Living in the top 12 inches of soil in many parts of the state is a microscopic fungus that can pose a serious health risk. When this soil is disturbed, either by natural (wind or dust storms) or human events (digging, trenching, grading, etc.), spores of the fungus —Coccidioides immitis —can become airborne and inhaled. Inhaling just one microscopic spore can cause valley fever.
Symptoms of valley fever can be similar to other common respiratory ailments such as the flu or COVID-19. These include fatigue, cough, fever, and shortness of breath. Most people who develop symptoms will recover on their own without treatment. Antifungals may be prescribed to people with severe disease or weakened immune systems where recovery can take weeks or months—resulting in significant time off from work. In rare cases, the disease advances into disseminated valley fever where it spreads beyond the lungs to other organs and may be fatal.
What your employees need to know about valley fever
Dust exposure is dangerous. Construction, agriculture, and other outdoor workers are at risk of exposure when they dig or disturb soil, operate heavy machinery, or work during windy conditions. Your Injury and Illness Prevention Program (IIPP) should include control measures to reduce dust exposure.
Case rates are on the rise. Although Kern County historically has the highest reported case numbers, rates are increasing on the Central Coast, northern Central Valley, and southern coastal areas of California. Since there is no reliable way to test for the fungus in soil, those working in areas where valley fever is common should presume the spores are present and take precautions.
See a doctor if symptoms persist. Because valley fever symptoms are similar to other common illnesses, diagnosis and treatment is often delayed. The California Department of Public Health encourages anyone working in valley fever exposure areas to report potential symptoms to a supervisor and see a doctor or healthcare provider if symptoms last longer than a week.
What your employees need to do to minimize valley fever risk
The best prevention is to limit their exposure to outdoor dust.
- Minimize the area of soil to be disturbed.
- Earth moving equipment operators should be in enclosed cabs with high efficiency air filtration and closed windows.
- Inspect door and filter seals regularly for wear and replace as needed.
- Workers on the ground should isolate themselves from heavy equipment and other dust generating processes.
- Use water, appropriate soil stabilizers, ventilation, and/or revegetation to cut down on how much dust becomes airborne.
- Use approved respiratory protection with particulate filters rated N95, N99, N100, or P100. Note to employers: all respirators and filters must be NIOSH-approved and provided by you.
- Clean tools, equipment, and vehicles with wet methods before transporting them off the worksite.
- Bring a change of clothes to the jobsite and change into them after the workday ends. Note to employers: change rooms and showers should be provided whenever possible.
What to cover at your safety meeting about valley fever
Construction employers working in highly endemic counties are required to provide effective awareness training to their workers about valley fever. Discuss how workers can be exposed and exposure prevention methods. Also be sure to cover the symptoms of valley fever and what personal risk factors might put someone at higher risk.
Remind workers that symptoms are similar to other common illnesses and to talk to a doctor if symptoms last more than a week. CDPH has developed this guide to help you meet training requirements.
Exposure to airborne dust particles is unavoidable for outdoor workers. Know what’s living in the soil and the risk your workers face. Don’t discount symptoms if you’ve been working in dusty conditions in endemic regions of the state. They could be valley fever.
Rev. 07/2024