This paper is developed for highlighting the required balance between establishment of minimum requirements for PREVENTING accidents related to toxic gas and Oxygen deficiency exposure and being prepared in case of emergency.


By reviewing different toxic gas exposure and Oxygen deficiency related accidents, it was obvious that the majority or almost all of these accidents had taken place due to absence of the prevention minimum requirements; e.g. supervision, permit to work, isolation procedures, risk assessments, training and awareness, work planning, etc.

On the other side, it is observed that many organizations feel confident and satisfied when distributing emergency escape devices and personnel toxic detectors to all personnel while these devices are just to help in case of toxic gas leak or release. In fact they may help or may not help at all - based on many different factors.

Confident and satisfaction can be achieved only when the minimum requirements for prevention are met plus being prepared for emergency situations by having all required prevention means including technical studies for concluding if personal detectors and emergency escape sets are necessary or not.

Personal toxic gas detectors could be not essential if the plant/work area is equipped with fixed hydrocarbons and toxic gas detection systems that can activate different levels of alarms and shutdown which mean more efficient than personal toxic gas detectors which will give only low or high alarm. Single personal toxic gas detectors would not help in case of inert gas or Oxygen deficiency atmosphere.

Additionally, it is observed that some organizations distribute filter type emergency escape devices which could be neither effective nor permitted for certain concentrations of toxic gases or hazardous atmospheres.

Experience showed that without practical training of the simplest types of emergency escape devices, most of personnel would not be able to use them in case of emergency due to lack of practical training plus panic.

Our conclusion is without having the minimum requirements for preventing this type of accidents; accidents would take place whether personal detectors and emergency escape sets are distributed or not (accidents history proving this)

Just for example, the H2S IDLH figure (immediately dangerous to life and health) is 100 ppm which means that there could be no time to put the emergency escape set in case of sudden high H2S gas leak or release. Serious health effect or immediate death would happen at certain levels of exposure for each type of toxic gases including inert gases.

Based on this, the way forward for preventing such type of accidents is to ensure having the minimum requirements of prevention and controls; i.e. supervision, plant maintenance and integrity, plant fire and gas detection, ESD, training and awareness, operation controls including permit to work, isolation, regulations, management of change, etc.

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