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*                             HAZARD ALERT                          *  
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*  Produced by:  Saskatchewan Human Resources,                      *  
*                Labour and Employment                              *  
*  Provided by:  Canadian Centre for Occupational Health and Safety *  
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WORKERS KILLED WHILE WELDING ON TANKS CONTAINING FLAMMABLE MATERIAL  
  
  
*** MARCH 1988 ***  
  
  A wroker attempted to do some welding on a tanker truck that had  
  contained 'emulsion' from an oilfield battery.  An explosion resulted  
  that wrecked the truck and the building in which the welding was taking  
  place.  The welder was killed and another worker in the building  
  injured.  No precautions had been taken to ensure that the tank was  
  free from explosive vapours.  
  
  
*** DECEMBER 1988 ***  
  
  A worker attempted to do some welding on a tanker truck that had  
  contained 'emulsion' from an oilfield battery.  An explosion resulted  
  that wrecked the truck and the building in which the welding was taking  
  place.  The welder was killed.  Although the tank had been steam-  
  cleaned in an attempt to purge vapours, there were still suffficient  
  residues to create an explosive atmosphere.  The tank should have been  
  tested for flammable vapours before and during welding operations.  
  
  
*** PREVENTION:  ***  
  
  Had Occupational Health and Safety Regulations been followed, it is  
  unlikely that an explosion would have occurred in either instance.  
  Section 272(2) of the regulations requires that:  
  
        An employer shall ensure that no hot work is performed where a  
        flammable liquid or explosive substance is or may be present until:  
  
        (a)  suitable tests properly conducted have been made that  
             indicate the work may be safely performed;  and  
        (b)  suitable procedures, including testing, have been adopted  
             and implemented to ensure continuous safe performance of  
             the work.  
  
  "Hot work" defined in section 272(1) includes welding.  
  
  Section 272(3) requires that:  
  
        When testing procedures are required during hot work, and  
        employer shallhave tests made at intervals appropriate to the  
        work being performed and the results recorded.  
  
  Finally, section 272(5) requires that:  
  
        An employer shall ensure that every tanker, tank, vessel or  
        piping that contains or has contained any combustible liquid,  
        flammable liquid or explosive substance is purged before any  
        hot work is commenced on that tanker, tank, vessel or piping.  
  
  
*** REQUIREMENTS FOR WELDING  
    ON TANKS CONTAINING EXPLOSIVE SUBSTANCES:  ***  
  
  Any welding on tankers, tanks or vessels that contain or have  
  contained any combustible liquid, flammable liquid or explosive  
  substance is considered to present an imminent risk to the welder.  
  Before the Occupational Health and Safety Branch will permit any  
  employer to engage in this type of welding, he or she must arrange to  
  have the tank purged.  In addition, the employer must have and use  
  appropriate equipment and competent employees at the worksite to test  
  the atmosphere in any tank - both before and during welding operations.  
  
  THESE ACCIDENTS ARE OF GRAVE CONCERN TO THIS BRANCH.  
  PLEASE TAKE STEPS IMMEDIATELY TO COMPLY WITH THESE REQUIREMENTS.  
  
  
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