Hi all. I did an FHA appraisal of a vacant home that was purchased as a foreclosure and remodeled. When I looked into the attic I noticed that the exhaust flue for the kitchen range was no longer connected to the roof vent. I asked the owner if he knew the range hood was no longer vented to the outside and he said yes, they installed a "non-venting range hood" when they remodeled the kitchen. The kitchen range is not located next to any windows.

My question is, does this appear to be unsafe since the new range hood won't be venting waste fumes to the outside, but just filtering the air and exhausting it back into the kitchen?

Thanks in advance.