Mould growth potential in the aftermath of storms

It may have been a flood; perhaps even a hurricane. The potential for harm from temporary fury unleashed is clear: downed communication devices, damaged infrastructure, and losses of productivity and resources.

But what about the calm after the storm, that time of clean-up, maintenance and normalization that may produce long-term concern in the form of mould?

Since water is an essential ingredient, mould can easily grow in flood-related conditions, namely standing water, humid air and wet surfaces, notes a statement from the American Society of Safety Engineers in Des Plaines, Illinois. And the longer these conditions remain, the more that existing mould can spread.

“For businesses, addressing mould and moisture after a flood disaster should be the first step to reduce the risk to others who may need to work in an affected building,” James Morris, III, an ASSE official and assistant director for the Virginia Beach City Public Schools, says in the statement.

The recommendation of the U.S. Environmental Protection Agency (EPA) in Washington, D.C.? Consider as potentially contaminated any surface that has been wet by clean water for longer than 48 hours; if there has been any contact with “dirty water,” consider the surface to definitely be contaminated.

Even without a flood, measures should be adopted to reduce the chances of a mould colony establishing itself on the job. A guide developed by the Occupational Health and Safety Division of Saskatchewan Labour Relations and Workplace Safety and Saskatchewan Health states that mould needs a few things to gain a foothold: a food source (such as cellulose and other carbohydrates in structural materials like ceiling tiles, ventilation insulation, wood, wallpaper or fabric); a place to grow (mostly in darker areas); and a source of moisture.

People with asthma, bronchitis, hay fever and other allergies, or who have weakened immune systems, are more likely to react to mould, notes an alert from Ontario’s Ministry of Labour (MOL) in Toronto. Common symptoms include runny nose, eye irritation, skin rash, cough, congestion and aggravation of asthma, the alert says.

When mouldy material becomes damaged or disturbed, the MOL notes that spores can be released into the air, causing exposure when inhaled. 

Of course, not every exposed person develops symptoms. This “depends on the characteristics of the mould, the degree of exposure and the susceptibility of the exposed individual,” adds the Saskatchewan guide.

Oftentimes, moulds are invisible to the eye. If a fuzzy or slimy blotch of black, grey, white, red, orange, yellow, blue or violet is visible, mould growth is already widespread.

The MOL alert notes that “the sustained and/or extensive growth of any visible mould on the interior surfaces of a building is unacceptable.” And the Saskatchewan guide suggests that certain signs are cause for concern:

• building materials or furnishings have visible mould;
• moisture problems have gone untreated; and,
• occupants have been medically diagnosed with building-related illnesses (and all other such causes have been eliminated and a health professional suspects mould exposure).

Preventive steps are necessary since moulds are not picky about where they set up shop. They can grow on virtually any substance – think wood, paper, carpet or food – providing that moisture is present, adds the EPA.