Vermiculite on a sailboat

[Meanderthal]

Good afternoon!

In terms of HEALTH RISKS, vermiculite, depending on the geographic source, *may* contain a very small percentage of asbestos, but it is only a risk if that asbestos is breathed into the lungs. The spindle fibers are shaped so as to potentially interfere with lung oxygen transpiration and *potentially* cause scarring over the long term, resulting in increased lung cancer risks. D/t the moral mandate to not conduct human trials (this is a good thing! but sad for the purposes of drawing firm absolutist conclusions), the variation in human physiology and exposure patterns, and the long latency between exposure and potential consequence, we have no idea what the minimum airborne dose of asbestos is for increased cancer risk...so we say there is no lower limit and any exposure *may* increase risk.

If the vermiculite was an epoxy stabilizer, unless the removal was for structural purposes (and that I have no idea--I'm strictly talking health risks), I wouldn't be concerned by its presence (or former presence, as the case may be...).

From what I can tell, the fumed silica in Cabosil is essentially manmade vermiculite (don't quote me on this!), and we slap that all over hell and gone on our boats. I've used perlite and vermiculite in DIY soilless seedling mixes, and as insulation for flame-resistant or awkward-to-reach areas. I stumbled across this thread in a vain search to ascertain any functional difference between vermiculite and fumed silica before embarking on a glassing project. If anyone can help me clarify THAT, I'd love to know more.

-Pauline
(Disclaimer: I know a little, don't know enough, want to learn more.)

[Jim Cate]

Excellent post, Pauline! Nice to get a reasoned rather than emotional, doom crying opinion on asbestos exposure.

Can't help on the fumed silica query, but a look at one of the standard industrial hygiene references should clear that up for you.

Jim

[DougM]

in general crystaline silica is carcinogenic (silicosis in miners). Amorphous silica (glass, fumed silica, silica aerogel) is just a irritant. That's why it is considered safe to use fumed silica in applications such as a thickener for resin.

[Meanderthal]

Originally Posted by Jim Cate

Excellent post, Pauline! Nice to get a reasoned rather than emotional, doom crying opinion on asbestos exposure.

Can't help on the fumed silica query, but a look at one of the standard industrial hygiene references should clear that up for you.

Jim

Thanks!

[Meanderthal]

Originally Posted by DougM

in general crystaline silica is carcinogenic (silicosis in miners). Amorphous silica (glass, fumed silica, silica aerogel) is just a irritant. That's why it is considered safe to use fumed silica in applications such as a thickener for resin.

So, the raw material selection is based on worker safety, as opposed to that of the end user. Thanks!

[Wotname]

Originally Posted by DougM

in general crystaline silica is carcinogenic (silicosis in miners). Amorphous silica (glass, fumed silica, silica aerogel) is just a irritant. That's why it is considered safe to use fumed silica in applications such as a thickener for resin.

Is it???

I always understood (perhaps incorrectly) that fumed silica was best avoided and to be very cautious when handling it. I'm talking the raw product here, not already premixed in resin etc. I note that it extremely fine and light when compared to say talc and the particles float in the slightest breeze when being added to a resin etc. This is one of the few times I insist on wearing a very good mask.

Perhaps I was over cautious ????

[DougM]

Nope your not overcautious, just being prudent as you should. Not a good idea to breath it (same with fine glass fiber particulate). They are a serious irritant and cause inflammation. The amorphous silicas are not carcinogenic like crystalline, but you really don't want to breathe either type.

[Rudderless]

I've done a lot of mould remediation in attics and have run into vermiculite several times. When in doubt, I've sent samples into a lab for testing at about $15 a pop. There may also be some air tests that can be done to determine if asbestos is present, but I'm not sure.

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