# CO poisoning - What I've been taught is a hoax?

In elementary school, I happened to ask my teacher:

What is $\ce{CO}$ they talk about these days?

I was then taught that Carbon monoxide "competes" with the oxygen in our blood (we were taught that oxygen gets to our cells via blood at that time) and replaces it and thus, doesn't let enough O get to cells and this will be fatal in extreme cases.

I didn't do any research about it after that because I later made the implication that $\ce{CO}$ is able to replace O and react with Hb instead; but

I recently became doubtful about my previous lessons and decided to do a research to see what really was going on:

Carbon monoxide mainly causes adverse effects in humans by combining with hemoglobin to form carboxyhemoglobin (HbCO) in the blood. This prevents hemoglobin from releasing oxygen in tissues, effectively reducing the oxygen-carrying capacity of the blood, leading to hypoxia. Additionally, myoglobin and mitochondrial cytochrome oxidase are thought to be adversely affected. Carboxyhemoglobin can revert to hemoglobin, but the recovery takes time because the HbCO complex is fairly stable. Wikipedia, CO poisoning

Wikipedia states that the problems are:

1. $\ce{CO}$ is able to combine with Hb to form HbCO.

2. This compound is fairly stable, so we'll have a hard time removing $\ce{CO}$ from hemoglobin.

Other sources, such as How stuff works, Answers.com and CDC.gov have given either only more explicit explanations of wikipedia, or the explanations weren't "chemical-biology" enough.

I haven't seen a single reference in which the first assumption was declined, or agreed with. Is what I'd learnt non-scientific?