In late 2015, the Brittany Regional Health Agency received reports of recurring complaints from employees of a company regarding symptoms and environmental nuisances. The company opened in 2006 near a composting facility for household waste and green waste. Its operations have evolved over time: in 2010, it expanded to include the composting of green algae; in 2012, it ceased processing green algae but continued composting household waste and green waste; and in 2016, it continued composting green waste only. The objective of this study was to describe the symptoms and environmental nuisances experienced by the company’s staff in their work environment. A descriptive epidemiological survey was conducted in late 2016 by the regional unit of Santé publique France using a face-to-face questionnaire. Twenty-two of the 23 employees present in 2016 responded (96%). Among them, 13 were already present in 2010, 20 were present during the 2012–2015 period, and 2 joined in 2016. The first symptoms were experienced starting in 2010. All employees (20/20) experienced at least one symptom during the 2012–2015 period, and nearly all (20/22) did so in 2016. The main symptoms reported in 2016 were a tingling sensation in the throat (82%), in the nose (55%), in the eyes (45%), headaches (55%), runny nose (41%), and coughing (33%). For each of these symptoms, excluding headaches, more than half of the respondents reported experiencing them at least once a week. Symptoms persisted in 86% (18/21) of respondents at the time of the survey despite management measures taken two months earlier. The most frequently cited nuisances were unpleasant odors outdoors (21/22) and indoors (21/22), as well as the presence of dust outdoors (20/22) and indoors (12/21) on the premises. No harmful social context was identified within the company. The symptoms described were consistent with the discomfort experienced in the workplace and the cited environmental factors contributing to discomfort. The management measures implemented in 2016 did not appear to have improved the symptoms or reduced the environmental nuisances. The additional management measures, implemented after this investigation, were evaluated by the company in 2018 and