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OSHA Hazard Information Bulletins
Potentially Hazardous Amoebae Found in Eyewash Stations

December 23, 1986




  • Director
  • Directorate of Field Operations


  • Director
  • Directorate of Technical Support


  • Health Hazard Information Bulletin: Potentially Hazardous Amoebae Found in Eyewash Stations

Region VI has brought to our attention a Department of Energy (DOE) bulletin indicating that Acanthamoebae, small amoebae capable of causing serious eye infections, have been found in numerous portable and stationary eyewash stations at several DOE facilities.

The infections caused by Acanthamoebae are difficult to recognize and treat and may result in loss of the infected eye. Acanthamoebae are able to survive conventional water plant treatment regimens, and clinical treatments with most antibiotics are ineffective against this amoeba.

Control by chlorination of the water (with a free residual of 25 ppm) has been tested and found to be effective in destroying Acanthamoebae. However, corrosion of the equipment occurred in some of the stainless steel eyewash stations. One-minute and three-minute flushings of the units were also tested. One-minute flushing was not effective in reducing the number of Acanthamoebae; three-minute flushings drastically reduced the number of positive samples.

Acanthamoebae are ubiquitous in tap water. The water can be tested using the method outlined at the end of this bulletin. In most instances the number of amoebae present will not be significant, but they proliferate in stagnant, residual water and then become dangerous. Until other control methods are investigated, such as the optimal level of chlorination, we recommend that the following DOE guidelines be used:

  1. Plumbed eyewash units should be flushed for at least three minutes weekly to reduce Acanthamoebae and to verify proper operation.
  2. Self-contained eyewash stations should not be used in areas where a continuous source of potable water is available. They should be used only in remote areas where installation of a portable water system is not economically feasible. The water in self-contained eyewash stations should be changed weekly.
  3. In general, squeeze bottles should not be used except where the hazard severity or distance from plumbed eyewash equipment requires personal equipment at work stations for immediate flushing prior to prolonged flushing at a plumbed or self-contained unit.

Compliance and consultation personnel should be aware of the possibility that eyewash stations filled with or connected to portable water supplies may be contaminated with the Acanthamoebae. Please disseminate this information to Area Offices, State Plan States, and Consultation Project Officers.

Method for testing water for Acanthamoebae:

  1. Filter water samples through 1.2 micrometer cellulose membranes
  2. Invert filters and place on non-nutrient agar plates coated with
  3. Incubate at 37 deg. C for 2-3 days which is the time necessary for amoebae outgrowths
  4. Observe trophozoites and cysts for morphology indicative of Acanthamoebae.
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