Valley Fever (Coccidioidomycosis)

Prevention in a work setting

Bulldozing Back Dirt

Photo by Getty Image

NIOSH recommendations in workplace health hazard evaluations have paralleled those of the California Department of Public Health (CDPH). CHPH has produced a useful web page that provides comprehensive recommendations for minimizing dust exposure and risk of coccidioidomycosis for those working in endemic areas.

Recommended controls include:

  • Stop work in dust storms or high winds.
  • Minimize hand digging; digging with heavy equipment having enclosed, air-conditioned, HEPA-filtered cabs is recommended.
  • Continuously wet soil while digging or moving earth.
  • Stay upwind of digging, when possible.

It is important that workers understand the potential hazards related to their work and how to protect themselves. The Occupational Safety and Health Administration (OSHA) has a Hazard Communication Standard known as the Right to Know Law – 29 CFR 1910.1200. This standard requires employers to provide their employees information about potential work hazards. It also requires employee training on safe work practices, procedures, and protective measures.

CDPH recommends that workers and supervisors be provided training on:

  • Endemic areas.
  • Symptoms and when to report them.
  • Workers at highest risk of serious disease.
  • Effective control to prevent exposures.

Respiratory protection is recommended for those who:

  • Dig manually.
  • Dig using equipment (including enclosed heavy equipment).
  • Work near earth-moving trucks or equipment in endemic areas.

Respirators for employees should be certified by NIOSH and provided within the context of a comprehensive respiratory protection program. This includes:

  • Medical clearance for using respirators.
  • Initial and periodic training and fit testing.
  • Monitoring the effectiveness of the respirators.

The OSHA Respiratory Protection Standard describes the components of a comprehensive respiratory protection program. Employers should assess associated risks and determine appropriate respiratory protection based on the types of respirators for dusts and spores. This is important because only one spore may transmit disease. Respirator information can be found on the NIOSH website.

CDPH1and Das et al.2 note that a fit tested half-mask respirator with particulate filter or a filtering facepiece respirator might be insufficient to protect workers. Some workers, such as those with beards, cannot wear tight-fitting respirators. Loose-fitting powered air-purifying respirators are an option in that situation.

Employers should:

  • Wash equipment before it is moved offsite.
  • Provide lockers and require workers to change clothing and shoes at the worksite. so they don’t take dust and spores home.
  • Arrange for prompt medical evaluation and treatment of those with possible disease.


California Department of Public Health (CDPH) [2013]. Preventing work-related coccidioidomycosis (Valley Fever). Date accessed: October 6, 2014

Das R, McNary J, Fitzsimmons K, Dobraca D, Cummings K, Mohle-Boetani J, Wheeler C, McDowell A, Iossifova Y, Bailey R, Kreiss K, Materna B [2012]. Occupational coccidioidomycosis in California: Outbreak Investigation, Respirator Recommendations, and Surveillance Findings. J Occup Environ Med. 2012 May;54(5):564-71. doi: 10.1097/JOM.0b013e3182480556. PubMed PMID: 22504958.