Around 11.30 am, the railway department reported a hydrogen chloride gas leak from a pipeline (MOP 8 bar, NPS 350) connecting two chemical plants due to the emission of fumarole. The surveillance and contingency plan relating to the structure was triggered. The pipeline was depressurised and subsequently drained by the employees.

The leak was caused due to localised external corrosion below the bridge over a stream. During repair operations, paint was directly applied to an iron oxide build-up without polishing the surface. Successive floods and the humidity below the bridge contributed to the corrosion. Water seeped in between the paint and pipe causing deposit corrosion. A specialised company temporarily fitted a watertight collar and a supporting prop onto the structure. The accredited inspection department of the company using the pipeline carried out an inspection on the 9 and 10 of October to ensure the absence of any area conducive to deposit corrosion (humidity, presence of water, retouching). The inspection led to the detection of a high-risk area, more specifically a pipeline passage on the same stream at about 50 m upstream to the previous zone showing corrosion. No additional faults were detected after further checks. The replacement of the pipeline section (20m) was planned during the next shutdown. Following the incident, the operator drafted a press release that was posted online on the company website.