BACKGROUND: Tetrahydrothiophene (THT) is frequently used to odorize natural (city) gas. Only sparse data on adverse health effects of THT on humans are available. METHODS: We performed a literature search and clinical investigations including case history and cardiopulmonary diagnostic tests in two symptomatic THT-exposed outpatients. RESULTS: The two THT-exposed city workers developed transient neurologic symptoms such as nausea, vomiting, headaches, as well as skin and mucosa irritation, chronic rhinitis, chronic obstructive pulmonary disease, arterial hypertension, and cardiac arrhythmia. The neurological symptoms and respiratory disorders were found to be caused by intermittently high THT exposures. In favor of a causal relationship were severe work-related neurological and respiratory symptoms in previously healthy workers, results of animal experiments, and another report with very similar findings in the literature. The etiology of arterial hypertension and cardiac arrhythmia, however, remains unclear. CONCLUSIONS: Our two case reports demonstrate that repeated high THT-exposures can--in addition to neurotoxic symptoms--elicit chronic obstructive pulmonary disease. We recommend improved primary and secondary preventive measures, including the establishment of a TLV.
