San Francisco is a land-locked city, in a land-locked province, something like fifteen hours from the nearest decent bit of coast-line in any direction, which is pretty hard to imagine coming from our small island in the north Atlantic. Even to reach a stream big enough for paddling means a trip of a hundred kilometres or so. And since we’re not exactly well served with swimming pools (one; open to the public sometimes on weekend afternoons during the summer), a pool in the back garden is almost an essential item. Posh people dig proper swimming pools, the rest of us buy a “pelopincho”; essentially a large paddling pool which we construct in November, and take down again in March. Ours is the smallest in the range, and is big enough for me n’ the kids to have a good splash while minimising the risk of accidental drowning (or either of them drowning the other on purpose).
Since even the littlest pelopincho still requires quite a lot of (expensive, metred) water, I went to the shop and asked what people normally do to keep the water clean for a while. “One of these….” being a white plastic container with a screw top and a few pinprick holes. Into the container goes a cake of chlorine. This floats around in the pool and releases chlorine into the water; she reckoned a cake would last a month or so. In it went and bobbed around for a week or two until I next uncovered the pool, only to discover that it had totally bleached one corner, while the other side was filled with wriggling larvae. This suggested that coverage hadn’t been as even as one might suppose, and I wondered if the chlorine cake was still alive and active.
So I took the white container out of the pool, undid the lid and sniffed.
“Chlorine gas is a pulmonary irritant with intermediate water solubility that causes acute damage in the upper and lower respiratory tract. Chlorine gas was first used as a chemical weapon at Ypres, France, in 1915…” (http://emedicine.medscape.com)
It took the first minute for my respiratory tract to regroup sufficiently to take the next breath; the necessary one with the fresh air in it. Maybe should have gone to A&E at that point, but a flick round the internet suggested that the treatment of choice is humidified oxygen and that most victims of chlorine gas poisoning go on to make a full recovery (apart from those subsequently shot by the Germans), so I figured that I had statistics on my side even if my own common sense appeared to have jumped ship. As for the humidified oxygen, the air in sweaty San Francisco is about as humid as it is possible for a gas to get without actually becoming a liquid, and probably has around 20% oxygen which is handy for things like supporting life. Meanwhile my recovering eyes, nose, throat and lungs serve as a reminder that we won’t do that again, will we boys and girls?