What happened

A small sulphur-trioxide release occurred while a fitting was loosened during maintenance on a sulphonation unit. On contact with moisture in the building air, the SO3 formed an opaque white sulphuric-acid aerosol. The operator attempted unsuccessfully to retighten the connection. This record describes the released chemistry precisely: sulphur trioxide was emitted and then formed sulphuric acid in humid air; it was not a bulk liquid sulphuric-acid tank rupture. No plant-wide shutdown, off-site impact, casualty total or quantified production loss was identified in the public ARIA summary used here. The marker is approximate to the Port-Jérôme industrial complex because the database withholds the operator and exact coordinates.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.