From time to time I like to look at RMP data for trends and interesting accidents that we can learn from. As in the past, Anhydrous Ammonia seems to always find its way into my research. Some will say it is because it is by far the most widely used RMP chemical and others will lay claim to other reasons, which I will leave up to you to draw your own conclusions. But the fact is the 5-year accident history incident that has the highest number of injured (71) was an 18,000 pound NH3 release that sent one (1) employee and thirty-six (36) residents to the hospital. But it is the incident details that we can learn from as I am seeing more and more NH3 refrigeration facilities using Carbon Dioxide (CO2) in conjunction with their ammonia refrigeration processes. Doing so increases the scope of the PHA for sure, including the “facility siting analysis” as is ever more evident by this incident…
NOTE: the numbers do not match because the companies submittal list 71 injuries and their narrative use 1 and 36 injuries. I do not know the correct figure from a reputable source.
NOTE 2: This facility is a brewery and the CO2 may not have been used in conjunction with the Ammonia refrigeration system, but was located such that it impacted the ammonia system anyway.
From their 5-year accident history…
The facility had an accidental release on October 6, 2007. A release of carbon dioxide and ammonia from Cerveceria India, Inc. located at Mayaguez, Puerto Rico, resulted in the evacuation of the residential population within a two (2) square mile area (2,000 people were evacuated in total). One (1) employee and 36 residents required medical attention and/or hospitalization. Seven (7) vessels, part of a carbon dioxide transfer system, failed and the resulting overpressure impacted an ammonia refrigeration system. The system failure resulted in a release of 85,000 lbs. of carbon dioxide and 18,074 lbs. of ammonia over a 3.5 hr. period.
So as we can see first hand from this incident, a CO2 process that works in concert with the ammonia refrigeration system AND/OR which is “cited” either “in, on, or adjacent” to the NH3 process should be considered a “hazard” within the PHA.
I will take it one step further and SUGGEST that the CO2 system that is used in conjunction with the ammonia system may indeed need to be managed as a PSM/RMP covered process since a failure within it could/can lead to a failure of our “covered process”. This is exactly what OSHA/EPA are driving when they defined a “process” using the following wording…
For purposes of this definition, any group of vessels which are interconnected and separate vessels which are located such that a highly hazardous chemical could be involved in a potential release shall be considered a single process.
Either way, it should be covered in the facility’s PHA(s).
Just something to consider when the time comes to re-validate your PHA or if your facility is considering using CO2 how this “change” should undergo an MOC.
CLICK HERE for the RMP referenced.