Is blown mineral wool safe for home owners?

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A bit of history

Man-made vitreous fibre (MMVF) is a generic name used to describe an inorganic fibrous material manufactured primarily from glass, rock, minerals, slag and processed inorganic oxides

Man-made vitreous fibres have some physical similarities to asbestos, in particular, their fibrous character which gives them the same aerodynamic properties and leads to their deposition throughout the respiratory tract.
What makes asbestos dangerous is its biopersistence - that is how well the body is able to clear it. A lot of this is down to fibre length and shape with the most carcinogenic causing chronic inflammation of the tissues.
Given the tragic number of occupational deaths from asbestos related cancers and the long lag (decades) between exposure and disease, there was some understandable concerns about MMVFs and the International Agency on Cancer (IARC) initially class mineral wool as 'Group 2B' - probably carcinogenic.

In 2001 (IARC) reclassified glass mineral wool fibres from Group 2B (possibly carcinogenic) to Group 3 (agent which cannot be classified as for their carcinogenicity to humans)
The 400 page report Monograph Vol 81, http://monographs.iarc.fr/ is summarised here.

The key conclusions.

  • There is inadequate evidence in humans for the carcinogenicity of glass wool.
  • There is limited evidence in experimental animals for the carcinogenicity of insulation glass wool
  • Insulation glass wool, continuous glass filament, rock (stone) wool and slag wool are not classifiable as to their carcinogenicity to humans (Group 3)


The studies in humans were long term case controls studies of occupational exposure almost exclusively in men, many of whom smoked or had worked in various plants including those that manufactured asbestos. These confounders made it more difficult to analyse the data.
Animal tests were conducted in rats and hamsters with various airbourne glass wool products and no significant increase in lung tumours and no mesotheliomas were observed in rats and no lung tumours or mesotheliomas were observed in hamsters exposed to insulation glass wool.

Two insulation glass wools that produced no increase in tumours when administered by inhalation did induce mesotheliomas when injected at high doses  into the peritoneal cavity of rats.

The key is biosolubility

The conclusion is that there is good evidence that glass fibre in the wrong place (pleura/gut lining can cause cancers similar to asbestos but so long as the wool fibres are considered 'biosoluble' the natural defences in the lung would likely clear the particles before they cause chronic inflammation and cancers.
Biosolubility is directly related to the length of the fibres which results from the manufacturing process and so the biosolubility protection can only be assured by quality control by the manufacuters.

How does this relate to our insulation product Cosytherm (our CWI)

Loft space overspill with airbourn fibers and breakdown products

Water contaminated by degrading glass wool fiber

What does the BBA certificate say in regards to fibre length and granulation? :



So the BBA does not check this directly. However there is European legislation regarding the labeling of products as carcinogenic and for mineral wool, manufacturers can omit the 'may cause cancer' label if they meet a strict criteria.

The EUCEB (EUropean CErtification Board for mineral wool products) was created in 2000 in order to increase confidence of authorities, customers and consumers in the safety of mineral wools by providing information related to their non-classification under the European regulation.

"Mineral wool products bearing the EUCEB trademark are not classified as carcinogenic. Specifiers, installers, building owners and the public can have complete confidence in mineral wool products that carry the EUCEB trademark."

As an example. Rockwool has the classification


I contacted EUCEB regarding 1st Insulation Partner's Cosytherm and received the following reply.

According to our database, the manufacturer of the product "Cosytherm white wool cavity wall insulation"  is not certified by EUCEB (not resume in our database).
Therefore, for the question regarding the insulation product in the water and the potential health effect, I recommend to contact them directly.

I have checked the old 1st Insulation partners (Cosytherm system designer) website and found no EUCEB certificate.
With 1st Insulation Partners no longer trading, it falls to CIGA to step in in place of the 'system designer' to investigate problems with workmanship and materials.

Concerns for the home owner

When I first raised concerns with CIGA about airborne glass wool in the loft space and in our water tanks and dotted around other living spaces such as under the bath I was persistently told by CIGA that it was 'harmless'.
CIGA however in an email also specified 
"The insulation was referred to as inert which means it is not considered a risk to health, but may become an irritant to skin if it is allowed to enter the water system and then used for bathing."
Even if the product carried EUCEB certification, there are limitations on any health claims that could be made because:
  1. The IARC classification was based on studies of industrial exposure. The assumption has always been that home owners would not be exposed to chronic dust and break down products of mineral wool - it was all meant to be contained in the wall. Exposure to the occupier was not studied by IARC.
  2. The IARC study was based on respiratory exposure rather than ingestion. The fact that we were initially brushing our teeth with water from the cold water tank is a pretty nasty thought.
  3. Even if the risk of lung cancer/mesothelioma is considered low.  The irritative effects of airborne glass wool are well described by the manufacturers themselves - which is why it's mandatory to wear respirators and to take care when exposed to skin.  I can attest to just how irritating this product is - just handling a small amount can cause severe itching and reddening of skin and simpy visiting the attic space triggers a cough immediately on entry. I will not enter without a respirator.
Given the irritative effects of the product it's not surprising that it might create foreign body reactions in various tissues.  Granulomas as immune generated scar tissue which result as the body attempt to contain foreign bodies that cannot be broken down chemically.
There is some evidence of a causal effect between mineral wool and sacroid like granulomatous diseases. Again this wouldn't be classified as carcinogenic under IARC studies.

Summary

If the mineral wool remains sealed in the walls and occupants are not exposed and a quality control scheme such as EUCEB is in place then direct toxicity of mineral wool itself probably represents a low risk to home owner.*

I cannot find a EUCEB paper trail which validates that Cosytherm met the requirement to be labelled as 'non carcinogenic' under European regulations, and there is no data on heath effect to home owner when the product is badly installed as it was with us. I would suggest that until this is established CIGA refrain from giving health advice on this product.


* Health risks associated with restricted ventilation, mold and damp will be a subject of a future blog post.

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  1. isoflex28 August 2019 at 03:51

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