A 24-kg leak of anhydrous hydrogen chloride (HCl) occurred around 4:30 pm inside a chemical plant (making organic products). In workshop no. 11, the technician loaded a synthesis reactor with a 37-kg bottle of liquefied anhydrous hydrogen chloride. The bottle was located outside the workshop. The hose broke, causing the atmospheric release of 24 kg (14 m3) of gaseous HCl. 6 site staff members suffered a malaise. The internal emergency plan was activated; within 10 minutes, the plant’s response team in appropriate gear had isolated the leak by closing the tap on the bottle, which was also watered throughout the intervention; the 3 m3 of scrubbing water were confined onsite and channelled to the effluent treatment plant. Local fire services dispatched an emergency medical assistance vehicle; the 6 ill staff members were hospitalised for additional analyses and were released that evening.

The damaged hose was made of reinforced Teflon (braided stainless steel) with a 70-bar service pressure (service pressure / effective pressure = 70/105 bar) and broke at 37 bar (pressure typically used in the workshop) for a still unknown reason (end piece screw thread corrosion?). It had been installed during the previous night. No replacement hose was in stock and so one had to be removed from another shop on a similar installation, although this other shop was operating at lower pressure (5 bar). Service start-up was not coordinated.

Before the plant’s annual closure, the operator checked all hazardous gas hoses and reviewed HCl implementation conditions in workshop 11 (new hose and layout, 5-bar working pressure, enhanced operational monitoring). Over the medium term, the operator agreed to adopt a policy of monitoring all hoses used with hazardous fluids, including end pieces, along with a storage procedure whenever hoses were no longer in use. A study was conducted for installing both a rigid hose between bottle and relief valve, and then a water curtain on the transfer facility. The operator upgraded the site’s inventory management system to ensure the availability of pre-fitted hoses.