Medical Surveillance Helps Protect Employees from Hazardous Cobalt Exposure
Employers in industries that use cobalt, a heavy metal, need to know that occupational health providers can support and reinforce their use of engineering controls to protect employees from potentially toxic exposures through the availability of medical surveillance services. Medical surveillance is a program of medical examinations and tests to monitor and detect ill-health effects due to hazardous exposures, enabling early diagnosis and intervention. Any delay in identifying and treating cobalt toxicity may result in poor recovery and more severe illness, including respiratory, hematologic, thyroid, and skin disease.1
Cobalt in growing demand for modern needs
The properties of cobalt – high-temperature stability, corrosion resistance, and magnetic performance – make it useful in many industries, including aerospace, machinery manufacturing, electronics, chemicals, and ceramics. Cobalt-60, a radioactive isotope, is used in medical radiological examinations and therapies.
Cobalt is used to make airbags and steel-belted radial tires, in manufacturing superalloys for jet engines, and in carbides for industrial cutting tools. It’s useful in materials for dental surgeries and hip implants, as an agent for pigments and catalysts in the petroleum industry, and in inks, dyes, magnetic recording media, and paint driers. Today, cobalt is in high demand as a component of rechargeable lithium-ion batteries in electric vehicles and in smartphones and other electronic devices to extend battery life between charges.2,3
Occupational exposure limits of cobalt
When cobalt exposure (metal dust or fume) exceeds the permissible exposure level (PEL) established by the Occupational Safety and Health Administration (OSHA), it can be toxic to health. (Ironically, in trace amounts in vitamin B12, cobalt supports health, red blood cell production, and metabolism.)
OSHA’s PEL for cobalt is an 8-hour time weighted average (TWA) of 0.1 milligrams per cubic meter (0.020 milligrams per cubic meter in California). The PEL for acute exposure to cobalt in an emergency situation is 20 milligrams per cubic meter; this is the IDLH, or immediately dangerous to life or health, level.
These levels are enforced under three OSHA standards: 1910.1000 (Air contaminants/Subpart Z Toxic and Hazardous Substances), 1926.1101 (Construction/1926 Subpart Z Toxic and Hazardous Substances) , and 1915.1000 (Maritime 1915 Subpart Z Toxic and Hazardous Substances).
Cobalt’s toxic effects to health
When occupational exposure to cobalt exceeds the OSHA PEL, it can be harmful to the lungs, thyroid, skin, and blood.
The International Agency for Research on Cancer (IARC) classifies cobalt and cobalt compounds as “possibly carcinogenic to humans,” based on sufficient evidence that they cause cancer in animals but inadequate evidence, so far, related to people.4
Cobalt safety: engineering controls, work practices
Employees can become exposed to cobalt through inhalation, skin contact, or ingestion. The National Institute for Occupational Safety and Health (NIOSH) recommends, if there is no feasible, less-toxic substitute for cobalt, engineering controls should be used to minimize hazardous exposures. Engineering controls include local exhaust ventilation and enclosing operations (such as welding booths).5
Properly designed and maintained ventilation systems prevent airborne cobalt-containing dust and fumes from accumulating and minimize the recirculation or release into occupational and community environments of raw materials, cobalt, and wastes.
Sound work practices also are important. After working with cobalt products, employees should thoroughly wash their hands and face before drinking, eating, or smoking. If skin contact with cobalt solutions occurs, the employee should wash the affected skin promptly or, if there is substantial cobalt contact, bathe in employer-provided showers. Employers should prohibit smoking and tobacco products, eating, food handling, and food storage in work areas because of possible cobalt contamination, NIOSH says.
Employees at risk for cobalt exposure should be trained to recognize hazards and, in some cases, wear protective equipment/clothing.
When to enlist medical surveillance for cobalt exposures
The NIOSH Health Hazard Evaluation (HHE) Program, through onsite evaluations, periodically uncovers violations involving employee exposure to hazardous chemicals and heavy metals, including cobalt. How does that happen if recommended engineering controls and good work practices are known and followed? The answer is, they aren’t always.
Here are some examples6:
- Welding booths at an aircraft powerplant parts manufacturer were not equipped with local exhaust ventilation (LEV). When mobile LEV units were available, employees were not trained in their use.
- At an orthopedic implant manufacturer, inspectors recommended the installation of LEV systems after an overexposure to cobalt was found. As a result, employees were required to wear safety glasses and steel-toed boots. Company-issued overalls, earplugs, protective gloves, and respirators were optional.
- Respiratory symptoms were reported among cemented tungsten carbide employees; both cobalt and nickel exposures were suspected. A NIOSH analysis found that reports of respiratory symptoms and physician-diagnosed asthma were about double the national average incidence.
Medical surveillance is an invaluable aid whenever there are hazardous chemical or physical exposures in work settings. With medical surveillance support, employers can determine if engineering controls need to be installed or upgraded to protect employees.7
OSHA requires medical surveillance for any employee exposed at or above the OSHA PEL on 10 days or more per year and any employee exposed to cobalt in an emergency situation at or exceeding 20 milligrams per cubic meter, the IDLH level.
Hazardous exposure protection done right
OSHA’s medical surveillance requirements are minimal:
- A physical exam at baseline with a written medical opinion
- Respirator clearance at baseline
- Any other test deemed necessary by the physician or other licensed health care provider (PLHCP)
Concentra, an occupational health care leader for 45 years, strongly recommends a more aggressive approach for optimal, proactive detection of toxic health effects and greater likelihood of better health outcomes. Concentra’s standard baseline/periodic cobalt surveillance services are:
- Surveillance physical exam with a written medical opinion provided to the employer
- A complete blood count (CBC) panel with differential
- Spirometry
- Chest X-ray at baseline, then every 2 to 3 years after 5 years of exposure, and if clinically indicated/at PLHCP discretion
- Urine cobalt test at employer request
- Respirator clearance
After a cobalt emergency, Concentra recommends:
- Surveillance physical exam with a written medical opinion provided to the employer
- A CBC panel with differential
- A comprehensive metabolic panel
- Thyroid function testing
- Pulmonary function testing
- Chest X-ray
- Urine cobalt test
What are your key takeaways for cobalt safety?
NIOSH recommends employers with cobalt exposures use the hierarchy of controls to prevent injuries, always read chemical labels and safety data sheets, and visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.
We would add one more. Contact Concentra for your own medical surveillance program.
NOTES
- Chen RJ, Lee VR. Cobalt Toxicity. StatPearls. July 29, 2023.
- Cobalt Statistics and Information. National Minerals Information Center. U.S. Geological Survey. Accessed: December 13, 2023.
- Jaishankar M, Tseten T, Anbalagan N, Mathew BB. Beeregowda KN. Toxicity, mechanism, and health effects of some heavy metals. Interdisciplinary Toxicology. June 2014;7(2):60-72.
- ToxFAQs™ for Cobalt. Agency for Toxic Substances and Disease Registry. Reviewed: February 9, 2023.
- NIOSH Occupational Hazard Assessment: Criteria for Controlling Exposure to Cobalt. The National Institute for Occupational Safety and Health. Centers for Disease Control and Prevention. October 1981.
- NIOSH Health Hazard Evaluations. The National Institute for Occupational Safety and Health. Centers for Disease Control and Prevention. Last reviewed: April 11, 2016.
- “What is Medical Surveillance,” by Michelle Hopkins. Concentra. January 6, 2020.
