At some time each evening, by telephone if not in person, my wife asks me if I’ve had a good day.

And I’m usually baffled about how to answer. I’m sure this will bring me an accusation of over-thinking a simple question but, please consider the following, even if you are not seated in a porch swing yourself. How good was the day if I didn’t get paid for anything I did, but perhaps maybe something I did will bring in some income in the future? How good was the weather if rain, wind and hail spent 45 minutes battering the neighborhood, but now the setting sun is softly highlighting everything in shades of pale pink, rose, red and gold? It was not good to find out a friend has an incurable debilitating disease, but it is good that my immediate family is healthy. It wasn’t good that I made only 3 of my 11 shots in basketball and my team got clobbered, but it is good that I got exercise playing basketball. The answer, I suppose, to whether I had a good day is so subjective that I can’t be wrong. Hey, if I can’t be wrong, maybe it isn’t such a tough question after all!

Subjective, though, doesn’t always mean that there’s no wrong answer. When it comes to DG regulations, it is definitely possible to get something wrong when the criteria are not objective. We are used to objective criteria in the DG world, numerical standards for properties we can measure. We can, and do, measure the exact height we drop packaging from in order to earn the specification mark. We do measure the flash point and boiling point of liquids, to determine possible inclusion in Class 3. We measure in response to regulatory requirements, how far apart certain packages are stowed from one another. But what do we do when there are no numbers?

If a material is analyzed and studied and measured, and has no characteristics that might put it into Class 1 through 8, but it smells bad; does it belong in Class 9 when offered for transport by air? How foul, gross, and nauseating does the odor have to be for it to interfere with the ability of a flight crew to perform their duties? If you classify a mildly bad odor-causing material as an Aviation Regulated liquid or solid, it will be hard to prove you right. But if ever a material classified as non-regulated escapes its package and causes a pilot to vomit while attempting to land a plane, the classification will have definitely been proven wrong.

If your “strong outer package” for a U.S. ground shipment of a limited quantity survives intact to the receiver, it may have been because it was quite strong, but it may have been because it was the only package on the pallet (skid) for a short delivery. But if your package crushes and bursts a seam while on the bottom level of a full pallet of boxes, it obviously was not “strong” enough.
Suppose you test a liquid on a number of animals in a variety of ways. Suppose it is not toxic to rats by ingestion, not toxic to rabbits by skin contact, and not toxic to rats by either of the inhalation routes (via mists nor via vapors). Is this liquid a 6.1 for transport if all the animal numbers say no, no, no, and no? Well actually, before any consideration is given to any animal data, the 6.1 definitions require a subjective assessment of human toxicity. If you answered “not 6.1” in response to the animal data question you may be wrong. See UN1230, Methanol, which is sometimes forced to bear a 6.1 subsidiary risk because of subjective human health concerns, and despite lots of animal toxicity data suggesting otherwise.

Is it a good thing or a bad thing to have a subjective definition in the regulations? That, I suppose, is also a subjective question. But, today may be a good day to ask it.

Written 8/24/2013 for HCB Magazine