Workers service the lavatories of commercial aircraft approximately 11 million times per year in the United States and may have exposure to the spectrum of pathogenic viruses, bacteria and parasites potentially found in human waste. An industrial hygiene walk-through of the workplace was conducted by an interdisciplinary occupational health and safety team, and lavatory waste operators and supervisors and the process was observed. Exposure to untreated waste can occur through dermal, ingestion, and inhalation in quantities ranging from droplets to large spills. Several engineering and administrative measures were advised to minimize worker exposure, including the effective locking of a critical valve, and a mechanism for communicating valve locking problems.