Over 20 people have been hospitalised with carbon monoxide poisoning at the Ice Arena in Thebarton, find out what could happen when exposed to the toxin

More than 20 people in SA have been hospitalised with carbon monoxide poisoning after a leak in an ice arena, exposure to the toxins can be serious, find out what can happen.

More than 20 people have been hospitalised with carbon monoxide poisoning after a leak at the Ice Arena at Thebarton on Saturday.

A low level of hydrogen cyanide was also detected in the venue, but SA Health said there was no sign that any patient had been exposed to that toxin.

A faulty ice-resurfacing machine has been blamed for the incident.

So far it seems that all patients are going to make a full recovery.

But this is how serious exposure to the two substances can be:

Carbon monoxide

Carbon monoxide poisoning happens when two much of it builds up in the blood.

According to the Mayo Clinic, a US-based centre focused on health education and research, it “affects the brain and heart the most” and can “lead to serious tissue damage or even death”.

“Carbon monoxide poisoning can be especially dangerous for people who are asleep, drugged or drunk. Carbon monoxide can cause brain damage or death before anyone realises there’s a problem,” it says.

The reason it can be hard to detect until it’s too late is that it has no odour, taste or colour.

“Exposure over time might lead to symptoms that can be mistaken for the flu without the fever,” the Mayo Clinic says.

But “clearer symptoms” can include headache, weakness, dizziness, nausea or vomiting, shortness of breath, confusion, blurred vision, drowsiness, loss of muscle control and loss of consciousness.

Even after recovery from the initial poisoning, longer-term effects related to the brain and nervous system can include “memory loss, personality changes (and) movement problems”.

Hydrogen cyanide

Hydrogen cyanide is a “colourless or pale-blue liquid or gas with a bitter, almond-like odour”, according to the US Centers for Disease Control and Prevention.

“Hydrogen cyanide interferes with the body’s use of oxygen and may cause harm to the brain, heart, blood vessels, and lungs,” it says.

“Exposure can be fatal.”

The chemical has many uses including for “fumigation, electroplating, mining, chemical synthesis and the production of synthetic fibres, plastics, dyes, and pesticides”.

The CDC says workers at risk include those who fumigate ships and buildings, agricultural workers who treat pest infestations in fruit orchards, staff in factories making acrylic fibres, synthetic rubber and plastic, and steel and iron workers “in plants that harden iron and steel”.

Safework Australia says hydrogen cyanide is “extremely flammable” and has also been used in the leather tanning and industry and for “rodenticide” (pest control), as well as fumigation.

“Hydrogen cyanide is a by-product from blast-furnaces, coke ovens, gas works, petroleum refining, photographic development and when certain materials, like nitrogen-containing plastics, are burned,” it says.

There are exposure standards that workplaces must not exceed, which may require air monitoring.

Key Safework Australia advice includes to keep workplaces and storage areas dry as cyanide salts can react with water to give off hydrogen cyanide.

“Isolating cyanides from incompatible substances to avoid dangerous reactions that could generate hydrogen cyanide or other hazardous gases, for example storing cyanides

away from acids, oxidising agents and other incompatible substances,” it advises.