A restaurant filed a complaint because a strong and unpleasant smell was spreading throughout a district of the town. Once alerted, the police and fire-fighters visited a chemical plant from where the smell was emanating. The production team and the site’s on-call staff immediately stopped the vacuum distillation of alkylbenzene sulfonate in the workshop concerned. This operation is carried out in 2 stages, the first of which obtains alkylbenzene sulfonate Acid, an intermediary used for the production of alkylbenzene sulfonate. A 5% soda water gas scrubber is used to reduce odours from the sulphur compounds and hexanol vapours released during the synthesis of this plant health product. The operator put forward two hypotheses to explain the incident: a poorly controlled start of distillation (risk of saturation of the condenser by the water and hexanol to be extracted) producing alcohol vapours in the gas scrubber (insoluble vapours in water), a phenomenon accentuated by the use of nitrogen which facilitates the distillation, or the release of sulphur degradation products such as SOx (efficiently processed by the current scrubber) and thiols (insoluble in the scrubber’s soda water). In spite of the precautions taken, this gas scrubbing installation has proven to be insufficient under normal production conditions. Following this complaint, the operator has implemented several measures: complete emptying and cleaning of the scrubbing column to prevent the a further release of the compounds trapped in the column, modification of the production operating conditions to optimise the distillation with an end to the use of nitrogen, lower vacuum setpoints to prevent clogging of the condenser and the emission of hexanol vapours into the scrubber, continuous monitoring of the condenser’s efficiency, modification of the production schedules to prevent the accumulation of 2 manufacturing runs that are likely to cause an adverse effect due to their simultaneous connection to the scrubber. The formulation laboratory is seeking to use additives in the scrubbing solution over the short term, which could solubilise the strong-smelling pollutants present in the scrubber. To control these pollution events, the environmental Inspection Authority has proposed a draft supplementary governmental order prescribing a study on unpleasant odours which should specify the nature of the emissions and suitable treatments.