Apart from the new substances entering the market, the phase out of existing ones, which have been definitely identified as damaging the ozone layer, is far from complete.
the phase out of existing ones has been an easy process
The context only states that the phase out is far from complete but does not mention how easy (or not) the process is. The process might be easy but it has just started, or it might mean it is long and tiresome process. The system likely misunderstood that because the process isn't complete, it means it is hard. 
( z1 process :ARG1 ( z2 phase-out :ARG1 ( z3 one :ARG1-of ( z4 exist ) ) ) :ARG1-of ( z5 easy ) )