I've worked on a few Ammonia refrig systems over the years. I went to the Servel AC class. Now for my story.
25 -30 years or so ago my customer was a Sea Food Distributor w/all R12,R22,R502 units. They wanted to purchase an ice machine, about 6,000 lbs of ice a day. The icer they wanted was an old Ammonia system,so I looked the old setup and said"sure",its OK. But being a 1man band, I could not,would not do all that massive amount of piping,wiring,humping,relocating, and redoing everything . The customer wanted "that" system, so they got it. They also got ( lets call him)"Rodger" the AMMONIA EXPERT out of NY City. Rodger put on his mask and Sawzalled the refrig lines, the Ammonia cloud went inland , the cloud passed by/over/around/in about 20 homes. If memory serves me correct there were about dozen Law Enforcement Agencies that responded to the "incident", the local Police,Sheriff, EPA,DEC , FireDept,Ambulances,Helicopters,and the Marine Bureau and some others. WOW!!!!!!!!!!!!!!!!!!!!!!!!
So "Rodger" setup the newly relocated ice maker in my customers bldg. and it purred and made LOTS of ice, and I was FORBIDDEN to even touch the ice maker, not even the steel refrig lines. What , me FORBIDDEN!?!? Well, "Rodger"didn't allow for any "overflow makeup" from the Cooling Tower on the roof, I mentioned this to the customer and then I was repremanded for having"LOOKED" at the icer w/o "Rodger" being present. OK OK , I know my place!!!! Now fast forward about 3 years , about the same time as the other bldgs in the industrial park were closing for the day. The water cooled cond ruptured,the Ammonia went into the water, the water went thru the Cooling Tower, the Ammonia went into the air, the air went into the neighbors parking lot , the air went into the peoples lungs, and ALL of those Law Enforcement people were responding all over again. Holy Moly!! Hay, what do I know ?