Carbon Monoxide Poisoning: A Hidden Danger in the Workplace (PDF)

What is Carbon Monoxide Poisoning?

Carbon monoxide or CO is a colorless, odorless, and tasteless toxic gas existing in a very small concentration in the atmosphere (normally < 0.001%), and is a product of partial combustion of carbon-based materials. Carbon monoxide poisoning is associated with a high incidence of morbidity and mortality. In the year 2020, 200 deaths occurred due to CO poisoning.

Carbon monoxide is a chemical compound consisting of one carbon and one oxygen molecule. As it can not be seen, heard, or smelled, CO poisoning does not provide any warning signs.

Carbon monoxide is generated by the incomplete combustion of carbon-containing materials like kerosene, natural gas, wood, coal, gasoline, etc. Also, when the combustion takes place with insufficient oxygen, carbon monoxide can generate.

Sources of Carbon Monoxide in the Workplace

One may be exposed to unsafe levels of Carbon Monoxide in workplaces by:

  • poor industry maintenance or unvented heating equipment;
  • poorly vented natural gas burning equipment;
  • vehicles in garages (car engine exhaust fumes) or other enclosed spaces;
  • during a plant fire (smoke from fires); etc.

Other sources may include the use of charcoal fire grills in confined spaces (e.g. tents). Poorly installed domestic gas heating appliances and incomplete combustion of butane and propane (e.g. in caravans) may lead to sub-acute, chronic, or occult poisoning.

Some of the sources of carbon monoxide are:

  • Generators
  • Concrete cutting saw
  • Welding fumes
  • Clogged chimney
  • Gas heaters
  • Corroded or disconnected water heater vent pipe

For example, assume that one man is working in a small enclosed non-ventilated room with a fired heater, and complaining of dizziness, severe headache, nausea, weakness, angina is chest pain. He is a patient with Carbon Monoxide poisoning.

Who is at Risk from Carbon Monoxide Poisoning?

All people are at risk for carbon monoxide poisoning. The elderly and people with chronic heart disease or respiratory problems are generally more at risk than others. In the condition of carbon monoxide poisoning, the patient must be moved away from the CO source to fresh air immediately. In an emergency room, oxygen therapy is the main treatment for carbon monoxide poisoning.

CO Poisoning Symptoms
Fig. 1: CO Poisoning Symptoms

Symptoms and Health Effects of Carbon Monoxide poisoning

Occupational carbon monoxide poisoning is not well recognized. Hence, regulatory measures should be implemented to prevent CO poisoning in the workplace.

Breathing CO can cause headaches, dizziness, vomiting, and nausea. If CO levels are high enough, one may become unconscious and even die. Exposure to moderate and high levels of CO over long periods of time has also been linked with an increased risk of heart disease. People who survive severe CO poisoning may suffer long-term health problems. Sleeping or drunk people can even die from carbon monoxide poisoning before showing any symptoms.

The following table in Fig. 2 shows the effects of carbon monoxide exposure levels in the air.

Effects of Carbon Monoxide Exposure Levels
Fig. 2: Effects of Carbon Monoxide Exposure Levels

Delayed Features of Carbon Monoxide Poisoning

Uncommon complications of carbon monoxide poisoning include well-defined neurological conditions such as:

  • Parkinsonism, chorea, and choreoathetosis (which correlate with lesions of the putamen and globus pallidus seen on computed tomography and magnetic resonance imaging)
  • cortical blindness
  • mutism
  • hemiplegia
  • peripheral neuropathy.

Mechanisms of CO toxicity

CO reduces oxygen delivery to tissues in several ways:

  • It combines with hemoglobin to form carboxyhemoglobin (COHb), reducing the amount of hemoglobin available to carry oxygen (CO has 240 times the affinity of O2).
  • Formation of COHb shifts the oxyhemoglobin dissociation curve to the left, impairing the liberation of oxygen to the cells.
  • CO binds to myoglobin and cytochrome oxidases (particularly cytochrome a and cytochrome a3) and may impair their ability to utilize the oxygen they receive.
  • Tissue oxygenation, particularly in vulnerable organs such as the brain, may be further impaired if poisoning is complicated by peripheral circulatory failure. Lipid peroxidation results.

Few more useful resources for you…

What is Engineering Process Safety?
Safety Rules during A Field Visit By A Design Engineer
An article on Crane safety during Construction
HAZOP (Hazard and Operability) Study: A brief introduction
An article on Excavation Hazards at Construction Sites
Hazardous Area- Theory, Classification and Equipment selection: A short presentation

About the Author: The author of this article is Mr. Amir Razmi, an International, dynamic, and multi-functional chemical engineer with more than 15 years of experience in engineering and EPC of oil and energy projects from pre-contract activities to execution, and closeout.

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Anup Kumar Dey

I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.

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