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What is Occupational Hygiene?

Geozone Environmental is involved in the anticipation, recognition, evaluation and control of occupational health hazards. The Occupational Health and Safety Act (OHSAct) places the onus on employers to ensure that the working environment is safe and without risks to the health of their employees.

In order to accomplish this, employers must, through the services of a competent person, assess the exposure of their employees to hazardous environmental conditions in the workplace.

Where an assessment indicates an on-going risk from exposure, these exposures must be measured and the results compared to prescribed standards. Steps must then be taken to comply with the provisions of the OHSAct. This process, known as monitoring, must be performed or verified by an Approved Inspection Authority.


Noise Surveys

Comprehensive noise surveys are conducted in accordance with the SANS 10083 – as required by the Noise Induced Hearing Loss Regulations (OHSAct). Ambient noise surveys are conducted in accordance with SANS 10328 and SANS 10103.

Airborne Contaminant Survey

Personal air sampling surveys are performed in order to assess worker risks of exposure to airborne contaminants in accordance with Regulation 6 of the Hazardous Chemical Substances Regulations (OHSAct) and HSE Guidance Note EH42. Reference is made to internationally accepted sampling methodologies which are in full compliance with legislative requirements.

Ventilation Survey

The effectiveness of Local Exhaust Ventilation (LEV) systems is formally assessed by measuring the face velocities and capture velocities generated by these systems. The results are compared to relevant Statutory requirements (OHSAct) and to recognised ventilation standards as published by the American Conference of Governmental Industrial Hygienists (ACGIH).

Illumination Surveys

Illumination surveys are performed in accordance with SANS 10114 as required by Environmental Regulation 3 of the OHSAct.

Ergonomics Risk Assessments

The Ergonomics Regulations were promulgated in December 2019 with the due date for implementation by June 2021.

Comprehensive ergonomics risk assessments are conducted using established National Institute of Occupational Safety and Health (NIOSH) and Occupational Safety and Health Association (OSHA) guidelines. The field of ergonomics is all encompassing and includes all physical, chemical and ergonomic stressors to which employees may be exposed during the course of their work. On-site ergonomics assessments are conducted during which time ergonomics checklists are completed. These checklists allow the investigator to work systematically through a detailed list of potential ergonomic stresses and note any deviations present within a particular working environment.

Indoor Air Quality Assessments

Comprehensive assessments of Indoor Air Quality (IAQ) are performed, including:

  • % CO2 concentration in ambient air
  • PM10 dust concentrations in ambient air
  • Relative Humidities
  • Ambient air temperatures
  • Airborne volatile organic substance concentrations (non-specific)

The findings are compared to internationally accepted IAQ standards

Thermal Stress Assessments

Thermal stress (cold stress and heat stress) surveys are performed in accordance with the requirements of Environmental Regulation 2 of the OHSAct. Reference is also made to the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs) which account for the impact of clothing ensembles and worker metabolic work rates on worker risk of exposure to thermal stress conditions.

Hazardous Chemical Agents Risk Assessments

Comprehensive Hazardous Chemical Agents (HCA) Risk Assessments are performed in accordance with the requirements of the Regulations for Hazardous Chemical Substances (OHSAct) These HCA Risk Assessments include:

  • The health effects (consequence) associated with exposure to each HCS
  • The potential frequency of employee contact with each HCS
  • The potential degree of employee contact with each HCS (risk of employee exposure)
  • The potential route(s) of exposure to each HCS
  • The suitability and effectiveness of existing control measures (including PPE)

Health Risk Assessments (HRA)

It is a requirement of the OHSAct for employers to conduct health risk assessments (HRA) for their workplaces. Geozone conducts comprehensive HRA for workplaces in which cognisance is taken of all existing and potential occupational hygiene stressors – i.e:

  • Chemical stressors (hazardous chemical substances)
  • Physical stressors (noise, thermal stress, illumination)
  • Ergonomic stressors (manual materials handling, lifting, repetitive work)
  • Biological stressors (hazardous biological agents)
  • Psychosocial stressors

Using a risk rating matrix, stressors are qualitatively evaluated based on frequency of employee exposure, duration of exposure and consequence of exposure. The derived health risk ratings are categorised into low, medium or high risk ratings per activity area, to allow for identification and prioritisation of the highest health risks on site. Cognisance is also taken of the following:

  • Existing engineering controls on site (general and local exhaust ventilation etc)
  • Existing administrative controls in place (job rotation, work:rest regimens etc)
  • Existing personal protective equipment

The appropriateness of these control measures is qualitatively assessed vv identified risks.

Based on the findings of the HRA, recommendations are made with regard to the need for employers to conduct additional (quantitative) occupational hygiene surveys in accordance with OHSAct requirements.

Asbestos Abatement Regulations

Asbestos risk assessments must be performed by a suitably competent person and must adequately categorise the risks of exposure to airborne asbestos fibres associated with each identified task. Asbestos risk assessments must be reviewed by a competent person every 24 months and subject to review and endorsement by an approved inspection authority every 6 years.

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