Hazardous Waste: what to watch for

Building jobs can bring with them many health hazards. It is especially important to be aware of these hazards in renovation, deconstruction or demolition projects. Five of the most common health hazards found in these areas are: asbestos, silica, mould, lead and mercury.

Asbestos

Asbestos is a mineral fiber that has been used commonly in a variety of building construction materials or insulation and as a fire-retardant and was regularly used in many buildings until the 1980s. Since then it has been phased out of construction. Once installed it is considered inert, however if disturbed by new construction, fine asbestos fibers can linger in the air. All forms of asbestos are considered to be carcinogenic and there are links between it and diseases like asbestosis and mesothelioma.

What to do? Demolition work on asbestos insulation and sprayed asbestos coatings can produce particularly high levels of dust. Asbestos insulation was often used to wrap air ducts, these materials should be removed by competent asbestos contractors before the start of demolition work.

Silica dust

Silica is a major component of the earth’s crust. Many building materials, like natural stone, bricks, cement, mortar, tiles and concrete contain silica. Any process involving breaking, crushing or grinding silica containing materials will generate silica dust. This fine powder can damage the lungs much like asbestos and can cause the condition known as silicosis, a disease with lung fibrosis causing difficulty in breathing.

What to do? Working in well ventilated areas, wearing a dust mask and damping down areas where silica is present reduces hazards associated with inhaling silica dust.

Moulds and Fungi

Moulds can be found almost anywhere; they can grow on virtually any substance, as long as moisture and oxygen are present. When excessive moisture accumulates in buildings or on building materials, mould growth can occur, particularly if the moisture problem remains undiscovered or unaddressed. It is impossible to eliminate all moulds and mould spores in the indoor environment, however mould growth can be controlled by controlling moisture indoors.

Elevated levels of exposure to many moulds can cause serious health problems. Mould spores are  a common allergen which makes life miserable for many people. Unlike silica and asbestos, which are dangerous after they are disturbed and become airborne, moulds constantly release spores and chemicals as part of their growing cycle.

What to do? Clean the mouldy surface with water and dish detergent (bleach is not necessary); mask if needed. Fix the underlying cause, whether due to water damage or excessive humidity and replace rotted materials. Small areas can be cleaned by homeowners, but precautions should be taken including hiring a professional for clean up if the affected area is large.

Lead

Lead additives have been phased out of building materials in Canada in recent decades. Lead in homes is primarily found in old white paint where it can be disturbed during renovations and demolitions. It is rare in homes built after 1960. Lead paint dust may accumulate in old carpets.

What to do? Testing for lead can be done by homeowners before renovations or a demolition project begins by removing a chip of paint or gathering paint dust and sending it in for testing. The Yellow Pages under “paint testing” lists costs, details and instructions.

Mercury

Since the 1970s, efforts have been undertaken to reduce the amount of mercury found in Canadian buildings. In older homes mercury may be found in appliance or lighting switches as well as thermostats. All fluorescent lighting contains mercury.

What to do? Switches and thermostats containing mercury should be turned over to a C&D processing facility for proper disposal. Keep these materials out of contact with other C&D materials to avoid releasing mercury. Fluorescent bulbs must be turned in to waste authorities as hazardous waste.

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