What could cause an AC compressor to blow the casing apart?

About a year ago I had my whole AC system replaced in my 2002 Stratus. A month later, BOOM!, totally destroyed the casing of the compressor. The mechanic figured it was just a bad compressor and replaced the entire system again.
Now, last week Im driving and the same thing happens less than a year later. WTF?

 

Something must be building up the pressure in the compressor. Or not enough oil in the system.

 

What exactly do you mean by "whole system"

 

everything in the engine compartment, hoses, condenser, drier, compressor....