SHS972 – Assignment 1
Workplace exposure standards in Australia are currently recognised by Safe Work Australia (SWA). Safe Work Australia was formerly identified as:
• The Australian Safety and Compensation Council (ASCC), 2005-2009 • The National Occupational Health and Safety Commission (NOHSC), 1985- 2005
NOHSC was initially assigned the task of assessing and setting workplace exposure limits for Australia. The exposure database NOHSC employed was originally obtained from:
• The American Conference of Industrial Hygienists (ACGIH) • The United Kingdom Health and Safety Executive (HSE)
The initial exposure limits were acquired from these organisations because of the wealth of experience and research that both America and the UK had with occupational exposures. The ACGIH specified exposure limits as Threshold Limit Values (TLV). These values were derived from animal and human research as well as industry knowledge and epidemiology.
Safe Work Australia creates exposure standards based on a range of information from work health and safety statistics to continuing formal research on exposures to substances found in the workplace. A significant increase in harmful health effects from a specific substance through statistical analysis prompts SWA to assess the current exposure limit to determine whether it needs to be controlled to protect the workforce. Proposed exposure limit changes are then put out into the community for feedback.
Exposure Standards listed under the NOHSC Adopted National Exposure Standards for Atmospheric Contaminants in the Occupational Environment (NOHSC: 1003, 1995) are then used as the limits for exposures in the workplace.
Where the government determines there to be a significant risk to workers, exposure limits are drawn up into legislation such as Acts and Regulations. This can be specific such as the case of lead which has an exposure limit of 1.45 μmol / L (30μg / dL) detailed in part 7.2 of the Model Work Health and Safety Regulations 2011. Exposure limits may also be called up into legislation through standards such as the Adopted National Exposure Standards for Atmospheric Contaminants in the Occupational Environment (NOHSC: 1003, 1995) which is also referred to in chapter 7 of the Regulations 2011.
Question 2: Part A
Dusts in the workplace may have negative effects on the health of workers if inhaled. These dusts range in size from 1μm to 100μm in diameter (Tillman, 2007). ISO 7708:1995 details the three size fractions of dust for health related sampling which are:
• Inhalable fractions: Inhalable fractions have an aerodynamic diameter of less than 100μm. Inhalable dust is airborne material that enters through the nose or mouth and deposits in the respiratory tract.
• Thoracic fractions: Thoracic fractions have an aerodynamic diameter of less than 10μm. This fraction has the ability to enter through the nose and throat and deposit in the respiratory tract and parts of the lungs such as the bronchi. • Respirable fractions: Respirable fractions have an aerodynamic diameter of less than 5μm. Respirable dust has the ability to penetrate deep into the lungs where gas exchange takes place. As such, respirable dust also has the ability to enter the blood stream through the lungs.
The size of a dust particle depends on the type of material and work process being used. In terms of health effects, dusts are usually classified as inhalable and respirable for measurement purposes in the workplace. Thoracic fractions are covered by the inhalable fraction.
Inhalable dusts with a large diameter (up to 100μm) deposit in the throat, nose and upper airway. Inhalable dusts can irritate these structures in the airway or have immediate toxic effects. During the past thirty years, wood work has been recognized as a source of respiratory diseases (Monier, Hemery, Demoly, and Dhivert- Donnadieu, 2008). Wood dust is an inhalable dust which can...
References: Busick, J 2011, ‘Crystallizing General Industry 's Approach to Crystalline Silica’, Safety Compliance Letter, no. 2528, p. 5.
National Occupational Health and Safety Commission (NOHSC) 1995, ‘Adopted National Exposure Standards for Atmospheric Contaminants in the Occupational Environment’, (NOHSC: 1003), accessed 16 September 2012.
Skovsted, TA, Schlünssen, V, Schaumburg, I, Wang, P and Skov, PS, 2000, ‘Hypersensitivity to wood dust’, Allergy, ISSN 1398-9995, 11/2000, vol. 55, no. 11, p. 1089.
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