Yes because I had one in 1979.
My mum and I moved into a tiny flat as she'd left her 2nd husband. Unbeknown to us the flue to the gas fire was blocked and carbon monoxide was coming into the flat.
We were both feeling unwell, sick and headaches. My mum took our small dog out for a walk so got out into the fresh air. When she got back, I went into the kitchen to wash up and fainted.
I remember hearing her voice but it seemed a long way away. I could see myself and her as if I was looking down on us from above. The only way I can describe what happened next is to say it was like a film camera being pulled backwards from the room it was filming in at great speed.
I felt as if I was floating but could still hear my mum telling me to wake up. I felt really peaceful and then was surrounded by the brightest white light I have ever seen.
My mum told me afterwards that she'd gone outside to try and get help but because she'd been affected, was staggering and it took a time for a car to stop, probably because they thought she was drunk.
I heard a voice say my name and tell me to go back because it wasn't my time but I wanted to stay there, where ever it was because I felt surrounded by love and a peace that I'd never experienced before, and have never felt since.
The next thing I remember was coming round in hospital early the next morning.
The doctors told my mum and Mr. S. (we were engaged at that time) that I was lucky to be alive as my entire central nervous system had been badly affected.
Despite what some say, that it's due to hallucinations and the brain not working properly due to medication or in my case, the affects of carbon monoxide, it was real.