Wood, upholstery and ceiling tiles are just a few places where dangerous mould could be hiding
In December 2013, a vicious ice storm swept across Eastern Canada, from Ontario to the Maritimes. Frozen and burst pipes, water leaks, broken drainage systems, roof destruction and flooding were just some of the issues it left in its tracks, causing a total of $3.2 billion in damages, according to the Insurance Bureau of Canada.
Whether it’s a natural disaster or a run-of-the-mill water leak, employers might find themselves with a lingering problem: mould.
There are many varieties of mould, with many varying effects. We eat mould (such as blue cheese). We make medicine from fungus (such as penicillin). But some forms
produce dangerous mycotoxins — toxins that slowly wear down the immune system, which can lead to respiratory problems.
Moisture or high-humidity environments can result in the growth of mould, fungus or yeast, and that can pose a serious hazard in the workplace.
And exposure to a biological contaminant is a personal hot button to most people. If people think they’re breathing something that’s unsafe, they tend to have a strong emotional reaction, says Christopher Liddy, occupational health and safety specialist with the Hamilton, Ont.-based Canadian Centre for Occupational Health and Safety (CCOHS).
In most cases, someone who reacts to mould will experience asthma-like symptoms: runny nose, nasal congestion, eye irritation, cough or congestion, rashes, headaches, fatigue or the aggravation of asthma.
In rare cases it can lead to hypersensitivity meningitis (scarring of the lungs). In other cases, there are no symptoms whatsoever.
But workers with a poor or weakened immune system (such as someone going through chemotherapy) could be at risk of developing a fungal infection.
Regardless, “you don’t want to have an office where you have a sinus headache all the time,” says Bruce Stewart, senior vice-president, indoor air quality and laboratory services, at Pinchin Environmental in Mississauga, Ont.
Compared to hazards like asbestos, which can cause disease 30 years later, exposure to mould will have an immediate health effect, he says.
But mould is fairly ubiquitous in that it’s almost everywhere — there are mould spores in the air we breathe, says Liddy. To be a problem in a building, there has to be the presence of mould combined with a source of nutrient and moisture. Unlike many chemicals, there isn’t always a cut-and-dry answer about how to handle it and determine if it is dangerous or not.
“There does tend to be a perception that there is one type of mould — it’s black and it’s really bad,” says Liddy. “(But) there’s so much variation.”
There’s no magic number, no safe or unsafe level, adds Weston Henry, principal and senior occupational hygienist at Safetech Environmental in Mississauga, Ont.
Assessing the workplace for mould often comes down to comparison sampling and interpretation of results, says Henry. But because mould can vary over space and time — some become active at certain times of the day or certain periods of the year — employers can’t haphazardly collect samples, says Liddy. That further complicates the issue.
He recommends developing a sampling plan. For instance, if there was a water leak in the building last week and you suspect there might be mould causing symptoms in employees, test that theory by taking samples, testing the air and testing the wall to see if there’s moisture.
Consider hiring a consultant because this process could involve employees divulging personal medical information, says Liddy.
Consultants also rely on visual assessment activities, such as signs of water damage, staining and peeling.
But mould doesn’t have to be visible to cause problems.
You might not see anything on the surface of the wall, but the back of the drywall might be covered in mould, which could be causing an issue for some individuals, says Henry.
In many cases, consultants use a moisture meter to take readings of drywall, wood framing or flooring surfaces. They may even use thermal imaging cameras for a recent flood or leak.
Mould can also hide in upholstery, fabric and drapery, under carpeting, behind wallpaper, on ceiling tiles, around leaking pipes, even inside ductwork. But finding hidden mould is tricky; if disturbed, it could release spores.
Even if it’s dead, mould can still be hazardous; it can contain mycotoxins, even if it’s not giving off spores.
Typically, there will be more than one type of mould present. When Pinchin consultants analyze mould growth back in the lab, they often find many types of mould growing on the same material, says Stewart.
Because there are no federal Canadian regulations for mould, many professionals follow guidelines for assessment and remediation from the Environmental Protection Agency, American Industrial Hygiene Association and the New York City Department of Health, as well as Mould Guidelines for the Canadian Construction Association.
Cleaning up mould isn’t straightforward either.
Controls vary on the level of infestation, as well as other factors. In general, a minor cleanup could involve using a disposable respirator, glove and eye protection. For larger remediation projects, most experts advise hiring a trained professional. This could involve isolating the
space with plastic sheeting, sealing ventilation ducts and using an exhaust fan with a HEPA filter to create
It also depends on the site itself. Is it in a children’s cancer ward or in an unoccupied parking lot? Is it on a piece of metal (where you can unscrew it and carry it out of the building) or is it growing on the carpet that’s glued to the floor (which means if you shred the carpet, it could spread spores)?
During remediation, employers might consider using materials that are less susceptible to mould, such as drywall with fiberglass backing. But it may involve more extensive work, such as re-insulating the building or waterproofing the foundation.
Yet another issue is that mould removal is not a regulated profession, so it’s buyer beware when hiring a consultant or remediation contractor, says Liddy. Sometimes they’ll give advice but not specific recommendations.
Liddy recommends reviewing several consultants based on education and experience; some may be a certified industrial hygienist with a PhD and 20 years’ experience, while others may have taken a weekend course.
Once removed, measures should be taken to prevent the mould from returning. Know the risk factors: water leaks, condensation, humidity or moisture, says Liddy. Building maintenance staff or other appropriate workers should also be trained to identify risks.
Employers should ensure they control humidity with air conditioners or dehumidifiers; keep the building’s HVAC systems in good repair; insulate cold surfaces to prevent condensation on piping, windows, exterior walls, roofs and floors; clean up any floods immediately (within 24 to 48 hours); and do not install carpet around fountains, sinks, bathtubs, showers or directly on top of concrete floors that are prone to leaks or condensation.
If underlying issues are not addressed, the mould will likely come back.
“I have consulted with a few organizations where that happens,” says Liddy. “The organization has spent large sums of money, lost productivity, goes through this hassle — and then they have to go through it again.”
Vawn Himmelsbach is a freelance writer based in Toronto. She can be reached at firstname.lastname@example.org.