Why do we keep using Helium balloons?

The world supply of Helium is running out, and it is being argued that Helium should be made more expensive so that it won't be used so much for party balloons and won't run out in the next 50 years, so that it will still be readily available for scientific and medical applications.

I tend to agree, since we really don't need them for balloons: we could just use hydrogen instead; we can never run out of hydrogen. sqr(twg) on Slashdot says:

This is indeed a good idea. A balloon filled with hydrogen is not much more dangerous than one filled with air. If you hold it over a flame, it will make about the same pop as an air-filled balloon. The 0.3 g of hydrogen in a balloon is not enough to produce any serious amount heat as it burns. (We did this back in high-school chemistry class. We had an awesome teacher.) Hydrogen is cheaper than helium, and does not diffuse as easily through the balloon surface, so balloons would last longer.

There is some danger in the handling of cylinders. If hydrogen leaks out in a room with poor ventilation, there is a risk of explosion. However, the same is true for propane/butane gas which is used in kitchen stoves, and most people seem to be able to handle that.

Another danger is when stupid people inhale balloon gas and asphyxiate. With helium, this problem is commonly solved by adding some oxygen to the mix. Hydrogen cannot be safely mixed with oxygen, so you'd either have to tell the stupid people not to do that, or accept a slight decline in the stupid population as they figure it out for themselves.

Actually, the entire danger of hydrogen cylinders might be avoidable. It can be produced directly from water and electricity; you just have to figure out how to separate it from the oxygen.

Now, helium is often mixed with air to make it cheaper. Similarly, perhaps hydrogen could be mixed with nitrogen to make it safer. (Larger helium balloons can still float with about 50% air content, although small balloons cannot, since the skin of the balloon, plus the string, will weigh it down too much.)

Of course, the nanny-state mentality will create some resistance to this idea. Too bad I'm not a chemist, or maybe I could suggest some other gas that is lighter than air, more plentiful than helium and safer than hydrogen. I know I'd rather give my child a hydrogen balloon than deprive him or her of such a wonderful childhood delight... but I might be concerned about filling a whole room with them.

• More on hydrogen safety - note that this page assumes large amounts of hydrogen; it is not concerned with tiny amounts of hydrogen like what a balloon would contain.