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Up Topic Welding Industry / General Welding Discussion / Thoriated Tungsten
- - By kmcquait (*) Date 07-11-2001 05:51
Why doesn't the government regulate thoriated tungsten? Thorium is a highly radioactive substance (alpha, high LET). Everyday I see some poor smuck grinding away without a care in the world. Even better yet, just after they're done grinding it they put it in their mouth. Does anyone else see, or think about this?
Parent - By RonG (****) Date 07-11-2001 14:02
"The Sky is Falling, The Sky is Falling"
Sure its radioactive, but so are many other things.

Where do you draw the line? A group of men working along side of Highly explosive cylinders using high temperature flames and arcs. How many times have you seen an can of D-spat or some other Aerosol can on a welding table? Talk about hazords! They can go off like a bomb.

Tell the "Poor Shumk" that it is radioactive, tell every body, put up a sign, but leave the government out of it. Unless you want to have to go to the NRA every time you get an electrode.

Have you ever been in a Nuclear power plant? Ever try to GTAW with a pair of cotton gloves under a pair of rubber gloves under you leather gloves and then if you touch your hood and crap it up you have to leave it in the area, same applys to your glasses or wrist watch.

Some good sense can replace a lot of government. Like changing to Lanthinated tungston and there are others that are not radioactive.
Parent - - By pipewelder_1999 (****) Date 07-11-2001 14:24
I would trade all of my consumed smoke and fumes from welding and grinding nickel, chromium, zinc, molybdenum, and other alloys for the amount of low energy radiation absorbed via thorium bearing tungsten grinding.

You do have a point that certain types of health hazard are much less noticed than the all important, cause for termination issue of safety glasses under your welding hood.

Maybe that could be because when I go to the doctor for an eye injury I am working for the company that was paying me when I got injured. However if I have severe respiratory problems when I am 40 I may have worked for 100 different companies doing various types of work with supervisors that no longer work for that company for the same reasons I don't. And nobody is responsible.

Have a safe day
Gerald Austin
Parent - - By CHGuilford (****) Date 07-11-2001 16:45
Are you aware that the silk mantles for Coleman lanterns are also thoriated and slightly radioactive? (I learned this from a nuke plant propaganda board) I guess the question is how much radiation will harm you and how does the source compare to natural background radiation?
I don't mean this to be a smart aleck reply,(although it's tempting to have some fun) I just don't know the answer. Since I like to go camping and sometimes work around people using thoriated tungsten, it might be nice to know when to worry and when not to. For now I guess I have to trust the MSDS sheet.

Then again how much EMF radiation from welding cables is considered harmful? Vapors from solvents and aerosol cans?
Have they ever solved the problem of TV picture tubes emitting X-rays from the back of them?

Gerald is right though. And we won't know what the long term effects are until many of the companies we worked for are out of business.

By all means, do have a safe day,

Parent - By kmcquait (*) Date 07-12-2001 04:21
actually, coleman lanterns no longer contain thorium, but, several brands manufactured outside of the U.S. do! like "American Camper" which is distrubuted by your local Wal-Mart.
Parent - By Lawrence (*****) Date 07-11-2001 16:47
The electrodes themselves present little threat of harmful radiation exposure to personnel. It's the fine airborne dust particulate, released by grinding and tip prep, which pose a threat of radioactive particles entering the body. So if your shop equipment is not properly ventilated it may be out of compliance, putting you at just about as much risk as your smucky coworker who puts the things in his mouth.

Regulations are indeed in place for thorium at both Federal and State levels. The best place for you to start is by obtaining an MSDS (Material Safety Data Sheet) from your electrode supplier. <--This is what the Germans think <--here is a balanced report given by a vendor of electrodes

Keep in mind whether alloyed with thorium or some other oxide, *Tungsten* itself produces irritant dusts during grinding, cutting and tip prep operations which are harmful to the respiratory system. Your shop management would demonstrate wisdom by employing the same fume/dust extraction methods for Lanthanum; Zirconium or Cerium alloyed electrodes as they do for thoriated electrodes.

Parent - - By kam (**) Date 07-11-2001 18:36
Check out these sites. Lots of interesting stuff.

Parent - - By kmcquait (*) Date 07-12-2001 04:26
People who don't understand the subject, should not reply!!!
Parent - - By RonG (****) Date 07-12-2001 20:18
What is it that you Understand that one else seems to?

If you know something we do'nt please share with us, most of us are in contact or very near this material every day.

As for understanding, I do'nt recall this material being discussed when I went through the NRA radiation training to gain unescorted access to a Nuclear power plant.

Nor did my torch ever set off any alarms and there were plenty of them around. Not to mention the body scans we went through several times a day. I carried my Tungston in and out of the RCA (radiation containment area) many times.

If you know something they failed to tell me I want to hear it.

Parent - - By pipewelder_1999 (****) Date 07-12-2001 20:55
As far as alarms go I have been held up when frisking with a pocket full of 3/32". Turning the meter to the regular level indicated no problem but I did have to take it out of my pocket.

I also left my dosimiter in the locker away from any kind of radiation source and came back from certifying for steam generator repairs and I had somehow received about 100 mrem.

We had 4 or 5 boxes of 5/32" or 3/16" 2 % in our cabinet on a ship I was on. The RM 3 would pick it up at if the cabinet door was open. Of course at the right setting the thing would pick up radiation given of by a mosquito doing a pushup (One ERG if I recall).

I recall reading a document once regarding surveys and the like. A nuclear powered cruiser had surveys taken of all of the occupied spaces while steaming. The highest level of radiation was in the CO's stateroom coming from a chelsea clock.

I am pretty sure the powers that be have evaluated the situation regarding the use of thoriated tungsten and based on evidence available feel no need to establish any further regulatory guidelines.

(DDT, PPH, ASBESTOS, LEAD) Had to throw that in :)

Whats the NRA? I'm ex navy as far as nuke work goes and would like to get up to date with all the civilian lingo that nuke welders use.

Take things lightly else they weigh you down

Gerald Austin
Parent - - By kmcquait (*) Date 07-19-2001 01:18
the detector being used is not a scintillation detector and it does not detect Alpha radiation.
Parent - - By pipewelder_1999 (****) Date 07-19-2001 05:01
What was it picking up then? I'm positive we had surveys and we had problems with tungsten and the dust in the vacuum cleaner in the grinder. If thorium is only an Alpha emmiter and an RM-3 wouldn't detect that then what was it?

We had two other types of survey instruments but I was almost positive that the RM 3 was the one that would detect the tungsten.

Maybe one too many steam generator jobs and not wearing head dosimetry. I may have some details wrong. But have been asked to clean out my pocket and for sure had problems in the jetline tungsten grinder cabinet.

Good day
Gerald Austin
Parent - - By MBSims (****) Date 09-01-2001 06:11

They were likely using the AN/PDR-56A, which is a scintillation detector. But as best I recall the radiation levels were pretty low. I'll do some checking tomorrow at work. In 25 years of welding, I have to say I've never seen a welder put tungsten is their mouth. Must work the same as that little pill that used to come with a new set of points for your car. Swallow the pill so you know how to gap them right.

Did you know bananas are radioactive too? You suppose the NRC needs to regulate bananas?

Parent - By pipewelder_1999 (****) Date 09-01-2001 13:35
Hey Marty,

I forgot about the 56. That may have been what was detecting it. I know the tungsten was never "controlled" but it was detectable.

Parent - By Lawrence (*****) Date 07-24-2001 20:47
Below is some well researched and authoritative information, Lifted from the fine website at (
offering depth to our subject while specifically speaking to State, Local and International concerns.
I hope this will add some credibility to the opinions offered above.

To speak to the original post, we have learned that Thorium is regulated and
inhalation of Tungsten dust is to be avoided. Now you know it.
The burdan of responcibility falls squarely upon you, to share your newfound awareness,
to keep yourself safe and your shop and its personel in compliance.

Thoriated Tungsten Radioactivity


For quite some time, tungsten manufacturers have added an oxide to pure
tungsten to improve the arc starting characteristics and the longevity of welding
electrodes. While 2% thoriated tungsten has been the most commonly used
tungsten material for many years, this electrode type is increasingly being
scrutinized because of concerns for the environment and for the safety of users of
this material. The concerns arise from the fact that the element thorium is
radioactive. On this basis, many organizations have evaluated alternative tungsten
types to see what changes in performance they would see by transitioning to
non-radioactive tungsten.

The Radioactivity Problem

The Thorium used in 2% thoriated tungsten is a radioactive element and therefore
can be dangerous to the health of those exposed to it and to the environment. It
is an alpha emitter, however when it is inside a tungsten electrode rod, it is
enclosed in a tungsten matrix and so there is little radiation emitted externally.
The main risk to the welder occurs in the ingestion of the material. This occurs
primarily during the inhalation of dust caused during grinding of tips for welding,
but also to a lesser extent during breathing of any fumes released during welding.

The American Welding Society, in their A5.12 "Specification for Tungsten and
Tungsten-Alloy Electrodes for Arc Welding and Cutting" states the following on this
issue: "Thorium is radioactive and may present hazards by external and internal
exposure. If alternatives are technically feasible, they should be used." They
confirm that the primary concern in using this material is in ingesting dust
produced while grinding points on electrodes. They go on to say:

...during the grinding of electrode tips there is generation of
radioactive dust, with the risk of internal exposure. Consequentially, it
is necessary to use local exhaust ventilation to control the dust at the
source, complemented if necessary by respiratory protective

Europe has also recognized the dangers of 2% thoriated tungsten. TWI (The
Welding Institute), which is the British equivalent of the AWS, reports that "The
British Health and Safety Executive (HSE) have issued an information document to
provide for the storage and use of thoriated tungsten electrodes. This states that
local exhaust ventilation should be provided during the grinding operation, and that
the dust from the grinding equipment and the spent tips are disposed of in a
sealed container to a landfill disposal site." Further, "The HSE has recommended to
factory inspectors that, where thoriated tungsten electrodes are not necessary
for the quality of the weld, users should be encouraged to look for alternatives."

In a highly detailed study conducted by the DVS (the German Welding Society),
they measured the amounts of radioactive alpha particles and gamma energy
sprectra in the ambient air during the grinding of tungsten electrodes. Some of the
recommendations of this study included:

1.It is recommended to work, if possible, without the use of welding electrodes
containing Thorium.
2.If this is not possible, precautions should be taken to protect employees
against the contamination with or the inhalation of grinding dust.
3.The working area shall be cleaned regularly in order to avoid contamination
caused by deposited dust.

Another study was conducted in Germany by the State of Bavaria, Department for
Development and Environmental issues. They concluded that in facilities where
there is no dust extraction system for thoriated tungsten grinding, the exposure to
harmful particles is four times greater than with extraction. However, even though
dust collection provides a significant improvement, levels may still be too high. In
addition, they mentioned that thoriated tungsten electrodes stored in boxes on a
shelf do not seem to pose any potential hazards. At the moment, a proposal has
been placed before the European Community Commission to drastically increase
the severity of legal regulations with respect to the use and disposal of thoriated

In the State of California, tungsten manufacturers now include packaging of 2%
thoriated tungsten electrodes that include a warning such as the one Osram
Sylvania uses, which is, "WARNING: This product contains or produces a chemical
known to the State of California to cause cancer. (California Health and Safety
Code 25249.5 et seq.)"

Finally, one of the major U.S. tungsten manufacturers, Teledyne Tungsten
Products, list the following cautions/warnings in their MSDS Sheets:

"Thorium is a naturally occurring low level radioactive element. Thorium
is primarily an alpha emitter. Daughters in the decay chain emit alpha,
beta, and gamma radiation. Radioactive elements are regulated by the
Nuclear Regulatory Commission. The NRC publishes regulations
regulations regarding radioactive materials."

"Effects of overexposure: ...Chronic inhalation of the dust may cause
lung damage in humans."

"Carcinogenic assessment: NTP-1 (Thoria). Note: NTP-1: Substances
or groups of substances that are known to be carcinogenic. 'Known
carcinogens' are defined by the NTP (National Toxicology Program)
report as those substances for which there is sufficient evidence of
carninogenicity from studies in humans to indicate a causal relationship
between the agent and human cancer."

"Toxicological Information: ...Heavy exposure to the dust or the
ingestion of large amounts of the soluble compounds produces changes
in body weight, behavior, blood cells, choline esterase activity and
sperm in experimental animals."
Parent - - By kmcquait (*) Date 07-31-2001 23:50
great replies fellas, thanks for the input!! LOL!!!
Parent - - By Daon (*) Date 08-26-2001 11:32
The German company JAS came out with a small, affordable high quality tungsten grinder that retains all of the grinding dust in a closed container so that there is no contamination.
Parent - - By MBSims (****) Date 09-06-2001 14:41
To answer the original question, here's what the NRC had to say:

Airborne Thorium From Welding Rods

HPPOS-255 PDR-9308020142

Title: Airborne Thorium From Welding Rods

See the memorandum from L. J. Cunningham to J. H. Joyner
(and others) dated June 18, 1993. This memo addresses a
question from a corporate health physicist at a nuclear
utility that had found airborne thorium in a nuclear power
plant. Although this regulatory position is presented
quite clearly in 10 CFR Part 40, it is being issued as a
health physics position to call attention to an exemption
that might otherwise be overlooked by Part 50 licensees.

A response was requested as to whether there are any NRC
regulatory requirements that apply to airborne thorium
caused by grinding the tips and using welding rods
containing thorium. The response stated that 10 CFR 40,
"Domestic Licensing of Source Material", in subsection
40.13 (c) (1) (iii), provides that any person is exempt
from the regulations in Part 40 and from requirements for
an NRC license to the extent that the person receives,
possesses, uses, or transfers any quantities of thorium
contained in welding rods. Therefore, there are no NRC
regulatory requirements that apply to airborne thorium
caused by grinding and using welding rods that contain

Additional technical information concerning the
considerations for the 10 CFR Part 40 exemption for
thoriated welding rods does not include any information on
the radiological hazards associated with their use.
However, some information on the radiation doses associated
with the use of these rods can be found in the following

1. NUREG / CR-1039, "Estimated Radiation Doses from
Thorium and Daughters Contained in Thoriated Welding
Electrodes," December 1979.

2. NUREG / CR-1775, "Environmental Assessment of
Consumer Products Containing Radioactive Material," October

3. NCRP Report No. 95, "Radiation Exposure of the U.S.
Population from Consumer Products and Miscellaneous
Sources," 1987.

4. E. M. Crim and T. D. Bradley, Abstracts of Papers
Presented at the Thirty-Eighth Meeting of the Health
Physics Society, Atlanta, Georgia, 11-15 July, 1993, Health
Physics, Vol. 64, Supplement 1, p. S85, June 1993.

Reference 2 includes the following summary statement
concerning radiation doses:

The maximum individual fifty-year dose commitment to bone
for welders was estimated at between 55 mrem and 2 rem for
a one-year exposure. Welders not engaged in welding at
home and occasional welders were estimated to receive a
bone dose commitment of 16 to 575 mrem and 1.3 to 115 mrem,
respectively. A maximum individual bone dose commitment
range between 30 and 230 mrem was estimated for nonwelders.
External doses for all group members were estimated to be
less than 1 mrem.

Reference 4 includes the following statement concerning
airborne thorium (Th-232) from welding rods:

The results for the grinding and welding operations to
date, show that all personal and area air samples are below
the maximum permissible concentration for Th-232 as well as
below the derived air concentration.

Regulatory references: 10 CFR 40.13

Subject codes: 7.2, 8.4

Applicability: Reactors

Parent - - By RonG (****) Date 09-06-2001 17:01
If only Thorated Tungston was the biggest safety concern for welders!

We live and we Learn and my feelings are that welding is hazardous work.

I may have been a little to sharp in my first reply but I have an on going battle concerning safety in our plant and Carelessness and poor house keeping do more harm than any thing else.

All the safeguards and information are in place but get ignored to point of threats of discipline, they express concerns about Thorated Tungston so we buy Lanthenated.

But they still chip and grind with out safety glasses and still leave aresol cans laying around where they present a very dire threat and think nothing of it.

Go figure.

Parent - - By pipewelder_1999 (****) Date 09-06-2001 18:39
I can understand the sharpness. I've been on jobs where you could get fired for not having safety glasses on under your welding hood but were never warned about the health hazards associated with welding smoke.

Have you ever seen anyone reprimanded or warned about a safety issue that was designed to prevent long term health risks? People talk about that in offices where the biggest concern is the how to reduce the cost of work through improved safety measures.

I have seen very few films that explain the long term effects of chromium, nickel, manganese and those other elements yet to be discovered. I have seen many about eye, ear, fall protection. At least if I die on the job during a fall my family has a chance of benefits.

If I die early or suffer from a poor quality of life due to the fact that my employer didn't provide adequate ventilation, who's gonna know? How many fab shops have an industrial health person on their payroll.

Think about this.

If I go to work every day without steel toe boots on will I die early from it?

If I breathe fumes above the PEL for various elements will it affect me?

Has anyone ever been sent home because they didn't have their respirator on when thay came in?

OK I'm done for now.

Good Day
Parent - - By RonG (****) Date 09-06-2001 21:12
Sorry to keep dragging this on BUT.

The ventilation is another battle that almost cost me my job, but I had to much documentation for them.

Now we have very good smoke eaters and a yearly physical for the welders with a respiretory check.

You said it very well dont stop! I wish I would've had some in my conner 30 years ago looking out for the unseen hazards.
Parent - By pipewelder_1999 (****) Date 09-07-2001 02:49
Thats great. I wish all in the industry would do the same.
Up Topic Welding Industry / General Welding Discussion / Thoriated Tungsten

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