Processes or equipment at your workplace can produce airborne contaminants that can be hazardous to someone’s health. For example:
- welding can generate fumes and other substances
- truck engines may omit diesel exhaust fumes
- grinding metals may release toxic metal dust or fume
- manufacturing wood products can involve solvent vapours from glues.
How people are exposed
You can be exposed to substances and mixtures by breathing them in, absorbing them through your skin, or ingesting (swallowing) them.
Most exposure occurs through inhaling vapours, dusts, fumes or gases. For some chemicals, absorption through the skin may also be a main source of exposure.
How people are affected
How your body responds to exposure to substances and mixtures depends on:
- the nature of the substance
- the health effects it can cause
- the amount of the substance or mixture absorbed by your body.
People can have differing abilities to metabolise chemicals, so everyone can be affected differently.
The extent to which someone is exposed depends on:
- the concentration of the substance or mixture in the air
- the amount of time they are exposed to it
- the effectiveness of risk controls.
Substances and mixtures may cause immediate and negative health effects or it may be decades before these effects show up.
To understand what airborne contaminants are, how they are generated and their health effects on a person, let’s look at welding.
Welding can generate fumes, mists, dust, vapours and gases. The amounts and types of fumes produced vary greatly, depending on the process involved and the materials being used such as metals, solvents, flux, paint and plastics.
The health effects of exposure can include irritation of the upper respiratory tract (nose and throat), tightness in the chest, asphyxiation, asthma, wheezing, metal fume fever, lung damage, bronchitis, cancer, pneumonia or emphysema.
Some welding fumes are easy to see. However, many fumes, mists, dust, vapours and gases are invisible.
Under the work health and safety laws, there are specific requirements to manage risks arising from exposure to chemicals.
These risks are best managed according to Safe Work Australia guidance material. See Exposure standards below.
There are a number of regulations must be complied with. Under most conditions, if you’re a person conducting a business or undertaking (PCBU), these regulations aim to ensure you:
- manage risks associated with using, handling and storing hazardous chemicals safely, including airborne contaminants
- make sure no one at your workplace is exposed to a substance or mixture in an airborne concentration that exceeds the exposure standard for that substance or mixture
- ensure air monitoring is carried out to determine the airborne concentration of a substance or mixture at the workplace that an exposure standard applies to
- ensure air monitoring results are recorded and kept for 30 years and readily accessible to anyone at your workplace who may be exposed to the substance or mixture.
Exposure standards state airborne concentrations of a particular substance or mixture that must not be exceeded. There are three types of exposure standard:
- 8-hour time-weighted average: the average airborne concentration of a particular substance permitted over an 8-hour working day and a 5-day working week
- peak limitation: a maximum or peak airborne concentration of a particular substance determined over the shortest analytically practicable period of time which does not exceed 15 minutes
- short term exposure limit: the time-weighted maximum average airborne concentration of a particular substance permitted over a 15-minute period.
Exposure standards are based on the airborne concentrations of individual substances which, according to current knowledge, should not cause adverse health effects or cause undue discomfort to nearly all workers.
Chemicals with workplace exposure standards are listed in Safe Work Australia’s workplace exposure standards for airborne contaminants produced. See Resources below.
WorkSafe Tasmania resources
Workplace exposure standards for airborne contaminants: Safe Work Australia (external link) and Changes to the workplace exposure standard for respirable crystalline silica: Safe Work Australia (external link)