Thanks for asking, XXXXX It absolutely will not eat away at the seals. Maybe he is confusing it with some other alternative refrigerants, such as HotShot or something.
Re. the flammability, it does contain propane, but it is a more refined grade then you would use in your barbeque, with a much higher autoignition temperature. The other ingredients of the blend further reduce the flammability risk. The autoignition temperature of the regular grade of propane is only 842°F, while Duracool's autoignition temperature is 1635°F. There are over 5.5 million cars running on Duracool and other hydocarbon blends, and I have never heard of a single incident. In fact, the manufacturer provides me with $1,000,000 of liability insurance, and I have a document on file from the insurance company showing that there has never been a single claim filed from a Duracool product. So although I wouldn't recommend smoking while charging the product, in case the hose burst and the whole tank was opened up (and you're using the small cans, anyway), it shouldn't be any concern once it is in the car and in such a small quantity. There is more chance of a fire from the hair spray your wife has in the car than from the small amount (less than a pound in most cars) of Duracool in the refrigeration system. I have heard of tests done where a car was rigged to let the whole charge of Duracool into the inside of the car, with a lighter to ignite it. It was barely enough to maintain a flame. So no worries. For more information, see:
http://www.idealcoolantsolutions.com/FAQ.htm#flammability
I know many of the shops are hesitant to use any alternative refrigerant because of horror stories they've heard about OTHER alternative refrigerants. I wouldn't touch Freeze12 or HotShot or some of the others out there, but hydrocarbons are the way to go. Let me know when you find someone open to the idea; I'd like to follow up with them and get them to switch over. I also have a referral program; I'll credit you 10% of the first order someone makes based on your referral, towards a future order you make if you need more for another car or something.
I have used Duracool in all my personal cars for several years now. If I get a new vehicle I change it over to Duracool as soon as I get a chance. The reason I became the distributor here is that when I moved back from Oklahoma, I found that there was no one in the area to buy more Duracool to recharge my system after I lost my charge due to a bad hose. So I decided I should make it available here.
What you often don't hear about R134a, the primary replacement for R12, is that it is quite toxic (causes cancer and breathing problems), is global warming (not as bad as R12, but still significant), and is corrosive (so the AC systems in newer cars with R134a wear out faster). So Duracool is a much safer way to go.
We guarantee that Duracool will not harm your AC equipment (actually it prolongs its life), and are covered with a million dollars worth of liability insurance in case anything were to happen (if it did, you would be the first incident ever!).
Hope this resolves your concerns. There is a lot of misinformation floating around out there.