In New Zealand, the Occupational Exposure Limits are called Workplace Exposure Standards (WES). These include Time Weighted Averages (TWAs), Short Term Exposure Limits (STELs) and Ceiling Limits. There are also Biological Exposure Indices (BEIs). A new WES/BEI book comes out most years showing any new or revised WES or BEI. Not all WES/BEI are reviewed each year, and substances chosen for review are prioritised according to available resource to carry out a review. The reviews and WES/BEI lists are administered by WorkSafe New Zealand, the health and safety regulator. WorkSafe is a Crown agency with a governance board whose members are appointed by New Zealand’s Minister for Workplace Relations and Safety.
Workplace Exposure Standards are almost all health-based guidelines for airborne contaminants and are endorsed by WorkSafe New Zealand. Many substances with WES are approved substances under the Hazardous Substances and New Organisms (HSNO) Act 1996.
The exposure limits are prepared by an expert committee (WES review committee) consisting of specialists from WorkSafe New Zealand and external toxicologists, and medical/scientific experts as required. The committee considers documentation from such organisations as the American Conference of Governmental Industrial Hygienists (ACGIH, US), the Health and Safety Executive (HSE, UK), Safe Work Australia, the Dutch Expert Committee on Occupational Safety (DECOS, Netherlands), Nordic Expert Group and MAK (Germany).
The WESs are intended to be used as guidelines for those involved in managing health risk in workplaces in accordance with the Health and Safety at Work Act (2015) and its regulations. A person conducting a business or undertaking is required to ensure so far as is reasonably practicable the health and safety of workers and other persons at a place of work.