B. Health and building materials: An overview
Production of building materials
The materials delivered or supplied to site derive from a range of enterprises, operating at different scales, levels of technology and types of operation. Each type of material and production technology has its own characteristic health hazards. Many building materials industries derive their raw materials from quarrying or mining of minerals, in which workers are exposed to risks from blasting and rockfalls, and to dusts which can give rise to a variety of lung and respiratory disorders.
The risks to asbestos workers were among the first identified hazards of building materials (Section I.C). Fine dusts are also a problem in many other material-production industries, especially lime, cement and gypsum manufacture (1). Dusts of organic origin can likewise create health hazards of tumours and various allergic conditions for workers in sawmills and wood-based industries (1, 2).
Timber treatment often takes place off-site, using a variety of toxic chemicals, insecticides and fungicides, in a concentrated form which can be exceptionally hazardous to the health of workers exposed to them, and to the health of neighbouring populations if care is not taken in the disposal of wastes (2).
Handling of the solvents used in the manufacture of paints and varnishes creates health hazards for the workers in those industries (Section F). Workers in building materials production plants are also exposed to a range of industrial accidents from high temperature kiln processes (in cement, lime, brick production), rotating machinery, chemical spills and toxic effluent releases, and smoke-laden atmospheres; and to hearing loss from intense noise (1).
Two factors mitigate the hazards to workers in material production plants. First, such plants are generally permanent registered factories, where health hazards to workers can be monitored and controlled by proper management, and are subject to health and safety regulations, and are liable for inspection. Secondly, although exposures are often concentrated, workers are exposed to the health hazards only during working hours. However it should be cautioned that in many developing countries, the bulk of the small-scale production of building materials takes place in the informal sector using rudimentally and inefficient technology and ignoring legislation (3). Thus these mitigation measures do not have much relevance to the operation of the informal sector producers.
Construction and maintenance
The principal materials-related health hazards associated with the construction phase are dust, fumes, solvents and gases, and insecticides and fungicides. Many of the risks are most acute during this phase, where workers are exposed to health hazards in a concentrated form, but often without the workplace controls of materials production. Some of the health hazards to which construction workers are particularly prone are lung diseases from inhalation of dusts (particularly mineral fibres); skin and eye irritation and allergies from volatile organic chemicals released from paints and varnishes; and poisoning from the use of insecticides. The workers most at risk are those involved in the application of finishes (e.g. painters, decorators, and flooring contractors); and in maintenance and renovation works, where the exposures are concentrated and often in confined indoor spaces. Maintenance work can also put building occupants at risk if the building continues to be inhabited. A special hazard arises from the removal of asbestos-based materials during maintenance, as it can introduce concentrations of fibres into the indoor atmosphere dangerous both to occupants and to workers. Removal of toxic metals-based paints also puts the inhabitants at risk. In both construction and maintenance, disposal of toxic or harmful wastes can create hazards to workers, occupants and to the general public.
The causal agents of ill health found in the indoor environment which are associated with building materials include dusts and particulate matter, inorganic and organic chemicals, microbes, and arthropods. Table 1 shows the range of such agents. The indoor environment typically contains numerous chemicals in the form of dusts or gases, only some of which are attributable to building materials. Some building materials contribute by emitted chemicals of which they are made, or by contributing to the dusts as materials disintegrate. Materials can also act as a sink, storing chemicals from the surrounding atmosphere, and later releasing them (4). Such releases can be absorbed by the human body through inhalation.
A further range of organic chemicals is rapidly entering the indoor environment as a result of new products for the treatment of materials and furnishings. These include formaldehyde, a group of volatile organic compounds used, for example, in plastics and other polymeric materials; and pesticides which are semi-volatile and thus can remain in the environment for a long time, becoming adsorbed in dust or soft furnishings and released later. All of these chemicals are also inhaled.
The inhalation of dust and gases can trigger a variety of responses. The possible health effects can be classified as toxic, irritant or sensitising (5). Toxic effects may be acute, resulting in direct damage to organs, or chronic, causing for instance cancer, genetic damage or birth defects. Irritant effects are those which affect the skin, or through inhalation, can cause discomfort or damage to the mucous membranes, the nose, lungs or eyes. Allergic effects include a variety of sensitivities, for example asthma, rhinitis or eczema.
Table 1. Causal agents of disease encountered in buildings.
Source: Crowther, D. (1994). Buildings and Health, Ph.D. Thesis, University of Cambridge, UK.
Microbes tend to thrive in the indoor environment. Damp, porous building materials can contribute to the conditions needed to enable these organisms to flourish. Arthropods inhabit buildings. In tropical regions some of these are carriers of debilitating diseases such as malaria and dengue which are carried by mosquitoes, and Chagas’ disease which is carried by triatomine bugs. When dead, their disintegrated remains and excreta collect in house dust, where they can cause a variety of allergic sensitivities. In northern climates, the most important arthropod is the house-dust mite whose faecal pellets are held responsible for a significant rise in asthmatic conditions (4). Other arthropods tend to inhabit small cracks and crevices in buildings; thus they are encouraged by the use of building materials which are liable to crack, such as unstabilised earth, or thatched roofs.
Another aspect of building materials which can impact upon human health is their radioactivity, leading to the production of radon gas. Although in most instances their contribution to indoor radioactivity is small compared with soil radon gas, building materials produced from industrial waste products can have significant emissions. Radioactivity has a variety of carcinogenic effects.
In controlling health hazards, in residential or office buildings WHO recommends:
• To ban excessively hazardous materials
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