here you go on the information.  The link is to the EPA website -- look at
footnote 1, you will see 409 has not been submitted for approval under the
SNAP program and thereofre is illegal.  Again, 409 was desinged as a HVAC
refrigerant not a MVAC refrigerant.
And byt the way Autofrost is designated R406A.  It is not 409. a link to the
autofrost site is below as well.

http://www.epa.gov/ozone/title6/snap/macssubs.html
WWW.Autofrost.com

As I said, I am no alternative refrigerant, but have done some research on
it.  And, to repond to Terry at the same time, there are lots of people using
lots of stuff, including Propane as refridgerants.  Lots of things will work
-- some seem very dangerous to me.  My point is for people to look into the
alternate refrigerants carefully.  that's it.