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FACEValue: Tank mechanic dies of asphyxiation in permit-required confined space

NIOSH’s Fatality Assessment and Control Evaluation Reports
Date of incident: Feb. 4, 2004

A 23-year-old tank mechanic died of asphyxiation after entering a permit-required confined space. The victim worked for a company that specialized in the manufacture and maintenance of transportation tanks. The company had a written confined space entry policy stating no one was allowed to enter tanks until the atmosphere had been checked and documented, but an OSHA investigation found that documentation was not always completed. The shipping container had been purged with inert nitrogen, and a dated memo was placed on the outside stating it had been cleaned and was free of hazardous material. The memo also said the atmosphere was breathable only if proper tank entry was followed. The tank mechanic used a ladder to climb on top of the tank, open the manhole cover and climb inside. He collapsed after entering the tank. A co-worker found the victim approximately one hour after entering the container. He called for help and jumped into the tank to retrieve the victim. The co-worker lifted him to workers above who attempted resuscitation. When these efforts failed, he was pronounced dead by emergency responders.

To prevent future occurrences:

Permit-required confined spaces should have written procedures, including posted documentation of test results by an authorized person. Employers must establish written entry procedures for permit-required confined spaces that include the following:

  • Evaluate hazardous conditions and post warning signs at entry.
  • Provide appropriate equipment for testing the atmosphere.
  • Document test results in a written entry permit and post outside the space. Workers entering must be trained in proper entry procedures.
  • Implement measures to prevent unauthorized entry. Prior to entry, a safe atmosphere must be ensured, usually involving continuous forced-air ventilation.
  • Continuously monitor the atmosphere in the space. Workers inside should be assisted by attendants outside to maintain communication and implement a rescue plan, if necessary.

Never enter a confined space without first testing the atmosphere and using proper personal protective equipment. The level of oxygen cannot be determined without a calibrated instrument. Workers cannot rely on sense of smell. All compartments where workers will be present should be tested, including the bottom, middle and top. OSHA recommends testing at 4-foot intervals. Workers should use all necessary physical protection, respiratory protection, ventilation fans and fall protection.


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