The Dangers of Rock Dust

By Glen Kuban

Keywords: Silicosis, pulmonary fibroisis, lung disease

Many collectors use a mechanical rock saw to cut, trim, or abrade rocks and fossils in the field or lab. Dangers of this activity include flying rock chips, wounds from the blade itself or broken blades, and ruck dust, which is extremely dangerous to inhale. Always read and understand the proper operation of any mechanical tool before using it. Whenever cutting or grinding rock, wear protective eye goggles. Also wear a good respirator, or use a dust collection system, to avoid inhaling rock dust, which accumulates in the lungs and can cause a variety of serious illnesses.

For those not convinced that rock dust is a serious danger, or that they can get away with not wearing a respirator or working under a hood (if working indorrs), I encourage you to read the messages below. The original message was posted on 7-14-97 in the Rocks and Fossils Newsgroups, and my reply was sent to that list as well as the Dinosaur List, VrtPaleo, and Fossil Nuts.

The original message I am responding to was posted in Rocks and 
Fossils, but I am sending my response to other paleo-related 
lists as well, because I feel this is an important safety issue.
It affects anyone who even occassionally cuts rocks or fossils, 
or does fossil preparation work.  It will be very worthwhile if 
it prevents even one person from suffering lung problems or dying 
prematurely.  With that deliberately omenous introduction, let 
me quote the post that prompted my response:

Pete Richards wrote:

> Last night I spent an hour cutting sandstone sidewalk 
>blocks with a composition blade made of fibreglass and 
>carborundum grit.  This is a dry saw and it was a still 
>night and clouds of dust were all around.  Some of it hung 
>in the air for minutes. I am not really concerned about a 
>one-shot exposure, but it did make me wonder if this is the 
>size of silica which DOES represent a health hazard. Of course, 
>I do not know for sure that the fine dust was silica, as opposed 
>to calcium carbonate (the cement in the sandstone) or material 
>from the saw blade...

It's funny, or really not so funny, that you should write now.  
I'm suffering a chronic lung irritation, and seeing doctors now, 
because of the results of a similar incident.  In short, yes, one 
or a few exposures to significant amounts of freshly-cut rock 
dust can cause serious problems.  Silicosis is only one of many
lung problems that can be caused by rock dust, many of which 
(like fibrosis) can occur no matter what the composition of the 
rock.  Wearing a good respirator or hood with dust collector if 
working indoors is a must. If you don't have the proper safety 
equipment, don't cut the rock!  
Unfortunately, I found out the hard way, I hope everyone learns 
from my mistakes.  About a year ago our fossil club went to 
Ontario to collect trilobites, and we took along a diamond rock 
saw.  I only sawed out a few trilobites for fellow members 
(without wearing a mask; I forgot to bring one) and I tried to 
not inhale the dust.  However, large clouds of it were kicked up 
each time, and it was impossible to avoid inhaling quite a bit of 
it.  My the next morning I had significant lung irritation, and 
have had it ever since--some days worse than others.  I have 
frequent coughing and uncomfortable sensation in my upper chest. 
After this went on a few weeks, I went to a doctor, not knowing 
if I had contracted a bacteria, fungus, or other microbe at the 
quarry, or just had accumulated too much dust in my lungs.  An 
x-ray was clear, but that is not unusual in such cases (it 
sometimes takes years for fibosis, TB, cancer, and other diseases 
to develop).  Apparently the rock dust itself is the cause the 
current lung irriration, and it may never get better.  In fact, 
it may worsen into other conditions, as explained below.   
Many people assume years of exposure to rock dust is needed to 
cause serious problems, and this is generally true when dealing 
with wind-blown, low concentration dust, which usually has 
already been weathered to some degree.  But not so with freshly 
cut rock.  After I started having my problems, I began talking 
to doctors and doing lots of reading.  I also talked to an uncle 
who used to work in a quarry, and is now dying of pulmonary 
fibrosis at the age of 55.  I'm now going to his doctor.   
It turns out that not only do rock particles of any composition 
tend to stay and accumulate in the lungs, but _freshly cut_ rock 
is the worst, and extremely pernicious. Even one or a few incidents 
of significant inhalation of such dust can cause lung irritation 
and a start process of increasingly serious lung damage.  The 
microscopic particles are like millions of razor-edged shards that 
damage lung tissue directly, as well as create conditions promoting 
the development of TB, microplasms, fibrosis, and cancer.  
Experiments with rats and other animals have shown that 
inhallation of fresh cut rock dust is far more damaging than worn 
rock dust of any composition, and leads to far greater rates of 
several diseases, including pulmonary fibrosis and lung cancer.  
(But even accumulations of worn rock dust in the lungs greatly 
increased chances of lung diseases).  
I've also made many fossil molds and casts over the years, and 
although I often wore a mask while working with plaster, but 
sometimes did not.  I may well have accumulated plaster in my 
lungs as well, which may have contributed to or aggravated my 
lung condition.  Plaster hardens when in contact with moisture, 
wherever it occurs, including one's lungs.  But I did not have 
the constant lung irritation until after the Ontario trip using 
the rock saw (on hard shales and siltstones), and have had it 
ever since.
I have another apppointment with a pulmonary doctor on Thursday, 
but from what I have learned such damage is generally irreversible, 
the best I may hope for is to have my condition not get worse.  
I may have to live with lung irritation and chronic caugh for the 
rest of my life, plus increased chances for the serious conditions 
I listed above.  
So PLEASE, whenever you are cutting or grinding rock of any kind, 
ALWAYS wear a respirator (not just a cheap dust mask).  If 
working indoors, use a dust collecting hood, or don't do it. 
Your health is not worth any rock or fossil.  
There are serious inhallation dangers in the lab also, including 
solvents, urethanes, glues, and other chemicals used on prep work.  
These too can have accumulative effects, and lead to a variety 
of heath problems.  Work with such chemicals only with very good 
ventillation, or under a hood, or don't do it.  Again, a rock or 
fossil is not worth your health.
If I scared anyone, I can't feel too bad, because I wish someone 
had scared me before I did what I did, and may have to pay the 
price the rest of my life.    
Pete, in your case, I hope you do not have any problems, and can 
only urge you not to do it again, at least not without wearing a 
respirator.  The dust you created by cutting sandstone probably 
included a mixture of siliceous sand particles, calcium 
carbonate particles, (from the cement between the sand grains), 
and fibers from the fibrous saw blade.  All could be dangerous to 

Thank you. 
Glen Kuban