The 9 most harmful substances in building, construction materials

Dangerous construction materials
Many buildings contain materials that are hazardous to our health. PHOTO/FILE
Hazardous construction materials, commonly known as red list building materials, are natural or synthetic chemical substances that are harmful to humans or the environment.

Though highly toxic, the chemicals can hardly be seen, tasted or smelt but they are present in both indoor and outdoor living spaces and get into human bodies through ingestion, inhalation or contact with the skin.

The nature and extent of health risks posed by these materials is dependent on the duration the person is exposed to the toxins and the level of exposure.

Based on the ever advancing scientific knowledge, the list of dangerous construction materials is bound to change but the latest list released in 2014 by The International Living Future Institute (ILFI), a US based sustainable building certification program, listed the following as some of the worst offenders:

1.) Lead
Lead is a heavy metal commonly found in roofing materials, paints, plumbing pipes. It is highly poisonous and is rapidly absorbed into the blood stream and simulates calcium enabling it to cross the blood-brain barrier.

It slowly accumulates in bones and soft tissues eventually destroying the nervous system. Close contact with lead also causes blood disorders, brain disorders, blindness, reproductive health complications, damage to the kidneys and eventually death.

2.) Polyvinyl chloride
Polyvinyl chloride (PVC) is a common low cost, lightweight but strong plastic commonly used in the production of water and sewerage pipes, insulation for electrical cables, gutters, door and window frames, roof membranes and moulding.

It is also used in flooring, wall covering and ceiling material as vinyl tiles which are inexpensive and common in many interiors such as offices, homes, hospitals, hotels and schools among others.

PVCs contain phthalates and dioxins which interfere with the production and normal activity of human hormones therefore affecting the functions of thyroid, pancreas, adrenal, pituitary and reproductive glands.

They are also classified as carcinogens and can lead to cancer, liver dysfunction, vision failure, birth defects, chronic bronchitis, asthma and genetic mutations.

The production of PVC and its disposal also exposes humans and the environment to toxic substances.

3.) Wood treatments
Various treatments are applied to wood to preserve it and increase its life span. Most of the chemicals used in wood treatment are water soluble.

Creosotes are applied to wood as preservatives to prevent rot and come in a variety of types depending on the material used to produce them such as wood tar creosote, coal tar creosote, oil tar creosote, and water gas tar creosote.

The coal-tar creosote is the most commonly used yet the most toxic since it directly causes cancer.

Arsenics are used in wood treatment to prevent insect attacks. Although trace quantities of the element are essential as a dietary element in different species including humans, larger than required quantities from contaminated ground drinking water can result in poisoning leading to abdominal pain, vomiting and bloody diarrhoea.

Long term effects include heart disease, darker and thickening skin, numbness and cancer.

Exposure to large amounts of Pentachlorophenol, another wood preservative, can lead to harmful effects on kidneys, nervous system, liver, immune system and can also cause cancer.

4.) Halogenated flame retardants
Flame retardants are chemicals incorporated in construction materials during manufacturing to slow down or stop the spread of flames either by forming a protective film or by inhibiting chemical reactions that support combustion in case of a fire break out.

When heated, these retardants degrade into toxic substances in gaseous form which then mix with dust and get into the body through ingestion or inhalation.

They can cause disruption of hormones especially thyroid, adverse developmental problems in foetus and children, immunotoxicity, cancer and reproductive problems.

5.) Asbestos
This was a popular building material up until the 1990s when it was discovered to be extremely dangerous leading to its ban in 1999. Though it is rarely found in modern building materials, it can still be found in pipe covers, flooring, fireproofing insulation and many adhesives among other construction materials.

It is a respiratory irritant that causes chronic obstructive pulmonary disease and can also lead to lung cancer.

6.) Cadmium
This is a soft malleable metal that is resistant to corrosion, insoluble in water and non-flammable when in solid state.

It has been widely used on other metals especially steel as corrosion resistant plating. Its compounds have also been used to stabilize plastic and to colour glass since they are available in red, yellow and orange pigments.

Cadmium fumes, highly soluble compounds or fine dust can cause pulmonary oedema (accumulation of fluids in the air spaces and tissue in the lungs), pneumonitis (inflammation of lung tissue) and death.

High levels of exposure to cadmium have also been linked to prostate, breast and lung cancer.

7.) Volatile organic compounds
VOCs are naturally occurring or man-made chemicals with a low boiling point resulting in large numbers of their molecules vaporising and filling the surrounding air.

In building and construction, VOCs are commonly found in solvents, paint, plastics, synthetic fibres, adhesives and protective coatings. Some of them such as formaldehyde which emanates from paint have boiling points as low as just -19 C.

VOCs usually cause irritation to eye and respiratory track, dizziness, memory impairment, damage to the kidney, liver and central nervous system. Some have also been found to cause cancer in animals and humans.

8.) Silica
Silica is a natural occurring substance found in stone, sand, concrete, tiles and bricks.

It is absorbed in the body through inhalation after construction or demolition involving cutting, dressing, grinding or blasting stone or concrete release it in the air.

Long term exposure to silica leads to lung infections and lung cancer.

9.) Fiber glass
Like the name suggests, this is a type of fibre made up of glass which is mostly used as a thermal insulator and as a roofing material.

Exposure to fiberglass is most prevalent among workers who cut, trim, chop and sand the fibres producing dust which mixes with air and dust and later finds its way into their bodies through ingestion or inhalation.

The fibres cause eye, skin and upper respiratory tract irritation and aggravate bronchitis and asthma.