage workers’ health risks when they have hundreds or thousands of employees? Performing risk assessments and monitoring on each individual worker would be far too time consuming and costly, exceeding even the largest EHS budgets. So, how do we evaluate workplace exposures and ensure the health of all workers while making the most efficient use of our time and resources? Similar exposure groups (SEGs) are the answer.

What are SEGs?

SEGs are the grouping and subsequent assessment of workers based on similar exposure risk factors. Common exposure risk factors and other work characteristics used to define SEGs include:




*Equipment/materials used

Here’s an example to help illustrate how SEGs are defined. Let’s say that a Houston-based Refinery has 250 employees that work as operators, administrative staff, maintenance and other key functions to operate the plant.

Following a site tour and detailed discussions with EHS professionals at the plant, we find that only five groups of workers have any significant exposures. These five groups are identified and formed into SEGs.

By grouping workers based on their similar exposures, we can focus on these five groups rather than on all 250 employees, dramatically reducing our risk assessment and sampling efforts.

Why are SEGs Important?

Quite simply, SEGs are the foundation of any industrial hygiene (IH) program. Once established, they offer a more convenient, easier-to-understand visualization of workplace job tasks and operations, and their associated exposure risks.

Perhaps the greatest advantage of SEGs is that they allow you to optimize your sampling activities by using data from a relatively small number of samples from the exposed population to accurately predict exposures to a wider population of workers. The information can also be used to compare exposure risks with other comparable SEGs at other locations. Once a SEG’s baseline exposure is established, the information allows you to more effectively allocate and prioritize exposure monitoring and control efforts, ultimately saving you significant amounts of time and resources.

SEGs can also be used to better manage risk profiles for workers who perform a variety of job tasks throughout the day and may be exposed to multiple workplace stressors. The average exposures for a shift (8-hour TWA) can vary widely depending on the time spent performing specific tasks. Identifying SEGs for specific tasks provides better visibility of which tasks present exposure risks, which then provides a more accurate determination of what controls, if any, need to be implemented.

Creating SEGs also helps to establish greater visibility and continuity of an IH program. In the past, IH programs relied heavily on the judgement or experience of seasoned IH professionals. Over the course of several years, these IH pros familiarized themselves with the jobs and tasks that had the highest exposure risks and simply knew where to prioritize their sampling and assessment activities.

Unfortunately, this knowledge was not well documented and existed as a loose collection of sample data and other records stored in Excel or Access. As the IH professionals retired or transitioned away from the role, incoming IH managers then had to analyze the data to figure out the status of the IH program, including what sampling was being done, why it was being done and where the exposure risks were.

Creating SEGs enables continuity and transparency of the knowledge gained through years of experience—knowledge that can be easily transferred and referenced by incoming IH managers or EHS professionals responsible for IH program management.

When it comes to communicating the exposure risks to workers or management, they will prefer to have the data summarized by the job profile or the tasks being performed. This also enables controls to be specified at the job or task level. For example, all operators conducting liquid sampling in Unit 1 should wear half-mask respirators. This control protects all workers performing the job and task, rather than just the individual worker that was sampled.

One of the biggest benefits in developing SEGs is having a consistent characterization of the workplace and ability to identify any groups of workers that have a potential for overexposure. So, when the IH manager with 30+ years of experience and knowledge at that plant retires, they can hand over the keys with all of that knowledge documented in a manner that can be easily utilized and managed.

How Do I Create SEGs?

Many EHS professionals are apprehensive to define their SEGs without a lot of supportive sampling data. I believe this is the wrong approach, and actually reduces the power of creating SEGs. Don’t be worried about being 100 percent accurate on identifying your SEGs on your first round. This is an iterative process that takes time to fine-tune. The most important thing is to just get started.

Start developing your SEGs by first observing the workers at your site and asking questions like:

*What common jobs/roles are workers placed into? (e.g. operator, maintenance, electrician, pipefitter)

*What tasks do they perform that create potential health risks? (e.g. welding, liquid sampling, opening vessels)

*Are there different methods or equipment used for similar tasks that effect the exposure risks? (e.g. open vs. closed systems, new vs. old equipment that hasn’t been properly maintained, etc.)

*What stressors are the workers potentially exposed to at their job or during the tasks? (e.g. noise, benzene, asbestos, lead, etc.)

If you have experience at your site and know the operations well, you can build an initial list of SEGs even before you go out into the work environment. If you don’t have that degree of familiarity, you’ll likely need to spend more time directly observing workers at your site. Again, the goal is to get started, not to be 100 percent accurate on your first attempt.

Here are some common examples of SEGs for various industries:

SEGs in most manufacturing environments can be characterized by a combination of location, job and task, but other industries may not require all of these attributes.

Industries with highly distributed work sites, like oil & gas pipeline transmission, typically don’t need to assign a location to their SEGs. The table above shows an example of a pipeline operator performing a blowdown of a pipeline containing crude oil. The potential for exposure to noise and benzene during this task is consistent regardless of their location, so it is not specified. This will save from having to perform air monitoring at every location where the operators perform blowdown procedures on the pipeline, and can help minimize the number of SEGs you ultimately need to create.

If you are feeling overwhelmed by the number of potential SEGs at your facility, you can break it up into different phases. A common approach is to start with full shift exposures (i.e., no tasks – all full shift TWAs), then identify the task, then maintenance activities. I have seen companies take this approach until they are confident they have appropriately assessed the full shift exposures. In reality, it may take a year or two to expand the scope of your SEGs to include tasks and maintenance activities.

Again, the most important step is to just begin this process, and continuously improve your SEGs over time. Rome wasn’t built in a day, and neither is a highly effective IH program.

AIHA provides downloadable spreadsheets1 that can help documenting the SEGs.

Documenting & Adjusting SEGs

At this point, you’re probably wondering how best to document and keep your SEGs up-to-date, knowing that SEGs should be tracked and refined on a continual basis over time. For decades, IH professionals have been forced to rely on a patchwork of paper records and spreadsheets to get the job done, all the while struggling to overcome the limitations of these systems—limitations that preclude the kind of visibility, communication and continuity necessary to optimize IH program performance for the long-run. Today’s IH professionals have it much easier with the availability of purpose-built software solutions designed and built by IH professionals to eliminate those limitations and manage SEGs and other IH program functions in the most efficient ways possible.

SEGs are just one of the many moving parts that make up an effective IH program. Your QEAs, sampling plans, lab analysis, data analytics and reporting systems, medical surveillance and program evaluation processes all deserve equal focus, and should be carefully coordinated to ensure optimum IH program performance.

This article originally appeared in the May 1, 2021 issue of Occupational Health & Safety.

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