Winter 2013 True Natural Health Magazine – Your Questions Answered
By Roger French


QUESTION:  I heard long ago that fibreglass insulation could be the ‘new asbestos’ in terms of lung cancer. This would, of course, mainly be a problem during installation when the fibres fill the air. Our house is entirely insulated this way and I was the installer. I did take great care to be well clothed, gloved and face-masked.

Is there any up-to-date information since 1994 when the US government classified glasswool as a potential lung carcinogen?

I and many others would no doubt be grateful for this information, especially anyone considering installing glass wool insulation or removing it during renovations.



You are quite correct, Ian. In 1994 the United States Food and Drug Administration classified glasswool as “reasonably anticipated to cause lung cancer in humans”. Fortunately, there is newer information.

Insulating our homes has a big effect on reducing the costs of energy. Fiberglass insulation, now called ‘glasswool’ insulation, is the most popular form of household insulation. Glasswool insulation consists of fibres blown or spun from molten glass and collected in an entangled mat. But it has been associated with various health problems, ranging from skin irritation to cancer.

Yes, it is capable of causing skin irritation in installers, but this is relieved by showering to remove the fibres from the skin, and is not a problem for the occupants of the insulated house or other building.

But what about the lung cancer fear? Fibreglass and asbestos are both very good heat insulators, but fibreglass became popular when the cancer-causing effect of asbestos became apparent. However, it was then discovered that some of the fibres in fibreglass insulation are as fine is those of asbestos and this initiated the lung cancer scare. Typically, glasswool insulation fibres are between 5 and 10 microns in diameter (a micron is one millionth of a metre), but a small proportion of the fibres are fine enough (less than 3 microns in diameter) to be breathed into the lungs and remain there indefinitely.

The situation has been substantially improved. Binding resins and oils are now used during manufacture to stiffen and bond the fibres together and to prevent them from becoming airborne. These binders can also cause skin irritation, but this is a relatively minor problem.  

Further, the development of biosoluble has been a major step forward. In 1995 European manufacturers perfected the technology to make glasswool and rockwool fibres more soluble in living tissue without impacting on product performance. Thorough testing showed that the persistence of biosoluble products is less than 10 days, well below the typical 20 days biopersistence of the everyday dusts we might encounter walking down the street.

In 1997 European regulators recognised that biosoluble glasswool insulation is not a likely cancer risk to humans. Even the American Lung Association declares that glasswool is safe “when properly installed”.

The Western Australian Department of Commerce states that The International Agency for Research on Cancer (IARC) changed its classification in November 2001 as follows: “Fibreglass is now not classifiable as carcinogenic to humans and is no longer considered ‘possibly carcinogenic to humans’”.

The reasons for the change are:


Now the Australian National Asthma Council’s ‘Sensitive Choice’ product advisory panel has concluded that both glasswool and rockwool insulation are low allergen products suitable for asthma and allergy sufferers.

Once it’s installed, glasswool rests safely between the panels, and only when it’s removed will fibers become airborne.

Western Australia has adopted the ASCC National Code of Practice for the Safe Use of Synthetic Mineral Fibres (see If the work practices in this Code are followed, there is considered to be negligible risk to employees using either ‘traditional’ or biosoluble glasswool insulation.

The prominent Australian supplier of glasswool insulation, BradfordTM, changed their formulation of glasswool and rockwool insulation in 2001 and now use biosoluble fibres, identified by the ‘FBS-1’ logo on their packs.

If people still want an alternative insulation, there is cellulose produced from recycled newspapers and the oldest form of home insulation. It is treated with chemicals to make it more fire resistant, although it always has the potential to burn. The chemicals are usually sodium borate, boric acid or ammonium sulfate, which are generally considered safe for human contact.