There are two common fibreglass products. 

• Continuous or woven glass filament, used as a reinforcement material in fibreglass pools, boats, tanks and other hard synthetic products. 
• Glass wool - such as batts - used for heat and sound insulation in buildings. 

Continuous glass filament is made by extruding molten glass through very fine holes to form thin strands. Glass wool is made by spinning or blowing molten glass. 

Fibreglass can be divided into two groups. 

1. 'Traditional' fibreglass which has been used since early in the 20th century. 
2. 'Biosoluble' fibreglass which is made from new materials that disappear from the body much more rapidly than the 'traditional'. 

All the fibreglass manufactured in Australia since January 2001 has been of the 'biosoluble' type. 

Continuous glass filament is too thick to be breathed into the lungs. High levels of irritant dust can be generated when fibreglass reinforced plastics are cut, ground or sanded. Extraction ventilation or the wearing of respirators may be necessary. 

While dust and fibres from working with continuous glass can cause irritation when they lodge in the skin, eyes and throat, they are eventually dissolved or expelled by the body and cause no long term damage. 

Even sanding and grinding glass filament on surfboards and boat hulls does not produce fibres small enough to be inhaled deep into the lungs, though the dust is irritating. 

Styrene vapours from polyester resins used in fibreglass products are, however, a more serious hazard, and may cause both short term irritation and long term effects to the nervous system. 

Epoxy resins sometimes used in the manufacture of fibreglass products can cause contact dermatitis and burns. Cured resins are practically non-toxic. 

Glass wool insulation consists of fibres blown or spun from molten glass and collected in an entangled mat. Without a safe work procedure, these fibres can also cause short term irritation to the skin, eyes and upper respiratory tract among workers involved in the manufacture or installation of insulation products. 

Typically, glass wool insulation fibres are between 5 and 10 microns in diameter (a micron is one thousandth of a millimetre). However a small proportion of the fibres are fine enough (less than 3 microns in diameter) to be breathed into the lungs. 

Binding resins and oils are used during the manufacture of fibreglass insulation to stiffen and bond the fibres together and to prevent them from becoming airborne. These binders can also cause irritation. 

Working with fibreglass fibres and dust, without safe systems of work, can result in irritation to the eyes, nose, throat and skin. 

Fibreglass dust and fibres may cause a stinging, itchy sensation when rubbed on the skin. This can happen to people working with fibreglass insulation, and it occurs particularly in folds of skin around wrists, collars and waistbands. Perspiration aggravates the condition. 

Most people quickly develop tolerance and hence the irritation may be temporary. Showering to remove the fibres will provide relief. 

Fibreglass insulation installed in buildings does not have adverse health effects on occupants. 

The International Agency for Research on Cancer (IARC) considers that fibreglass is not classifiable as carcinogenic to humans, because: 

• studies of occupational exposure during manufacture of fibreglass show no evidence of increased risk of cancer; and 
• there is an increased use of 'biosoluble' fibreglass, which has been tested and found to be non-carcinogenic. 

Western Australia's Occupational Safety and Health Regulations adopt an exposure standard for glass wool and continuous glass filament of 2 mg/m3 inhalable dust. Certain special purpose glass fibres (eg those used for high temperature applications) also have an exposure standard of 0.5 fib/mL.

Occupational Safety and Health Regulation 5.19 says that employers, main contractors or the self-employed must ensure that no person at the workplace is exposed to a hazardous substance in a concentration that exceeds the specified exposure standard. 

The Occupational Safety and Health Act says employers must provide information, instruction and training, safe work systems and personal protection against such hazards. Employees have a complementary duty to protect themselves and others from hazards. 

Employers must provide safe working procedures to minimise hazards. However, in cramped or enclosed spaces where fibreglass insulation is generally installed, dust may exceed recommended levels and may be difficult to control. 

Here a class P1 or P2 dust mask should be worn. Protective overalls should be worn to avoid skin irritation, and these should be washed regularly. Suitable gloves, tucked under overall cuffs, will prevent hand irritation. Goggles should be worn. 

Safe working procedures for glass filament are different. Handling continuous fibreglass filament before it is bonded into hardened plastics does not usually generate sufficient dust or airborne fibres to cause even short term irritation. 

However, once it is in a solid form, irritating dust may be generated by cutting, grinding or sanding, and ventilation or personal protective equipment may be required.