Is it safe to "biodegrade" chipboard for mulch?   I have old laminated
kitchen counter tops (c. 1976) to dispose of.   If the material was
safe, I'd put it out in the rain until it decomposed into laminate and
a pile of sawdust, and then use the sawdust for mulch. I know from
experience that it will come apart with water.  But I don't know what
chemicals are involved in the glue.

Hello there

This relates to another question I worked on recently about the safety
of older construction products.  Your laminated tops date from 1976.
http://answers.google.com/answers/threadview?id=389928

Not only is there a formaldehyde content as mentioned by Probo, there
is a chance the material contains asbestos.  Some older chipboard may
contain asbestos and some was actually made of it.  Asbestos was also
used in some cases as a "facing" on chipboard.  Since the board is
laminated, there is also a chance asbestos is part of the binding
material for the laminate.
http://www.lhc.org.uk/members/pubs/newslet/54dh.htm - "The Daily
Hazard - No 54, March 1997"

When researching this, it is amazing the number of websites which
advertize "asbestos free" chipboard.  The restrictions against
asbestos didn't go into effect till 1977 and chipboard containing it
may have remained on the market for sometime after.  I doubt very much
they would make such a point of it if there had not been a problem in
the past.

While there is a chance your chipboard may be asbestos free, why take
the chance.  Adding it as mulch just creates an easy way for asbestos
fibers to enter the air if they are present.

You may want to have the wood tested if you do decide to compost it.

If I may clarify anything, please ask.

Cheers
Digsalot

Thank you very much.   I'm always hoping to turn waste into something
good, but I'm beginning to see how important the Cradle to Cradle
design concept is.  If we want to do that, it has to be designed that
way to start with.  Thanks again.

I am not a chemist but I believe that formaldehyde is used in
chipboard and I believe that you have every reason to be cautious.

Let's hope someone knows the answer.