Reprinted from the ACJ - May, 1994
The man, weary and drained from his travels, saw across the darkness a glow. A greenish gleam from water's surface. The pool an emerald liquid. Its glass like surface broken only occasionally by the small ripples sent radiating outward by something stirring beneath the surface. Golden droplets rising through the transparent water. A voice broke the eerie silence and startled the man -- a lilting voice like that of an angel.
No, this voice was more of earth than heaven, he thought. Yet it seemed ethereal and all knowing. He saw her then. Tall and lovely. She stood beside the pool, though he felt that she was somehow one with it. A water nymph perhaps. Certainly mistress of the green pond. She gazed at him, her eyes wise beyond her apparent years. Her demeanor made him sense a naivety. A willingness to explore, to learn, to add to her already considerable knowledge. He looked long at her and a feeling of confidence grew in him. He broke his gaze at last and his interest was averted once again to the pool.
For the first time he realized something indeed lay beneath the surface. A shining metallic object. Glowing with the light of the pool. Long and thin, a sword perhaps. But then again he could not be sure. The maiden sensed his wonderment and seemingly without movement bent to the pool. Her arms entered the jade-colored liquid and became one with the glassy water. She eased the object upward, breaking the surface of the pool. He moved backward, filled with a sense of awe and anticipation. Raising the dripping object, she held it out to the man as if in presentation. The lady of the lake raised her eyes to him and spoke so that the man would understand.
Her voice drifted across the short distance between them... "You got a tube to header leak right here near the outlet neck. We can get ya fixed up in a jiffy!" She then flung the core to her bench guy and escorted the man back to the office to write up a work order.
Happens everyday, right? OK, so your inspection tank is greasy and dirty. The light in the shop is a flickering fluorescent bulb. The lady of the lake is Jim the service writer and the shiny object an old copper/brass core out of a Dodge. But one thing is the consistent. The water is a fluorescent green and small bubbles do rise to ripple the surface of the water.
It would seem that the inspection, or test, tank would be one of the safest pieces of equipment in your shop. Generally speaking, this is true. But as with all topics we talk about, there are some reasons for caution. Why else would it make it into a Health Watch column?
Typically a test tank is filled with a solution of water and someone's brand of test tank compound, myself being biased toward a block or powder produced by a certain company in Iowa. These compounds are formulated to provide several benefits. They contain a dye that when mixed with water provides a fluorescent green hue that accentuates differences in the index of refraction of water and air. In other words it makes bubbles easy to see in the water.
The hazards associated with this dye are minimal. It is listed as moderately toxic when injected into the abdominal cavity of a test animal. So try not to stab yourself with a test tank block and you should be all right. This dye is used in several places around the country to color certain rivers green in celebration of St. Patrick's day.
The worst thing I can say about it is that it will stain your fingers orange. Another bit of party conversation, the reason it turns from orange powder to green in water is due to a slight pH change upon dilution.
The other major component in test tank compounds is a carbonate salt. This is a chemical similar to the active ingredient in products such as Alka-Seltzer. Now, just so you can't say I didn't tell you, they are not exactly the same so don't eat test tank powder to remedy an upset stomach. The carbonate salt in the compounds does indeed perform the same antacid function. It helps neutralize any acid or acidic flux residue that may be carried over from cleaning or repair of the core.
It also helps keep the water clear by complexing with metal ions and flocculating dirt that will then settle to the bottom of the tank. Keep in mind that continual immersion of metallic cores, solder drippings and flux residue into the tank will raise the heavy metal content of the liquid. When it is time to change the water, treat it for these contaminants and/or dispose of it in accordance with local, state and federal regulations (I always wanted to talk like a lawyer).
Healthwise the carbonate salt is only slightly more hazardous than the dye. It has a high LD50 for oral poisoning and is not considered toxic. Its main problem is skin, eye and mucous membrane irritation. Repeated or prolonged exposure of the powder to your skin can cause irritation, redness, and mild burns.
Extreme overexposure such as wearing it as eye shadow for twenty years can cause sensitization, making you more susceptible to irritation when exposed in the future. But don't be too alarmed because after soaking a rabbit in a 500 mg solution of Sodium Carbonate the rabbit suffered only moderate skin irritation. I'm sure mentally he was a bit more irritated, downright PO'd I'll bet.
Because the tissue of your eyes, nose, throat, and lungs are more sensitive and moist, the irritating action will be heightened. It may produce a burning or redness in your eyes and a scratchy or tickling feeling in your nose or throat.
Precautions are easy. Wear a dust mask if an orange cloud floats into the air. Wear goggles if splashing of the solution is possible. And wear gloves when reaching into the tank. One side effect I will mention is the fact that these test tank compounds heat up when water is added to them. This is called an exothermic heat of solution. It is not a problem when adding one bag or block to a 200 gallon tank. But if you have ever accidentally added a little water to the block or bag of powder itself, you know that the concentrated mixture can get pretty warm. So store it in a cool dry place and avoid making a paste out of it.
Now after all this has been said about how relatively harmless these products are they do have one troubling characteristic. Due to, I believe, the bright color of the product and the solution, OSHA inspectors always single it out to check for proper documentation and precautions. I have received more calls concerning it's ingredients and asking for MSDS information than for any other product. So word to the wise, keep a current MSDS on hand. You never know when the Lady of the Lake may turn out to be the Lady of the State.
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