Cement
Cement mixes are a well-known cause of skin disease. Both irritant and allergic contact dermatitis can result from proximity to wet cement. Prolonged exposure to wet cement (for example, if you kneel or stand in it) may cause cement burns or ulceration of the skin. The following precautions should be taken:
– Avoid breathing in cement dust, as well dust created by the surface treatment of hardened concrete which may contain a high silica content, by wearing suitable respiratory protective equipment.
– Protect the skin from contact by wearing long-sleeved clothing and full-length trousers, with rubber boots and gloves when required.
– Protect the eyes; if any cement gets into the eyes, rinse them immediately with plenty of warm water.
– Immediately wash off any dust or freshly mixed cement that gets on to the skin.
– Clean off your clothing and boots after work.
Asbestos
Breathing in asbestos dust can kill by causing irreversible lung damage and cancer. There is no known cure for asbestos-related diseases. The more asbestos dust breathed in, the greater the risk to health. There are control limits for the various types of asbestos. You are likely to find asbestos in the following situations:
(a) as asbestos insulation or coating used for:
(i) thermal insulation of boilers;
(ii) fire protection of structural steelwork;
(iii) thermal and acoustic insulation of buildings;
(b) as asbestos insulating board used in a wide variety of places such as:
(i) fire protection on doors, protected exits, structural steelwork, etc.;
(ii) cladding on walls, ceilings, etc.;
(iii) internal walls and partitions;
(iv) ceiling tiles in a suspended ceiling;
(c) as asbestos cement, which is found as:
(i) corrugated sheets (roofing and cladding of buildings);
(ii) flat sheeting for partitioning, cladding and door facings;
(iii) gutters and downpipes.
Before starting work
If it is not clear whether insulating material, boarding, and so on contain asbestos, bulk sampling and laboratory analysis are necessary. This must be done by someone with suitable training and experience. Alternatively, you may assume that the material contains crocidolite (blue), amosite (brown) or chrysotile (white) asbestos and take appropriate precautions.
Before starting any work with asbestos, an adequate assessment must be made to work out the precautions needed to control the exposure to the substance. Work with asbestos may range from cleaning brake drums of construction plant and vehicles to full-scale asbestos removal.
Carrying out work with asbestos
In many countries those who work with asbestos to any extent, and in particular in removing and disposing of asbestos, require to be licensed or to hold a permit. In working with asbestos insulation board, workers will probably need to wear suitable protective clothing. Only working methods that keep asbestos dust levels as low as possible should be used (e.g. use hand tools and avoid breaking boards).
Asbestos cement is less likely to generate dust than many other asbestos products, but the risk of asbestos dust release is still present.
When cutting asbestos cement, use hand tools (or power tools fitted with exhaust ventilation equipment). Where it is not possible to keep asbestos dust levels under control limits, respirators should be worn. Protective clothing will probably be required for any significant work with asbestos cement. If you have to clean asbestos cement sheeting encrusted with lichens or mosses, a system of wet scraping/brushing is preferred.
Methods of limiting exposure to asbestos dust include:
– removing asbestos materials before starting major demolition work. This prevents accidental exposure to asbestos;
– wet methods of removal (to suppress dust);
– prompt removal and bagging of waste asbestos, and disposal at an approved waste disposal site;
– separating asbestos work areas from other general work areas.
Lead
Inorganic lead is found in many construction products, e.g. electricity cables, pipes, gutters and old lead sheet roofs. Organic lead is added to motor fuels, and storage tanks will be heavily contaminated.
There is a risk to health from inhaling dust or fumes created by burning or cutting materials containing lead, including painted surfaces, by welding, by grinding or cutting, and by spray painting of leaded paints. Lead can be absorbed when swallowed, usually when food is contaminated, and adequate washing facilities should be provided. Organic lead compounds are readily absorbed through the skin.
Excessive lead absorption causes constipation, abdominal pain, anaemia, weak muscles and kidney damage. It can also affect the brain, causing impaired intellect, strange behaviour, fits and coma. If you work with lead in any form, you should take the following precautions:
– Wash your hands regularly, and always before eating; you are at higher risk if you smoke with lead on your hands.
– Use the protective clothing and respiratory protective equipment which should be provided whenever lead levels exceed national control limits.
– Wear work clothing on the job and store your “street” clothing where it cannot be contaminated by your work clothing.
Discussion
• What precautions have been taken at the site to prevent exposure to hazardous substances?
• Where asbestos is known or suspected to be present at the site, are adequate steps taken to prevent workers from being exposed to the dust?
• Have you noticed or heard any of your co-workers complain of symptoms which you think might be related to or caused by exposure to hazardous substances?
• Can you think of any other hazardous substances used on construction sites?
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