A large cylinder tank measuring 4 feet and 9 inches tall holds 242 cubic feet of helium gas. This amount of helium is enough to fill 465 11- to 12-inch latex balloons.
Helium is nontoxic, colorless, odorless and tasteless. Also, being an inert gas, helium is very stable, second to only neon in terms of having low reaction rates. Among all the known elements, helium has the lowest boiling and melting points. This is why it only exists in gaseous form except when subjected to extreme conditions.
Helium gas is used in balloons and blimps because aside from being the second-lightest element, it is also nonflammable, making it safe for use. Helium is also known to temporarily change a person's voice when inhaled; although this gas is nontoxic, caution is advised as asphyxiation may result from oxygen deprivation.