A leak of hydrogen, methane and hydrogen sulphide from a pipe in a refinery

The leak occurred on a process pipe of a pressurized at 17 bar and located 3.5 m from the ground. The gaseous mixture composed of hydrogen, methane and hydrogen sulphide (density: 0.6) was released to the atmosphere.
The operator evacuated a hundred employees, stopped the production and put the establishment in the safe mode.
The emergency plan was triggered. Water curtains were put into action and measurements of toxicity and explosimetry were carried out.
After a hour, the pressure in the pipe reduced 0to .5 bar and the measurements of toxicity and explosimetry in the ambient air returned to satisfactory level. The emergency plan was terminated.
Public firefighters are on site but did not intervene.

pressurised gas process pipe (17 bar) located 3.5 m from the ground

14:30 Leak detected from a pipe at 17 bar. The operator evacuates a hundred employees, stops production and puts the establishment in the safe mode. The emergency plan is initiated.
Water curtains are put into action and measurements of toxicity and explosimetry are carried out.
15:30 The pressure in the pipe at 0.5 bar. The measurements of toxicity and explosimetry in the ambient air being satisfactory,
15:45 Emergency plan is terminated
Public firefighters are on site but will not intervene.