Health Hazard Evaluation Report: HETA-2009-0100-3135, July 2011. Evaluation of Exposures Associated with Cleaning and Maintaining Composting Toilets - Arizona.

摘要

In February 2009, NIOSH received an HHE request from management at a national park in Arizona. The request concerned employees' potential exposures during the cleaning and maintenance of the pit and composting toilets in the park. Park management also wanted to know whether the PPE used by employees was appropriate. NIOSH investigators visited the park in May 2009. We held an opening meeting to discuss employer and employee concerns; observed work practices; talked to employees about their work and health; reviewed records; and collected air samples for ammonia, hydrogen sulfide, enteric bacteria, and thermophilic actinomycetes. Our investigation showed that instantaneous ammonia concentrations were highest when the pit toilets were first opened, but these levels dropped very quickly. Thermophilic actinomycetes, an indicator of the microbial contamination found at the higher temperatures needed to compost organic material, were detected in PBZ air samples collected while employees cleaned composting toilets. No hydrogen sulfide or enteric bacteria were detected. Heat stress was not evaluated during this site visit but could be a potential problem on the basis of ambient temperatures, workload, and useof PPE observed. Other potential exposures for employees included scorpion and bee stings, spider bites, and airborne hantavirus from rodent nests and rodent feces. Employees were also potentially exposed to hepatitis A and hepatitis B viruses through first responder duties and through handling of untreated human waste and feminine hygiene products. Shoveling out the toilets by hand resulted in awkward postures. One of the composting toilets had a blocked leachate line that caused liquid to back up into the waste vault. Working inside the composting toilet vault meets the criteria for a confined space under NIOSH guidelines. Recommendations to address these potential hazards, such as development of standard medical procedures to address scorpion and bee stings and spider bites, are included in this report.