If an employee is potentially exposed to any amount of hexavalent chromium, then OSHA requires the employer to determine the exposure concentration, through exposure monitoring or objective evidence, and notify the employee of the result. On the surface this requirement appears simple and practical, but meeting the requirement may lead to conflict if care is not exercised. Below are six issues that should be addressed to help manage this risk.
OSHA believes that welders make up almost half of the employees affected by the hexavalent chromium standard. The focus is toward welders who weld or burn on stainless steel and other metals that have chromium added into the product. The intense heat during welding or burning on metal containing chromium may create airborne hexavalent chromium.
Chromium is not intentionally added to mild steel and other metals, such as aluminum, but because the steel- and metal alloy-making process often employs the use of scrap, a trace amount of chromium may occur in metals. Following OSHA’s February 2006 final rule on occupational exposure to hexavalent chromium, some manufacturers began listing in material safety data sheets and product labels trace amounts (e.g. below 0.01%) of chromium in mild steel and other metals. Even if chromium does not appear on an MSDS for mild steel, its presence should now be assumed.
The quantity of chrome in a product is a component of exposure. Another component of exposure is time. Although welding is often performed for short periods - maybe just a fraction of time during a workshift - and shorter time means less exposure to hexavalent chromium, OSHA does not have a cut-off limit for how long an employee may be exposed to hexavalent chromium before an exposure determination is required.
Therefore, issue #1 is whether you should conduct exposure monitoring or develop objective data to demonstrate that employee exposure to hexavalent chromium is below 2.5 ug/m3 as an 8-hour time-weighted average (TWA) during any welding or burning on mild steel or other metals where chromium is not intentionally added but suspected to be present in the product.
There are many variables to consider when sampling welders for hexavalent chromium exposure. Sampling inside a welding helmet is one example. Time, as mentioned above, is another. If sampling is conducted for a short time, the volume of air in the sample submitted for analysis may cause the lab to report a “less than” result. Assume the result is reported as: < 2.5 ug/m3. Is the true exposure just below the result, one half of the result, or zero? How is the non-sampled time interpreted? The number or result chosen will need to be compared to not only the OSHA PEL and action level but to a recognized safe limit. A professional IH may be needed to make sure the true exposure number gets reported to employees.
OSHA revised the notification requirements in the exposure determination provisions of the hexavalent chromium standards (effective June 15, 2010) because it believes “significant health risk exists at exposures below the PEL” and “making employees aware of such exposures may encourage them to take whatever steps they can, as individuals, to reduce their exposures as much as possible.” See Federal Register 75:12681-12686 published 03/17/2010.
If OSHA’s PEL is not the safe limit, what limit is considered safe? If we look to NIOSH, the current Recommended Exposure Limit (REL) for all hexavalent chromium compounds is 1 ug/m3. NIOSH’s draft Hexavalent Chromium Criteria Document, however, suggests an REL at 0.2 ug/m3 for an 8-hr TWA exposure, during a 40-hr workweek, over a 45-year working lifetime. NIOSH’s draft Hexavalent Chromium Criteria Document Update is found at http://www. cdc.gov/niosh/docket/pdfs/NIOSH-144/0144-090108- ExternalReviewDraft.pdf. Although the current and draft REL do not carry the force of law, they provide scientific evidence and recommendations for “safe” exposures.
Note: The proposed REL may be rephrased as 200 nanograms/m3. “Nano” is the prefix for a billionth. One part per billion is equivalent to one second in 32 years. The point is, just a little exposure to hexavalent chromium may exceed the proposed REL.
In March 2009, the Electric Power Research Institute (EPRI) provided peer review comments for NIOSH’s proposed REL for exposure to hexavalent chromium. EPRI’s preliminary research finds that unless significant technological improvements were made in local exhaust ventilation, “employees engaged in welding activities will likely need to rely on other control techniques to maintain exposures below the proposed REL. This would most likely occur by the use of respiratory protection whenever they are welding on or with any chromium bearing metals.”
The health effects from exposure to hexavalent chromium are highly controversial and often in the public’s eye. Non-scientists, such as Erin Brockovich, who gained fame from the movie with her name in 2000, continue as activists against the “dangers” from hex chrome exposures. Most recently, Brockovich assisted in the filing of an April 2009 lawsuit against Prime Tanning Corp. in Missouri because of alleged hexavalent chromium concerns. In June 2009 she began investigating hexavalent chromium found in well water in Midland, Texas. Dr. David Michaels, who heads up OSHA, has a deep involvement with hexavalent chromium. Dr. Michaels’ 2006 article “Selected science: an industry campaign to undermine an OSHA hexavalent chromium standard” may help explain OSHA’s current emphasis on hexavalent chromium exposures. See article at http://www.ehjournal.net/content/5/1/5.
Concerns about welding and hexavalent chromium are a risk that should be addressed methodically. Conformance with ISO 31000 is one method to fully address the risk. Risk communication follows the hierarchy of employee curiosity, concern, controversy, and conflict. It is generally easy to provide effective risk communication at the curiosity stage. EHS pros have a greatly diminished role with risk communication at the conflict stage, where senior management and lawyers, both within and outside the employment organization, are dominant. A full appreciation and engagement of the six issues provided here about the concerns with welding and hexavalent chromium exposures will help head off the possibility of conflict.