Councils issue warning over use of laughing gas
9 August 2014 Last updated at 08:10 BST
Councils across England and Wales have issued a warning about the dangers of "laughing gas".
The gas, also known as nitrous oxide, is used by some as a recreational drug and inhaled from balloons.
It is not illegal but there are some concerns about potentially dangerous side-effects, and so the Local Government Association is highlighting the risks.
Mark Sanders reports from East London, where many street vendors have had their laughing gas seized.