Shop heater for cold shop

Mr. Heater vent free blue flame 30,000 btu natural gas heater. either free standing or wall mount
model MHVFBF30NGT I got this from Amazon by mistake as I needed a propane unit and these are not convertible. Amazon gave me a refund but would not take the unit back due to liability with gas appliances. Unit is new in box and never opened. Retail is around $200 +/-. I am open to most any offer or an interesting trade, (nothing that eats or has a face.)

Bill, that is a good heater for someone who has Nat gas.
Do you think it would be safe in a shop? Does it draw shop air for combustion? Years ago I installed one in my Dads one room cabin that he lived in. It was propane, radiant heater. after he used it awhile I had to vent it out. it gave him headaches and I did too when I visited. In a shop there is always a small amount of saw dust in the air, and if any finishing gives off vapors too. Besides the fire hazard concerns,breathing the residues from the burning dust and vapors, can be a health hazard too. I don’t mean to put a kibosh on your sale, just airing my concerns .

I have no problem with the propane replacement, but my shop is a long way from air tight. I absolutely agree that one needs to be very carefull with any form of combustion in a shop environment. There are very specific instructions with the unit as to air requirements. That being said it is a very different heat source than a radiant disc. If someone has a use for it great, if not Habitat for Humanity will have a new item. I greatly appreciate your candor if there are doubts, better safe than sorry

Bill, I bet if you listed it on Craigs list, it would go in a minute. Better than giving it away.