Mould Inspection and Testing by Occupational Hygienists 

What is mould?

Moulds are naturally occurring microorganisms which belong to the fungi kingdom. They are ubiquitous, meaning they can be found everywhere, and play a vital role in the ecosystem by breaking down nutrients which recycle energy. Some moulds can also produce beneficial by-products such as penicillin, or form part of some foods such as cheeses.

However, some types of mould can produce a secondary toxic metabolite, mycotoxins, which can be harmful. Mould can affect people differently due to individual susceptibility based upon differences in genetic make-up between individuals and the different genera/species of mould.

Those who are immunocompromised such as the elderly, pregnant or those with other underlying health conditions or disease may be more susceptible. Health effects can range from allergy type symptoms including runny nose, lethargy, sneezing, cough, headaches, irritation of the eyes and skin, asthma attacks and respiratory infections.

Unlike other hazards, mould can be a little more difficult to manage as it is a biological agent and people may not be affected the same way.

Mould proliferation is attributed to microenvironmental reservoirs becoming sources of contamination through the accumulation of settled spores and actual growth. Ultimately, growth typically occurs in optimal conditions influenced by three main factors:

• Moisture source;

• Nutrient source; and

• Optimal ambient conditions (temperature, humidity etc.).

The moisture source, often referred to as a water ingress event, may be attributed to an active and recent event such as:

• Heavy rainfall;

• Flooding;

• Sudden failing of pipework integrity; or

• Related to ongoing events such as poor building design resulting in:

• High levels of humidity;

• Rising damp;

• Poor ventilated buildings and subfloors;

• Poorly installed or failing waterproofing; or

• Slow leaks in pipework or plumbing systems.

Typically speaking, elevated moisture should be dried within 24 – 48 hours to mitigate mould growth.

Mould can grow more rapidly on some material types than others as they provide a nutrient source, such as wood, textiles and cellulose-based materials (e.g. paper and cardboard). Settle dust can also be a nutrient source due to organic content.

Optimal ambient conditions can accelerate mould proliferation, particularly when humidity levels are high, which provides a moisture source, and inadequate ventilation (either natural or mechanical).

The key concerns to an individual’s health within an environment where active mould growth is present come from two components of biological contaminants:

1. Mould spores

2. Mycotoxins

What are the most common types of mould?

There are many genera of mould and somewhere between 90,000 and 120,000 species. All can present in many different shapes, sizes, and colours (e.g., white, green, grey or black mould). All may have the ability to produce secondary metabolites, which may or may not affect individuals in a negative way. 

Fungal ecology plays a big factor in mould assessments. Different genera of mould can be associated with higher levels of moisture (water indicators) which can indicate if a site is subject to a recent water ingress event, or if conditions have allowed mould proliferation for a longer time period. 

However, the only way to know exactly which type of mould is present is through sampling and analysis by an accredited laboratory.

What is a mould inspection?

There are two main types of mould assessments that our Occupational Hygiene Consultants can carry out:

• Mould contamination assessment (MCA); and

• Mould post remediation verification (MPRV).

Mould contamination assessment 

This is undertaken to attempt to determine the location and extent of mould contamination. The assessment typically is prompted following a water ingress event, visible mould growth or even from malodours. There is no ‘one size fits all approach’;, each assessment is bespoke for the particular site and client we deliver to. 

Typically, the assessment will start with a site walkover with a client/site representative, where the consultant may ask some questions to understand the site history. A visual inspection will be undertaken to note any visible mould and water staining, etc. A moisture and psychometric assessment will also be undertaken to note down the moisture content of building materials, relative humidity and temperature. This is usually supported with a sampling program which may be airborne and/or surface sampling.

Samples will be submitted to a specialised laboratory for the purpose of mould microscopy analysis. Upon receipt of the results a report will be formalised to detail the findings and any recommendations where applicable.

The assessment process is undertaken in accordance with industry guidance and best practice.

Mould post remediation verification 

This is undertaken following mould remediation works at a site, normally undertaken by an appropriately experienced remediator (typically trained in relation to the IICRC). This is undertaken to assess the efficacy of the remedial works.

The purpose of this assessment is to assess, by similar methods to the contamination assessment, if remedial works were satisfactory to return a site to a ‘pre-event condition’.

What is mould inspection by an occupational hygienist?

At this time in Australia, there are no legislated qualifications or accreditations required to undertake these assessments, therefore it is important that the hygienist and company is both experienced and familiar with these types of assessment.

Mould contamination assessments and mould post-remediation verifications are undertaken by EDP’s Occupational Hygienists, who carry multiple years’ experience in the mould contamination industry. EDP ensures all consultants undertaking these assessments are competent and remain up-to date with relevant industry guidance.

Can I have my house tested for mould?

Mould has the potential to grow in any structure if conditions are correct (source of moisture or humidity and organic material), therefore mould contamination can be found in any building – residential, commercial or industrial.

Due to the huge variance in mould species and genetic variability between individuals, a predisposition to health impacts from the presence of mould may make working or living in a particular place uncomfortable, or even unbearable. Given the amount of time spent in your home, it is important to ensure you are not being exposed to something which will result in a negative impact on your quality of life.

If you have concerns as to active mould growth in your house, either from visual observations or noting a musty malodour, a mould contamination assessment should be undertaken.

Different state regulators have varying guidance in what to do when mould is present in a workplace. As an example, SafeWork NSW states that there is a responsibility for the Person Conducting a Business or Undertaking (PCBU) to mitigate the risk of mould exposure to workers, visitors, and other individuals in a workplace. 

This means that employers have a duty to ensure mould contamination is appropriately addressed in a workplace, such as commercial or industrial buildings.