It's still in use in silent (Einstein) refrigerator units. One reason might be that we had to evacuate our office when our small refrigerator in the pentry pop

It's still in use in silent (Einstein) refrigerator units. One reason might be that we had to evacuate our office when our small refrigerator in the pentry popped and vented all ammonia. It took a while to get sorted, and it can't have been much in that small unit.