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Poisonous Yew & Laburnum

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Mike Garnham28/02/2008 08:45:00
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Hi,

I thought that this was important enough to start a new thread even though the contents were used also in the "Laburnum Mushroom" thread.

I've had a little look around on the internet, and it seems my suspisions were right.

Both Laburnum and yew are poisonous to humans (as well as most animals). The dust of yew is definitely poisonous, and I read reports of wood-turners being hospitalised after breathing in yew dust. 

Laburnum dust is a little more controversial.  Whilst various scientific bodies report "all of the tree being poisonous", some say the dust is no more dangerous than any other wood. Some say that it is just as poisonous as yew.

I am sure someone who reads this will have the definitive answer, but my suggestion is to treat these woods with extreme care and wear a mask, use extraction, and don't let the shavings or dust near any children or animals. 

Mike

PS Did you know that British demand for yew for longbows was so great that by the end of the 17th century there were virtually no yew trees left in all of Europe?

Bob28/02/2008 11:48:00
85 forum posts

Mike,

No, I didn't know that!

As I understand the historical situation, the YEW longbow was regarded as the "Rolls-Royce" of 'bows; most people used what they could lay their hands on. Apparently ASH will make a reasonable 'bow, not as powerful and it doesn't last as long.

For more information, and working bowyers; see this website: www.bushcraftuk.com

Bob.

Big Al28/02/2008 17:31:00
1536 forum posts
63 photos
Hi Mike Its not just yew and laburnum that can be harmful. Most hardwoods dust can be harmful to humans, take a look at this link for more info http://www.vwa.org.au/des_dangwd.htm. One of the guys that I work with is allergic to iroko dust. Taking everything into consideration we really should be using effective dust extraction where possible, and suitable dust masks. Al
Mike Garnham28/02/2008 17:48:00
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Al,

you're right, but these two can put you in hospital or worse. Apparently, some landfill sites won't take the dust or shavings from yew and laburnum (although you can't really imagine the landfill staff having the knowledge to enforce this properly). 

The danger with lists like the one you provided the link for, is that people say "well, I worked with such-and-such a wood and it didn't do me any harm, so everything on this list must be just an exaggeration". Additionally, of course, it is Australian so doesn't have our native species on it.

Both these trees kill stock in our countryside.......so I would assume the worst! 

Mike 

Malc06/03/2008 20:30:00
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Mike,

This is the reason that you find Yew trees in church yards. The church yards on estates where walled so that animals could not get in. This meant that you could grow yew for bows and not put your flock/herd at risk.

I just knew that this bit of trivia would come in handy one day.

Malc.

Bob13/03/2008 11:54:00
85 forum posts

Malc,

I've heard this story too; but it appears to be a partial red herring!

Someone, (presumably with nothing better to do), went around and measured the age of the YEW trees and found that a lot were in the ground and growing before the church was built. Apparently the church authorities built the new churches on previously sacred (pagan) sites, to 1) purify them; 2) to provide continuance for the uncouth locals; and 3) to physically to remove/demolish the old religion.

Bob.

Olly Parry-Jones13/03/2008 18:47:00
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2776 forum posts
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Iroko's a common one, although symptoms may not show until a large and considerable amount of time has passed - always take the neccessary precations!

Greenheat is one of the ones to really watch out for though. The dust from this stuff can give you cardiovascular problems. And, I'm sure I've mentioned this before, but one of my colege tutor's suffered a cardiac arrest (heart attack) after turning this stuff - and have taken the basic precations!

Woodworking is a very expensive hobby - perhaps even more so than we can realise, once things go wrong. 

Mike Garnham13/03/2008 22:20:00
4114 forum posts
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Shhhhhh........Olly's real job is working under-cover for the HSE!!!!!!
Oddjob13/03/2008 22:30:00
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1635 forum posts
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Without doubt all of the above is good advice.  I have to admit that I am low on dust extraction gear (expensive on space and noisy) but I rarely work without a good mask and regularly change the filters.

No-one has yet mentioned MDF.  Lots of us use it from time to time (not Mike of course) but how many of us are aware that it produces some of the most toxic dust?  MDF processors pay a fortune to gather and dispose of their dust because there are very few disposal points that are allowed to accept it.

Richard 

  

Mike Garnham13/03/2008 22:49:00
4114 forum posts
1 photos

Interesting Richard.......

.......and I'm sure Olly will soon tell us the facts. My understanding is that there isn't anything inherently more dangerous about MDF dust than any other similarly sized dust. The point is that it makes an especially fine dust, which penetrates further through our defences, and clogs up more efficiently as a result. I could be entirely wrong. Nevertheless, I'm scared of the stuff, and I hate it! I can't help thinking of it as glorified cardboard.

A friend asked me recently to make a whole room full of furniture in MDF, clear varnished. A few hours later I had persuaded him that what he really meant was solid ash!!!!!

Mike 

Oddjob14/03/2008 13:14:00
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Mike

You mean there is a difference between MDF and solid ash?!!!!! 

You may well be right about MDF dust - I only know that commercial disposal of it is subject to special measures.

Richard

Mike Garnham14/03/2008 14:08:00
4114 forum posts
1 photos

Richard,

I have cut and pasted the following extracts from a quick trawl around the internet. Don't treat this as gospel......as I say, Olly will probably have the latest...........

"Some of the latest research specific to the machining of MDF that I’m aware of was compiled in the UK by the scientific sub-group of the Advisory Committee on Toxic Substances, the Working Group on the Assessment of Toxic Chemicals (WATCH) (forms part of the UK Health and Safety Executive).

Although there was some evidence for more frequent reporting of respiratory symptoms in workers receiving exposures arising from machining MDF compared to other forms of wood or wood products WATCH endorsed the conclusion that there is no evidence that the ill-health effects associated with exposure arising from the machining of MDF are different from those associated with similar exposure arising from machining other forms of wood."

"Recent assessments of the risks The Health and Safety has classified MDF as a soft wood and therefore not designated as a carcinogen in the UK. However, the International Agency for Research on Cancer (IARC) does not distinguish between hardwoods and softwoods, and it groups ?wood dust? as ?carcinogenic to humans?.

Formaldehyde, which is included in bonding resins used in MDF, is also classified by the IARC as ?possibly carcinogenic to humans?. They argue that, even at low levels, inhalation of formaldehyde can cause irritation to the eyes, nose, throat and mucous membrane. It can also affect the skin, leading to dermatitis, and to respiratory system causing asthma and rhinitis.

MDF in other countries Reports that MDF is banned in the USA and Australia are speculative. However, there are tighter restrictions on its production and use. In the USA, there are limits on formaldehyde emissions from MDF and home owners in California have to be warned that their new home has been built using MDF which ?contains a chemical known to cause cancer, birth defects or other reproductive hazards?. Australian workers are warned that formaldehyde is ?a probable carcinogen?.

Is it safe to use MDF? A HSE spokeswoman stated that ?at present there is no evidence to suggest it (MDF) poses a risk and can be compared to other risks like asbestos?.

However, despite these assessments of MDF and health risks, it is still shrouded in controversy. Therefore, it is advised that anyone using MDF follows these guidelines:

?Try to use an alternative to MDF - some manufacturers sell low formaldehyde or zero formaldehyde emission boards

?If there is no alternative, try to ensure the following: -Always use a protective face mask and eye wear when sawing or sanding MDF board -Only saw outside or in a well ventilated room -Wear gloves to avoid the formaldehyde coming into contact with the skin Compensation claims Accident Compensation People (www.accident-compensation-people-uk.co.uk), who specialise in compensation claims for people affected by airborne cancers, say it?s too early to speculate about the possibility of compensation claims against manufacturers, or employers who fail to protect their staff from the dangers of MDF."

I follow the advice in the second last line.......try and find an alternative to MDF.

Mike....(waiting for someone who knows the answer!)

PS   Depending on the response, it may be worthwhile starting this as a new thread under a title  referring to the dangers of MDF.

Robert Barnatt14/03/2008 15:11:00
8 forum posts
5 photos

Low or zero formaldehyde mdf has been readily available for some time from suppliers like Richard Russell in Croydon. I seem to remember that the new Scottish Parliament building used massive ammounts of the stuff.

Although I rareley use mdf in my projects, I do find it's uniform dimensions and smooth surface ideal for temporary jigs. 

Oddjob14/03/2008 17:52:00
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1635 forum posts
79 photos

Mike

Thanks for doing a bit of research for us.  Whilst there is nothing absolutely condemning the stuff there is obviously some doubt and some disagreement between the "experts."

I shall certainly take extra precautions on the few occasions that I might use MDF in the future.

Richard 

Olly Parry-Jones14/03/2008 19:50:00
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2776 forum posts
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Hi Mike. Sorry to dissapoint you but, it's officially the weekend now so, I'm unable to tell you any more than the following right now. Looks like you've found some very good information yourself though. The HSE website does have some very useful information - as well as some horror stores on what can go wrong with woodwork machinery...

All I can really add right now is that we weren't allowed to use MDF in school because of the dust, in my DT lessons, going back five-years now. But it really is worth taking precautions when working with MDF. I've read about guys having to go to see a doctor and have their synuses [spelling?] pumped because they have repeatedly ignored the warnings. Apparently, it is not at all a pleasant experience to go through. And, there are several other ways in which this stuff can get to you (I don't think it's as severe as greenheart though?).

I certainly think it is safe, practical and very cost-effective to use MDF regularly - provided you seriously consider the risks and take all necessary precautions.

It's funny that you should speculate on my involvement with the HSE as I'm at this point in my life where I'm still not sure what I want to do with my life and I'm open to many considerations - getting involved with Health and Safety is one that has briefly crossed my mind!

At the company where I worked until last year, we had a HSE guy come round and visit us every few weeks and he's pick up on the most insignificant of matters, such as the dangers of leaving the keys in the ignition of an un-manned forklift...!

When it came to lack of extraction from the crown guard of our circular saw among other things, machinery-related, he seemed to simply look the other way!

If I was in his shoes, I know I'd come down hard on matters like this. But, it baffles me sometimes... 

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