Abstract
Dear Editor,
I’m writing in response to an article that appeared in the January 2018 edition of Workplace Health & Safety. The article, starting on page 34, titled “The Relationship of Welding Fume Exposure, Smoking, and Pulmonary Function in Welders,” contains a number of inaccuracies as well as statements that require clarification. While on the whole the article provides an informative overview, and I share the author’s concern for protecting the health of welders in the workplace. Nevertheless, I feel compelled to provide the following comments.
I am a Certified Industrial Hygienist and a Certified Safety Professional in practice for over 25 years—with 12 of those years working within the welding industry for The Lincoln Electric Company. Importantly, the author repeatedly asserts that “exposure to welding fume” poses a significant risk to welders, or that “exposure to welding fume” results in effects such as pulmonary impairment. It is important to note that it is not simply “exposure” that causes occupational injuries or illnesses, but rather, overexposure that has the potential to result in an undesired outcome. Within the disciplines of industrial hygiene, toxicology, and epidemiology, a lot of effort goes into characterizing and defining the effects of various levels and routes of exposure to myriad chemical and physical agents, and then establishing effective workplace exposure limits, given the current level of scientific understanding. While a discussion of the various exposure limits could easily warrant its own lengthy article, in my experience, workers rarely sustain injuries or illnesses as a result of exposures which are kept below the exposure limits indicated by a conservative application of available workplace limits and guidelines—and through countermeasures, such as appropriate ventilation, and/or respiratory protection, when necessary. The author points out several flaws in welding fume studies, one of which is the lack of credible quantitative exposure data for the welders who are the subject of these studies, which I believe is the most consistent, glaring flaw. (As the author points out, another common flaw is the lack of specificity around the nature of the welding processes involved.)
In the “Purpose” section on page 35, it states, “It is the responsibility of occupational health providers in collaboration with safety managers to assess the risk of illness and injury by evaluating employees via PFT.” It is important to note that overexposures also have the potential to result in non-pulmonary effects. But it is also important to note that it is actually the role of industrial hygienists to anticipate, recognize, evaluate, and control exposures to workplace health stressors. Ideally, occupational health practitioners should be working closely with industrial hygienists who can identify the level of risk posed by the physical and chemical agents used—or generated within the work environment—and who are best suited to identify the specific exposure scenarios where medical surveillance is advised.
There are a few technical inaccuracies requiring correction. A major source of worker exposure to Cr(VI) occurs during “hot work” such as welding on stainless steels containing chromium metal, but not with mild steels that typically do not contain chromium metal. (Note: Cr(VI) compounds may be used as pigments in dyes, paints, inks, and plastics. It also may be used as an anticorrosive agent added to paints, primers, and other surface coatings. The Cr(VI) compound chromic acid is used to electroplate chromium onto metal parts to provide a decorative or protective coating). Generally speaking, exposure to hexavalent chromium is not a risk factor with mild steel welding activity.
In addition, the “Significance of the Problem” section states that Cr(VI) is added to steel to increase corrosion resistance and hardenability. Cr(VI) is not added to any steel. For stainless steels and high alloy steels where metallic chromium (Cr0) is added, Cr(VI) can be formed during the high temperatures of welding from the metallic chromium in the stainless or high alloy steels involved. It is important to understand though that mild steel welding accounts for about 90% of all welding that takes place. Mild steels do not have any chromium metal added. So again, it is not a significant risk factor for mild steel welding. As mild steel welding is such a vast majority of all welding work conducted, the reader needs to be presented with this distinction. (It should be noted that the degree to which the formation of Cr(VI) takes place during welding with alloys that do contain chromium is highly dependent upon the particulars of the welding process in use—as well as the composition of the chromium alloys involved.)
Finally, in the last paragraph before the “Problem Statement” on page 34, “location, air movement and ventilation” are listed as factors influencing the composition of welding fume. These factors would not be expected to influence the chemical characteristics of welding fume; rather, they would be some of the factors influencing an individual welder’s potential for exposure to welding fume or its constituent compounds.
As a parting comment, over the course of my career, I’ve noted the often missed opportunities for the practitioners of occupational medicine to work closely with industrial hygienists to take advantage of their valuable expertise—even when it is readily available to them. Likewise, the industrial hygiene community apparently needs to do a better job of communicating its role and value to all occupational health disciplines that serve to protect the health and well-being of those employed in our workplaces.