mfety in the chemical labor~tory
edited by
MALCOLMM. RENFREW University of Idaho Idaho 83843
MOSCOW,
Disaster in the Laboratory The Poison Gas Crisis Bruce Bawrle Mesa College, Grand Junction, co 81502
Storage shelves in your s t m h m collapse, smashing glass bottles of eoncentrated acids onto a floor covered with broken jars of dry chemicals! A veritable explosion of highly toxic chemical gas (similarto those originating from accidents at major chemical plants) floats out into the classroom and down the hallway. Students are involved. Would you know what to do? Accidents involving poison gas are very real threats that extend far beyond the hypothetical classroom situation suggested here. Three out of every four Americans face potential danger from the more than 11,WO chemical manufacturing plants mattered throughout our urban areas. With railroad cars and tanker trucks making daily deliveries of these substances, a disaster like that which struck Bhopal, India, in 1984, could he a distinct possibility. Smaller scale (hut just as lethal) toxic gas clouds could result from accidents that involve many common household c b e m i ~ those r stored in vour high m h d chemistrv staekroom. - since-chemistry teachek are likely candidates for frantic calls from local fme departments, police departments, and other emergency services in times of disaster, it would seem prudent to learn as much about poisonous gas as. pmible. Furthermore, it would make sense to develop a full classroom lecture on this touic. A lecturefdemon~. ~~-~~ stration could raise interest among your students, promote safety, and provide survival skills that may prove useful in Later life.
The initial clue that something is wrong will come from either your eyes or your nose. Even if a toxic cloud is invisible, the pain and watering in your eyes will help you determine its presence. The actual effect would be similar to that experienced by peeling onions. Your nose might be able to detect a unique odor even before your eyes react. The characteristicsmells of ammonia, chlorine, and the additives in natural gas could be obvious early-warning sign&. I teach students to recognize these smells by making "sniffing containers" out of film canisters (Fig. 1).Each has a specific substance (like cleaning ammonia, household bleach, gasoline, onion juice, eto.) poured over a folded paper towel inserted in each canister. I even use a clamped h d w n , filled with natural gas, for students to sample.
Symptom The key to surviving a toxic gas involves instant recognition of symptoms that suggest such fumes may be in the atmosphere and reacting immediately. The terrible aftermath of pain, blindness, and death from theBhoual incident serves to remind us that little has been done to alert the public ahout how to react to such an event. B ~ c . BauwIe 16 a professor of biology and ewlogy at Mesa Collep in Orand Junction. Colorado. He teaches courses in many areas of field biologl and has a unique class in survival, for which he has written a textbaok, "Urban Survival".
A188
Journal of Chemical Education
When you notice such symptoms,positive actions must be taken immediately to protect the sensitive tissues of your eyes and lungs. At the same time, an escape route must be planned. Nothing works better than an orygensupplied gas mask for protecting the eyes and lungs. But, in an absolute emergency, many readily available household items could provide some protection. A) Protection for the eyes could take the form of chemistry/ski goggles (vents sealed), swim masks, or even plastic hags and wraps (Fig. 2). Vision would be necessarv onlv to the extent that vau would n&d m i d g e majorobjeets when running-and it would be advisable ta keep one's eyes closed as much as possible during an escape because of the potential for small leaks. Many plastic hags are somewhat permeable to gases, but could still provide barrier-type protection for a quick escape. B) An emergency method of lung protection would involve breathing through a sopping wet towel (Fig. 2). A n y acids caused from gas reacting with water should farm within the thickness of the wet towel. rather than in the moist- of -~ your lungs. Do not get your clothes or other skin wet, however, since a reaction could occur in them. Dry skin is somewhat impermeable to most gases, and may not be damaged by a brief encounter. Clothing, and especially a rainmat, would provide additional skin protection as you run for safety. C) When fleeing the scene, take note of the wind direction. Move perpendicular to it in order to get out of the gas plume. Particular gases will rise or sink due to their densities. The od& are that there will he more types that are heavier than air. If you recognize the odor, a prediction is possible. Ammonia (smells like household cleaners) tends to rise. Chlorine (an odor like bleaches or swimming pools) will usually sink. It will lodge in low spots and basements and will ohen ~
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Reactlorn
Figure 1. SMent learning to identify toxic gap smells by cautlws inhalation of sample In "snming cannister" desuibad in text.
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Figure 2. lmpovised emergency potectlon mat allows escape horn a toxic clwd.
result in a mustard-like odor. Therefore, with chlorine you should run in the diredon perpendicular to the wind, and uphill. Propane, natural gas, gasoline, and butane are dangerous in that they explode with tremendous force. They also tend to displace air. This results in a lack of oxygen-and ean result in a black-out after only one or two breaths. These fuels ¬ toxic or irritating to sensitive eve and Iune tissues as are chlorine, ammonia, or other compounds Cora short exposure,but danger of suffocation introduca the problem of where to obtain an air supply. D) I have developed a method that could provide an emergency air supply for extreme situations. "Bag breathing" involves whipping plastic trash hag through the air to f i it. Early recognition of poison gas symptoma should allow you time to fd it with the cleanest air possible, before the entire area is contaminated. Tbb mav mean that vou will need u, grab yo& supply from a nearby dmet (protecteddead-air space) or from the side of the rwm opposite from where you f m t recognized the odor. Bag hreathingis simple for adults, hut more difficult for anyone younger. The obvious danger of suffocation from a plastic bag over the face should be noted. Take time now to practice this technique with your class! And remember, an oxygen-supplied gas mask is much superior, if it ia available. AISO
Journal of Chemical Education
Fbure 3. Use of a plastic trash bag as an emergancy clean air wiy.
Imagine that your trash bag is a scuba
tank.After f h g it, place the clamped opening over your mouth (Fig. 3). Inhale a breath from the air contained in the bag by squeezing the bag gently to force it out. Then exhale through your nose. Practice this to develop a proper rhythm. Breath as slowly as possible to conserve air. See how far you can run, using this technique. Could you make it to your car,roll up the windows, and drive several miles to safety? Since there is plenty of oxygen in air, you can easily double your effective supply by breathing the air in your bag twice. This involves inhaling from the hag, exhaling hack into the bag, then inhaling out of the hag again, and finally exhaling the second time out of your nose. Double bag breathing requires even more practice and coordination, but it d m work! Since you normally only take in about one pint of air per breath, alarge trash bag could give you a 10-min (or % mi run) supply. In a true emergency, this technique might provide a chance for rescuing astudent who has passed out in your classrwm. Grab him by the belt and drag him (Fig. 4). E) Continue hag breathing or breathing through a wet towel until well out of the danger ares. Then immediately begin riming all parts of your M y with fresh water. You eannot overdo this rinsing. Milk, baking soda! and other buffers mieht to allenate some burnine of " hel~ the skin, but water always works bestespecially for the eyes. Seek medical at. tention as won as possible. Be sure to warn others who might start to enter the area. Another good rule would he to post the phone numbers of national and state organizations that could provide authorative information when there has been a spill of toxic chemicals in your area.
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DBmonsbation ot ttw use "bag bream Fi. ing"toall0w timetorescue an Unconsciwsvictim.
Summary 1) Knowledge about toxic chemicals. 2) Early identificationof symptoms. 3) Immediate reaction with a sound defensive strategy. Just discussing these three topics with your students could do much to alleviate the threat of toxic gas injuries in your area. It is worth your time to teach about them. National number for information on tracking, identifkation, and treatment: CHEMTRAC 1-800-424-9300
Volume
Number 8
August 1986
