More must be done to raise awareness of the harmful effects of laughing gas, council leaders have said after it emerged that officials are seizing "hauls" of cannisters from the streets of England and Wales.
It is "deeply disturbing" that people widely view nitrous oxide as a "safe" legal high, the Local Government Association (LGA) said.
The Association, which represents around 400 councils in England and Wales, said local authorities are seizing "hauls" of canisters.
For instance, Hackney Council in east London said that it confiscated more than 1,200 cannisters of the chemical on just one Saturday night in July outside the pubs and clubs in Shoreditch.
While inhaling nitrous oxide is not illegal, council officers seized the cannisters - used to fill balloons with the gas that are sold to users for around £5 - under unauthorised street trading regulations.
Meanwhile officials in Norfolk, Hertfordshire and Thames Valley have reported increasing numbers of cannisters being found.
The LGA also raised concerns that a number of children inhaling the chemical have emerged on the internet, "glamorising" the drug.
It said that the chemical - which is regularly taken at nightspots, festivals and parties - has been linked to a number of deaths. A busing nitrous oxide can lead to oxygen deprivation resulting in loss of blood pressure, fainting and even heart attacks.
The LGA estimated that it is used by almost half a million young people across the country
"It is deeply disturbing that this drug, which can be highly dangerous, is still widely viewed as safe," said Katie Hall, chairwoman of the LGA's Community Wellbeing Board.
"It is imperative that users understand just how harmful it can be. This gas can kill and much more needs to be done to get this message across.
"We are particularly concerned about internet pages and uploaded clips which are effectively 'promoting' this as a harmless drug. The web giants must do more to crack down on this, they cannot simply sit on their hands and ignore what is happening on their own sites.
"We are calling on the big internet corporations to step up to the plate and show responsibility by providing health warnings and links to drug awareness charities. It is wholly unacceptable that this craze is being glamorised and encouraged in this way."