Created on March 7, 2017

Hi all, see you on my monthly SafetyBuzz. Let me come up here with the topic of:

“Confined Space Entry – Worker and Would-be Rescuer Asphyxiated”

  1. Matrix was contracted by Premcor, Inc., the previous owner of the refinery, to serve as the primary maintenance contractor during the fall 2005 maintenance turnaround (unit shutdown)
  2. A few days before the incident, a temporary nitrogen supply is installed for purging the system in the hydrocracker Reactor (R1) as part of the catalyst loading procedure. However, contrary to the Valero refinery safety procedures, a nitrogen purge warning sign and barricade were not in place in the work area.
  3. To begin work on the hydrocracker unit, a Valero hydrocracker unit operator issued a safe work permit to “install the top elbow,” or pipe assembly. However, the permit was not amended to limit the work to “set up only.” Furthermore, the nitrogen purge status was marked “N/A” on the permit even though the reactor continued to be purged with nitrogen.
  4. While the boilermakers were cleaning the manway flange surface, a roll of duct tape was lying on the distribution tray about five feet below the opening. The reactor cleanliness criteria prohibited leaving the tape inside the reactor, so they discussed retrieval options with their foreman.
  5. They considered entering the reactor to retrieve the tape, but knew entry would require a specially trained and equipped crew and confined space entry permit, which would delay their work, possibly beyond the end of their work shift. Instead, they decided to make a long wire hook and lower it through the manway to retrieve the tape.
  6. A few minutes before the incident, nearby workers saw the first victim standing next to the studs surrounding the open manway trying to retrieve the tape with the wire. One worker saw him kneeling next to the studs while he worked with the wire. Nobody saw him enter the nitrogen-filled reactor, but he either fell in or intentionally went into the reactor.
  7. An eyewitness working on the platform of an adjacent reactor saw the boilermaker foreman (the second victim) and the nightshift contract administrator looking through the manway into R1. The eyewitness watched the foreman hurriedly grab a ladder, insert it into the reactor, and immediately climb down. The eyewitness next saw the nightshift contract administrator approach the ladder, hesitate, and then heard him urgently call for help on his radio. The site emergency siren then activated.
  8. Valero Emergency Response Specialists and Matrix safety personnel arrived on the platform in less than two minutes, and saw two victims lying motionless inside the reactor on the tray five feet below the manway. They inserted an oxygen meter through the manway and it immediately alarmed—the oxygen concentration was near zero.

Based on incident investigation report, the below lesson learned that can be summarized:

  1. Oxygen-deficient atmospheres in confined spaces can be deadly in only a few breaths.
  2. Entering oxygen-deficient atmospheres should never be attempted under any circumstances without training and proper air-supplied breathing equipment.
  3. Confined space hazard warnings and barriers should be maintained around open purge vents at all times during purging activities.
  4. Workers suddenly involved in emergency activities must not allow emotions to override safe work procedures and training. Only qualified and trained personnel equipped with the necessary safety equipment should attempt a rescue.


You can observe the detail report of this incident in:


Dedi Irawan, ST, SFS
Process Safety Engineer

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