I>Reprinted from the ACJ - September, 1994
Car bombs explode in Dublin. Wildfire scorches the Pacific Northwest. An organism eats away human flesh. Unseen fallout causes disease and injury. Explosives, flammables, corrosives, irritants, sensitizers — this could be a bad day on "World News Tonight," or an average day in a radiator shop.
The number of chemical hazards and their detrimental effects on your body are somewhat daunting. Every day the radiator repair person is exposed to any number of dangers. It is only their understanding of these hazards and a knowledge of how to control them that separate the back shop from a minor disaster. Chemicals can affect your body in a number of ways. Let's take a look at a few specific routes of injury.
Pressure related injuries will occur usually due to an explosion of some kind. An explosion occurs when a substance is restricted within an enclosed space and then expands to the point where the enclosure can no longer hold the pressure back. It ruptures and the rapidly expanding substance forces its way out, usually throwing bits of the container ahead of it.
A good example of this is a spray can of paint. The solvents inside would prefer to spread out as a gas and fill the room, but instead we squeeze enough solvent into the can so that it remains a liquid under the inner pressure. Every time we push the nozzle, it allows some of the solvent to escape and to expand into a gas. If a blow to the container occurs, weakening the can enough to fail under the inside pressure, or if the can is heated enough to cause increased internal pressure to the point that the can can't hold it in, an explosion occurs.
Certain other chemicals can react with water, or with air, to release gases and build up pressure in a closed container. Others, such as nitroglycerin, need only physical jarring to cause an expansive reaction. Luckily, we don't have these touchy chemicals in our shops. But we do have gases under pressure: spray cans, refrigerant, oxygen and acetylene bottles. We must be careful not to physically abuse or excessively heat these items. Chains to secure gas cylinders and cool storage locations are a good idea.
Another major concern in the shop is fire. Many of the substances used are flammable. Although this is a major hazard, it is also one with which we are somewhat familiar and comfortable with controlling. Always follow fire safety practices and wear the proper protective equipment, glasses, goggles, aprons, heat resistant gloves, etc., when using torches, solder baths or flammable products. It is a good idea to keep an eye on your co-workers or customers who may not be as familiar with the hazards. All you need is one customer to fire up a cigarette at the wrong time, in the wrong place, for an impromptu fireworks display.
A corrosive substance is defined as one which lies outside the neutral pH range. What it really means is these chemicals have a desire to grab onto or shed electrons from their molecular structures. These corrosives will pull electrons from anywhere possible: metals, concrete, etc. We say they are corroding the metal, but in actuality they are reacting with it to form a new material that doesn't look like the wrench or fixture or whatever it started out to be.
Another easy way for corrosives to get electrons is by reacting with H+ (hydrogen) or OH- (hydroxide) ions. The best source for these is water (H-OH). The easiest source of water in the shop is your skin, eyes and mucous membranes. It is this stealing of water from your body that causes the type of burns associated with corrosives. It is also the reason we wear gloves, goggles, face shields and aprons when we are working with caustic or muriatic acid. One difference between heat burns and corrosive burns is that corrosives will continue to burn and destroy tissue until they are neutralized. So wash any chemicals off as fast as possible to help stop their corrosive action. This continuing burn is also the reason that certain products have a "Do Not Induce Vomiting" warning on them. If swallowed, the corrosive nature of the substance has burned its way down your throat and is resting in your stomach, which is used to an acidic environment. Any regurgitation will re-burn tissue and may cause your throat to close or burn through. Seek medical attention immediately for neutralization.
These same substances that burn skin, as well as chemicals and solvents that remove oils from our skin, are found in the irritants category. A much weaker acid solution may not destroy the skin, but rather turn it red with its corrosive action. A parts cleaning solvent may leave your hands dry, cracked and red. This is irritation. It really is just a mild case of tissue damage, stopping short of actually killing the tissue.
Irritants usually leave no permanent damage unless they are also sensitizers. Then the body reacts to form antibodies to combat the reaction the irritants, called allergens, have with your body. The only problem is that your body can overreact to the substance and lock in its memory this antibody-producing reaction. When you are exposed to the allergen again, your body goes crazy producing antibodies and may actually cause an irritation itself. Certain epoxies, amine-based fluxes, plant pollen and formaldehyde in glues can cause sensitization. Be sure to wear gloves when using these compounds and wash thoroughly when finished.
So far, all of these hazards have been straightforward and are grouped together because they are generally "point of contact" concerns. In our next article, we will talk about chemical hazards that cause damage away from the site of contact. These are the toxins.
So until then, avoid the terrorists, keep your shop a safe place and leave the disasters and terrorism to the nightly news.
The above article was written by David M. Brown, Chief Engineer of Johnson Manufacturing Company, Inc. and is published by JOHNSON with the expressed approval of the National Automotive Radiator Service Association and the Automotive Cooling Journal. Other reproduction or distribution of this information is forbidden without the written consent of JOHNSON and NARSA/ACJ. All rights reserved.
JOHNSON MANUFACTURING COMPANY
114 Lost Grove Road / PO Box 96 / Princeton, Iowa 52768-0096
Phone 563-289-5123 or Fax 563-289-3825