That's the problem with people today. They're not willing to have a few explosions and 3rd degree burns just to have a little fun.
Cynicism aside, I loved balloons as a kid and seeing people around DL with the trademark mickey head balloon is a staple. If they can't discover some better lighter-then-air gas to use then just use one of the pre-existing ones and quit sweating the impact.
I know that sounds irresponsible and maybe a little cavalier but I'm so tired of society deeming this or that is unsafe to the point that everything fun is outlawed. I get why lawn darts don't exist anymore, but we're talking about a frickin' BALLOON. I don't recall any news articles about "the great helium theme park massacre of '61" or similar. Just how much radiation would we get from hemium versus all the time we spend in the proximity of wireless communication devices, antenna's and repeaters, microwave ovens, and a slew of other lesser thought about ways that we're bombarded with radiation each and ever day?
In the end, there might be a certain wisdom in just understanding that there will always be some risk and some trace amount of ( insert harmful substance here ) and the pursuit of avoiding it is ultimately just putting ourselves into some protective bubble and hoping the world doesn't hurt us.