Concerns have been raised after young people were seen throwing pressurised canisters into a fire they had started.

Firefighters were called to Hoo Common, Chattenden, at 9pm yesterday to reports that a gate was on fire.

The fire was put out within minutes but the crew were concerned to discover nitrous oxide containers within the ashes.

A spokesman from Strood station said: "The gas isn’t flammable but comes in pressurised containers, so if they had exploded they could have done serious damage to passersby or the youths themselves.

"It may be laughing gas but it's no laughing matter."

Nitrous oxide, commonly known as laughing gas, hippy crack, or NOS, is the second most used recreational drug in the UK and is inhaled from a balloon.

It is set to be made illegal under new legislation implementing a blanket ban on legal highs.

KFRS Operations and Development Manager, David Escudier said: “We always advise people to never throw any kind of aerosol canister into a fire, no matter how big or small.

"The pressure in a can will build up so much that it will eventually explode, especially if exposed to a naked flame. The explosion is caused when the liquefied propellant, even if only a little left inside, turns into a gas and the pressure increases until the pressure becomes too much and simply explodes. This can happen at temperatures as low as 50°C.

“The consequences of throwing anything like this onto a fire can be devastating. We would urge anyone thinking of doing this for fun to consider how many lives can be changed as a result of one person’s ill thought through action."

A police spokesman said they were initially called at just after 8.30pm to a report of a fence on fire.

He added: "It was also reported a group of young people had congregated around the fire. Police attended and the group were not located, while officers contacted KFRS to put the fire out."

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