Occupational Hygiene and Workplace Monitoring Services

Comprehensive Occupational Hygiene Assessments

Our highly skilled team conducts comprehensive Occupational Hygiene assessments to identify workplace hazards, potential exposure risks, and to recommend appropriate control measures. Ensure a safe and healthy work environment for your employees with Opterra’s expertise.

Workplace Air Quality Monitoring

We offer Workplace Air Quality Monitoring services to assess indoor air quality, ensuring a comfortable and healthy atmosphere. Our monitoring solutions identify pollutants and provide data-driven recommendations for improved air quality.

Noise Monitoring and Control

Opterra conducts Noise Monitoring and Control assessments to evaluate noise levels in your workplace. With our recommendations, you can implement effective noise control measures, protecting employees from noise-related health issues.

Personal Exposure Monitoring

Using advanced monitoring techniques, Opterra conducts Personal Exposure Monitoring to assess individual exposure to hazardous substances. We help you mitigate risks and ensure compliance with safety regulations.

Respirable crystalline silica monitoring

Since 1 September 2024, a business that processes any material containing at least one per cent crystalline silica has had to assess whether that work is high risk. Where it is, the duties are specific: a written silica risk control plan before the work starts, accredited training for the workers involved, air monitoring, and health monitoring. In NSW those workers must also be recorded on SafeWork NSW’s Silica Worker Register, which has been mandatory since 1 October 2025.

The workplace exposure standard for respirable crystalline silica is 0.05 mg/m³ over an eight hour shift. The risk assessment turns on a lower figure again, because it asks whether airborne silica is reasonably likely to exceed half that standard, and it has to be made without counting respirators or administrative controls. In practice that is not a question a business can answer from the office, which is where personal exposure monitoring comes in.

Opterra samples in the worker’s breathing zone and uses NATA accredited laboratories for analysis. We carried out this assessment for the stonemasons at Rookwood General Cemetery, where our recommendations covered local exhaust ventilation, water suppression, personal protective equipment and decontamination.

Welding fume monitoring

Welding fume has been classified by the International Agency for Research on Cancer as a Group 1 carcinogen, carcinogenic to humans, since 2017. In January 2024 the Australian workplace exposure standard for welding fumes not otherwise classified was cut from 5 mg/m³ to 1 mg/m³, a fivefold reduction that took effect immediately in NSW. The standard for aluminium welding fume was reduced to the same figure in November 2025.

Total fume is only half the question. Each component carries its own exposure standard, and which ones matter depends on what is being welded and what it is coated with: manganese, hexavalent chromium and nickel from stainless steel, zinc from galvanised sections, ozone and nitrogen dioxide from the arc itself.

From 1 December 2026 the exposure standards are replaced by workplace exposure limits, and two changes land on welding at once. Hexavalent chromium moves onto the non-threshold genotoxic carcinogen list and loses its numerical limit altogether, so “below the standard” stops being an available answer and the duty becomes reducing exposure so far as is reasonably practicable. Nickel metal drops from 1 mg/m³ to 0.1 mg/m³ on the same day.

Opterra measures welding fume exposure in the breathing zone, tests for the specific metals present rather than total fume alone, and reports on whether the ventilation and respiratory protection in place are doing the job they are relied on to do.