OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 4 Chemical Hazards, Biological Hazards and Harmful Substances

Section 43.1 Controlling mould exposure

Mould is found almost everywhere in our environment. Mould needs the right combination of water, nutrients and a suitable temperature to grow. Moulds are often relatively harmless e.g. Cladosporium or common “leaf mould”. Moulds can also be useful, as in the preparation of foods and medications. In other circumstances however, they may pose a health hazard.

The presence of mould at the work site does not mean that it is a hazard to workers. The first step in determining whether or not mould poses a hazard to workers is to conduct a hazard assessment as required by section 7. This may include a thorough assessment of the work space where the issue is or may be a concern. A request for a mould assessment is usually prompted by indoor air quality complaints, an uncontrolled water intrusion event or observed visible mould growth.

The requirement to control mould in accordance with section 9 is based on the results of the hazard assessment. Employers will need to control mould exposure when:

(1) visible uncontrolled mould growth or elevated airborne mould concentrations (compared to a control area such as outdoors) are present, but cannot be immediately remediated. This may include situations where remediation is planned at a later date or the contamination is not readily accessible without significant damage to the building;

(2) mould clean-up or abatement is actively being conducted in the building; or

(3) workers are medically diagnosed as having adverse health effects consistent with mould exposure at the workplace, even though visible mould growth and/or conditions likely to support mould growth such as damp indoor conditions are not readily apparent.

The types of controls implemented – engineering, administrative or personal protective equipment – will be based on where mould is present and who may be affected by exposure. Note that the prevention of mould growth as a proactive step is the most effective way to manage potential mould hazards at a work site. Because mould spores can be found almost everywhere, the key to preventing mould growth is to limit the availability of water. This is done by keeping building materials dry. Mould cannot be effectively managed at a work site unless the conditions that created the initial mould growth are addressed.

For more information
Best Practice – Mould at the Worksite