Bill Pentz and Cyclone Test

[Will Blick]

John, Bill P is locked out of SMC till further notice, I certainly hope he returns.... a few comments on your post...

I agree with your methodology of trying to determine just how damaging the fine wood dust is (or even the large wood dust) by looking back at history. I too think it holds some of the answers to just how risky wood dust is. Like mentioned prior in this thread, there seems to be some analogies to smoking cigarettes here, i.e. some can smoke and die of lung cancer at 40, while others smoke till they are in their 90's and die from something else.

Grain workers have suffered a lot of respiratory healthy problems due to fine dust. I suspect their industry has better clearing house of these types of problems, and therefore their fine dust gets more media exposure.

I too was trying to find more answers regarding what % of long term woodworkers have dust related illnesses. The data seems a bit elusive, hence why i was probing Bill P for his comments on this subject, because in the absence of hard data, sometimes we have to rely on the closest thing we can find - such as a clearing house of data, and it maybe, that might be Bill P is the closest thing we have to a clearing house.

Hopefully when Bill P returns to this thread, he will provide a bit more data in this area.

[Ken Fitzgerald]

I don't think you have to be a rocket scientist to realize that long term exposure to any foreign matter that can be inhaled will have some effects on one's lungs. The rate of the effect or the severity will depend on each individual, their physical conditioning, their genetics and the state of their lungs and the particulant matter inhaled, the length of the exposure and the concentration of the exposure. If something can be breathed in sufficient quantitites it will eventually have an effect. Whether the effects are acute or chronic will depend the type of matter, the concentration of the matter and the length of exposure and each person's individual physical characteristics.

I would suspect that the type of wood dust inhaled will have a great effect too. If you are breathing "treated" wood dust versus the same dust of untreated wood for example.

I think there are a lot of unknown, unproven, undocumented theories. I don't have a lot of trust of "studies". In today's world too many people rush studies to get the admiration of their collegues and the general public. Everyday new studies are released reversing or contradicting another study that was also a recent release. I also want to know who funded directly or indirectly a given study. I also want to know what the pre-study personal opinion of the person or group performing the study. Often I wonder if it's not easier to prove a preconceived theory than to perform a unbiased study for a scientic result.

I come from a long line of hillbillies. My paternal grandmother smoked a pipe and cigarettes until the day she died. She died at age 89. My two oldest children still refer to her as "Great-grandma who smoked a pipe"...I had to quit smoking cigarettes at age 56........that was 40 lbs. ago......

JMHO......

[Dave MacArthur]

John, there is a post earlier in the thread which I think anwsers your post well,
http://www.sawmillcreek.org/showpost...4&postcount=37

One problem with any discussion on dangers of any substance on humans is that people want to be able to treat "woodworkers" as an exact replicable quantity; that is, we want an answer similar to "at dust levels of WALNUT of 200 ppm, a woodworker will begin suffering mild alergic reactions, at 400 ppm it will grow chronic.." Now, of course when you read it like that, you remember we're all different and folks react differently, but it seems the instant people begin citing examples of 4 boat builders who have never had any problems, they've completely forgotten this truth.

No citation of individual cases of HEALTH is really a valid argument in this discussion. The only valid methodology is the same one followed by the FDA for drug testing--collecting statistically significant numbers of examples, study the rare cases where someone has a bad reaction to the test material, attempting to correlate problems with wood dust as a causal agent by ruling out questionable causal examples. Then correlating results to give some probability distributions on first how many people will have negative reactions to wood dust at various levels, and of those people, a probability of how severe the reaction will be.

Saying that a minority of woodworkers have problems, therefore it can't be that dangerous, is the EXACT SAME logical argument as this:
"Most people driving their car today will not die, or even suffer any injury. Therefore it must not be that dangerous. Therefore, discussion and efforts to make it more safe, and further reduce an already very small accident rate, must be a misguided waste of time and money".
It's a valid philosophical stance ONLY if you always happen to be in the car that arrives home safely. For the 500 people that die tonight on the road, it's errors are easily perceived.
We each must ask ourselves how much we'd like to depend on having the best genetics possible for tolerating wood dust, versus how much we'd like to guard against being "the guy hit by a mack truck on the way home". For many, it is worth the cost to take risk management measures--perhaps totally un-necessary for me, but maybe needed for my brother, no one knows ahead of time.

[John Stevens]

John, there is a post earlier in the thread which I think anwsers your post well...

Hi, Dave. I think you misunderstand my point: the OSHA standard isn't a good one for gauging risk.

I'm not an oncologist or a statistician. My educational background is history and law, which is equally as important as science when it comes to understanding how executive agencies like OSHA set their standards for things like exposure to wood dust. Although these standards are based upon the testimony of scientists, there are varying degrees of political influence that bear upon which scientists testify and whose testimony is believed. The political influences can cause a standard to be based on testimony that is not the most scientifically accurate. The OSHA standard given by Bill Pentz is a good example of this, as common experience shows.

In the case of the OSHA standard, Bill Pentz quoted an inspector who told him that the amount of fine dust dissipated inside a two-car garage after hand sawing a seven-inch cut in a piece of wood 3/4" thick would be above the allowable standard. Now we all know how little dust that is. Anyone who rides in a car and sits in a line of traffic waiting for a light to turn is exposed to that much fine dust on a continuing basis. Anyone who sweeps their home is exposed to that much fine dust. I could go on, but I trust you get the point: nobody seems to worry too much about these other sources of fine dust, and the usefulness of the activity is so obvious and the risk so negligible that we're not even conscious of the risk-benefit tradeoff.

No offense intended, but I think you missed one of the points of Dr. Pan's post: we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits. Common experience shows that the OSHA standard cited by Bill Pentz is not a reasonable standard for gauging risk in regard to health problems caused by exposure to fine wood dust.

Regards,

John

[Will Blick]

Ken, your points are very valid.... and it seems you have some fabulous genes :-)

Dave, thanks for that link, its the first "semi" scientific study, or at least abstracts I have seen.

John, you wrote:

>we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits.

John, this is what it all boils down to.... I am sure I am stating the obvious here.... for me, its not a question of risk-free ww.... but rather, how do I perceive these risks, and how much inconvenience am I will to live with in the shop, respirators, DC, not tracking dusty clothes into the house, cleaning shop on a regular basis, constantly exhausting air, etc. etc.


I am sure many of us have the same approach... the level of risk we perceive often dictates the level of response. The other real value of these threads is knowledge of the symptoms. As with many health problems, its often difficult to find the culprit... prior to Bill P's web site, I would have never suspected wood dust being the culprit of skin irritations or even mild nasal allergies, since I have suffered them on/off most of my life. I have already experienced some nasal responses to those dusty days. Of course, I often just thought there was some high levels of pollen in the air, as my allergic responses were often delayed, which adds to the confusion.


Unlike cigarettes, where they are relatively similar (of course they vary also in the tobacco used, filter, additives, etc. etc.), the biggest variable is cigs smoked per day, and for how many years. And of course, there is some good historical data in this field. But with ww dust, we have MUCH less data, and IMO, a real "wild card" - wood types.


Obviously MDF is needs to be treated with respect as it has many toxic chemicals. But it's these sensitizer woods that really have me worried. I fear working with a sensitizer wood (which their is MANY, and not all species are known whether they are sensitizers), which leads to the start of health problems, which then makes me sensitive to all wood dust, like Jims locksmith. Then, for me, I will be finished ww. I am trying to avoid this "judgement day." Due to internet data on this subject, (mainly Bill P and wonderful threads like this) I am armed with the basic premise of the risks, wood types, etc.... which I will use prudently.

So thanks to everyone that takes their time to share what knowledge they have in this area.

[Hank Phillips]

[/color]
Try reading the "controversy" article on Bill's website, and connecting the dots (since he doesn't come right out and name them... BTW, Oneida has a patent on a dust-less floor sanding system):

http://billpentz.com/woodworking/cyc...fm#Controversy

I also remember Bill P. singing Oneida's praises not too long ago. Oneida has some of the older Pentz web pages on their site as well as an email dialog between bill and Oneida.
http://www.oneida-air.com/newsite/comments.php

[Ken Fitzgerald]

Folks.....this thread is very closely being watched. We won't allow it to degrade to a discussion on Bill P, Onieda or any other company and their entertwined relationships...fallouts.....who did what to whom.....etc. Any further drifting in that direction and I will close and move the thread.

[Wilbur Pan]

In the case of the OSHA standard, Bill Pentz quoted an inspector who told him that the amount of fine dust dissipated inside a two-car garage after hand sawing a seven-inch cut in a piece of wood 3/4" thick would be above the allowable standard.

This may seem silly at first glance, but let's do some math.

The OSHA level for hardwood exposure is 1 mg/m3. The density of hardwoods is in the 35-45 lbs/ft3 range. Let's use 40 lbs/ft3 as a middle of the road number. A 20'x20' shop with 8' ceilings has a volume of 3200 cubic feet, or 90 cubic meters. That means that once you hit 90 mg of wood dust, you've hit OSHA levels.

90 mg of wood dust is 0.0002 pounds. At 40 lbs/ft3, that's 0.000005 cubic feet of wood, or 0.0086 cubic inches. A Lie-Nielsen dovetail saw has a kerf of 0.026 inches. If you use an LN dovetail saw to cut 3/4" thick wood, a 1/2" long cut in a 3/4" board with a kerf 0.026" wide gives you 0.0086 cubic inches of wood dust, if the conversion of the wood in the saw kerf to dust is 100% efficient. Now, some of that wood in the kerf won't be converted to dust, but may be sawn into shavings. Suppose only 5% of the wood cut by a handsaw gets cut up into dust. That's a 10" long cut that generates enough dust to hit OSHA levels. So the OSHA guy may not be completely off base.

No offense intended, but I think you missed one of the points of Dr. Pan's post: we can't live risk-free, and that we should be reasonable about reducing risk in order to achieve benefits. Common experience shows that the OSHA standard cited by Bill Pentz is not a reasonable standard for gauging risk in regard to health problems caused by exposure to fine wood dust.

Since you're referencing my post, I'd like to make one thing clear. I don't think that OSHA standards are reasonable. I think they are too lax in regard to health problems. The Europeans have a much better handle on worker safety issues than we do in the US, and they have stricter standards. There is a lot of evidence to show that increasing wood dust exposure leads to an increased incidence of lung disease.

Now, as you rightly point out, you can't live risk free, and this does not stop me from building a woodworking shop in my basement. But this does not mean that the OSHA standard has no basis, even though I think it should be stricter.

By the way, the fine dust generated by wood has a particular irritating effect on the small airways of the lungs that the fine dust from car exhaust and house dust do not, primarily due to the structure of the cell walls of the tree and the subsequent difficulty of the lung's mechanisms to clear wood dust particles. About the only things I can think of that is similarly irritating to the lungs are the fine particles generated from cigarette smoke and asbestos.

For the record, when I'm generating dust, I have a dust collector with a very short hose run that I move from machine to machine, I have a 1 micron air cleaner that is sized to circulate the air in my shop about 25 times an hour, and I wear a mask with a P100 filter.

[Dave MacArthur]

very interesting responses, which I've enjoyed thinking about.

[John Stevens]

There is a lot of evidence to show that increasing wood dust exposure leads to an increased incidence of lung disease.

Dr. Pan, as you probably realize, this statement is only meaningful if we know (at a minimum) what the baseline risk is and what the risk is after exposure at the 1mg/m^3 level for a specified period of time. Can you give us some numbers here?

EDIT: It would also be useful to define the term "lung disease" and disaggregate it, since most people are probably worried about COPD and cancer rather than illnesses that will clear up after a short time without any treatment other than avoiding exposure to wood dust.

Thanks in advance.

Regards,

John

[Wilbur Pan]

By lung disease I do mean COPD and cancer. Those are the diseases that are looked at in the studies I cited.

Here is a post I made regarding how to interpret this data. In a nutshell, people want to know, "If I spend 4 hours in my workshop each weekend, what are my chances of developing COPD?" From a medical perspective, this is not a useful number, or a number that is possible to give to an individual. This assumes that all people are equal and that the only issue is how much dust you are exposed to. This is certainly not the case. The chances for developing COPD from wood dust exposure is different for a woodworker who smokes, a woodworker who does not some, a woodworker with a family history of asthma, and so on.

The other issue is that the health risks from dust exposure follow a dose response curve, so that issues of lung function start to occur as soon as the wood dust exposure happens. That's why the issue of a "safe" level doesn't really exist. But in the interest of conserving electrons, please read my original post.

As far as acute vs. chronic effects on lung function from wood dust is concerned, you can read why you can't separate the two here.

[Rick Schubert]

[quote=Will Blick;736611]OK, I found the data on the 3m dust cartridges
The filter is tested at 99.97% of airborne particles 0.3 micrometers (µm) in diameter.

This is pretty impressive IMO...


Will,

Which model of 3M filter cartridge is this?

Thanks, Rick

[John Stevens]

In a nutshell, people want to know, "If I spend 4 hours in my workshop each weekend, what are my chances of developing COPD?" From a medical perspective, this is not a useful number, or a number that is possible to give to an individual.

I acknowledge that from a medical perspective, this is not a useful number. However, the issue I raise (whether the OSHA standard is a useful one for gauging risk in woodworkers) is not a purely medical one. There's a whole body of thought in law and economics that deals with problems such as this. Although it's not possible to determine individual risk, government safety standards such as the OSHA standard in question, are supposed to be the result of a balance of aggregate risk (injuries/illnesses per x number of man-hours), the costs of those risks, and the costs of preventing the illnesses and injuries, against the benefits of the activities that cause them. Your earlier posts (to which you linked) are informative as to the health risks of woodworking, but they're not dispositive as to the utility of the OSHA standard for gauging risk for woodworkers.

I usually avoid reading and participating in these threads about wood dust because they uniformly generate more heat than light. This one is no exception, so with that I'll just thank you for the conversation (sincerely, no sarcasm here) and say so long for now.

Cordially,

John

[Phil Thien]

However, the issue I raise (whether the OSHA standard is a useful one for gauging risk in woodworkers) is not a purely medical one. There's a whole body of thought in law and economics that deals with problems such as this.

My original response: Yeah, but the last time I checked my pulmonologist was a doctor, not a lawyer.

My updated response: I'm not sure what you were driving at, and perhaps I shouldn't have been too dismissive. If you do return, I would like to hear more about this angle.

However, I do feel that ultimately, working in a small home shop (and having nobody to blame but myself for my lack of diligence in controlling the dust), that I should take Dr. Pan's linked studies very seriously. The way it comes down is this: Workers in commercial shops that have better dust controls than I have suffered from the exposure to woodworking dust. I cannot imagine I am somehow immuned because I only work a few hours here and there.

But again, perhaps I am missing your point about the OSHA standards and if you do return to this thread, I'm all ears.

[Art Hackman]

As a new member & this being my first post, I apprecialte Bill Pentz & his thankless (for the most part) effort. After reading almost all of his web site info several years ago, and as a registered engineer licensed in the state of Missouri (retired), I could only agree with him. The first major expense in building my first real wood working shop was the purchase of a Clear Vue.
Thank you again Bill for all your effort.
Respectfully,
Art