Advisory notations for sensitisers in the Workplace exposure limits for airborne contaminants

The Workplace exposure limits for airborne contaminants (WEL list) includes advisory notations for some airborne contaminants, in addition to the mandatory exposure limits. These advisory notations provide information about additional risks that some airborne contaminants pose. 

New advisory notations for substances that can cause sensitisation have been introduced for some airborne contaminants in the WEL list. Sensitisers are substances which cause a specific immune response in some people, like an allergic reaction, which is called ‘sensitisation’. Sensitisation can either occur when workers are exposed:

• to a substance over time (even at low concentrations), or
• for some substances, after a single high-level exposure.

Sensitisers are divided into 2 categories:

• Dermal (skin) sensitisers (‘DSEN’): substances that can cause an allergic response after contact with skin.

• Respiratory sensitisers (‘RSEN’): substances that can cause hypersensitivity of the airways after inhalation. 

A person conducting a business or undertaking (PCBU) must eliminate or minimise the risks from sensitising substances in the workplace, so far as is reasonably practicable. Once sensitised, a worker may react to the chemical, even when airborne concentrations of the chemical are below the exposure limit. In these circumstances, sensitised workers must not be exposed further to the chemical. 

For more information on managing the risk of chemical exposures, see the model Code of Practice: Managing risks of hazardous chemicals in the workplace.

Related information

• Workplace exposure limits for airborne contaminants (WEL list)
• Airborne contaminants
• model Code of Practice: Managing risks of hazardous chemicals in the workplace
• Resources in this collection