On November 30, 2015, an employee entered a large transformer, top cover removed, which had previously been filled with nitrogen. The employee fell unconscious one he/she entered the space. Another employee entered to retrieve the first employee and also fell unconscious. Another employee (#3) followed and also fell unconscious. Employees #1 and #2 died. Employee #3 was hospitalized.
So for some visual effects, I wanted to show how a large “transformer” can be a confined space, much less a PRCS. Here is an image from the business showing one of their transformers… (with a worker in the picture for size comparison)
So the OSHA case file state the atmosphere inside the transformer was Nitrogen (N2), which is the leading cause of Hazardous Atmospheres. But how would N2 find its way inside a transformer? These transformers can be ordered with a “Nitrogen Generator” which is designed to provide an inert gas-blanketed enclosure. I have no idea, as the OSHA file does not state how and I have not seen an accident report for this tragedy, but one can guess that since these transformers can be equipped with an N2 Generator so as to inert the atmosphere within it how an N2 atmosphere was generated (no pun intended). I also do not know if this was a newly manufactured transformer or one they received to be reworked.
I am just always amazed at the size of these transformers when I am at my power plant clients. What I did not know until following up with this PRCS accident is the N2 blanketing some of these units have. Makes for an interesting CS/PRCS Evaluation! The business has contested all five (5) of the seven (7) citations and OSHA vacated the other 2, so the fine sits at $35K. The OSHRC decision should shed some light on what happened.
