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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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WORKER OVERCOME BY H2S WHILE WORKING WITH BRINE WATER CONTAINNG  
MINERAL ACID  
  
  
*** INJURY:  ***  
  
  A Saskatchewan oilfield service rig hand working over an open pit  
  was recently overcome by H2S at a lease undergoing completion.  
  
  
*** CIRCUMSTANCES:  ***  
  
  The well was to be perforated with a "tubing conveyed perforating  
  gun."  The tubing had been pickled with 15% Hydrochloric acid (HCl).  
  Acid was then backwashed from the tubing, using produced water from  
  a nearby lease.  Returns were then pubped into an open pit.  As the  
  worker added soda ash to the pit, the water began to bubble and give  
  off vapours.  The worker moved away, but collapsed nearby due to  
  exposure to H2S.  Shortly afterwards, he regained consciousness.  
  
  
*** PREVENTION:  ***  
  
  Production water with dissolved sulfate is likely to produce sulfide  
  over time when contaminated by bacteria.  If acid or similar material  
  is mixed with water containing dissolved sulfide, H2S will be released  
  into the surrounding work area.  In this instance, release was increased  
  by agitation created by the reaction of soda ash with acid.  
  
  Water containing sulfides must not contact acid.  When production  
  water is used, it should be pretreated to elimate or reduce sulfide  
  contamination so as not to endanger the health and safety of workers.  
  
  
*** REGULATIONS:  ***  
  
  The 'Occupational Health and Safety Regulations', Part VIII, requires  
  employers to take all reasonably practicable measures to prevent  
  harmful exposure of workers to any chemical substance.  Employers must  
  inform workers of health effects and provide insturction on safe  
  handling procedures for chemical substances.  
  
  
*** FOR MORE INFORMATION CONTACT:  ***  
  
  The Occupational Health and Safety Branch, 1870 Albert Street,  
  Regina, Saskatchewan S4P 3V7 (phone 787-4496).  Saskatoon office:  
  3130 - 8th St. East, S7K 2H6 (phone 933-5052).  
  
  
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