eTools Home :Legionnaires' Disease Safety and Health Topic Page | Scope | FAQ | PDF | Credits
Legionnaires' Disease

Section III: How to determine if a workplace is experiencing an outbreak

InvestigationA Legionnaires' outbreak (that is, two or more confirmed cases) is both an occupational and a public-health concern. The investigation will include local public health departments and possibly the Centers for Disease Control and Prevention (CDC). To minimize employee risk and maximize the effectiveness of the effort, close coordination among OSHA, other public agencies, and the employer is necessary. It is important to remember that Legionnaires' disease in workers may have its origin in the community and may not be related to the work environment.

Investigation Protocols:

OSHA has developed two investigation protocols available for differing levels of suspected exposure to Legionnaires' disease bacteria (LDB). Both investigations follow the same general pattern and include a preliminary opening conference and walk-through of the facility to conduct a physical assessment of the water systems. A more detailed examination of the systems involves a review of maintenance records, assessment of findings, and a closing conference to present control actions based on findings. The degree of certainty that the site is the source of illness determines the course of action taken during an investigation.
  • Conduct a level one investigation when LDB contamination is suspected or no more than one case of probable or confirmed Legionnaires' disease is recognized.

  • Initiate a level two investigation when more than one probable case of Legionnaires' disease has been reported.

Keep in mind Keep in mind: Individual circumstances may require changes in the investigation. These procedures are provided only to assist in the investigation of potential Legionnaires' disease cases. All cases require sound professional judgment in deciding the appropriate course of action.
eTools Home :Legionnaires' Disease Safety and Health Topic Page | Scope | FAQ | PDF | Credits