A booklet on safe dust control, dust collection

211 Seton Rd. Port Townsend, WA 98368
www.edensaw.com
360-3857878
A booklet on safe dust control, dust collection,
dust protection, and wood toxicity.
Dust - The Overlooked Hazard of Woodworking
One would venture to guess that in all, the biggest threat to a woodworker comes not in the form of bodily injury from a
power tool, but from wood dust. Not to overlook or minimize the importance of hearing, eye, and overall physical safety
when dealing with power tools, it is the small stuff—the tiny and easily overlooked wood dust particles—that can cause the
most long-term damage.
So, just how does wood dust affect a woodworker?
Long-Term Damage: Forget about the large chips and visible sawdust: perhaps the most damaging element is the invisible
fine dust (sometimes called “coarse inhalable particles” ranging from 2-10 microns). Basically, these tiny bits of sawdust
float around the air and linger even after the tools have stopped running. These invisible particles get inhaled and cause
tiny wounds and scarring to our lungs: each time this happens, it causes a very small amount of irreversible damage. The
immediate effect is unnoticeable, but over long periods of time, this can result in significantly decreased lung capacity, and
a number of other health issues.
Irritants: The most common way that wood dust affects a woodworker is by being an irritant. This simply means that it can
irritate our skin, our eyes, and our lungs. This can mean reactions such as itching, sneezing, coughing, runny nose, rashes,
and asthma-like breathing problems.
Sensitizers: Taking things a step beyond being just irritating, some woods can make us more and more sensitive upon
each successive exposure. So even if you don’t experience any sort of allergic reaction to the wood or its dust upon first
exposure, each time you breathe the dust or handle the wood. Sometimes the eventual reaction can be quite strong,
resulting in rashes or boils, severe sinus or respiratory pain/inflammation, or a number of other conditions depending on the
wood species.
Toxins: Not nearly as common, some wood is considered to be directly toxic. One example of this is Yew, which even
according to ancient Roman knowledge, was capable of causing fatality in certain cases. (See the introduction of the article,
Wood Allergies and Toxicity below.)
Carcinogens: If you look at the toxicity chart of wood species, you’ll notice that some species have been shown to cause
NPC. That is, Nasopharyngeal Carcinoma, or nasopharyngeal cancer.
Now that we’ve seen the health detriments to inhaling and being exposed to wood dust, we’ll look at some of the ways that
we can minimize risk and reduce the likelihood of having a serious health reaction.
To see a complete list of all the wood species, along with the most commonly reported reactions to their wood dust, see the
Wood Toxicity and Allergen Chart on pages 6 - 14.
Safety Measures
Different safety measures can be employed depending on what tool you’re using, and what procedure is being done on the
wood. (For instance, resawing an 8″ tall board on a bandsaw will create a lot more dust than simply ripping it at 1″
thickness.) So, since there are a variety of operations that can be done, there are also a variety of protective measures.
I’ll start with the easiest and most common, the ones that can be used in any situation:
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Dust mask: Available at a variety of hardware stores, these masks are just disposable cloth
with an elastic band. Some of the better ones have an exhalation valve on the front. They’re
better than nothing, but the serious woodworker would probably do best to find a solution that
is more efficient and form-fitting than these disposable products.
In stock at Edensaw Woods.
Respirator: A step up from a simple dust mask is a respirator. These filter airborne particles
with fairly good efficiency, and have replaceable filter pad(s) that can be swapped out when
they get clogged, saving money in the long run.One advantage that these units have over
their disposable counterparts is that they are made of flexible rubber, which forms a much
better seal than cloth/paper masks. There are also larger models and/or optional filter pads
that use charcoal to also filter out solvents and other chemicals. These cartridge respirators
are a great choice when applying wood finishes in enclosed areas, especially during winter
months when ventilation can be difficult. In stock at Edensaw Woods.
Powered Respirators: Taking this personal protection one step further, there are also
powered respirators which enclose your entire head and actively pump fresh air in/out of the
mask. These units offer the ultimate in wood dust protection, and are well-suited for those with
extreme wood allergies. Easily special ordered at Edensaw Woods!
Air filter: Another all-around useful item to have in your shop is an air filter. These are
typically ceiling-mounted units that run while you are working in your shop, and collect
airborne dust particles with minimal intrusion or hassle. Air filters most commonly will use
furnace filters for the pre-filter, with an array of felt-like bag filters on the inside. Depending on
how fine of a dust you’d like to filter, you can buy HEPA furnace filters for the pre-filter (though
this can slow down the overall CFM through the filter), or washable/reusable filters, or
even charcoal filters to remove organic vapor from the air. Yet despite the versatility and
convenience of using an air filter, it certainly shouldn’t be relied upon as a woodworker’s only
line of defense against wood dust. It should instead be viewed as a backup: helping in the
background while you minimize your exposure to dust in the first place. In stock at Edensaw
Woods.
Air exhaust: Despite all of helpfulness of the previous items, one of the very best ways you
can protect yourself from wood dust is to blow it out of your shop. Just because you can’t see
any dust doesn’t necessarily mean that there aren’t any particles left in the air. You may think
the coast is clear, and take off your dust mask, but there’s probably a host of very fine wood
particles still floating around in the air: soon to be in your lungs. This is where an exhaust
fan can come in handy. Instead of using so many resources, expensive filters, masks, etc.,
sometimes the very best thing is to get a breath of fresh air, and exhaust the old, dusty,
polluted air out of your shop. Easily special ordered at Edensaw Woods!
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Tool/Job-Specific Safety Measures
Dust collector: A staple tool in every serious wood shop. They usually use 4″ dust collection
hose, and will filter large chips and dust from a variety of woodworking machines. The beauty of
a dust collector is that they are designed to create a lot of CFMs of suction, and unlike shop
vacs which use a small internal filter, dust collectors use a giant bag (or a canister) and almost
never lose any suction with continued use. You can also outfit your dust collector with an
upper felt bag to increase the efficiency of collecting smaller dust particles: a feature that is very
helpful when using a collector on a drum sander which creates finer dust. In stock at Edensaw
Woods.
Cyclone Separator: Another option on the opposite side of the spectrum, (that is, if you are
creating a lot of large wood chips/shavings as from a planer or jointer), is to use a cyclone
separator with your dust collector. This is essentially a giant vortex-shaped pre-filter piece that
allows larger chunks of wood to drop and fall into a trash can or other large container:
prolonging the life of the dust collector’s bag and greatly reducing the frequency that you have
to empty it. Bill Pentz has written and studied wood dust safety and cyclone dust collectors
extensively, and is his website is a recommended resource for those wanting a thorough
defense against wood dust. Common tools that are typically used with a dust collector
include: tablesaw, jointer, planer, downdraft table, drum sander, and bandsaw. As you can see,
most shops would be quite messy if a dust collector wasn’t in regular use! Easily special
ordered at Edensaw Woods!
Downdraft table: This is simply a specialized table/platform where sanding or other shaping
operations can be done almost dust-free. The table is full of holes or slots, and a vacuum or
dust collector is attached, creating a continuous downward suction on the table. There are
also stand-alone downdraft tables that have a built-in motor which can be used for industrial
types of situations. Easily special ordered at Edensaw Woods!
Vacuum/direct dust extraction: The last option is to connect a vacuum to a specific tool. This
is usually done with a hose adapter of some sort, and the vacuum is only switched on when the
tool is running. Some vacs have an auto-on feature to work with a sander or other small tool to
kick on when the tool is switch on. In most instances, the tool is actually plugged directly into
the vacuum. One advantage to this method is that it can be very precise, so that even though
only a moderate amount of suction is created with the vac, it is in just the right place for
optimum dust extraction. Vacuums are typically used with miter saws, sanders, and other small
handheld tools that have a dust port. If you don’t have an auto-start vacuum, one useful tool
that can perform the same function is called the i-Socket. What this small device does is plug
into any standard electrical outlet, and has two plug-in sockets: one for a tool, and another for
the vacuum. It then will sense when the tool is turned on, and automatically turn on the vacuum
as well. It also leaves the vacuum on for a few seconds after the tool has been switched off to
help clear any lingering dust from the hose. In stock at Edensaw Woods.
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Not to omit any one of them, the yew is similar to these other trees in general appearance . . . It
is an ascertained fact that travelers’ vessels, made in Gaul of this wood, for the purpose of
holding wine, have caused the death of those who used them.”
–Pliny the Elder, from
Naturalis Historia, ca. 77 AD
Looking at the above quotation, (taken from a writing nearly two thousand years old), ought to bring—at the very least—a
small bit of respect and attention to the matter of safety as it pertains to wood toxicity. If this subject has been known and
reported as “ascertained fact” since ancient history, how much more ought we to take heed in modern times, considering
that we have so many more well-developed means of communication and testing?
Wood Toxicity and Allergen Chart
On the next page you’ll find a chart of various wood species, along with their reported effects and properties. The information
on this chart has been compiled from many sources, with references given at the bottom. When viewing the chart, please
keep the follow in mind:
Just because any given wood is not listed on the chart,
does not mean that it is completely safe to use. It simply
means that adverse reactions have not been reported as of yet. (The wood may be very obscure or unknown.) One helpful
thing to do if you have confirmed that you’re allergic to a specific species of wood, is to check for related species (listed at
the end of each wood profile page). Many times, a wood in a particular genus will share similar allergic compounds with
other related woods, resulting in cross-reactions.) For example, Cocobolo is in the Dalbergia genus, and is also closely
related to other woods such as Kingwood, Tulipwood, Honduran Rosewood, etc. Also, you may notice two wood types that
sound like they’re related, such as Black Cherry (Prunus genus) and Brazilian Cherry (Hymenaea genus), but they are
actually quite unrelated.
All inhaled wood dust is hazardous to your long-term health. This chart simply lists specific woods that
can aggravate symptoms through allergic reactions, or woods that are outright toxic in and of themselves. However, all
woods produce fine dust when worked, which in turn can damage your lungs and cause a number of other adverse health
reactions. (This particular health issue—and the unhealthy buildup of such dusts in small woodworking or hobbyist shops—
has been dealt with at length on Bill Pentz’ website.)
A common question: is this wood safe to use as a plate/bowl/cutting board/etc.? Despite the very long list of woods
below, very few woods are actually toxic in and of themselves. But what a great number of woods do have the potential to
do is cause allergic reactions in sensitive individuals. This risk for finished wood projects is greatly lessened (but not
eliminated) with the application of a food-safe finish. In the end, using almost any wood is a calculated risk, and the question
boils down to this: how much of a potential risk am I comfortable with? 1 in 10? 1 in 1,000? 1 in 1,000,000?
Wood Toxicity and How to Protect Yourself. Woodworkers need to take precautions against dust when working with any
lumber, whether the wood is domestic or exotic. Wood dust is no good for your lungs or eyes, and some wood dust can
also react with your body. Possible reactions include skin rashes, watery eyes, respiratory problems, headaches, dizziness,
or nausea. The degree and type of reaction depends on an individual’s susceptibility to certain allergies, as well as the
concentration of dust and the amount of time exposed to dust. The same reactions from person to person are not always
a certainty.
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Reaction
Wood Species
Abura
irritant, nausea, and giddiness
African Blackwood
irritant, sensitizer
African Boxwood
irritant, headache, asthma
Afrormosia
irritant, nervous system effects, asthma,
splinters go septic
Afzelia
irritant, sneezing
Agba
irritant
Ailanthus
irritant
Albizia
irritant, nausea, pink eye, giddiness, nose
bleeds
Alder (Alnus genus)
irritant
Alligator Juniper
irritant
Alpine Ash
irritant
Amboyna
irritant, asthma
Andiroba
irritant, sneezing
Araracanga
irritant, asthma
Ash (Fraxinus genus)
irritant
Ash, Mountain
irritant
Australian Blackwood
irritant, sensitizer, asthma
Australian Cashew Nut
irritant, skin lesions, nosebleeds
Avodire
irritant, nose bleeds, internal bleeding, asthma
Balsa
irritant
Bamboo
irritant
Birch (Betula genus)
irritant, sensitizer, nausea
Black Cherry
wheezing, giddiness
Black Locust
irritant, nausea
Blackbean
irritant
Bloodwood
irritant, excessive thirst, salivation, nausea
Bloodwood, Red (Australian)
irritant
6
Area(s) Affected
Potency
Reaction
Wood Species
Blue Gum
irritant
Blue Mahoe
sneezing
cross reactions possible once sensitivity to
Bocote
other woods have developed
Bosse
irritant, sensitizer, asthma, nausea, headache
Box, White
irritant, rash
Boxwood
irritant, sensitizer
irritant, headache, nausea, swelling skin,
Brazilwood
Brigalow (Acacia
blisters
harpophylla)
irritant
Brownheart
irritant
Bubinga
irritant, lesions
Buckthorn
irritant, sap can cause dermatitis
Bulletwood
irritant
Camphor
irritant, asthma, headaches, giddiness
Cashew
irritant, sensitizer
Catalpa
irritant
Cedar, Alaskan Yellow
irritant
Cedar, Aromatic Red
irritant
Cedar, Atlantic White
irritant
Cedar, Australian Red
irritant, asthma, migraine, giddiness,
bronchitis, stomach cramps, NPC (rare)
Cedar, Incense
irritant, rashes
Cedar of Lebanon
irritant, asthma, respiratory disorders
Cedar, Northern White
irritant, asthma
Cedar, Port Orford
irritant, runny nose, asthma, kidney problems
(diuresis)
Cedar, Spanish
irritant
Cedar, Southern Red
irritant
Cedar, Western Red
irritant, sensitizer, asthma, nervous system
effects, NPC (rare)
7
Area(s) Affected
Potency
Reaction
Wood Species
Chechen
Chestnut, Chinese (Castanea
mollissima)
irritant, sensitizer
irritant
Chestnut, Sweet
irritant, sensitizer
Chico Zapote
irritant (nasal)
Chinaberry
irritant, headaches
Cocobolo
irritant, sensitizer, nausea, asthma, pink eye
Cocuswood
irritant
Coolibah
irritant
Copaia
irritant
Crow’s Ash
irritant
Cuban Mahogany
irritant
Cypress
sensitizer
Cypress, Australian
irritant, asthma, swelling of eyelids, boils, NPC
(rare)
Cypress, Gowen
irritant
Cypress, Leyland
irritant
Cypress, Mediterranean
irritant, rashes, headaches
Cypress, Mexican
irritant
Cypress, Monterey
irritant
Dahoma
irritant, sensitizer
(Acacia
tetragonophylla)
irritant, splinters go septic
Djohar
irritant, skin discoloration, keratitis
Douglas-fir
irritant, giddiness, splinters go septic, nausea
Ebony (Diospyros genus)
irritant, sensitizer, pink eye
Ebony, Brown
irritant
Ebony, Macassar
irritant, sensitizer
Ekki
irritant
Dead Finish
8
Area(s) Affected
Potency
Reaction
Wood Species
Elm (Ulmus genus)
irritant, sensitizer, NPC (rare)
European Beech
irritant, sensitizer, NPC (rare)
Eyoum
irritant
Fir (Abies genus)
irritant
Fir, Balsam
irritant
Freijo
irritant, sensitizer, dryness/thirst
Garapa
irritant
Gedu Nohor
irritant
Goncalo Alves
sensitizer
Grasstree
irritant
Greenheart
sensitizer, wheezing, splinters go septic,
cardiac and intestinal disorders
Guanacaste
irritant
Gum, Lemon-Scented
irritant
Gum, Spotted
irritant, rashes
Gum, Yellow
irritant
Hackberry
irritant
Hemlock, Eastern
irritant
Hemlock, Mountain
irritant
Hemlock, Western
irritant, NPC (rare)
Hophornbeam
irritant
Hornbeam (Carpinus genus)
irritant
Idigbo
irritant
Imbuia
irritant
Indian Beech
irritant
Indian Laurel
irritant
Ipe
irritant, headache, asthma, vision effects
Iroko
irritant, sensitizer, asthma, boils, giddiness,
HP
9
Area(s) Affected
Potency
Reaction
Wood Species
Ironwood, Desert
irritant, sneezing, coughing
Jacareuba
irritant, fainting, insomnia, kidney damage
Jarrah
irritant
Jatoba
irritant
Jelutong
irritant
Juniper, Phoenician (Juniperus
phoenicea)
irritant, headache, nausea
Karri
irritant
Katalox
irritant
Keruing
irritant
Kingwood
irritant, sensitizer, pink eye
Koto
irritant
constitutional effects (nausea, vomiting,
Laburnum
headaches); direct toxin
Lacewood
irritant
Larch (Larix genus)
irritant, hives, lesions
Leadwood (Combretum genus)
irritant
Lebbeck
irritant
Lignum Vitae
irritant
Limba
irritant, hives, splinters go septic, asthma,
bleeding of the nose and gums
Machiche
irritant
Magnolia (Magnolia genus)
asthma, runny nose
Mahogany, African
irritant, sensitizer, NPC (rare)
Mahogany, Honduran
Mahogany, Santos
Makore
Mango
Area(s) Affected
irritant, sensitizer, boils, nausea, giddiness,
asthma, HP
irritant
irritant, nausea, headache, giddiness, nervous
system and blood effects
irritant
10
N/A
Potency
Reaction
Wood Species
irritant, sensitizer, nausea, sneezing,
Mansonia
headaches, nosebleeds, splinters go septic,
asthma, giddiness, cardiac disorders
Maple (Acer genus)
irritant, sensitizer, asthma; HP in spalted
maple
Maple, Queensland
irritant
Marupa
irritant
Meranti (Shorea genus)
irritant
Merbau
irritant
Mesquite (Prosopis genus)
irritant
Messmate
irritant, asthma
sap is poisonous, causes irritation to eyes
Milky Mangrove
and/or temporary blindness, headache,
burning of throat, blistering of skin
Mimosa
Missanda
irritant
irritant, headache, giddiness, nausea,
disorders of bowels and stomach
Moabi
irritant (mucous membranes)
Molopangady
irritant, sores
Monkeypod
irritant
Mora
irritant
Movingui
irritant
Muhuhu
irritant
Mulga
irritant, headache, nausea, wood contains a
(Acacia aneura)
virulent poisonous principle used for spear
heads by aboriginals
Muninga
irritant, asthma, bronchitis
Myrtle
irritant, sensitizer
Myrtle, Tasmanian
irritant
Narra
irritant, asthma
New Zealand White Pine
irritant
Norway Spruce
irritant, asthma
11
Area(s) Affected
Potency
Reaction
Wood Species
Nyatoh
irritant
Oak (Quercus genus)
irritant, sensitizer, asthma, NPC (rare)
Obeche
irritant, sensitizer, runny nose, hives, asthma
Okoume
irritant, cough, asthma, pink eye
Oleander (Nerium
oleander)
irritant, nearly every part of the plant is toxic,
cardiac effects
Olive
irritant, sensitizer
Opepe
irritant, sensitizer, nervous system effects
Osage Orange
irritant, sap can cause dermatitis
Osage Orange, Argentine
irritant, sap can cause dermatitis
Padauk (Pterocarpus genus)
irritant, sensitizer, nausea, asthma
Palm
(Arecaceae family)
irritant, constitutional effects
Parinari (Parinari genus)
irritant
Partridgewood
irritant, hives, coughing
Pau Ferro
irritant, sensitizer
Pau Marfim
irritant
Pau Rosa
irritant
Pau Santo
irritant
Peroba Rosa
irritant, sensitizer, nausea, asthma
Persimmon
irritant
Pheasantwood
cavities in the wood can contain powder that
is an irritant
Pine (Pinus genus)
irritant, runny nose, asthma
Pine, Huon
irritant
Pistachio
irritant
bark irritating to skin, dust may cause asthma,
Poison Walnut
nausea, giddiness, sap is toxic and corrosive
Poplar
irritant, blisters, asthma, bronchitis
Primavera
irritant, sensitizer
Purpleheart
irritant, sensitizer, nausea
12
Area(s) Affected
Potency
Reaction
Wood Species
Quebracho
irritant, nausea, NPC (rare)
Quina
irritant
Ramin
irritant, splinters go septic, asthma
Redwood
irritant, sensitizer, asthma, HP, NPC (rare)
Rengas
sap is strongly irritating, blisters, ulcers, fever,
constitutional effects
Rhodesian Teak
irritant
Rose Butternut
irritant, pink eye
Rosewood (Dalbergia genus)
irritant, sensitizer, asthma
Rosewood, Brazilian
irritant, sensitizer
Rosewood, East Indian
irritant, sensitizer
Rosewood, Siamese
irritant, rash, hives, sensitizer
Rubberwood
irritant, sensitizer (latex allergy)
Saffron-Heart
irritant, splinters go septic, lung congestion
Sassafras
sensitizer, nausea, respiratory, direct toxin,
NPC (rare)
Sapele
irritant, sneezing
Satinwood, East Indian
irritant, headache, diarrhea, sensitizer
Satinwood, West Indian
irritant, diarrhea, rash, blisters, sensitizer
Shittim
(Acacia seyal)
Silky Oak, Northern
Silky Oak, Southern
irritant, coughing
irritant
irritant, sap may cause blistering of skin,
eyelid inflammation
Sissoo
irritant
Slash Pine
irritant, asthma
Snakewood
irritant
Sneezewood
irritant, oils within the wood cause violent
sneezing
Spruce (Picea genus)
irritant, sensitizer
Sucupira
irritant
13
Area(s) Affected
Potency
Reaction
Wood Species
Sumac (Rhus genus)
irritant, bark may cause blisters
Sweetgum
irritant
Tambootie
irritant, diarrhea, blindness, direct toxin
Tatajuba
irritant
Teak
irritant, sensitizer, rash, nausea, asthma,
vision effects, pink eye, HP
Thuya
irritant
Turpentine
irritant, swelling
Tzalam
cold-like symptoms
Utile
irritant
Verawood
sneezing
Walnut, African
irritant, systemic effects, NPC (rare)
Walnut, Black
irritant, sensitizer, NPC (rare)
Walnut, English
irritant, NPC (rare)
Wamara
irritant
Wenge
Western Hemlock
Western Juniper (Juniperus
occidentalis)
irritant, sensitizer, splinters go septic, nervous
system effects
irritant, NPC (rare)
irritant
White Peroba
irritant, sensitizer, asthma
Willow (Salix genus)
sensitizer, nausea, NPC (rare)
Yew (Taxus genus)
irritant, nausea, direct toxin
Yellowheart
irritant
Zebrawood
sensitizer
Ziricote
cross reactions possible once sensitivity to
other woods have developed
14
Area(s) Affected
Potency
References:
 Woods Toxic to Man, author unknown
 Woods, B., Calnan, C.D., Toxic Woods, Br. Journal of Dermatology, 1976
 ILO Encyclopedia of Occupational Health and Safety 1983
 Lame, K., McAnn, MEDIUM., AMA Handbook of Poisonous and Injurious Plants, AMA 1985
 Poisondex, Micromedix Inc. 1990
 List of woods and toxicity characteristics, Roy Banner, 1989
 Toxic Woods Information Sheet, (Woodworking sheet #30), Health and Safety Executive, UK
 Campbell, Bruce, Wood/Dust Toxicity, 2006
 Ellis, Neil, Health Hazards & Wood, 1998
 Mitchell, John, and Arthur Rook, Botanical Dermatology, 1979
 Pentz, Bill, Medical Risks, 2008
 Timbers & Health, Woodturners Society of Queensland, Inc.
 Robison, Nick von, Potentially Toxic Woods, Musical Instrument Makers Forum, 1998
 Chudnoff, Martin, Tropical Timbers of the World, Forest Products Laboratory, 1980
 Kukachka, Francis, Properties of Imported Tropical Woods, Forest Products Laboratory, 1969
 Sims, Michael, and Erica Skadsen, Wood Hazards, BMEzine.com LLC, 2006
 Wikipedia, the Free Encyclopedia, Wikimedia Foundation, Inc., 2008
 Forest Products Laboratory, United States Department of Agriculture
What is a Sensitizer?
You’ve probably already heard the term desensitized—usually in reference to violent movies or images—meaning that we start off as
naturally being sensitive to something, and upon more and frequent exposure, we become less and less sensitive to its effects. Well, with
some woods that have been classified as being a sensitizer, the opposite is true: the more we are exposed to a wood’s sawdust or other
fine particles, the more sensitive we get to its exposure, and the more severe and adverse the reactions become. If you ever have an
allergic reaction to any wood that has been identified as a sensitizer, use extreme caution in handling or using that species (and related
species) in future instances. Some have reactions so severe that they simply have had to stop and discontinue using certain wood species
altogether. (Cocobolo is notorious in this regard.)
What is HP?
Hypersensitivity pneumonitis (also called extrinsic allergic alveolitis, EAA) is an inflammation of the alveoli within the lung caused by
hypersensitivity to inhaled organic dusts. HP on PubMedHealth.com
What is NPC?
Nasopharyngeal carcinoma, or sometimes called nasopharyngeal cancer. Basically, it is a cancer of the upper area of the pharynx or
“throat,” where the nasal passages and auditory tubes join the remainder of the upper respiratory tract. NPC on MayoClinic.com.
This free safety booklet is for informational purposes only.
Edensaw Woods, Inc. is not responsible for the content in this booklet.
c by the www.wood-database.com
Content of this book is provided
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Wood Safety Series Booklet # 1 ~ Courtesy of Edensaw Woods, Ltd.
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