What is balloon gas?

Helium supplied to the balloon industry is sometimes called balloon gas because it is a mixture of air and helium. The term “balloon gas” distinguishes it from the 99.99 percent ultra-high purity gas used for other purposes, such as the medical field.

You do not have to request "balloon gas" from your helium supplier, as the term is not widely used. Suppliers will know what gas to supply you with.

You may have noticed that different companies have varying gas compositions. BOC (Binary offset carrier) helium gas is typically used to inflate balloons. BOC cylinders are available in a variety of different sizes. The 124CV cylinder is designed with a built-in regulator, which makes it great for smaller events. This cylinder is mixed with 3.0 percent air and 97 percent helium. 

Helium should be respected and used properly. See more details here.