Hexavalent chromium—commonly called hex chrome—is a toxic particulate produced while welding stainless steel. The fine particulates produced in this welding process pose a serious inhalation risk. The substance is known to cause cancer as well as affect the respiratory system, kidneys and liver.
The Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit for hex chrome of 2.5 micrograms per cubic meter of air.
Here are four steps to reduce exposure to hexavalent chromium:
- The first step in cutting exposure is to look at process improvements. Changes in process and materials can significantly cut welders’ exposure to hexavalent chromium. These methods are usually less expensive and burdensome than addressing weld fumes after they have been created and released into your facility. The first change recommended by air quality engineers is a change in welding wire. If you are using flux-core wire, a change to solid wire will drastically reduce your weld fumes and reduce welders’ exposure to hex chrome.
- Next, use engineering controls such as a dust collection systems to protect welders from hex chrome. For manual welding, source capture systems such as backdraft tables or fume guns capture weld fumes—and particularly dangerous substances such as hex chrome—with a high degree of efficiency. If welding operations involve very large pieces (ones that won’t fit under a hood or on a table), the best solution might be a fume gun combined with a secondary ambient capture system to capture any leftover fumes. Robotic applications should be kept under hoods whenever possible.
- Your third step is to consider an ambient dust collection system. This collector will mitigate fumes throughout a facility and could cut exposure to a safe level. While never adequate as a standalone air quality solution, ambient collectors are highly effective when paired with source capture equipment.
- If exposure levels are still excessive, look into implementing personal protective equipment (PPE) such as powered air-purifying respirators (PAPR’s) for welders. When used correctly, PAPR systems can protect a welder in nearly any welding situation. Remember that OSHA considers PPE to be a last resort; engineering controls must be used whenever it is technically feasible.