Import and use of R22 refrigerant in US

My company is looking at importing a line of environmental chamber that are manufactured in
Asia. For cooling the chamber uses the refrigerant R22 (the literature says its K22 but we assume
its the same). For those that know what the current US laws are for commercial systems using
R22 I have a few questions:

1) Is it legal to import into the US, install and operate a new system that uses R22?
2) If its legal to import, is the unit supposed to be shipped dry or can it be charged with R22?
3) On the install of the unit (again assuming its legal) does the charging of the unit have to be
done by a licensed individual (what type of license) and also for topping off over time?
4) Is there an EPA document that covers my question above?

Thanks in advance for any help on this topic.