Released balloons should be latex balloons only (not microfoil) and always be hand knotted with no ribbon, string or fishing line attached to them. Balloon releases are very beautiful and if done properly are environmentally safe.
In NSW the maximum amount of balloons you are legally allowed to release at one time is 19.
The Carr Governement banned the mass release of balloons in 1999. The great state of NSW is the only Australian state that has adopted this illogical piece of legislation. Other states have considered it, but threw it out of parliament due to lack of scientific evidence. I’m not sure what the NSW parliament was thinking when they decided to enact the ban, but unfortunately we are stuck with it.
What happens when balloons are released? About 95% of these released balloons will rise to about 8,500 meters where the air is thin and very cold. The cold temperatures will cause the latex to weaken. Thin air causes the helium balloons to expand and shatter into tiny pieces. These tiny pieces fall to earth and scatter over a large area. The pieces are usually small enough that is they are ingested by any sealife, they will pass through and cause the animal no ill effects.
The remaining 5% of released balloons that do not rise high enough to shatter, drift with the wind currents for approximately 8-14 hours before coming down to begin the biodegradable process.