http://www.hse.gov.uk/diving/video/co2video.htm

The piece does seem to sensationalize and dramatize things.

I've had 3 massive hits after between 10-15 minutes from a bad check valve in the upstream side of the DSV that could not be seen and all I got to show for it was feeding the fish back on the boat and a headache that felt like someone creamed me in the head with an axe.

I did suck/blow on the front loop hose/dsv assembly and it seemed to work, but in retrospect it only checks the downstream valve, and it was the upstream valve that the center rubber post had failed and the check valve disc had flopped off to the side.

I can't believe anyone remixes their Sofnolime.