NIOSH Recommends Measures to Reduce Exposure to Coccidioides Fungus

Published February 26, 2014

In response to managers’ concerns about potential employee exposure to the fungus Coccidioides at two state prisons in California, NIOSH evaluated those work sites as part of the agency's Health Hazard Evaluation (HHE) Program. The fungus Coccidioides grows in the soil of semiarid areas such as the Central Valley of California, where the two prisons are located, and can cause the disease coccidioidomycosis, or valley fever.

NIOSH investigators found 103 confirmed cases of coccidioidomycosis among prison employees over a four and a half year period, but it is unknown if the disease was caused by exposures on the job or outside of work. The agency also concluded that employees are likely exposed to the fungus in both the indoor and outdoor work environment.

Because coccidioidomycosis is caused by the inhalation of Coccidioides fungus spores, NIOSH’s report recommends measures for reducing employees’ exposure to dust, including:

  • wet soil before it is disturbed
  • plant grass and other vegetation in outdoor areas
  • keep doors and windows closed as much as possible
  • improve building ventilation
  • reduce employees’ time spent outside
  • consider the use of NIOSH-approved respirators for employees who must work outside during dusty or windy conditions

None of the recommended actions will fully eliminate exposures to Coccidioides , NIOSH notes, but the dust reduction measures may help lower the risk for localized airborne dispersion of the fungus spores.

For more information, see NIOSH’s full report. Other NIOSH HHE reports are available on the agency’s website.