For further info you all may want to review this website.
http://www.cdc.gov/niosh/rtecs/ux2ab980.html
For further info you all may want to review this website.
http://www.cdc.gov/niosh/rtecs/ux2ab980.html
I apologize but I forgot to add this one.
http://www.ci.tucson.az.us/arthazards/photo2.html
Ah hell, Kevin apparently you did not read all that has been said here, specially by Kirk and me.
Lets see, your arthazard link, shows pyro as "can be lethal, DONT USE." Once again these people apparently read an MSDS and copied it, probably to cover their ass and not be sued. This is no different than what Shaw did in her lousy book.
Your NIOSH link, now we are talking, NIOSH is a very credible source. They cite lowest oral lethal dose in human reported as 28 mg/kg. I am thinking: "damm, this crap might be more toxic than arsenic after all." But then you click on the reference and it is a study done in 1969. I dont know, but is seems to me that this person who died from such a small dose of pyro had far greater health problems already. All these numbers have to be taken into perspective of the possible contamination, concentration and method of introduction into the system as well as the general health of the subject. To any of you who read this link, when you come to the number lethal dose dog intravenous, please think, is it any wonder the damm dog died if they injected the pyro directly into the blood stream? Hell I am surprised it took 80 mg/kg!
I give up....in the end is just a developer. If you choose to think it is too dangerous to use, by all means it is for you and stay away from it.
Paul - good question. Despite our best intentions, accidents do happen.
Jorge gave some excellent advise - pay attention to what you are doing, keep the lid on the bottle when not in use, and that the procedure used to clean up a pyrogallol spill is no different than what you would do for any other of your darkroom chemicals. Simply wipe up the material with a wet towel to help hold the powder together, and then wash the affected area with soap and water. The wetted pyro powder will not go into the air and also has the benefit that pyro is very water soluble and will be easily cleaned up with just water. One thing I do after every printing session is to wash down the area where may chemicals have been. I also to this when I'm weighing out chemicals when mixing solutions - I wash the area before I weigh things out, wiping up any spills as I go along, and then again wash the area when I'm finished.
I do have one comment on thing you suggested - tranfering what you buy into smaller bottles. If you are trying to minimze your exposure to something, this is not really a good idea. The act of transferring the material to a smaller bottle will increase your risk of causing a spill and increasing your exposure.
A better approach is to buy your stock reagents in smaller quantities if you want to minimize your risk. So only buy a 100g or 250g at a time, instead of 1 kg or more. You then have less material to spill in the first place so that will greatly minimize any exposure in case of an accidental spill. There will simply be less material to launch across the room. If for some reason you do spill a large amount and you do generate a lot of dust in the air, you can simply leave the area and allow the dust to settle before returning and then cleaning up.
Keep in mind that chemicals like pyro belong to the aromatic class of compounds and as you may have already figured out by that name, they typically have very distinctive and easily detectable oders. It doesn't take very much pyro dust in the air before you can smell it, but it is certainly a very small amount and not seriously hazardous.
And as I mentioned above, part of the arsenal of personal protective equipment that we should all have at our disposal should be gloves, a lab coat, safety glasses, and particle mask. A spill like this is probably one of those times that you may wish to wear them, to minimize your risk of exposure. As Jorge pointed out, pyro really is similar to many of our other commonly used developing agents - so that suggests that you may want to follow this scheme of PPE when cleaning up other developer agent spills as well. Other's may not feel that it is necessary. That's where I'm suggesting that you make a decision as to what level of protection you wish to take to minimize your risks.
Buying smaller amounts of your more hazardous chemicals can also have the benefit of having fresher reagents since you use the smaller amounts up faster. I know this goes against our penny-pinching urge to save money by mixing our own chemicals, but if you are serious about minimizing exposure to something, that is your best bet.
Here's a little anecdotal story for you. Accedents to happen to everyone sooner or later. I was working in the chem lab in a hood trying to dissolve some tin/lead solder in acid - a very difficiult thing to do as you have to use both nitric and hydrochloric acid in just the right ratio or the solder will not dissolve. Too much nitric and the tin drops out of solution, too much hydrochloric and the lead drops out of solution.
I was using a little glass 60ml dropper bottle for the nitric, slowly adding the acid to the beaker in a hood. Well, I set the bottle on the edge of the counter, and then proceeded to knock it off! I saw it go, and it was falling right next to me, so I did my best imitation of a hacky-sack move and stuck my foot out a little to deflect the glass bottle so it would not hit the floor straight on. The acid spilled on my pant leg, and went down in to my sock and shoe. While I did manage to keep the bottle from breaking(!), I got about 50 mls of concentrated nitric acid on me in the process. As I had been using nitric for some time at work by that point, I knew my flesh wasn't going to be melting off my bones, but I also knew that the simplest thing to keep things from getting worse was to just put my foot up into a nearby sink and run a lot of cold water on all the affected areas (lower leg, foot, and clothing). So that's what I did. I did not even get the yellow stain that one often gets from skin contact with nitric acid. My shoe did not fair so well - one, and only one, of the many layers of plastic in the sole of the shoe proceeded to fall apart during the rest of the day, but I escaped unharmed and no one else in the room was injured either. So I guess the point I'm trying to make is that by minimizing the amount of hazardous materials you are handling, you can greatly reduce the risks associated with them. That story would certainly have had a much more serious outcome if I have been using a 500 ml or 1 L bottle of acid. And going further with the lesson that can be gleaned from my story, if you did have a catastrophic accident where for some reason you did get a LOT of material on yourself, you should consider things like rinsing the affected area, removing the affected clothing, and proceeding to a shower. If time is of the essence in minimizing an exposure - proceed to the shower clothed and wash the material off and then remove the affected clothing. Remember, DON'T PANIC!!!
One nice thing about darkrooms, is that there is usually water readily available and that can be a great aid in reducing your exposure risk. Simply wash the material off before it has a chance to do any harm. But again, if you are spilling that much material on yourself, then you are probably buying too large of quantities in the first place.
Another thing for home darkrooms, do not ever prepare solutions in area where food are prepared. That means like in your kitchen. OK, some things would be fine, but it really is not a good practice in general.
So Paul, like you said, taking *informed* risks is the important thing.
Kirk - www.keyesphoto.com
Kevin - thanks for posting those links. But the suggestions at the City of Tucson web site are really very conservative, and could be considered overly cautious, especially if you've been reading the info I've been giving on how to minimize your risks when handling chemicals.
I noticed that their list had Ammonium Hydroxide listed as highly toxic in all three categories of exposure, but they didn't go on to say that is should not be used. I personally consider ammonium hydroxide, at least in the concentrated form, to be a much greater health risk than pyrogallol when used in the average home darkroom. First off, concentrated ammonium hydroxide spontaneously evolves gaseous ammonia. it is a very strong, pungent, and choking gas - it wasn't used in WWI as a poison gas, but it has many similarities with gaseous chorine which was. Pyro is a solid in the lab and does not really have this gaseous hazard. If you've ever had a whiff of concentrated ammonia, you will quickly respect it for how hazardous it can be. Ammonium hydroxide is a strong caustic with a high pH and will damage your skin if exposed for long enough, and it is very dangerous to get into your eyes, like any other caustic material. But for some reason they did not see fit to recommend not using it, perhaps because most people are more familiar with ammonium hydroxide than pyro and there is less percieved danger from it.
I agree with Jorge about the NIOSH reference being much better info, but some of it is pretty hard to digest.
Keep in mind that when a reference says something has a lethal dose of 28 mg/kg, that means that if humans are affected at that concentration, and you wiegh 80 kg, then the lethal dose for you would be calculated at 2240mg (80 kg * 28 mg/kg). That's about 2.25 grams. That's quite a lot of pyro to be ingesting. And I really don't see how you are going to come anywhere close to ingesting that amount unless you intentionally ingested it, or perhaps you were working in industry and fell into a vat of the material and swallowed some. That's why Jorge is getting upset, it is really not a very likely thing to happen.
And as we pointed out above, everyone really need to be more concerned with dermal contact as that is your greatest pathway to exposure. And if you follow some of my suggestions above, you can pretty much eliminate any dermal contact with it by using items like gloves and still use pyro to your heart's content.
Kirk - www.keyesphoto.com
Just a small clarification as it may appear Kirk and I are at odds. I agree with him that 2.8 grams is a lot of pyro to ingest at one time, yet IMO it is a relatively small dose compared to other compounds we know are really dangerous.
As I said, many of these studies, specially old ones have to be read and the methodology examined.
The NIOSH study has a lot of numbers, many of them quite alarming if not examined carefully, for example; they cite lethal dose dog intravenous as 80 mg/kg, right below they cite lethal dose dog oral at 28 mg/kg. Am I the only one who sees something wrong here? Unless pyro has some property that causes the gastro-intestinal tract to turn to s*it when you swallow it, I dont see how the oral dose can be smaller than the intravenous dose. This could be possible, I admit I dont know anything about biology, veterinary or medicine. But I find this sort of strange.
I think I will shut up now, Kirk has said it all and better than I have.....
Thank you very much, Kirk and Jorge. At least I feel considerably more informed now; I hope others do as well. Because of my particular handling procedures, dermal contact has always been very limited; it has always been the mixing process that concerns me most.
BTW, Jorge, you really shouldn't assume that I am not concerned about D-76. I understand that you are tired of the "Pyro is dangerous" crowd, but short of good data, outsiders like me have every right to be concerned about an agent we don't know. I am aware of D-76 and its hazards. One significant difference is that *I* don't mix D-76, so my exposure (in terms of strength) is more limited then if I was to mix Pyro from scratch. That being said, one of the irritating things about D-76 is that you tend to get some airborne when you mix it. Some of the particulate is very small. BTW, I was the "safety officer" for a photo lab for a while and am educated on many of the risks, though more in a highly prolonged exposure setting.
People's approach to life vary. My approach it certainly different than many peoples. I believe nothing is zero-risk. I believe I will commit evil acts. I believe lots of weird things. What I endevour to do is understand these things and weigh the value of the outcome. I have taken some extreme risks because the outcome pleased me greatly. I am actually fairly surprised to have lived this long, though my tolerance for risk has diminished over the years. Although I enjoy photography very much, I do not think the outcome of using one developer over another is sufficiently interesting to take any risk beyond minimal. If I am going to die, or get sick, I want it to be for something that I can say "at least it was a great ride". Mixing chemicals don't qualify. So, for me, it isn't paranoid; the chemicals really are dangerous and I just wanted to know those risks.
From what I have read here and a few other places, I would conclude that it is safe to mix if you use caution. I think for my particular darkroom circumstances, I would be better off using something pre-mixed or partially pre-mixed, but I would now be comfortable mixing it myself if necessary. For *me*, the handling of mixed photo chemicals has always been pretty circumspect, so it was not a big issue.
Now, Steve, hire a toxologist to write a real article. Really, I think it would be a great idea. And then on a web page, do a safe-darkroom practices page.
Jorge - We ARE very much on the same side. Thanks for helping on this subject.
Kirk - www.keyesphoto.com
LD50 definition:
"An LD50 value is the amount of a solid or liquid material that it takes to kill 50% of test animals (for example, mice or rats) in one dose."
Source: http://www.ilpi.com/msds/ref/ld50.html
In addition to Jorges excellent lead: http://grants.nih.gov/grants/guide/notice-files/NOT-ES-02-009.html This relates to a grant being given "to evaluate the toxicologic and carcinogenic potential of (.... ), and pyrogallol".
Apparently a grant has been given to conduct this study. See here on page 17: http://www.hhs.gov/osdbu/read/nih.pdf
Estimation completion dates are given as 09/30/05 and 06/30/04. One of these dates is very soon. This could be interesting.
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