Balloon

It's a wonderful thing, Helium.
Many uses, some helpful, some recreational.

This canister, bought full of precious gas
Now dumped on a country lane
I hope the party balloons were fun?

Helium, y'know just leaks into space
After its leaked from our balloons
Lost to arc-welders around the globe
Controlled atmosphere lost from the atmosphere.

But don't worry, more is produced by radioactive decay
Of Thorium and Uranium to name but two
It lays in pockets below the earth
It will be released in future
To fill our balloons.