Standardization of Cab Air Quality - Defining Dust - Part 3

I recall getting the call to come to a coal mine and conduct a review of it’s Management System. A coal miner had been diagnosed with simple pneumoconiosis during routine health surveillance. He had been working in the mining industry for 15 years.

Exposures to dust based on the type (toxicity) and level (amount) can result in both short-term term (acute) and long long-term (chronic) occupational illness and disease. Continuous dust exposures can lead to lung diseases, including,

• Coal worker pneumoconiosis;

• Mixed pneumoconiosis;

• Silicosis;

• Asbestosis;

  • chronic obstructive pulmonary disease (COPD):

  • chronic bronchitis;

  • emphysema;

  • lung cancer.*

*Lung cancer may also have non-occupational causes but may be caused by carcinogens in the mine atmosphere, including respirable silica dust, diesel exhaust emissions, and welding fumes.

Dust lung diseases such as pneumoconiosis result from respirable dust causing damage to the fine structures in the alveolar spaces. Particles become trapped in the tissue, causing irritation and triggering a response from the immune system.

Immune cells repeatedly try to heal the irritated area, and small nodular scars begin to form. This is called fibrosis. If enough scar tissue forms, lung function can be reduced.

Chronic obstructive pulmonary diseases (COPD) differ from pneumoconiosis in how they damage the lungs. Instead of causing nodular scars, the air passages and air sacs of the lungs become inflamed and damaged. (Tobacco smoking also causes COPD).

All these occupational lung diseases are preventable. Limiting exposure to respirable dust can stop the development of the disease in its early stages.

As we consider standards for operator enclosures (e.g., for mobile equipment), it is essential to ensure the engineering controls recommended by the standard are effective in preventing dust from entering the cab and effective at removing the dust that comes into the cab on the operator or through the open window or door.

Reference: RSHQ Website, www.rshq.qld.gov.au