"Family Handyman" is a fun magazine to read if you're a do-it-yourself-er, but an article about composite siding made from coal ash in Summer 2017 didn't mention personal protective equipment AT ALL. They didn't publish my letter...

Dear Editors,

In the recent July-August edition of Family Handyman you described a number of synthetic trim board options. The article was interesting, but I was surprised that in the discussion of poly-ash boards more emphasis wasn't put on personal protective equipment (PPE).

Coal ash consists of the parts of coal that don't burn in an electricity generating power plant. The ash contains (toxic) heavy metals like Mercury, Cadmium, and Arsenic (ref 1), and, because of the concentrating action of combustion, the ash carries enough radioactive Thorium and Uranium to make the coal ash more radioactive than nuclear waste shielded by dry or water cask storage! (ref 2) It isn't clear to me what process Boral is using to produce their trim boards, but mixing the ash with plastic resin doesn't make it any less radioactive. As Boral does not discuss "cleaning" the coal ash before making trim boards, I am assuming that their boards are made with ~70% generic coal ash, ~20% plastic, and ~10% fiberglass, per the SDS sheet available on their website.

Both Thorium and Uranium radioactively decay primarily by emitting an alpha particle. Alpha particles can be shielded (stopped) by a few inches of air, but alpha emitters are VERY dangerous if ingested - you might remember hearing about the KGB (purportedly) poisoning A. Litvinenko with Polonioum-210, another alpha-emitter, a few years ago (ref 3). Radon gas is another alpha-emitter and the second leading cause of Lung Cancer in the US - many of your readers probably have radon remediation systems installed in the lower levels of their homes.

If you choose to buy and use trim boards made from coal ash, be absolutely sure to wear a high-quality dust mask or respirator to reduce the chance that you ingest (inhale or swallow) dust or sawdust from the coal ash based trim. In sufficient quantities, the heavy metals will destroy your nervous system, kidneys, liver, etc, and ingesting alpha-emitters will increase your risk of cancer. My kids love to play with pine sawdust in our shop, but it seems especially important that children or women who may become pregnant not come in contact with the dust from coal-ash based trim, as young bodies are more susceptible to the effects of these toxic materials.

Apologies for being such a killjoy.
Ref 1, https://www.epa.gov/coalash/coal-ash-basics or for detail, https://pubs.usgs.gov/bul/1528/report.pdf
Ref 2, https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/
Ref 3, https://en.wikipedia.org/wiki/Poisoning_of_Alexander_Litvinenko