The Editor, Sir:

Regarding the hazards of chlorine. I view with dismay the video shown of students, parents, and others, at a school on the Wednesday, October 15, on TVJ evening news. It is clear that the people shown, excepting the firemen, are ignorant of the hazards of chlorine gas.

They are clearly unaware of European history, particularly World War II, where the Germans released chlorine gas to kill and disable their enemies.

Ineffective dust mask

The teacher(?) wearing a dust mask is clearly unaware that chlorine gas will pass right through the mask. A damp cloth may remove a small amount from the air reaching her, but, the best response to a release of chlorine gas is, first, RUN! DO NOT WALK! away from the source of the gas release (upwind if you're smart); second, if you want to hang around for a (very) few minutes, you better be wearing a full face gas mask with an activated carbon filter cartridge set; third, for extended operations (such as the search for, and rescue of victims) in an area where a chlorine release has occurred, the only suit you should be in, is a full-body chemical resistant suit with a full-face mask with a Self-Contained Breathing Apparatus (SCBA) which has a compressed air cylinder feeding it. The latter, because chlorine in high concentrations also attacks any exposed skin.

Another dismaying observation is that everyone seemed to have, more or less, ignored the presence of the compressed gas cylinder until it ruptured (apparently due to corrosion)! Any compressed gas container must be viewed with suspicion. Even if it contains compressed air under high pressure, a rupture as a result of corrosion, impact, etc, can be fatal. If it contains a hazardous (flammable, explosive, or poisonous) gas, the danger is far greater.

Likelihood of rupture

If you are knowledgeable in such matters, you could look at the condition of the body of the cylinder, the type of valve and its condition. These would tell you, based on the type of valve seen (likely to be a standard valve made to one of the Compressed Gas Association (CGA) standards, what is in the cylinder; and the likelihood of rupture.

A point to remember is that flammable/explosive gases generally have valves that have a screw thread that screws on the 'wrong' way. That is, opposite to the ordinary bottle cap.

If you are not knowledgeable, seek to become so as soon as possible, and until then, seek the advice of the fire brigades, companies such as Industrial Gases Ltd, a chemical or mechanical engineer, or the nearest chemistry teacher if you come upon any compressed gas lying around.

I am, etc,

HOWARD CHIN, P.E.

hmc14@cwjamaica.com

Mechanical Engineer,

Member Jamaica Institution of Engineers