The risk of hydrogen-sulfide (7783064) exposure to workers with tympanic membrane defects (perforated eardrums) is reviewed. Several statutes and recommendations exclude workers with perforated eardrums from being occupationally exposed to hydrogen-sulfide. The rationale behind this is the belief that sufficient hydrogen-sulfide may enter the worker's body through the perforated eardrum to compromise the respiratory protection. The nature of tympanic membrane perforation is described. It is noted that most perforations heal by themselves within 7 to 10 days without problems. The anatomy and physiology of the eustachian tube are discussed. Under normal resting conditions, the eustachian tube is closed. Pressure differentials on the order of 320 to 400 millimeters of water are required to cause passive opening of the eustachian tube in normal subjects. Higher pressures are required in some abnormal patients with perforated eardrums. The pathology of the eustachian tube is discussed. Respirator operating characteristics are reviewed. Eustachian tube air flows under normal, obstructed, and non functioning conditions are described. The authors conclude that individuals with perforated eardrums should not be excluded from working in a hydrogen-sulfide environment. Normal workers and workers with perforated eardrums should be provided with positive pressure, supplied air, or self contained breathing apparatus with full face pieces.