Sure, but ‘synthetic’ is a weird word. At root it just means ‘made via synthesis’. Rayon is not made by synthesizing cellulose, though - it is made by extracting natural cellulose. You could say the fibers are synthesized - but cotton needs to go through a spinning process too. Where do you draw the line between ‘synthesis’ and ‘manufacturing’?

Sure, for rayon the cellulose extraction process is chemical, unlike the physical process used to get cellulose fibers out of cotton, but the raw material is still natural, plant grown cellulose.

There are plenty of things that are made by taking natural ingredients, shoving them in a vat of toxic chemicals to transform them, then taking them out to use, which are generally still considered ‘natural’ products: leather, bleached flour, pressure treated wood, dyed cotton…

> Where do you draw the line between ‘synthesis’ and ‘manufacturing’?

I assume the layperson will respond: "Synthesis uses chemicals, and manufacturing doesn't!" (visualizing a bandsaw or a punch-press machine)

Of course manufacturing uses plenty of chemicals, but we don't always think about that when visualizing mechanical assembly processes.

> Sure, but ‘synthetic’ is a weird word.

Every word is weird if you think about it too long.

At least in the US, this is pretty simple, even if it offends the sensibilities of category pedants.

"Natural" fibers are cotton, wool, linen, etc. Processing is fine, so long as it isn't "too processed".

It is "Synthetic" if it ends in '-on', or feels like plastic or rubber.

Right.

But thinking of Rayon and viscose as ‘synthetic’ means people assume it is not biodegradable, which isn’t the case. It’s about as biodegradable as cotton, or cardboard.

In fact cardboard and paper are good analogs - I think people are comfortable thinking of them as ‘processed’ natural products, but not ‘synthetic’. There is value in getting people to think of rayon as more like that than true synthetics like nylon and polyester, which create non biodegradable micro plastic pollutants.

Pressure treated wood is highly toxic...

There are several different kinds of pressure-treated wood.

The old bad stuff is CCA, which uses arsenic. It's been restricted (in the US) for about two decades, though still available for some applications. Home Depot does not carry it.

The newer stuff is ACQ (several types) which are Al and Cu-based. Not considered toxic by the EPA, however some people (including myself) are still not comfortable using it for, e.g. garden beds.

Sawdust of all woods is considered an irritant, toxic, and a possible carcinogen.

Work outside, and/or use good dust collection. Always wear a dust mask.

Yes, it’s a construction material. I wouldn’t recommend eating it. Same advice goes for reinforced concrete slabs and steel girders.

It’s treated with a copper sort of poison usually. We handled it without gloves once after it had gotten wet and all got really sick.

I would advise not eating any kind of concrete.

Oh, I don’t know. I had a concrete from Freddy’s a couple of weeks ago, and it was quite good. Peanut butter cups and bananas I believe.

:)

There is also an article specifically on bamboo textiles: https://en.wikipedia.org/wiki/Bamboo_textile