Clearing the air on workplace exposure standards

The airborne hazardous chemicals workplace exposure standards are under review. Safe Work Australia Director Occupational Hygiene Policy Jackii Shepherd talks us through some of the changes and the review process.

Workers across many industries and occupations are routinely exposed to airborne hazardous chemicals in the form of fumes, gases, vapours or dust. The health risks associated with chemical exposure range from an immediate, acute impact through to long-term adverse effects — which can take years or decades to present in some instances.

The level of exposure is determined by three factors: a) chemical concentration in the air; b) exposure time; and c) effectiveness of implemented controls.

In Australia, published standards dictate the legal concentration limit of a chemical that must not be exceeded in the workplace. The workplace exposure standards (WES) are maintained by Safe Work Australia (SWA) and currently cover around 700 chemical substances. While the standards prescribe airborne concentrations of a chemical that are not expected to cause adverse effects on the health of an exposed worker, some individuals may experience adverse health effects at lower levels.

SWA commenced a thorough consultation and review process to examine the role of WES, which will culminate in the December 2019 publication of revised WES for airborne contaminants. The review is intended to ensure standards are based on the highest quality evidence and that development is supported by a rigorous, scientific approach.

Heading up the task is Jackii Shepherd, Director Occupational Hygiene Policy at SWA, and we spoke with her to gain some insight into the review intention and process. From her perspective, it’s important to recognise how WES fit in with general duties under the model work health and safety laws.

“Although the review is being carried out, WES don’t sit in isolation. They are part of the broader primary duties and general duties approach under which persons conducting a business or enterprise (PCBUs), eg, employers, must ensure the safety of their workers. The elimination of a hazard is still the optimum outcome, with minimisation through implementing the hierarchy of controls the goal only when elimination is not possible. PCBUs must be aware that the standards do not indicate acceptable exposure levels of hazardous chemicals, they are the maximum allowable limit as prescribed by legislation,” Shepherd said.

Why the review?

Given that several hundred chemicals are already covered by the standards, what has triggered the review?

“Since implementation of the standards in 1995, there has been significant change. Firstly, our understanding has evolved, and we now know much more about these chemicals and their subsequent impacts on health — both chronic and acute effects.

“Another major change is in the chemicals themselves. In the last 20-odd years, there has been marked development and evolution; new synthetics, new forms and new combinations. In the chemicals manufacturing industry, particularly, that change has been rapid.

“The review and reworking of existing standards will enable us to integrate all of the available information and to make it more robust and meaningful,” Shepherd said.

Part of that integration is inclusion of notations that provide information about GHS (Globally Harmonized System of Classification and Labelling of Chemicals), which came into effect 01 January 2017.

Image credit: ©stock.adobe.com/au/Scriblr

“The inclusion of notations makes it simpler for employers to put meaningful controls in place and for employees to understand why those controls are there. For example, if a substance is identified as carcinogenic or known to cause skin and respiratory sensitisation, that information is easily seen and the reason for high-level controls automatically makes sense.

“The WES are not a dividing line between a healthy and unhealthy workplace and some workers may still feel adverse effects at lower exposure levels. By integrating information about the hazardous chemicals at a workplace and clearly presenting it, we’re aiming to deliver better outcomes for workers,” Shepherd said.

The approach

This is clearly a mammoth undertaking, requiring a rigorous and systematic approach. SWA is utilising publicly available information from trusted domestic and international sources as a basis. Evaluation of that information will drive recommendations for change.

“There are many international and domestic organisations that we are looking to. For some, evaluating data to establish or amend a WES is all they do. We’ve developed a methodology that uses their work in a holistic way to help determine an appropriate standard,” Shepherd said.

Primary data sources include:

• American Conference of Governmental Industrial Hygienists (ACGIH) — Threshold Limit Values (TLV)
• Deutsche Forschungsgemeinschaft (DFG) — Maximum workplace values (MAK values)
• EU Scientific Committee on Occupational Exposure Limits (SCOEL) — Occupational exposure limits (OEL)
• American Industrial Hygiene Association/Occupational Alliance for Risk Science (AIHA/OARS)
• Health Council of the Netherlands (Dutch Expert Committee on Occupational Safety)
   

“We’re using only identified and trusted sources of data, evaluating that information and putting it all together to determine the best standard for Australian workplaces. Each organisation uses their own method for making decisions and comes at it from a slightly different angle. Where there is any uncertainty or data gaps, we can draw on identified secondary sources for additional information,” Shepherd said.

Then it’s on to individual chemical evaluations, which will also incorporate an independent peer review. This process will result in recommendations for the WES values, notations and the list of chemicals. Once approved by SWA members, the new standards and supporting information will then be published in individual evaluation reports for each chemical.

The upshot

Any industry or workplace where airborne hazardous chemicals are found will be impacted by the changes, including those featuring substances previously not covered by existing WES.

“We’ve been able to identify new chemicals and will be looking at adding them to the list. For example, substances like polycyclic aromatic hydrocarbons (PAHs) and diesel emissions around roadworks and peracetic acid used in poultry and fruit production are now on the radar,” Shepherd said.

Jackii Shepherd, Director Occupational Hygiene Policy, Safe Work Australia.

Evaluations are expected to be finalised mid-2019, and a public consultation period due to run between January and August 2019. It is intended that the final revised standards will be published in December of the same year. For further information, including a full list of chemicals under review, consult the SWA website.

Top image credit: ©stock.adobe.com/au/Athipat