We have a video blog this week, illustrating two classic behaviours of carbon dioxide (or CO2). CO2 can smother anything that requires oxygen. In the video, it smothers candle flames, but it can smother a person just as easily. Any gas other than oxygen would do the same. CO2 is also heavier than air, so, if there is a leak, it fills a confined space from the bottom up. You could be knee-deep in CO2 and you might not know without a detector. This can be seen as the bottom candle goes out first, then the middle and finally the top candle; and again as the CO2 “pours” down over the last candle. Watch the video. It’s illuminating!