<p>Serpentine units can certainly host asbestos deposits, and possibly all of them do, to some (non-commercial) extent. But so too do other rocks : just last week I was nosing around some laybys in a medium-grade schist region, knowing that my mother had collected some lovely cm-scale veinlets of asbestos from that stretch of road.</p>
<p>Asbestos in a vein in a lump of rock isn't really a significant health hazard - it's unlikely to be <em>shedding</em> appreciable numbers of fibres into the air. At the crushing plant in the quarry, it's likely to be more of a hazard - and I'd expect the quarry manager to be looking for asbestiform veins in each new segment of wall for extraction <em>before</em> drilling the blasting holes. (And if they were found, that'd be a call to Head Office, while drilling next week's shot holes in some other section of the quarry face.)</p>
<p>It's like uranium (or the potassium in bananas) - the material itself isn't a problem, it's whether it gets inside you that matters. A banana in the tree, or a uranium pellet in a reactor - not a radiation hazard ; put the same atom in your body, then have it decay - then you potentially have a problem. Similarly, asbestiform minerals inside a rock in your garden are not a measurable risk ; drill into a hidden vein of the mineral while planting a rock-bolt, then inhale the drilling dust - then there's a small hazard.</p>
<p>Remember also - there is a strong dose-effect relationship with all these things. Your exposure from a rock-bolt hole is like 5 minutes at lunch break for the asbestos miners or insulation laggers who are dieing of mesothelioma after 10 years working with the dust 200 days a year.</p>
<p>Yes, I do eat bananas. Potassium is both radioactive and an essential nutrient.</p>

CC BY-SA 4.0
2024-10-06T23:27:23.513Z
2024-10-06T23:27:23.513Z
Rockdoctor
<p><a href="https://en.wikipedia.org/wiki/Serpentine_subgroup" rel="nofollow noreferrer">Serpentine</a> can contain asbestos and some deposits of serpentine have been used as a source of asbestos when it was more widely mined in the past.</p>
<p><a href="https://en.wikipedia.org/wiki/Asbestos" rel="nofollow noreferrer">Asbestos</a> is a known carcinogen. However, asbestos is the &quot;commercial&quot; name given to six fibrous (also known as <a href="https://en.wikipedia.org/wiki/Asbestiform" rel="nofollow noreferrer">asbestiform</a>) minerals that had once been &quot;useful&quot; to humans. I'm yet to see any research done on fibrous minerals that are not classified as asbestos and what affect they can have on human health. Being cautious, it would be best to avoid all fibrous minerals.</p>
<p>In early 2024, <a href="https://www.berniebanton.com.au/asbestos-awareness/about-asbestos/the-difference-between-bonded-and-loose-friable-asbestos/" rel="nofollow noreferrer">bonded asbestos</a> was found in garden mulch in public spaces in two major Australian cities: <a href="https://www.epa.vic.gov.au/for-community/incidents/response-to-potential-asbestos" rel="nofollow noreferrer">Melbourne</a> and <a href="https://www.abc.net.au/news/2024-02-14/asbestos-nsw-identified-recycled-mulch/103461862" rel="nofollow noreferrer">Sydney</a>. Bonded asbestos is bonded with cement in cement sheet, previously used as a building material. The discovery caused significant public concern and a rash of reports in the media, resulting in the closure of parks and schools until the offending contaminated mulch was removed.</p>
<p>Bonded asbestos is possibly lesser of an issue than loose asbestos, as occurs naturally in rocks, but still a cause for concern.</p>
<p>I would advise avoiding any material that has the potential to contain any amount of any form of asbestos, or fibrous minerals.</p>

CC BY-SA 4.0
2024-10-07T00:49:33.263Z
2024-10-07T00:49:33.263Z
Fred
<p>Some landscaping rockyards where I live (northern California) sell lovely green crushed rock that I understand to be serpentine (it's often called &quot;Cal Green&quot; at the rockyards). I know that serpentine sometimes carries toxic minerals, including asbestos. Should I be concerned about this when deciding whether to use this rock for my landscaping?</p>

CC BY-SA 4.0
2024-10-03T08:43:06.120Z
Hi dyoung, welcome to es.se. The "regulations" part may not be on topic for this site - but the "should I be concerned" question seems like a reasonable one. I hope you get some good answers.
Semidiurnal Simon
CC BY-SA 4.0
2024-10-03T15:46:56.850Z
Thanks for the feedback Simon. I removed the "regulations" sub-question.
dyoung
<geology>
Crushed serpentine landscaping rock: health hazards?
dyoung
# Crushed serpentine landscaping rock: health hazards?

(Asked by: username_0 on 2024-10-02)

Some landscaping rockyards where I live (northern California) sell lovely green crushed rock that I understand to be serpentine (it's often called "Cal Green" at the rockyards). I know that serpentine sometimes carries toxic minerals, including asbestos. Should I be concerned about this when deciding whether to use this rock for my landscaping?

**Tags:** geology

> **Comments:**
> **username_1**: Hi username_0, welcome to es.se. The "regulations" part may not be on topic for this site - but the "should I be concerned" question seems like a reasonable one. I hope you get some good answers.  
> **username_0**: Thanks for the feedback username_1. I removed the "regulations" sub-question.  

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## 2 answers

### Answer by username_2 on 2024-10-06. Score: 2 | Accepted answer

Serpentine units can certainly host asbestos deposits, and possibly all of them do, to some (non-commercial) extent. But so too do other rocks : just last week I was nosing around some laybys in a medium-grade schist region, knowing that my mother had collected some lovely cm-scale veinlets of asbestos from that stretch of road.

Asbestos in a vein in a lump of rock isn't really a significant health hazard - it's unlikely to be *shedding* appreciable numbers of fibres into the air. At the crushing plant in the quarry, it's likely to be more of a hazard - and I'd expect the quarry manager to be looking for asbestiform veins in each new segment of wall for extraction *before* drilling the blasting holes. (And if they were found, that'd be a call to Head Office, while drilling next week's shot holes in some other section of the quarry face.)

It's like uranium (or the potassium in bananas) - the material itself isn't a problem, it's whether it gets inside you that matters. A banana in the tree, or a uranium pellet in a reactor - not a radiation hazard ; put the same atom in your body, then have it decay - then you potentially have a problem. Similarly, asbestiform minerals inside a rock in your garden are not a measurable risk ; drill into a hidden vein of the mineral while planting a rock-bolt, then inhale the drilling dust - then there's a small hazard.

Remember also - there is a strong dose-effect relationship with all these things. Your exposure from a rock-bolt hole is like 5 minutes at lunch break for the asbestos miners or insulation laggers who are dieing of mesothelioma after 10 years working with the dust 200 days a year.

Yes, I do eat bananas. Potassium is both radioactive and an essential nutrient.


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### Answer by username_3 on 2024-10-07. Score: 2

[Serpentine](https://en.wikipedia.org/wiki/Serpentine_subgroup) can contain asbestos and some deposits of serpentine have been used as a source of asbestos when it was more widely mined in the past.

[Asbestos](https://en.wikipedia.org/wiki/Asbestos) is a known carcinogen. However, asbestos is the "commercial" name given to six fibrous (also known as [asbestiform](https://en.wikipedia.org/wiki/Asbestiform)) minerals that had once been "useful" to humans. I'm yet to see any research done on fibrous minerals that are not classified as asbestos and what affect they can have on human health. Being cautious, it would be best to avoid all fibrous minerals.

In early 2024, [bonded asbestos](https://www.berniebanton.com.au/asbestos-awareness/about-asbestos/the-difference-between-bonded-and-loose-friable-asbestos/) was found in garden mulch in public spaces in two major Australian cities: [Melbourne](https://www.epa.vic.gov.au/for-community/incidents/response-to-potential-asbestos) and [Sydney](https://www.abc.net.au/news/2024-02-14/asbestos-nsw-identified-recycled-mulch/103461862). Bonded asbestos is bonded with cement in cement sheet, previously used as a building material. The discovery caused significant public concern and a rash of reports in the media, resulting in the closure of parks and schools until the offending contaminated mulch was removed.

Bonded asbestos is possibly lesser of an issue than loose asbestos, as occurs naturally in rocks, but still a cause for concern.

I would advise avoiding any material that has the potential to contain any amount of any form of asbestos, or fibrous minerals.


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