Avoiding That “Oh No” Moment


Having well thought out and properly used operating procedures is important, but having good plans and people in place in case something goes wrong can make a world of difference. Think back to your own past. Have you ever been doing something and all of a sudden you get this cold queasy feeling in the pit of your stomach and breakout in a cold sweat? Well here is one of those “oh no” moments and a great lesson learned.

This particular company put a lot of time and effort into developing good standard operating procedures, or SOP’s, and in training and documenting training of all of their refrigeration operators. One of their SOP’s addressed oil draining. In order to do the oil draining procedure, the person had to not only understand the procedure, but be trained under supervision then finally authorized to do the procedure.

In this particular procedure, the direction was that “two refrigeration operators” would be involved in any oil draining procedure. It also directed that the appropriate personal protective equipment would be worn. The PPE in this case includes a full face ammonia cartridge mask, chemical resistant gloves, and coveralls.

On the day in question, two refrigeration men were tasked with checking and draining any oil from several surge drums that served a refrigerated room. One man did the draining, while the other stood by ready to assist if needed. At the third surge drum, the refrigeration operator started unscrewing the steel plug from the oil drain hand valve. As he unscrewed the plug he started to hear something. That’s when he got that cold queasy feeling. Two things happened almost instantly. First, the man thought, “Did I check that the hand valve was closed?” And second, the plug blew out spraying oil and a lot of ammonia out of the valve.

The surge drum had approximately 30 psig of pressure, and unfortunately the hand valve was far from closed. The pressure sent oil and ammonia splashing onto the operator, even covering his full face cartridge mask. Wearing that full face ammonia cartridge mask may have saved his life.

Even in the turmoil of the situation, the refrigeration operator who had just gotten hit with oil and ammonia made the effort to stop or slow the leak by trying to close the oil drain hand valve.

He got the valve about a turn from fully closed before he started to get a strong smell of ammonia through the mask ammonia cartridge, at which point he realized he had to get out of there!

The second person was standing where he had to pass by the release point to exit. He said that he could just see the shining of one of the overhead lights through the haze of the ammonia cloud, but that is how he knew where to go. Both men quickly exited the area and notified their supervisor.

For this incident and from the follow-up incident investigation, several lessons were learned for this company and all of their refrigeration personnel. First, always, always verify that the hand valve is fully closed before removing a plug.

This is not only for oil drain locations, but anywhere in an ammonia system where a valve can open directly to atmosphere. In this incident the oil draining person’s attention was on something else and he skipped a very important part of the procedure.

He had checked the hand valve position on the previous surge drum, but not on the one that really counted.

The second lesson learned is always wear your PPE. This incident strongly reinforced the wearing of PPE for both men. Wearing PPE very likely saved the life of one, and possibly both of these men.

The third lesson here is to verify that there is an alternate escape route. In this case there was an alternate escape route, and both men thought they had checked it, but it was later found to be inoperative. There may be locations where there is only one escape route. If so, develop a plan on what to do if an emergency happens so you can safely and quickly exit that location.

Fortunately, both of these men had on sufficient PPE and were able to escape.

The fourth lesson was to identify any valve that is out of its normal position. If that procedure had been followed, this incident may never have happened.

The sixth lesson was, if possible, try to remove as much ammonia from the equipment, vessel, pipe, etc. before attempting to drain oil.

Finally, have contact phone and cell numbers readily available. Being able to quickly make a call had a big impact on what happened next in this incident.

After the call was made to the supervisor, the supervisor used the control system to electrically deenergize the zone, which closed the liquid feed solenoid and greatly limited the release.

The next call went to the Manager of the Refrigeration Department who quickly activated the company’s ammonia response team, then began notifying the NRC, State, LEPC, and the Fire Department. While this was going on the man who had been hit with the ammonia was washed down with water. Due to the clothes they had on and the other PPE, neither of the men suffered any injuries.

The company’s well trained ammonia response team quickly assembled and, following the Incident Command System, began to deal with the release. The Fire Department served only in a “standby” role since they did not have hazmat capability, but they had trained many times with the company and each was familiar with the others capabilities.

Zones were quickly established (Cold, Warm, Hot). Any employees in the affected area were evacuated, the area was blocked off to prevent others from entering, area ammonia monitoring began, and isolation valves to that section of the building were closed as an added precaution. When all was ready, and all response team members set (entry, backup, decon, medical, safety, etc.) the entry team prepared to go into the release location. Before the entry team went into the area, ventilation had been set in place so when the entry team reached the leak location, the area was clear of ammonia, and one turn of the oil drain valve ended the event.

Many important lessons about the oil draining procedure were learned here, but the response to this incident is one of the most valuable lessons learned. The event reinforced the prior emergency training efforts.

In the response to this emergency the employees knew what they were to do, and did it right. The Refrigeration Department Manager said he couldn’t have been more pleased with the response of the ammonia team. The refrigeration operator’s “oh no!” moment is a lesson that will not be forgotten by him. Hopefully others can learn from this experience and avoid a similar one.