ADVANCED MANUFACTURING SOLUTIONS

Updating Hexavalent Chromium Detection Capabilities

The industry needs rapid detection to truly improve the safety of at-risk personnel.

Hexavalent chromium [Cr(VI)] is a toxic material typically produced in industrial processes like welding of stainless steel or other alloys containing chromium, abrasive blasting of equipment to strip chromate paint or primer, smelting processes of ferro-chromate alloys, and chrome electroplating that uses a solution of chromic acid. Cr(VI) is most commonly exposed to personnel via respirable fumes and dust but can also cause allergic skin reactions in some cases. Inhalation of Cr(VI) can significantly increase risk of lung cancer, so OSHA has mandated that a permissible exposure limit (PEL) eight-hour time-weighted average to be 5 micrograms or less per cubic meter of air. OSHA also recommends periodic monitoring every six months only if initial monitoring shows exposure over the action level of 2.5 micrograms per cubic meter of air.

Considering that Cr(VI) exposure at the PEL is approximately seven times more likely to result in death from lung cancer than asbestos, this frequency of workplace safety evaluation may not be sufficient. This is especially true in facilities where the layout of equipment and processes that produce Cr(VI) change often, which is the case in many industrial environments like aerospace maintenance, repair, and overhaul (MRO) facilities. Testing methods need to adapt to ever-changing industrial environments to provide shorter time-sample results, like five- or ten-minute increments, and with accuracy near laboratory testing. Such capability will significantly enhance visibility on exposure, but what’s even more impactful is the ability to determine potentially unknown sources of dust or fumes that expose unprotected personnel.

In the United States Air Force depot at Hill Air Force Base, there was an issue just like this. Within a large building where abrasive blasting takes place in a large walk-in blast booth, OSHA found Cr(VI) exposure to be far in excess of mandated PELs. This shed light on a series of unidentified sources in the building that were generating Cr(VI) fumes and dust.

In another corner of that building, the welding cell was welding stainless steel and thus exposing many personnel to Cr(VI) without any personal protective equipment (PPE). Here, a rapid detection system would be immensely useful. Spending time working on one problem only to find out later that it wasn’t the problem after all is frustrating and costly. It would also help map out various sources in a large industrial building where many processes occur simultaneously and provide better ventilation as needed.

Much of these challenges that the Air Force experiences are the same as facilities in commercial aerospace (and other industrial fabrication and maintenance industries) where welding, thermal spray, paint application, and paint stripping all produce hexavalent chromium fumes. As technology advances in so many industries, it seems unfortunate that advancement in safety technologies is driven by reaction rather than proactive action. In many cases, the core technology necessary to improve safety is available, but unless there is a push, as there was in the Air Force, the time and money needed to develop those advancements falls to the back burner.

Modern industry needs to push both with spending and priority to get ahead of occupational health issues before they become widespread. This will yield a reduction in operating costs in the long run by reducing worker compensation and costs incurred from OSHA violations, but also from an ethical standpoint it will protect workers from short- and long-term health complications that can reduce quality of life.

Advanced Technological Solution

In an age where various technologies are intelligently integrated, industry needs ventilation capabilities that can use energy efficiently while maintaining safe working environments. A rapid chromium detection system integrated with a ventilation control system would enable automated ventilation systems to ensure OSHA compliance and safe working environments. It would require little to no user intervention and would operate in the background humming along and adjusting to spikes in chromium dust and fumes as they arise. With most ventilation systems, simply increasing ventilation speed and operating that condition all the time consumes far more energy.

Typically, with large industrial blowers higher RPM operation (and thus faster ventilation air speeds) increases power draw exponentially, so optimizing ventilation speed operation will ensure PEL compliance as well as efficient energy usage. In large industrial facilities, blowers can consume immense amounts of energy and thus increase operational overhead, so efficiency is critical to prolonging system life as well as reducing utility costs.

Moreover, an automated ventilation system such as this would document each sensor data point and associated ventilation speed control signals to provide validation that OSHA compliance is continuously maintained. In the event of an OSHA visit to determine compliance, this system would show proof of exposure below the PEL. Facility managers could set the thresholds at which the ventilation speed will increase to ensure an even safer environment than OSHA requires or to adjust in the future should OSHA mandated exposure limits change. Future-proofing high-cost systems such as industrial ventilation is important to reducing operating costs over time.

Other Dusts of Concern

In addition to hexavalent chromium, many industrial processes such as thermal spray and plating produce cadmium, nickel, and many toxic gases. These other materials can be accounted for by integrating specialized sensors into the ventilation control system as suggested with chromium. Many of these toxic materials are invisible, odorless or both, so it is important to rely on technology to aid us in the prevention of health issues for our personnel.

This article originally appeared in the September 2019 issue of Occupational Health & Safety.