A canister of hazardous waste was found dumped on the roadside of a quiet residential road in Mitcham last week.

The incident sparked an investigation by Merton Council’s environmental health department and raised fears children could have been seriously injured had they come into contact with the liquid refrigerate.

Quick-thinking Victoria Road resident, Neil Malcolm, moved the canister off the roadside but was alarmed to find that if the vapour, used in air conditioning systems, was inhaled, it could cause burns, frostbite or even instant asphyxia.

He said: “I’m just worried about how a canister of seriously harmful gas has ended up on the roadside. It needs to be investigated.

“You only need to briefly search on Google to find out just how dangerous the gas could be. Fortunately the canister wasn’t damaged but can you imagine if some children got their hands on it or opened the tap?”

A-Gas, suppliers of the canister, said it was registered to a company called the Climate Centre based in Brentford and it would retrieve the canister from Mr Malcolm.

A spokesman for the Climate Centre said: “We take our health and safety responsibilities seriously and all our loads are checked prior to leaving and on returning to a depot. I can confirm no missing items have been reported.”

She added the canister could have been dumped by someone who purchased the refrigerate from them.

Merton Council's cabinet member for environmental sustainability and regeneration, Councillor Andrew Judge, said: “We are very grateful to Mr Malcolm for alerting both our environmental health and the police to this potential incident and are investigating this matter.

“Our overall advice to members of the public is not to remove canisters or any potential harmful substances, and ask that if anyone comes across anything like this they should notify the fire brigade on the emergency number 999.”