At around midnight, a leak occurred on piping conveying anhydrous hydrogen chloride (a hazardous gas depending on the concentration of the cloud and the duration of exposure). The authorities initiated a chemical alert in two communities. The 36,500 inhabitants were confined to their homes. The municipalities also requested that ventilation systems (air conditioning) not be used. Automobile traffic was stopped on a bridge located near the leak. The pipeline manager and the emergency services responded to stop the release.

The leak was located on an instrumentation rack of a pipeline (DN 450) in an ancillary installation. The accident occurred during major flooding in the region caused by Hurricane Harvey (ARIA 50399).