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Author: Subject: How dangerous are chemicals really?
Murexide
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[*] posted on 9-12-2019 at 02:51
How dangerous are chemicals really?


Most of us seem to work around carcinogenic chemicals at least occasionally. What isn’t really clear is - how dangerous are these chemicals really? IARC doesn’t seem to be of much help, as it only ascertains if something CAN cause cancer, not WILL.

So I’ve always thought of DCM (IARC 2B) as worse than Nickel sulfate (IARC 1). Dichromates actually seem to be one of the most carcinogenic chemicals most of us encounter around here - I simply refuse to work with them (like many carcinogenic metal ions, they require inhalation, but best to avoid the risk if you can!).

What about other chemicals that aren’t carcinogenic, but cause permanent organ damage? They seem just as scary - things like mercury and lead salts (or even dimethylmercury :o), persulfates and various aromatic amines like diphenylamine (polycystic kidneys :o).

What are your thoughts on these?
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[*] posted on 9-12-2019 at 03:19


Good lab practice (gloves, use dilute solutions where possible, small quantities where possible, don't lick your fingers, avoid dust inhalation, work in a fume cupboard if there are fumes or dust etc.) These keep you clear of most hazards.

Carcinogens are rarely problematic on a single exposure or even with repeated but infrequent exposure. Where they are a problem is chronic exposure such as is commonly encountered in industrial work places.

I am much more concerned about acute toxins. Thallium, arsenic and others similar come to mind. I can probably keep myself safe enough. But my concern is keeping my environment perfectly clean and handling all waste in such a manner that I do not cause a hazard for someone else.
There are some compounds that I will never work with. Again the acute toxicity is the concern. Organic mercury compounds and organic cadmium compounds come into this category.

The other significant problem that many of us have to deal with is gaseous compounds. I have a number of experiments on hold since I do not currently have a fume hood. Of these I am most concerned about those gases that can cause irreperable harm without being detected. Cl2 for example does not particularly worry me since I know that it is going to get very uncomfortable and require me to evacuate before it gets to a concentration where it will harm me. CO, phosgene, HF, these are not to be trifled with.

But to answer your question in few words, cancer-causing substances are generally easily managed and many here can handle them safely without concern.
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Sulaiman
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[*] posted on 9-12-2019 at 04:25


I think that it is not possible to give a short answer to the above question,
it is better to research chemicals before you obtain them,
and research products of any experiments that you plan,
uncertainties can then be specifically discussed here.

'Dangerous' is also somewhat subjective,
e.g. some people would freak out if they got a whif of chlorine,
others (like me) are not so concerned.

also see : https://en.wikipedia.org/wiki/The_dose_makes_the_poison

P.S. given that a little basic research on reactants and products has been done,
due to the research we are careful and attentive and make preparations for accidents,
so 'scary' chemicals are often less hazardous than more mundane chemicals, reactions and procedures,
where we sometimes get a little lax with our precautions.

[Edited on 9-12-2019 by Sulaiman]




CAUTION : Hobby Chemist, not Professional or even Amateur
(suffering from separation of me and my chemistry stuff)
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draculic acid69
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[*] posted on 9-12-2019 at 04:52


Some chemicals I'd never work with like hcn,h2s,anything that dangerous.i think with adequate precautions most of what one would want to do can be accomplished within reason with a fumehood, respirators,gloves, protective suits and good chemical hygeine methods.but also I think even being careful with the above methods long term exposure to stuff like toluene,ethyl acetate or dusts like diatomaceous earth or pottery materials dust like oxides of metals and dichromates can add up over years and cause problems whereas occasionally using them won't cause a problem even if u cover your self in them.
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[*] posted on 9-12-2019 at 08:35


Both professional and amateur scientists, severely overestimate their ability to avoid spills.
Working with intensely colored compounds can be very insightful to get a good sense for how difficult it really is to avoid contaminating your workspace.

For amateur scientists there is generally a limit to how much you can invest into equipment, and to what extent you can comply with laws.

With the right tools and precautions anything can be handled 'safely'.




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[*] posted on 9-12-2019 at 09:17


how much a compound is dangerous depends only on your safety precautions. sodium hydroxide is a very common chemical in real labs and amateur labs, a solution of it is not really considered dangerous, but it could easily turn into a dangerous one if used incorrectly.

water is considered safe, but milions of people drowned during history, should we place warning signs on water bottles?





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andy1988
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[*] posted on 9-12-2019 at 09:42


One reference you could search are the U.S. National Library of Medicine (NLM) databases/resources here:
https://envirotoxinfo.nlm.nih.gov

That search engine searches databases created under various U.S. initiatives over the decades... not easy to navigate in my opinion. You click on the database you want to see results for, each database has its own specialties.

I'm not sure how to best search it myself, I'm working through the 'ToxTutor'. I was surprised to see distinctions between terminology I didn't know before reading it. In a book on the U.S. NLM I'd skimmed through it claims that poison control representatives are trained on how to search it in order to help people who call in.

Quote: Originally posted by Murexide  
Most of us seem to work around carcinogenic chemicals at least occasionally. What isn’t really clear is - how dangerous are these chemicals really? IARC doesn’t seem to be of much help, as it only ascertains if something CAN cause cancer, not WILL.

I guess the ITER database would be relevant at a glance.

Quote: Originally posted by Murexide  
What about other chemicals that aren’t carcinogenic, but cause permanent organ damage? They seem just as scary - things like mercury and lead salts (or even dimethylmercury :o), persulfates and various aromatic amines like diphenylamine (polycystic kidneys :o).

Maybe ITER as well, in the non-cancer tables/results skim for non-reversible damage.

If you do handle hexavalent chromium consider taking supplemental vitamin C and E (antioxidants) as a precaution. Feel free to read on its metabolism here, esp regarding glutathione.

Causes cartilage damage, especially in nose by welders exposed to vapor, but can damage cartilage elsewhere like throat, heart, joints, etc. Poorly healing or non-healing pitted lesions.

[Edited on 9-12-2019 by andy1988]




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B(a)P
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[*] posted on 9-12-2019 at 10:53


The ATSDR is a great source of toxicological data.
https://www.atsdr.cdc.gov/toxprofiledocs/index.html
I also find the CDC NIOSH pocket guide very useful.
Tip - it will not fit in your pocket ;)
https://www.cdc.gov/niosh/npg/default.html
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Murexide
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[*] posted on 10-12-2019 at 00:54


Very interesting that many consider acute toxins to be worse than chronic toxins.

To me, the possibility of exposure building up over years and causing issues which don’t turn up until many years later (e.g cancer) are worse.

I do consider arsenic and thallium to be rather chronic however. Acute would be like cyanide.
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Murexide
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[*] posted on 10-12-2019 at 00:59


@Draculic Acid what does long term exposure to toluene and ethyl acetate do? Are they not rather harmless (precluding intentional exposure obviously)?
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[*] posted on 10-12-2019 at 03:21


Toluene chronic effects (inhalation) include renal, neural and hepatic (though only observed in animals) toxicity. Hepatic toxic effects in humans have largely been observed to be reversible in humans.
Ethyl acetate chronics effects (inhalation) include anaemia and leucocytosis toxicity.
While these toxic effects have been observed in intentional exposure scenarios, they have also been observed in an occupational setting.
For amateur chemistry it is hard to determine what is a safe exposure limit for chronic exposure, as most are based on an 8 hour working day for the average duration of a working life, which is very conservative for most amateur chemists. Even so, this level of conservatism probably provides comfort rather than frustration to most.
That being the case you would want to limit your inhalation exposure to toluene to an average of 100 ppm and for ethyl acetate 400 ppm. These numbers are based on the current CDC recommendations. Without proper care it would be very easy to exceed these exposure limits if you regularly worked with these compounds.
I would certainly not classify them as harmless.


[Edited on 10-12-2019 by B(a)P]
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Herr Haber
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[*] posted on 10-12-2019 at 04:18


Quote: Originally posted by phlogiston  
Both professional and amateur scientists, severely overestimate their ability to avoid spills.
Working with intensely colored compounds can be very insightful to get a good sense for how difficult it really is to avoid contaminating your workspace.

For amateur scientists there is generally a limit to how much you can invest into equipment, and to what extent you can comply with laws.

With the right tools and precautions anything can be handled 'safely'.


I couldnt agree more !
With a fluorescent heavy metal nitrate I found out that I contaminated the surroundings *just by opening the container!*
Finding ways to detect the contamination or neutralize it even if it's not there are good ideas.




The spirit of adventure was upon me. Having nitric acid and copper, I had only to learn what the words 'act upon' meant. - Ira Remsen
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Ubya
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[*] posted on 10-12-2019 at 09:42


Quote: Originally posted by Herr Haber  
Quote: Originally posted by phlogiston  
Both professional and amateur scientists, severely overestimate their ability to avoid spills.
Working with intensely colored compounds can be very insightful to get a good sense for how difficult it really is to avoid contaminating your workspace.

For amateur scientists there is generally a limit to how much you can invest into equipment, and to what extent you can comply with laws.

With the right tools and precautions anything can be handled 'safely'.


I couldnt agree more !
With a fluorescent heavy metal nitrate I found out that I contaminated the surroundings *just by opening the container!*
Finding ways to detect the contamination or neutralize it even if it's not there are good ideas.


you can see it even with potassium permanganate. how many times do you need to rinse your glassware before you don't see pink anymore? way more times than if you did the same with a colorless salt





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