Methyl methacrylate vapours leaked when a tank truck was being filled with liquid waste (methanol, ethanol, isopropyl alcohol, acetone, acetonitrile and water) at a pharmaceutical site. A third party, duly commissioned by the operator, transferred the waste stored in barrels using a vacuum pump at 9.20 am. The air in the tank was expelled to draw the waste via a hose but the emitted vapours were collected around 9.35 am by an airconditioning device in the building near the transfer area.
The transfer operation was stopped at around 10.00 am and the building evacuated. The driver of the private company informed the operator that the methyl methacrylate emissions surely originated from its transit on 31/05 during waste transfer in another industrial site. On the previous day, the tank was only rinsed with water. The analysis carried out by several laboratories confirmed the presence of methyl methacrylate in the waste samples from the tank truck (ratio > 60 between the barrels and truck). The cleaning operation was inadequate and not carried out in an authorised facility. Acute poisoning with methyl methacrylate in concentrations greater than 2,000 ppm could result in neurological disorders along with symptoms like headache observed in the employees. Out of nine people poisoned, eight were hospitalised (four were discharged the same evening and the remaining four on 02/06). One person received medical attention onsite. Two people were on medical leave for 10 and 20 days.
A visit by inspection authorities revealed that five provisions were not respected: accident not declared by the operator, clean-up certificate not produced before transfer of waste as provided for by the safety protocol between the industrialist and the service provider, compliance with safety protocol and state of cleanliness of tank before authorising transfer not verified by the industrialist, technicians not trained in the application of safety protocol and ensuring compliance, safety protocol not drafted in form of an operating procedure.
The inspection authorities took note of these facts. The prefect was advised to issue a formal notice demanding compliance with the recommendations of the prefectoral order.
