For years fibreglass dust has been considered to be a nuisance (irritation) dust which does not cause disease. Now studies show that fibreglass dust can be dangerous, maybe as dangerous as asbestos dust. The implantation of fibreglass into the lining of the lungs of animals has caused cancer in the same way that asbestos does. Scientists now believe that asbestos causes cancer because of the physical shape of the fibre and not because of its chemical make up, This belief raises the concern that all fibrous materials could cause cancer.


What is Fibreglass?

Fibreglass is a part of group called Synthetic Mineral Fibres. Synthetic mineral fibres are fibrous inorganic substances made primarily from rock, clay, slag or glass. These fibres are classified into three general groups: (1) fibreglass (glass wool and glass filament), (2) Mineral wool (rock-wool and slag-wool), and (2) Refractory Ceramic fibres (RCF),

*Glasses are a class of materials made from silicon dioxide with oxides of various metals and other elements that solidify from the molten state without crystallization.

** A fibre is considered to be a particle with a length-to-diameter aspect ratio of 3 to 1 or greater, respirable fibres have mass medium aerodynamic diameter approximately 3,5 urn or less,


Generally, fibreglass is light, strong, resistant to moisture. odours, rot, and easily formed into complex shapes and they are dimensionally stable. These qualities make fibreglass an excellent material to be used in the construction of buildings and for pluming and air handling systems such as the HVAC insulation. Also fibreglass can be found in a large number of products: It’s used in vehicles bodies, vessels, insulation, fabrics, wire insulation in electronics, and replacement insulation for asbestos.

Health Hazards: A Myth or Fact?

Synthetic mineral fibres are believed to cause respiratory cancers and other adverse respiratory effects, Typical fibres from continuous filament fibreglass are not small enough to travel deep into the lungs. Instead, these larger glass fibres can be very uncomfortable and irritating to the skin. Smaller fibres associated with fibreglass wool have been developed for some industries, and can travel deep into the lungs. Once there, these smaller fibres have shown signs of being potentially carcinogenic (cancer-Causing) in humans,

In 1988 the Internal Agency of Research on Cancer (IARC), a branch of the World Health Organization (WHO), classified fibreglass as a possible carcinogen. However, it must be noted that there are no conclusive facts that show that it does cause cancer.

Evaluating the Exposure

Dermatitis (rash), bad itching, sore throat, painful running noses, and excessive coughing are common complaints of people exposed to fibreglass and indicate the need for additional controls. The primary routes of potential human exposure to glass wool are inhalation and dermal contact. An exposure, which may cause long-term damage to health, such as: exposure to damaged or old dry loose fibreglass wool insulation inside the air conditioning duct system: grinding operation or any other operation causes a visible release of dust into the air. Large diameter (greater than 3.5 micron) glass fibres have been found to cause skin, eye, and upper respiratory tract irritation. While smaller diameter fibres <3.5 micron has the ability to penetrate the alveoli or deposit in the Alveolar regions of the lung, where gas exchange occurs (WHO, 1903). This is a potential cause for concern and is the primary reason that the fibres are subject to special controls,

To determine if the indoor dust is small enough to be inhaled, industrial hygiene measurements are needed.

National Institute for Occupational Safety and Health (NIDSH) NIOSH has proposed a new standard, which gives some guidance in controlling fibreglass dust. This standard is not yet enforceable in the US by U.S. Department of Labor Occupational Safety S. Health Administration (OSHA). The proposed standard measures both the total weight of all dust and the number of tiny fibres. The proposed limits for Total Dust Recommended Exposure Limits (REL] is 5 mg/m3 (5 milligrams per cubic Meter of air] for 10-hour Time-Weighted Average (TWA), While for Tiny fibres it is 3,000,000 fibres per cubic meter of air, NIOSH REL -TWA Fibrous Glass Dust Total for dust fibres with diameter equal or less than 3.5 urn (Micron), and length equal to or greater than 10 um is 3 f/cc (fibres per cubic centimeter of air). The TWAs apply to any 10-hour shift in a 40-hour work week (NIOSH, 1977). Scientists, view this standard as a minimum level of control but recommends air measurements to help evaluate the exposure.


OSHA endorses major agreement with industrial groups in the US to protect workers exposed to fibreglass insulation similar to NIOSH safe levels. The Health and Safety Partnership Program (HSPP) has established a voluntary PEL (Permissible Exposure Limit) for fibreglass exposure, makes comprehensive work-site recommendations for the proper and safe handling of insulation materials, and organises ducation and training programs for workers. OSHA classifies glass-wool fibre as a “Particulate Not Otherwise Regulated,’ with a workplace permissible exposure limit (PEL) of 5.0 mg/m3 for respirable dust and 15.0 mg/m3 for total dust.

US EPA regulates particulate emissions from glass-wool insulation manufacturing plants under the Clean Air Act (CAA] .

Medical Examinations

NIOSH recommends the same medical testing for workers exposed to fibreglass as it does for asbestos: yearly physical examinations which include lung function tests (pulmonary function], chest x-rays, and medical histories. Subsequent annual examinations should give attention to the skin condition. The examinations should be given to anyone exposed at half the limit (REL).

Control Measures

As with any other potentially dangerous air contaminant controlling the dust, its source should be the first line of defense. Possible controls are:

  • Process design changes such as substitute materials and regular cleaning;
  • Engineering controls such as enclosures and exhaust ventilation;
  • Work practices such as vacuum cleaning with HEPA (High Efficiency Particulate Air) filtration.

Special precautionary measures need to be taken to ensure comfort and health of all that come into contact with fibreglass. Special clothing that prevents contact of fibreglass dust with the skin should be used while dealing with fibre class. Respirators are the last resorts and temporary measures.

Dust collection system should be used whenever fibreglass exposure may exceed either established particulate standards or recommended fibre standards.

If fibreglass particles accumulate on exposed skin areas, do not rub or scratch. Remove the material by washing the skin thoroughly but gently with warm water and mild soap.

Fibreglass is and will continue to be one of the most useful construction materials available. Its strength and insulating properties and its durability under adverse circumstances make it the one choice for insulation in many cases. Following the above stated recommendations for handling and control of fibreglass products will help to minimize the danger and discomfort people are exposed to in using fibreglass products.