This harrowing video footage - shot in May 2012 - shows the effects of Carbon monoxide poisoning (a colourless, odourless and tasteless toxic gas) on a driver.While behind the wheel of his Toyota MR2, Carbon monoxide (CO) fills trackday driver Sami Mäkäräinen's cabin while he narrates his lap. Shortly thereafter, he spins his car off the track due to CO exposure, which has dulled his senses and made him drowsy. Because Finnish race regulations stipulate that a car's windows must be closed, the deadly gas continues to fill the cabin.After pulling off the track, Mäkäräinen sits and waits for the marshals to attend. As he waits, the gas continues to fill his lungs and he loses consciousness. When marshals finally smash the window, unlock the doors and drag him to safety, the driver's blood oxygen level measures just 63 per cent. According to the man himself, he suffered a 'strong headache' for three days after the incident. The shocking video below shows these events unfold and raises an important question:As Mäkäräinen states in the video description, please be respectful towards the medics and marshals; 'They did everything they were trained to do'