# MacGyvered chlorine gas protection

I was watching Periodic Video's chlorine video, which discusses chlorine's ferocity in stripping electrons whenever possible, and the professors mentioned its consequent use in WWI as a chemical agent. This got me thinking, if I were in that situation (say Syria if they decided to go old-school or a chemical leak), what could I do to protect myself against gaseous chlorine using the chemistry of everyday materials around me?

I imagine a wet towel won't help much to prevent the chlorine from getting in my lungs. Are there any easily obtainable substances I could safely breath through that would neutralize the chlorine? Or are there any (realistic) MacGyver solutions to quickly building a semi-functional gas mask? Just kinda curious what could be done.

## 1 Answer

Interestingly, the British had such a solution in WWI: the Hypo Helmet. This was simply a bag soaked in sodium thiosulfate solution and worn over the head. Thiosulfate reduces chlorine (and halogens generally) to chloride (halide) ions:

$\ce{2 S2O3^{2−} + Cl2 → S4O6^{2−} + 2 Cl^{−}}$

As the article notes, this was not the best solution, but I think it fits your criteria for rough and ready protection.

• Very interesting! Any ideas how to MacGyver some sodium thiosulfate from everyday chemicals? – 0x24a537r9 May 23 '14 at 20:33
• It might surprise you that hobbyists still develop black & white film. Hypo is used to "fix" the final print after developing. So it's easy to get. It's also sold to de-chlorinate water. It might not be everyday, but it's readily available. – user467 May 23 '14 at 21:09