An accident involving 2 employees occurred in asbestos removal in an ethylene oxide unit. In order to remove the asbestos insulation around the system generator safely, the removal company was told to build a plastic tent with a lock round the steam generator.A form was drawn up for this purpose which stated that flanges and valves could not be built in the tent and 'without roof'. An oxygen test was carried out on the tent in four different places on man's height and each time, normal values were measured. Based on this, the foreman gave permission to continue working. Almost immediately of mounting the ladder in the tent, the two workers started to feel sick, became dizzy and everything turned black before their eyes. They managed to stumble outside and report the incident to the foreman.Within 10 minutes of the accident, the oxygen test by the operator was done again which gave normal values. The general foreman carried out another test with another meter and normal values were noticed again. Later inspection showed that the tent was built with a closed roof and a bypass line on the nitrogen line was built in the tent with two locked block valves. Several used spray cans of glue and other substances were found in the tent and it was stated on the cans that they should only be used in ventilation rooms.
The actual cause of the accident is unknown and although nitrogen leaks in the tent cannot be excluded, there is reason to assume that other gases may have caused the symptoms of the 2 workers of feeling sick, throat irritation and breathing difficulties.
Lessons
1. It is now required to enter the tent and carry out the job with two people.
2. In the specific case of tents around ethylene oxide reactors in which nitrogen leaks can never be excluded, the tent must be built with windows of translucent plastic on each wall and entering the tent and execution of works in the tent is exclusively reserved for people carrying fresh air masks.
3. A safety guard will watch the tent for the whole period of the activities equipped with air apparatus and a knife to cut open the tent if necessary. The guard must be trained in using compressed sir apparatuses. A guard must also be provided for each work level.
4. Oxygen tests must be carried out every two hours on different heights.
5. The use of spray cans of glue or polyurethane in closed tents is prohibited unless the roof is open.
6. Asbestos removal personnel will be formally re-instructed about the procedure and that the conditions on the form must be observed
Source:ICHEME
The actual cause of the accident is unknown and although nitrogen leaks in the tent cannot be excluded, there is reason to assume that other gases may have caused the symptoms of the 2 workers of feeling sick, throat irritation and breathing difficulties.
Lessons
1. It is now required to enter the tent and carry out the job with two people.
2. In the specific case of tents around ethylene oxide reactors in which nitrogen leaks can never be excluded, the tent must be built with windows of translucent plastic on each wall and entering the tent and execution of works in the tent is exclusively reserved for people carrying fresh air masks.
3. A safety guard will watch the tent for the whole period of the activities equipped with air apparatus and a knife to cut open the tent if necessary. The guard must be trained in using compressed sir apparatuses. A guard must also be provided for each work level.
4. Oxygen tests must be carried out every two hours on different heights.
5. The use of spray cans of glue or polyurethane in closed tents is prohibited unless the roof is open.
6. Asbestos removal personnel will be formally re-instructed about the procedure and that the conditions on the form must be observed
Source:ICHEME
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