Hexavalent Chromium Safety
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Hexavalent chromium (Cr(VI)) is one of the valence states of chromium and it is usually produced by an industrial process. Cr(VI) can cause cancer and it also targets the respiratory
system, kidneys, liver, skin, and eyes. OSHA 29 CFR 1910.1026 and 1926.1126, Chromium (VI) standard, establishes a Permissible Exposure Limit (PEL) for Cr(VI) of an average of 5 micrograms per cubic meter (µg/m3) over an 8-hour work shift.
Here’s how Cr(VI) is used in industrial applications:
- Chromium metal is added to alloy steel to make it harder and corrosion resistant. A major source of worker exposure to Cr(VI) occurs during "hot work" such as welding on stainless steel
and other alloy steels containing chromium metal.
- 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.
Requirements to protect workers from Cr(VI) exposure are addressed in specific OSHA hexavalent chromium standards covering:
Hexavalent Chromium Exposure
More than 500,000 workers in a variety of occupations are potentially exposed to Cr(VI) in the United States. Workplace exposures occur mainly in the following areas:
- welding and other types of "hot work" on stainless steel and other metals that contain chromium
- use of pigments, spray paint, and coatings
- operating chrome plating baths
Occupational exposure to hexavalent chromium can occur from:
- inhalation of dust, mists, or fumes containing hexavalent chromium, or
- eye or skin contact.
Exposure to CR(VI) can be controlled through a number of strategies; Engineering controls, administrative/work practice controls, and personal protective equipment (PPE):
- OSHA Cr(VI) standards require employers to use feasible engineering and administrative/work practice controls to reduce and maintain employee exposures at or below the permissible exposure limit (PEL).
- Wherever feasible engineering and administrative/work practice controls are not sufficient, the employer should use such controls to reduce employee exposure to the lowest levels achievable, then
supplement those controls with respiratory protection and, in general industry, establish a regulated area to warn employees and limit access.
- Include hygiene areas and practices, housekeeping and cleaning methods, medical surveillance, and employee information and training.
- Where a hazard is present or is likely to be present from skin or eye contact with Cr(VI), the employer should provide appropriate personal protective clothing and equipment.
How to Reduce Exposure
General work practice controls to reduce exposure include:
- Clean welding surfaces of any coating that could potentially create toxic exposure, such as solvent residue and paint.
- Workers should position themselves to avoid breathing welding fume and gases. For example, workers should stay upwind when welding in open or outdoor environments.
- General ventilation, the natural or forced movement of fresh air, can reduce fume and gas levels in the work area. Welding outdoors or in open workspaces does not guarantee adequate ventilation.
In work areas without ventilation and exhaust systems, welders should use natural drafts along with proper positioning to keep fume and gases away from themselves and other workers.
- Use local exhaust ventilation systems to remove fume and gases from the welders breathing zone. Keep fume hoods, fume extractor guns and vacuum nozzles close to the plume source to remove the
maximum amount of fume and gases. Position portable or flexible exhaust systems so fumes and gases are drawn away from the welder. Keep exhaust ports away from other workers.
- Consider substituting a lower fume-generating or less toxic welding type or consumable.
- Do not weld in confined spaces without adequate forced air ventilation.
On the next several tabs, we provide some useful videos about Hexavalent Chromium Exposure Control.
These videos are an excellent source of information on Cr(VI) safety. The University of Washington and the State of Washington Department of Labor and Industries produced these videos.
This video introduces sources of occupational exposure to hexavalent chromium, health effects associated with overexposure to hexavalent chromium, and steps that can be taken to reduce exposure.
HexChEC Module 1
This video introduces an exposure assessment tool for stainless steel welders.
HexChEC Module 2
This video introduces ventilation controls and how to effectively use local exhaust ventilation to reduce exposure to hexavalent chromium in welding fumes.
HexChEC Module 3
This video demonstrates the effectiveness of local exhaust ventilation controls in reducing welding fume exposure using video exposure monitoring.
HexChEC Module 4
This video introduces alternative exposure controls other than ventilation that may reduce exposure to hexavalent chromium.
HexChEC Module 5
This video explains some requirements for complying with Washington State Labor & Industries hexavalent chromium regulations.