At around 9:30 a.m., a pungent odour of sulphur was released while soluble oils were being loaded into a tanker truck at a hazardous waste transit and treatment site. The odour wafted towards a nearby agricultural college. Suspicion of a gas leak caused the alarms to be triggered. Fifteen students were sickened by the odour. The secondary school’s 500 students were evacuated as a precaution. Firefighters measured and tested the air at the waste site with an explosimeter. They found no risk of pollution or explosion. The odour disappeared at 11:00 a.m. once the truck had finished being loaded. The students returned to their desks at around 11:45 a.m.

The empty tanker truck (30 m³) that had come to load the soluble oils contained residues of previous waste consisting of light petroleum distillates. This waste had fermented organically. The resulting gas caused the offensive odour. Due to the compatibility between the previous substance (petroleum distillate) and the substance to be loaded (soluble oils), the tanker truck had arrived at the site without a degassing certificate.

The operator of the waste site held an information meeting with the school to discuss the matter. A tour of the site by students is being considered.

After the incident, the operator:

• sent the carrier a letter asking it to no longer bring tanks that have contained substances that could result in organic fermentation;
• plans to acquire its own logistics equipment (purchase of a 30 m³ tank).