Fears have been raised over the easy access of a "potentially harmful" chemical after two large canisters were discarded in a playing field.

The 560-gram nitrous oxide metal containers were discovered in Fitzmaurice Park, off Pound Lane, in Thorpe St Andrew, at around 3pm on November 28 by Gary Cooper, 67, from nearby Hopton Close in Dussindale.

Nitrous oxide is also known as 'laughing gas' and is a colourless non-flammable gas.

It is used as a propellant, and has a variety of uses from rocketry to making whipped cream but can be used as a recreational drug.

Norwich Evening News: The nitrous oxide gas canisters left discarded by benches in Fitzmaurice Park in Thorpe St Andrew, Norwich, on November 28, 2022The nitrous oxide gas canisters left discarded by benches in Fitzmaurice Park in Thorpe St Andrew, Norwich, on November 28, 2022 (Image: Gary Cooper)

Mr Cooper, who was on a dog walk at the time, said the half-empty canisters were next to metal seats near the American Football pitch and were surrounded by several burst balloons.

Norwich Evening News: Husband and wife Tracey and Gary Cooper, who are both retired, and live in Dussindale, Thorpe St Andrew, in NorwichHusband and wife Tracey and Gary Cooper, who are both retired, and live in Dussindale, Thorpe St Andrew, in Norwich (Image: Tracey Cooper)

His wife, Tracey Cooper, 57, said: "We have got to raise this subject with young people. Nitrous oxide is not harmless and can kill people.

"People can readily buy it online. There is no legislation stopping them from buying it.

"There was a situation two years ago when there was a problem with people leaving small silver nitrous oxide canisters around the estate and it would seem the issue has raised its ugly head again. 

"Over the years it has been known as laughing gas and people mistake it as fun. People can collapse from it. It is terrifying.

"It should not be easily available and people should have to prove their age to buy it. It should not be sold to under 25s."

She added she had not reported it to the police but had alerted Thorpe Town Council.

Her husband said younger people commonly sat around the bench area.

The school said: "This is a field with open access, which the school does not use."

Ian Mackie, Conservative county and district councillor for Thorpe St Andrew, said: "It is shocking to find this kind of thing.

"It tends to be on the increase particularly with young people. I don't think they are aware of the dangers.

"There needs to be an awareness campaign."