Beware of the Toxic Twins!

The deadly duo you should know about.

While Carbon Monoxide (CO) gets a lot of attention in various fields, Hydrogen Cyanide (HCN) is often found alongside it, and the two together are referred to as the "Toxic Twins." These gases are powerful asphyxiants, which inhibit the body's ability to process oxygen. They are dangerous on their own. When they're combined, they're much more deadly. Carbon Monoxide (CO) is a colourless, odourless gas released from burning materials like wood, plastics, and chemicals. It is produced by the combustion of natural gas, oil, wood, and coal fuels. Carbon Monoxide(CO) can cause headaches, dizziness, and nausea when inhaled at low levels of exposure or brain damage or death at high levels of exposure. Hydrogen Cyanide (HCN) is a colourless gas with a bitter almond-like odour released from burning materials like plastics, polyurethane foam insulation, and furniture upholstery. Carbon Monoxide (CO) can cause minor CO poisoning in small doses, leaving people nauseous, disoriented, and short of breath. High concentrations of the toxic twins can result in reactions such as loss of consciousness and death. As these gases are dangerous individually, exposure to both is considerably more harmful.

Toxic gases are emitted into the air while computers, couches, refrigerators, cleaning supplies, and other things burn: hydrogen cyanide, vinyl chloride, polyvinyl chloride, formaldehyde, and nitrogen oxides, to mention a few. Oxygen levels drop during a fire. The environment is likely to include high amounts of Carbon Monoxide (CO) and a variety of other harmful chemicals to people and the environment. Long-term health impacts are a concern even at considerably lower doses.

Regardless of its thickness, colour, or movement, smoke creates toxic gases. Toxins are present in heavy, turbulent smoke, but can also be found in lighter-coloured smoke or even haze. It's not uncommon for firefighters to have headaches, sore throats, and nausea after a fire. Unfortunately, few firefighters link these symptoms to hazardous gas inhalation. According to the US Centres for Disease Control, early signs of Cyanide poisoning include lightheadedness, fast breathing, nausea, vomiting, a feeling of neck constriction and suffocation, confusion, restlessness, and anxiety.

Both Carbon Monoxide (CO) and Hydrogen Cyanide (HCN) restrict oxygen from reaching essential organs, with HCN causing heart attacks and long-term damage such as cancer if ingested. Headaches, chest tightness, dizziness, and burns around the mouth and nose are all possible side effects of CO and HCN. While firefighters are exposed to harmful substances both through their lungs and skin, the lungs are 300 times as efficient in allowing toxins into the body. While a single high-concentration HCN exposure is dangerous, repeated exposure throughout a lifetime of firefighting can cause long-term harm to the human body. Each exposure harms cells, in the heart, brain, and the most vulnerable nerve system. This is why it's critical for firefighters to keep an eye on gas levels during an overhaul.

Firefighters must also be aware that soft body tissue such as the lungs functions as a sponge, and fire victims absorb many combustion byproducts. When a victim is taken out of a contaminated setting and placed in the fresh air, some pollutants begin to outgas from their body. As a result, emergency responders treating the victim are exposed to the same pollutants, including Hydrogen Cyanide (HCN) and various other substances. As time goes on, the cumulative impact of such cell death at repeated exposures can result in chronic heart and nervous system disease.

After a fire, most firefighters appear to be exposed to Carbon Monoxide (CO) and Hydrogen Cyanide (HCN) during overhauls (salvage and clean up). The presence of harmful gases cannot be determined just by visual inspection. Using a gas detector to detect invisible risks takes little time or effort. The blazing flames, billowing smoke, and scorching heat serve as stark reminders that negligence can have deadly results. However, once the fire has been doused, the process moves to the salvage and overhaul phase. First responders may be lulled into a false feeling of security at this time since the most critical hazard—toxic vapours in the environment—is now entirely undetectable. Before, during, and after fires, people need to be more aware of the dangers these gases pose. According to the Fire Fighter Cancer Foundation, cancer is the leading cause of mortality among firefighters over the long term.

Like always, stay informed and stay safe!

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