[eesmith]

Key line: "Are the cost savings by using a 8.5% mixture of hydrogen worth all the trouble and effort it will take to convince your customers that the mixture is safe, as opposed to avoiding the safety questions altogether by using 100% helium?"

[KMnO4]

I understand the author poses this as a rhetorical question, but obviously the answer is more complicated than “just use 100% helium”. It’s much more likely that someone has already done the cost and risk analysis and determined that 8.5% hydrogen is worth the trouble.

Sorry it’s not the answer [the author] is looking for.

[jonnycomputer]

I guess that might depend on the cost of Helium.