I am building a cabinet for my sister and was planning to use potasium dichromate to match their antique mohagony cabinet in their house. I hadn’t heard this before, but I came across one person claiming this on Woodweb.
My question is this “stain” truly a carcinogen? How worried should I be?
Replies
I haven't heard that it's a carcinogen, but everything I have seen/heard says to use a charcoal respirator. I would imagine that if you google it, you'll get whatever info you need. I will probably do some treating with this stuff soon, and need to get the info as well. Anything that changes something else via chemical reaction is worth being careful of.
Paul,
Below is an exerpt from the JTBaker material safety data sheet for potassium dichromate:
http://www.jtbaker.com/msds/englishhtml/p5719.htm
3. Hazards Identification
Emergency Overview
--------------------------
POISON! DANGER! MAY BE FATAL IF SWALLOWED, INHALED OR ABSORBED THROUGH SKIN. STRONG OXIDIZER. CONTACT WITH OTHER MATERIAL MAY CAUSE A FIRE. CORROSIVE. CAUSES SEVERE BURNS TO EVERY AREA OF CONTACT. AFFECTS THE RESPIRATORY SYSTEM, LIVER, KIDNEYS, EYES, SKIN AND BLOOD. MAY CAUSE ALLERGIC REACTION. CANCER HAZARD. CAN CAUSE CANCER. Risk of cancer depends on duration and level of exposure.
J.T. Baker SAF-T-DATA(tm) Ratings (Provided here for your convenience)
------------------------------------------------------------------------
Health Rating: 4 - Extreme (Cancer Causing)
Flammability Rating: 0 - None
Reactivity Rating: 3 - Severe (Oxidizer)
Contact Rating: 3 - Severe (Life)
Lab Protective Equip: GOGGLES; LAB COAT; VENT HOOD; PROPER GLOVES
Storage Color Code: Yellow (Reactive)
------------------------------------------------------------------------
Be careful,
Tom
OK, I looked it up, too and found the same info. Once it's dried, finished and somewhat inert, from what I have heard there isn't so much risk, although I wouldn't use it for anything children can chew on.
"I cut this piece four times and it's still too short."
Once it is sealed the risk to the user is not great, but there is risk to your health in applying it. Dye works. So does a weak lye solution. Many safer options. There are enough toxic things in the world already. You really need to contribute another?
Paul,
In a word, yes.
Hexavalent chromium (which is the form in the "dichromate" part of potassium dichromate) is carcinogenic.
Risk depends upon exposure, but yes, it is a carcinogen.
Cheers,
eddie
Hexavalent chromium... this is the 'bad stuff' that was central to the movie Erin Brockovich.
It is a carcinogen, and contact with it is likely to cause burns. Repeated exposure to low levels might cause cancer. When you put it on wood, it forms color by oxidizing the wood, and in the process the chromium becomes reduced. The reason this is relevant is that the reduced form of chromium is much less dangerous: it does not cause burns or cancer. Thus, you will bear most of the risk, not your sister or her family. (Wear gloves and try to keep it off your hands. If you get a drop on your glove, remove and replace the glove. Don't count on the glove protecting you for long.) The problem is that traces of the dangerous form might persist. Once you put a film finish over it, it will be encapsulated and contact prevented. But of course, things wear, and children and animals chew on things.
If it does cause cancer, you will never know that this was the cause, and if someone does get cancer, you will never be sure this wasn't the cause. I work with such toxic chemicals all the time in a laboratory with proper safety precautions that are impossible at home. It is quite plausible that you could handle it safely, and that there would be no adverse health consequences at all. There is some risk, and the benefit of its use seems to me very small since there are plenty of other options for staining that don't involve chromium. I wouldn't use it.
Alan,
Thank you and everybody who has responded to my question. I think I will play it safe and try an alternative finish to potassium dichromate. I don't believe it is worth the risk.
So any suggestions for a safer alternative?
Look for books on wood finishing. I have one somewhere that goes into the methods of changing the color of different woods with various materials. Both toxic and non-toxic are listed along with their characteristics. These particular chemicals react with the wood. Others are dyes and stains. Try UV light. I was thinking of using lye to darken some cherry and decided to try regular chlorine bleach. It worked pretty nicely. Maybe it works on mahogany, too. It won't look the same as potassium dichromate, but you should be able to approximate it. I'll look for the book and post the name/author. By the way, hazardous chemicals like these should be handled with neoprene gloves. It won't soak in and they can be washed off.
"I cut this piece four times and it's still too short."
Hi Paul,I have used potassium permangenate to stain some things. I don't think it's as powerful as dichromate, but as you can see from the MSDS, it's not nearly as dangerous.http://www.jtbaker.com/msds/englishhtml/P6005.htmTomps. Don't let the dark purple color fool you, it gives a nice rich brown color to most things.
Permangenate works OK. Also can start fires in contact with sugars or other things. Available in the plumbing department since its used to recharge certain types of water filters. A whole lot of chemicals will color wood. Muriatic acid, nitric acid, lye, washing soda, ammonia. Any reasonably strong oxidizer, acid or base. A problem with all chemical treatments is that the results are not very consistent from board to board or heartwood/sapwood. Ammonia and washing soda are pretty gentle. Lye gives more darkening. In reasonable concentrations, those are all fairly safe.
I've used lye to color cherry, but I've never used acid. Permangentate is the only oxidizer I've used.Is there a text on chemical conversions in wood?Tom
Don't let potassium permanganate and glycerine combine. Unless you want a really hot fire. This stuff will burn the bottom out of an aluminum kettle. Ask your kid's science teacher about this one.
"I cut this piece four times and it's still too short."
I don't know a book that specifically concentrates on chemical treatments. Most good finishing books mention a few and I've picked up my knowledge from a lot of places. Any strong acid or base will do something. Nitric acid or Potassium Nitrate is sometimes used on maple to pop the curl. Ferric Acetate works to blacken or grey any wood with enough tannin. If it doesn't have tannin, add some using tea. Ammonia works well. The old trick before household ammonia in the bottle was to bury it in the barnyard under the a natural ammonia source. Bovine or poultry or equestrian. Natural extracts have been used for a long time. Logwood and brazilwood and henna and saffron and that sort of stuff. I frequently use ammonia because its so easy. Most other stuff I leave alone. Dye is so much simpler.
I'm not an expert on finishing, but there are a lot of good books available, many from Taunton. Flexner, Dresdner, and Jewitt are frequently recommended authors on the subject.There is a 50% off sale at Taunton press right now, and several sale books are on finishing:
http://www.taunton.com/store/pages/nmbm026_ww.asp
Jimeny crickets! I remember turning my fingers purple with it in Chemistry Lab several times.
Frank
We used to turn the fountains pink in Trafalgar Square on New Years Eve with it and add detergent to make bubbles
Almost everything is carcinogenic in enough quanitity.
If you want to use potassium dichromate, use the appropriate cartridge respirator, a good exhaust* or do it outside and nitrile gloves, doubled up.
You can wear a Tyvek jump suit if you're concerned about it on your clothes, toss the suit and wash your bvds immediately, have a spare set of clothes in the laundry room.
*Note: EXHAUST. As in a cubic yard/min at least. Not recirculated with a fan and filter. Suck it outside, this in not the time to go cheap on the heating/ac bill.
Good luck.
One of the problems with the excessive warnings on chemicals is that the really nasty ones don't seem so different from the others. Chromium VI is one of the nasty ones.
< Almost everything is carcinogenic in enough quanitity.>Potassium Dichromate is a LEVEL 4 CARCINOGEN
For comparison, gasoline is only a level 3 flamability hazardThis is a good example of why you should learn to read a Material Safety Data Sheet. They are available online for any chemical commercially available.Tom
One of the great advances of the internet. Years ago it was not easy to get the safety datasheets. Now I read them for everything I use.
Although, I've been told by more than one source something about the total volume dose for potassium dichromate. They claim it isn't as bad as the datasheet says and some datasheets present things in a different light than others. But, since cyanide is only level 3 and this stuff is level 4, I no longer have any in my shop. I remember playing with mercury in school. We had hundreds of pounds of it. Spill some, no big deal, sweep it up. Now spill an ounce and its a major toxic spill. A local school had a whole flask spilled last year. Some kid found it in the stockroom. They closed the whole school for a month to do the cleanup. He spilled a lot on himself. They went to his house and gutted it to the studs. We get a little smarter about things sometimes. Some stuff is just not worth the risk. I don't want to risk dropping a bottle of dichromate in my shop.
Bob,
I had no idea mercury was so toxic and that a spill is a major event like that.
Like you, I remember playing with the stuff in school. We used to put our hands in it! We could buy it at our drug store. We used to coat coins with it all the time. Made them real shiny.
How toxic can the elemental stuff be?
Rich
Lots of elements are highly toxic or highly reactive. Most heavy metals. Arsenic, beryllium, chlorine, fluorine and dozens more. In compounds some are safe. Sodium chloride is just salt. But, you wouldn't want to get too close to a bunch of either one alone.
Ever notice that mercury thermometers are not sold anymore? Mercury is a cumulative toxin. So is lead. No lead in plumbing solder anymore. Your body can't get rid of it. So, even small amounts are not good. Especially for children. Lots of stuff that was around when we were kids is now considered dangerous. Used to be able to buy DDT and lots of other pesticides. Not anymore. Used to have x-ray machines in the shoe stores. We've gotten smarter about some things and dumber about others. Some stuff is banned because it's truely dangerous. Some is not sold because people are not assumed to have any common sense. Didn't used to have a warning on a cup of coffee. Warning! Hot! Anyway, some stuff is actually more dangerous than its worth. If it really is dangerous, I expect there to be a label and I'll read it and make my decision. Problem is that industrial items don't need the same warning labels as consumer items. You have to look them up yourself. Hence the importance of the MSDS sheets.
Well, that explains a lot... those mercury spills I had in High School Chem class... I guess it wasn't the 60's that got me afterall - LOL!
I guess I fall somewhere between the over-the-top lawyer-induced reactions/CYA reactions we have to everything today and being smart and prudent. Cancer isn't pretty. I certainly try to avoid the nasty stuff, and wear a good respirator when appropriate. Potasium Dichromate definately falls in the avoid category.
I read them and use them on an almost daily basis.I also work with deadly stuff on a daily basis. I'm just vewwy, vewwy cawefull.Regards,Leon Jester
This forum post is now archived. Commenting has been disabled