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Focus on… Installation: what lies beneath?

Hazardous materials may be hiding in the walls, waiting above the ceiling tiles or concealed in many other places where line and cable installers tread. Workers must take all of the necessary precautions to avoid close encounters with such substances.

May 1, 2002  

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Across this country and around the world, vast networks of wires and cables provide consumers and businesses with electrical power and telecommunications, data and television services.

But hazardous materials may be lurking behind walls, above ceiling tiles or in other places where line and cable installers and repair crews tread. Hazardous materials may not be as dramatic as other dangers that come with the job, but close encounters with hazardous materials can have negative health effects over the long term, with latency periods of upwards of 20 to 25 years. In addition, workers can take contaminated dust and debris home to the family, warns Chris Beatson, Ontario Ministry of Labour central regional construction program co-ordinator.


The hazardous materials that installers are most likely to encounter are frequently found in older buildings, Beatson says. For instance, if installers are running lines up elevator shafts or above ceilings of buildings built before 1980, there is a good chance they will run into asbestos fireproofing — unless the building has been retrofitted and the asbestos has been removed. Asbestos may have also been used on insulation on electrical wiring, plumbing pipes and air handling units, all of which installers may come into contact with.

Asbestos is used in building materials, insulation, fire-proofing (and even vehicle brakes) because it resists heat and corrosion. Inhaling asbestos fibers can cause serious diseases, primarily of the lungs and other organs.

On the roofs of older buildings, installers may encounter coal tar, a coke oven by-product used as an epoxy coating to protect steel and concrete in severely corrosive environments. Coal tar is carcinogenic and can lead to the development of skin cancer in workers. It has been designated a hazardous substance in Ontario.


In buildings where there has been sand blasting (an old warehouse converted into a condominium complex, for instance) installers might encounter respirable silica if it has not been thoroughly cleaned off beams, columns and joists. According to the Center for Disease Control (CDC), exposure to respirable silica dust can lead to the development of silicosis — a debilitating and potentially deadly lung disease.

Lead based paints can also be found in older buildings, says Beatson. The toxic effects of lead are well documented. The CDC points out that exposure to lead can damage the central nervous, cardiovascular and reproductive systems and the kidney, and can increases the risk of cancer.

Then there are PCBs (polychlorinated biphenyls). PCBs may be present in lighting ballasts and electrical (indoor) transformers. The likelihood of contamination from these units is remote. However, the known toxic effects of PCBs in humans include an acne-like skin eruption (chloracne) and pigmentation of the skin and nails. Workers exposed to PCBs have also reported digestive disturbances, burning of the eyes and impotence.

Installers can also be exposed to droppings from birds, rats, bats and other animals that roost on or travel across roofs or nest in attics. Disturbed droppings can become airborne and then inhaled by workers. Some of the medical problems associated with inhaling or touching droppings include: hypersensitivity pneumonitis, an allergic lung disease; Histoplasmosis, which can cause infection; Hantavirus Pulmonary Syndrome (HPS) carried by rodents, especially deer mice, that can lead to fever, chills, headache, muscle pain, shortness of breath and even death. Encounters with droppings can also cause salmonella poisoning.

Exposure to excessive dust and moulds that may be growing in damp places can lead to ear, nose and throat irritation, respiratory problems and infections.


The good news is that installers may not actually enounter most of these hazardous materials. And they should be able to adequately prepare for such encounters should they occur.

Under the Ontario Health and Occupational Safety Act (and similar acts in other provinces), a building owner, before the commencement of a project, must provide list of substances designated hazardous so that contractors can include the cost of appropriate protective gear and clean up facilities in their quotes, says Beatson.

Protective gear can include full or partial respirators to keep workers from inhaling hazardous dust and fibers, and disposable protective suits or coveralls that keep dust and fibers off of clothes.

If a situation is extremely hazardous (a great deal of asbestos insulation, for instance), the building owner may hire contractors to remove the material as part of general renovations before the wiring and cabling work begins.

“We are highly conscious of safety,” says Blake Clothier, operations and project manager at Able Electric, an electrical and communication cabling contractor based in Halifax. Before the company starts large jobs, especially in older buildings, a full safety inspection and environmental assessment is conducted. The assessment includes an inspection for hazardous materials.

In most cases, asbestos and other hazardous materials have been removed before the Able Electric installers arrive. But if hazardous materials are identified and cannot be removed, installers wear the appropriate respiratory equipment and coveralls.


The extent to which installer come into contact with hazardous material on the job has “to a great degree” decreased over the last 20 years as awareness of the dangers has increased, says Ed Ryan, loss prevention officer with Guild Electric in Toronto.

Many of the buildings — including government offices, schools and hotels — that had asbestos have been retrofitted and the asbestos has been stripped out completely. However, some of the spray-on insulations used in buildings have a high concentration of fiberglass and when working around any insulation, workers have to wear respiratory equipment.

If installers are going above a false ceiling that has been sprayed with asbestos fire-proofing, they have to enclose the area and put up warming signs so that members of the public not wearing protective gear know to stay away from the area.

While in such an environment, workers have to wear respirator masks with cartridges that filter out asbestos and may also have to wear disposable coveralls. When in the area, they are not allowed to eat, drink or smoke or do anything that might cause them to ingest fibers. And they need to use a HEPA vacuum to thoroughly clean the area.

Again, the responsibility of identifying potentially hazardous areas rests with the building owner. If workers encounter an unknown substance, they can report it to a supervisor and work is halted until the substance is identified. This may require having an environmental company come in to conduct tests.

Clothier finds building owners co-operative when it comes to identifying and removing hazardous materials. While they may want the job done as expediently as possible, owners are generally aware of the cost of lawsuits related to health and safety when there is negligence.

On large construction or renovation sites, there is generally a worker safety representative or even a joint health and safety committee, and any safety concerns should be referred to them for inspection and action, says Ryan.


“We are very safety conscious,” says Rob Stevenson, Guild Electric communications division manager. “We emphasize if workers don’t feel safe, they should identify their concerns.”

Guild Electric has over 400 communications and electrical field employees in Ontario. “As a large company, we have someone responsible [for health and safety],” says Stevenson. “We have policies in place and we keep up to date on government issued literature.” However, Stevenson is concerned about smaller companies and independent contractors who may not have the resources to keep fully informed.

One such independent contractor, who preferred not to be identified, has “drilled through floors and met with unidentified subs
tances” as well as live mice and “all they drop behind them.” When doing home and small office cabling work, nobody really looks at the potential hazards, she says. “Gloves and masks are standard, but I don’t know how much they really protect me.” Now, whenever possible, she subcontracts network cabling work to larger companies.

If an installer encounters a hazardous material, it should be reported and the necessary precautions should be taken. This may involve vacuuming, hosing or otherwise cleaning dust or fibers off of skin or clothes.

But the sad reality is, there is little one can do if contaminated dust or fibers are inhaled or otherwise ingested. The common refrain: “See your doctor.” Minimal exposure to many of the hazardous materials described here should not result in death or serious injury, but any exposure is not to be taken lightly.

Installers also have to be aware of potentially hazardous materials they use on the job, such as plastic conduit and joint compound glues. Such material may cause skin irritation and may emit fumes that should not be inhaled. Gloves, protective clothing and respiratory equipment may be required.

Installers frequently have to place insulation over conductors and seal splices with moisture-proof covering. If such insulation material is hazardous, the installer must wear gloves and appropriate coveralls and possibly a mask or other respiratory equipment.

When it comes to hazardous materials, the bottom line is: the job is not as dangerous as it was 15 or 20 years ago, but that is no excuse for dropping the health and safety guard because hazardous materials are out there. And to avoid risk, building owners, contractors and individual workers should take all necessary precautions to avoid close encounters with such materials.

Paul Lima is a Toronto-based freelance writer. He can be reached online at

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