Tom? Nitrous Oxide is far from being a harmless substance......I suggest you read the MSDS.
http://www1.boc.com/uk/sds/special/nitrous_oxide.pdf
I'm not saying it's not harmful, I'm saying it is non-flammable, which the link you provided appears to support.
If you are refering to my comment on damage to the engine, well I am only repeating what is known in the car world. The reason I don't have NOS in my car is simply because I do not know what effects it may have. However I will be putting it into my track car (BMW E36) that I'm working on with my mech collegue - he appears to know what he's doing - I hope lol.
Tom