Hexavalent chromium, Cr(VI), is a hazardous man-made compound found in a variety of industrial processes. The Occupational Safety and Health Administration (OSHA) estimates that more than 550,000 workers in the U.S. are potentially exposed to Cr(VI). Also known as Hex Chrom, HexaChrome, Chromium 6 and similar offshoots, Cr(VI) exposure can occur during “hot work” activities, such as welding and grinding on stainless steel and other alloy steels containing chromium metal. Exposure can also occur while working with dyes, paints, primers and other surface coatings that contain Cr(VI), and during chrome metal plating operations.
Prolonged inhalation of airborne Cr(VI) can cause lung cancer. In addition to its carcinogenic properties, Cr(VI) exposure can lead to a number of other negative health consequences. Impacts on the respiratory tract can range from irritation to damage of the throat, nose, nasal passages and lungs. Direct contact with chromate dust or chromic acid can cause permanent eye damage. Skin exposure can lead to dermatitis and skin ulcers; in some cases kidney damage has been linked to high levels of skin exposure.
On Feb. 28, 2006, OSHA published the revised Cr(VI) standard. OSHA determined that the revision was necessary to reduce significant health risks posed by occupational exposure to Cr(VI).
In order to tailor requirements to the unique circumstances found in general industry, construction and shipyards, OSHA established three standards for governing occupational exposures to Cr(VI): general industry (29 Code of Federal Regulations (CFR) 1910.1026), shipyards (29 CFR 1915.1026) and construction (29 CFR 1926.1126).
The revised standards also address:
- Requirements for exposure determination
- Preferred exposure-control methods, including a compliance alternative for facilities where compliance with the new exposure limit is not feasible
- Respiratory protection
- Protective clothing and equipment
- Hygiene areas and practices
- Medical surveillance
- Start-up dates that included four years for the implementation of engineering controls
The new standards lowered OSHA’s permissible exposure limit (PEL) for Cr(VI) and its compounds, from 52 to five micrograms (5 µg/m3) of Cr(VI) per cubic meter of air as an eight-hour time-weighted average (TWA) and established an action level of 2.5 µg/m3 calculated as an eight-hour TWA.
Each employer who has a workplace or work operation involving potential exposure to Cr(VI) must determine the eight-hour TWA exposure for each employee exposed. Employers must perform initial monitoring to determine the eight-hour TWA exposure for each employee on the basis of a sufficient number of personal breathing zone air samples to accurately characterize full shift exposure on each shift, for each job classification, in each work area. Where an employer does representative sampling instead of sampling all employees, the employer must sample the employee(s) expected to have the highest chromium (VI) exposures.
If initial monitoring indicates that employee exposures are below the action level, the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring. If monitoring reveals employee exposures to be at or above the action level, the employer must perform periodic monitoring at least every six months. If monitoring reveals employee exposures to be above the PEL, the employer must perform periodic monitoring at least every three months. If periodic monitoring indicates that employee exposures are below the action level, and the result is confirmed by the result of another monitoring taken at least seven days later, the employer may discontinue the monitoring for those employees whose exposures are represented by such monitoring.
Employers must perform additional monitoring when there has been any change in the production process, raw materials, equipment, personnel, work practices or control methods that may result in new or additional exposures to Cr(VI), or when there is any reason to believe that new or additional exposures have occurred.
Monitoring for Cr(VI) is accomplished with a sampling pump and filter. Results are obtained from a laboratory; you cannot use a direct-reading, badge-type monitor for Cr(VI). When monitoring for Cr(VI), employers must use a method of monitoring and analysis that provides values within plus or minus 25% of the true value at least 95% of the time for airborne concentrations at or above the action level. Examples of methods that meet this criteria are OSHA method ID215 (version 2) and NIOSH methods 7600, 7604, 7605 and 7703.
Employers are required to provide workers with respirators when feasible engineering and work practice controls are unable to reduce worker exposure to Cr(VI) to levels at or below the PEL. Where respirator use is required, the employer must establish a respiratory protection program in accordance with OSHA’s Respiratory Protection standard (29 CFR 1910.134). The level of respiratory protection depends on workplace conditions and contaminant levels. Respirator manufacturers, such as 3M, suggest the following:
- N95 filters may be used where there are no oil aerosols
- R or P95 filters may be used where oil aerosols are present (refer to packaging for time-use limitations)
- Filtering facepiece respirators (elastomeric half-facepiece respirators and full-facepiece respirators) may be used up to 10 x PEL of 5 µg/m3 with appropriate filters when qualitatively fit tested
- Full-facepiece respirators with appropriate filters may be used to 10 x PEL of 5 µg/m3 when qualitatively fit tested, and may be used up to 50 x PEL of 5 µg/m3 when they are quantitatively fit tested and equipped with appropriate filters
- Loose-fitting facepieces may be used up to 25 x PEL
- Tight-fitting full facepieces, hoods and helmets with supplied air, and powered air-purifying respirators may be used up to 1000 x PEL
It is critically important that employees recognize the hazards associated with exposure to Cr(VI) and understand the measures they can take to protect themselves. OSHA’s revised Hazard Communication standard (29 CFR 1910.1200) establishes requirements for employers to provide workers with information on hazardous chemicals, such as Cr(VI), through comprehensive chemical hazard communication programs that include safety data sheets (SDSs), labels and worker training. A specific reference to this standard is made in regards to the disposal of bags or containers of waste, scrap, debris and any other materials contaminated with Cr(VI). The impermeable bags and/or containers must be labeled in accordance with the requirements of the Hazard Communication standard.
Find even more information you can use to help make informed decisions about the regulatory issues you face in your workplace every day. View all Quick Tips Technical Resources at www.grainger.com/quicktips.
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The information contained in this publication is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This publication is not a substitute for review of the current applicable government regulations and standards specific to your location and business activity, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.
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