Module 01, Sub-module 01G, Closure, Fall 2005
Closure sub-modules contain my responses to student questions and sometimes
other material related to that module, which I realize I missed the first time
around. The items that are important, in the sense they are part of course content,
are indicated by two or more asterisks (***) and have been grouped first. Items
that relate to administrative issues are grouped second. The answers to other
questions are grouped last. Some of this last group is my philosophical rambling,
which you might find interesting but of itself will not be on the tests unless
it is later presented again.
Comment. Quirks. The only quirk I ran into was in posting the electronic picture.
I couldn't figure out how to save the photo so when I uploaded it, it didn't
take up the whole page. I had the same problem last semester but somehow I was
able to figure it so I just reused the same photo but I'd like to learn how
to do it correctly.
A. You need to modify the picture with some sort of graphics tool. For quick,
easy, and cheap, get SnagIt from http://www.techsmith.com/ . It has a "studio"
program that does simple graphics.
***Q How are the lethal dozes ( LD50 ) of any chemical defined for humans by conducting experiments on animals, when they have different degree of tolerance for the same chemical?
A. You have hit on one of the great problems with practical toxicology. You often hear of the “animal to human extrapolation,” but that is not an extrapolation in the mathematical sense of the word. Rather, it is an assumption based on the fact that many biological and biochemical systems are the same in humans and animals. The gap is covered, perhaps, by using factors of safety.
**Q. After reading the definition of risk I am having trouble understanding
what an unsafe act is relative to risk?
A. It is completely relative and depends on who is calling something “unsafe.”
**Q. What time period is used to determine the number of affected individuals when testing dosages (ED10, etc)? Is it that if the individual is affected within 96 hours, the exposure is acute, whereas if it takes longer, it is chronic? These distinctions seem rather arbitrary.
A. “Acute” and “chronic” are vital concepts in toxicology, but the name itself does not give details about the test length – they are relative terms. (Compare the financial concept of “broke.” It means different things for me and Delta Airlines.) The length of the test is often given, such as, “96-hour test,” a length which is common for several reasons, including use in law and regulations. The standard 96-hour test is usually considered acute.
**Q. In your example for the definition of waste, you say that the moment the foreman is cognizant of the condition of his explosives, it becomes waste. Does this mean that ignorance could be an excuse in this type of case. Was he not responsible for knowing the approach of an expiration date and the dangers of the material's packaging becoming damaged and possibility of this event? It seems to me that this falls in the realm of foreseeable dangers.
A. Sure, it would be dangerous. Here we are just talking about the definition of "waste," under US law, and trying to answer the question, when does something become a waste? In other words, it is not necessary to take the stuff out to a dump or anything special, just the moment it is no longer useful, it becomes a "waste," even if no one touches it.
** Q. I am not in agreement with your answer to quiz question no. 4 regarding
whether an IH job involves evaluating risks from a safety standpoint. I
visited the following site http://www.aiha.org/aboutAIHA/html/ih-info.htm .
Please explain your rationale to not consider safety based on AIHA IH
definition. Thanks.
A. I certainly consider “safety” and every IH should as well. The question follows the module's intent to differentiate “health hazards” from “safety hazards” and “injuries” from “disease.” People, the AIHA website in this case, use the term “health and safety” in a general way to mean well-being. There is nothing in IH training or the CIH exam that treat hazards such as explosions or pressure vessels, which are “safety hazards.”
*Q. My question is about injury vs. disease. While working on the North Slope the company reported frostbite and frost-nip as work related diseases. According to the definitions in the module I'm not sure why they would classify them that way. It seems more intuitive to call frostbite a work related injury to me. Frost-nip perhaps could be called a disease because it might happen over a days worth or weeks worth of exposure? (As I understand frostbite is actual tissue damage and frost-nip is skin irritation, reddening due to cold exposure. There was certainly a lot of ambiguity among the management on these definitions though. I guess this comes into the realm of reversible vs. irreversible also.) What is your take on this?
A. I agree, frostbite would be an “injury” from an “accident” and I guess frost nip would be too. If one frost nipped an extremity many times over the course of employment and eventually say a finger lost sensations, that would be a “disease,” perhaps “finger neuropathy” and the cause would chronic exposure to cold.
*Q Shouldn't ED50 (for any specific effect) or LD50 for human beings be based on the geographical location, e.g. some xyz bacteria or chemical may be harmful to people living in USA but people of India are immune to its effects?
A. Toxicology generally only deals with chemicals. Bacteria and viruses are trouble enough, but they are not toxicology. Certainly there are vast differences between individuals and groups in “sensitively” to certain chemical. Again, this is usually compensated for with the use of safety factors.
*Q A person goes to an environment which has certain pollution (e.g. noise, radiations or any chemical pollution) that causes him health problems e.g. headache, but with time he becomes accustomed to it and finds no more health problems in the same environment. Is it an example of reversible toxic effect or we can't categorize this situation w.r.t. reversibility?
A. Of course that would depend on many things, but often the first exposure is called “acute” or a series of acute exposures. Later the person builds up a resistance to some aspect of the chemical or no longer displays a particular symptom. That is not the same as a “health problem,” rather it is the health problem that caused the symptom. The underlying health problem might be getting worse. On the other hand, many of the minor irritations are indeed things that people simply get accustomed to.
Q. I was also wondering what remediation was done on the Minamata site, other than natural attenuation. Do the organisms of the area still show evidence of the poisoning, or has it dispersed enough now that its affects are only seen in organisms that lived in the area during the time when the dumping was occurring?
A. I don't think anything was done. Metals and radioactive elements do not attenuate with time, unlike organic compounds, most of which do attenuate. Metals might slowly diffuse, in the case of mercury microorganisms (for there own reasons, which are obscure to me) incorporate it into organic compounds, which are soluble in the lipids of (micro)organisms and thus slowly diffuse through the ecosystem and out of the local environment. The rate of this attenuation might be very slow. I'm sure work has been done in this area, which might be a good paper topic if you are interested.
Q. As I understand frostbite is actual tissue damage and frost-nip is skin irritation, reddening due to cold exposure. There was certainly a lot of ambiguity among the management on these definitions though. I guess this comes into the realm of reversible vs. irreversible also.I suppose there could have been political factors involved for classifying things that way, (for example… trying to reduce the number of injury statistics reported to the client.)
A. Maybe. But in most “accident” reporting plans, and incidence of disease must be reported as well. The pressure is to keep it at the “first aid” level, which does not get reported versus the “time lost” level, which does get reported.
Q.So, I guess the REAL question is who is the winner for dealing with winter cold; the safety officer, OR the industrial hygienist?
A. OK. If I was an arbitrator trying to decide between the IH union and the CSP union, I would award all indoor cold work, like in walk-in freezers and cold producing equipment, to the IH's and all the outdoor cold work to the CSP's. Don't ask me to defend my decision.
Q. In the case study “Minamata Disaster”, one of the points under legal cluster is “Decision breadth: 1”. What does decision breadth mean? Also, in the same case study under the point (2), the last line of second last paragraph has a typo “waster (for water)”. I believe it is good that these case studies have links to related cases, which are quite interesting to read. I found this module quite informative and interactive.
A.
I'm not sure what that means. I found that to be a informative site for our purposes – I'm not sure of the exact purpose of the site.