[OT]:: Safety of end products from composting wood+glue panel products (chipboard, particleboard, ...)

[RussellMc]

Does anyone have any information on exceptions to the "rule" that most
wood + glue bonded products will 'rot down' to something that is
essentially harmless in due course ?
This has a New Zealand focus, but comments from elsewhere re exceptions may
be useful.

I'm interested in the "compostability" of various types of composite wood
products.
Especially, is a given source material liable to result in decomposition
products which are harmful to people, animals, soil organisms or plants?

Product names include: MDF, particle board, chip board, bison-board,
fibreboard, customwood, OSB* (less likely: plywood, triboard). ...
* (Oriented Strand Board).

*NOT*: cement bonded boards, melamine products (MFC, ...) .

I'm less concerned about emissions "along the way" (eg formaldehyde) and
time taken to decompose, but any information on these aspects may be
useful.

There is a lot on this subject on the internet.
Knowing what you start with "seems likely" to be a necessary step towards
knowing what you end up with.


Russell

_____________________________


* A Literature Review on the Composting of Composite Wood Products 2007 *
http://www.mitchellplainfarm.com/uploads/2/9/4/4/2944849/compwoodreview.pdf

International yellow pages list of particle board companies:
http://www.business-yellowpages.com/Particle-Board/24714/page-6

[RussellMc]

I sent my query to a friend who works in the processed wood industry.
He sent it to an expert in the field, and I got the following response.

_______________________________


Off the top of my head I can confirm your correspondent’s view that
composite wood products do “rot down” over time……….based on my
understanding of the term “essentially harmless”.



Wood and wood fibre is obviously not a problem, rotting to CO2 (or more
correctly turning back into atmospheric CO2 from whence it came via
photosynthesis.) (That’s assuming you are not a believer in climate change
in which case emissions of CO2 are a problem and us homoeothermic
vertebrates should do our part to save the planet from climate change by
holding our breath!!!)



The predominate glues used are urea formaldehyde and phenol formaldehyde. I
forget the % by weight of the finished product but it is small. They do
off-gas generating formaldehyde at low levels, all covered by the e-rating
of boards. The glue itself also breaks down over time and in wet conditions
being an organic molecule. I have not heard of it being a problem but
haven’t investigated it specifically (which is a positive thing because
when I worked for wood products I spent my time understanding those aspects
of our products others considered a problem and complained about them.)



Some board products contain a small amount of paraffin wax as a short term
water barrier. I don’t know its fate but assume it’s either inert in soil
or (more likely) broken down over long periods to CO2 and water through
exposed to UV and other high energy light.



Some board products are treated, usually plywood for external use. This is
either CCA ( Copper Chromium Arsenic ) or Tributyl Tin (TBT). CCA is very
stable unless burned. (There has been screeds written on it……..for a good
summary look up Dr Deborah Read an epidemiologist working for the (now)
EPA as part of their 2001 review of the safety of the product. She gives
it a clean bill of health…… provided you don’t burn it and inhale the smoke
in large quantities.)

TBT breaks down in sunlight to tin oxide.



Not sure if that helps but let me know if you would like me to comment
further on the subject



I realise some people get bent out of shape over scary chemicals like
Arsenic. I usually point out that it is naturally occurring in volcanic
soils in Auckland* at between 8 and 14 ppm……and in Rotorua** they charge
people $20 a head to walk in 10,000ppm as they go around the geothermal
areas. Moral of the story, “the dose makes the poison.”


______________


* Where I live

** A geothermal area with many related tourist attractions.

10,000 ppm = 1% may be a 'slight exaggeration' - but you may not know it by
the smell there.

Post by RussellMc
Does anyone have any information on exceptions to the "rule" that most
wood + glue bonded products will 'rot down' to something that is
essentially harmless in due course ?
This has a New Zealand focus, but comments from elsewhere re exceptions
may be useful.
I'm interested in the "compostability" of various types of composite wood
products.
Especially, is a given source material liable to result in decomposition
products which are harmful to people, animals, soil organisms or plants?
Product names include: MDF, particle board, chip board, bison-board,
fibreboard, customwood, OSB* (less likely: plywood, triboard). ...
* (Oriented Strand Board).
*NOT*: cement bonded boards, melamine products (MFC, ...) .
I'm less concerned about emissions "along the way" (eg formaldehyde) and
time taken to decompose, but any information on these aspects may be
useful.
There is a lot on this subject on the internet.
Knowing what you start with "seems likely" to be a necessary step towards
knowing what you end up with.
Russell
_____________________________
* A Literature Review on the Composting of Composite Wood Products 2007 *
http://www.mitchellplainfarm.com/uploads/2/9/4/4/2944849/
compwoodreview.pdf
http://www.business-yellowpages.com/Particle-Board/24714/page-6