View Full Version : Is cobalt is a carcinogen?

03-16-2016, 10:21 PM
I use 50% inserts and 50% HSS-w 10% cobalt.
Is grinding the HHS 10% cobalt toxic?
Was watching a machining video and they mentioned that cobalt is a carcinogen?

03-16-2016, 10:30 PM
Cobalt dust is,it does damage the lungs like anything other than air does,but unless you're grinding a lot of it and breathing in the dust I wouldn't worry too much.Otherwise grind wet and wash your hands before eating.


03-16-2016, 11:13 PM
What might be worse is tungsten TIG electrodes 2% thoriated, if you do a lot of TIG welding and pointing.
For years welders used to point them with out any protection, most on a bench grinder and never worried about it. A few years ago, maybe 12 or so I bought a box of 3/32" 2% and there was a warning on the box about radioactivity. A little late.


03-16-2016, 11:23 PM


Make your own judgement and proceed with necessary caution.

03-17-2016, 12:14 AM
Cobalt is very toxic. It has strict OSHA exposure limits.

See here: https://www.osha.gov/dts/chemicalsampling/data/CH_229100.html

Especially this "Death at exposures of 1-2 mg/m3"

EPA carcinogenic classification: Not listed

03-17-2016, 01:05 AM
Ain't nothing good fer ya any more!:eek:

03-17-2016, 01:06 AM
I have posted this here before but here we go again.

I worked in a large mfg. plant in the toolroom. We had a few grinding departments: die room, toolroom and R+D department. There were probably upwards of 75 grinder hands at one time. Eventually I spent some time grinding late in my career. One of the older grinder hands and I were talking one day about how many of the grinder hands had died of cancer. He said "they all did". I said come on, not all of them. He said "name one that didn't". He had me there. I couldn't name a single one but I sure could name a bunch of them that did die of cancer.

Most of them had been grinding since before the installation of dust collectors and breathed a lot of dust. Carbide, cobalt and you name it, they ground it. By the time I went into grinding full time we had dust collectors as well as monitors that we wore on our belt with a tube going to a intake that we wore on our lapels.
We wore the monitors once a year and they were sent to a lab for testing. They always came back well within the osha limit for ppm of particulates but my wife who also worked at the same plant wanted me to put in for a different job. She had heard the horror stories. I told her not to worry.

I did see some of the old timers live to a pretty old age. I just saw one guys obit this week who ground for about 40 years. He was 88 years old and a WWII submarine vet. I learned a lot from him.

Breathing that stuff is a lot like smoking. Some people can smoke cigarettes and live to be 100 but I wouldn't plan on it. As they say "better safe than sorry"


03-17-2016, 01:38 AM
Ain't nothing good fer ya any more!:eek:

Still no warning on paste...

03-17-2016, 01:52 AM
Cobalt has gotten more interesting since they discovered that hip implants containing even traces of the stuff are causing several other things besides cancer, particularly hearing impairment, tinnitus, even complete deafness, how bizarre is that!
New implants are cobalt free, apparently nano particles of the stuff break off the surface of the implant and cause the tumers, and the deafness, very peculiar!
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Scary old world, thorium is a radioisotope btw, shove a radiation monitor next to a packet of thoriated tungsten electrodes for a suprise, but saying that the green glass ornaments that flourecess under UV Light contain uranium and are radioactive too, as are old watches and flight instruments from the radium in them

03-17-2016, 03:57 AM
Up until 1990 all the gas mantles for camping lanterns and similar contained radioactive thorium. Even much more recently there were still a lot on the market with thorium and there are most likely some still on the shelves, especially if they aren't big name brands. The main problem occurs when it is burnt off when first lighted. Don't breath fumes!

03-17-2016, 09:36 AM
I don't know about nowadays, but back in the 50's cobalt was used in treating cancer.
My dad received those treatments for bladder cancer. It was a painful ordeal for him, but it worked. ...he died in 1995.

Lew Hartswick
03-17-2016, 05:01 PM
I don't know about nowadays, but back in the 50's cobalt was used in treating cancer.
My dad received those treatments for bladder cancer. It was a painful ordeal for him, but it worked. ...he died in 1995.

[Why does the return jump backward?]
I can't even get below the first line I type. FERGET IT!!!!

Yea probably Cobalt 60 , the radioactive isotope. as a source to kill the cancer

03-17-2016, 05:39 PM
I don't know about nowadays, but back in the 50's cobalt was used in treating cancer.
My dad received those treatments for bladder cancer. It was a painful ordeal for him, but it worked. ...he died in 1995.

Thread diversion, but pertinent to this post.
I had radiation and chemo treatment for cancer, some of which included metals.
Yes, I'm alive, yes it was painful, yes there are residual effects.
Yes, I'm enjoying my kids and grandkids!
Hope you had that w/ your Dad.

03-17-2016, 06:33 PM
They are now using tightly focused cyclotron beams for a lot of the radiation treatments. The availability varies a lot depending on where you live. We have a high powered cyclotron here in B.C. so it is available here. They were considering treating me with that but it turned out that my stroke problems were most likely caused by traumatic brain damage when I fell and hit my head with around 100 gees of impact. My risk for another stroke now is very low, approaching normal for my age. No radiation, thank you. I have had plenty already from CT scans.