Silicosis

Silicosis

Silicosis is a respiratory disease caused by inhalation of silica dust, which leads to inflammation and scarring of the lung tissue.

Three types of silicosis are seen:

Simple chronic silicosis : Results from long term exposure (more than 20 years) to low amounts of silica dust. Nodules of chronic inflammation and scarring provoked by the silica dust from in the lungs and chest lymph nodes. This diseases may feature breathlessness and may resemble chronic obstructive pulmonary disease (COPD)

Accelerated silicosis: Occurs after exposure to larger amounts of silica over a shorter period of time

(5 - 15 years). Inflammation, scarring and symptoms progress faster in accelerated silicosis than in simple silicosis.

Acute silicosis: Results from short-term exposure to very large amounts of silica. The lungs become very inflamed and may fill with fluid, causing severe shortness of breath and low blood oxygen levels.

Causes of Silicosis

Silica is a common, naturally-occurring crystal. It is found in most rock beds and forms dust during mining, quarrying, tunneling and work with many metal ores. Silica is a main component of sand, so glass workers and sand-blasters also receive heavy exposure to silica.

·         Caused by breathing small particles of crystalline silica.

·         Afflicts thousands of miners and millions of other workers engaged in hazardous dusty occupations

·         One of the most dangerous occupational health problems in the world.

Mechanism of Silicosis

·         Airborne silica dust enters the body primarily by inhalation.

·         The inhaled air passes through the upper airways, the trachea, bronchi and smaller branches eventually reaching the bronchioles and in the alveoli (or small airways)

·         These particles cause “fibrosis” or scar tissue formation in the lungs.

·         It then causes the lung tissue to form nodules.

·         As the disease progresses, the silicotic nodules merge and form a continuous mass of fibrotic tissue called progressive massive fibrosis.

·         These are responsible for cancer.

·         This also reduces the lung’s ability to extract oxygen from the air.

Symptoms:

·         Shortness of breath with exercise, usually in patients who have progressive massive fibrosis.

·         Chronic cough

Additional symptoms that may be associated with this disease, especially in acute silicosis:

·           Fever

·           Cough

·           Weight loss

·           Severe breathing difficulty

Respirable Concrete Dust – Silicosis Hazard in Construction Industry

Activity studied:

·         Abrasive Blasting

·         Concrete pavement Sawing and Drilling

Asphalt or concrete milling

Recommendations:

·         Power tools and equipment used to disturb silica containing materials must be designed to allow workers to operate them safely.

·         Need to eliminate the abrasive blasting of concrete.

·         In concrete drilling water should be used through the drill stem and high velocity dust collection systems should be used.

·         Similarly in asphalt or concrete milling water spray system should be used.

·         Tools and equipment should be developed to effectively capture the dust generated.

·         Provide appropriate personal protective equipment (PPE) such as Respirators

·         Workers should wear washable or disposable protective clothes and should shower and change before leaving the worksite.

·         Medical examinations, including periodic x-rays, should be provided to all workers who are potentially exposed.

·         Workers should practice good personal hygiene to prevent unnecessary exposure. Workers should wash their hands before eating, drinking etc.

  “Carelessness doesn’t bounce; it shatters”