Silicosis

How silica damages the lungs

Crystalline silica (quartz) is found in sand, granite, sandstone, concrete and especially engineered (artificial) stone, which can contain more than 90 percent silica. When these materials are cut or ground, they release tiny particles that reach deep into the lungs. Immune cells (macrophages) engulf the particles but are damaged, releasing inflammatory chemicals. This triggers nodules of scar tissue that gradually merge and stiffen the lungs, reducing oxygen transfer. The damage continues even after exposure stops.

Who is at risk

• Engineered stone countertop fabrication: an emerging cause of severe, rapidly progressive silicosis in young workers, including cases needing lung transplants
• Construction and demolition: cutting concrete, brick and tiles
• Mining, tunneling and quarrying
• Sandblasting
• Foundries, glass, pottery and ceramics manufacturing
• Hydraulic fracturing (fracking) sand handling
• Dental technicians and jewelry workers in some settings

Dry cutting, poor ventilation and lack of respiratory protection greatly increase risk.

Types of silicosis

Symptoms

Early silicosis often causes no symptoms and is found on chest X-rays. As it progresses:

• persistent cough, with or without sputum
• shortness of breath, first with exercise, then at rest
• fatigue and weight loss
• chest tightness
• in advanced disease: swelling of the legs from heart strain, blue lips, respiratory failure

Complications

• Tuberculosis: silicosis greatly increases TB risk. See tuberculosis.
• Lung cancer: crystalline silica is a known human carcinogen.
• COPD and chronic bronchitis.
• Autoimmune diseases: rheumatoid arthritis, systemic sclerosis, lupus and vasculitis are more common.
• Chronic kidney disease.
• Pulmonary hypertension and right heart failure.
• Collapsed lung (pneumothorax).

Diagnosis

1. Detailed work history: jobs, tasks, duration, dust controls and protective equipment.
2. Chest X-ray: small rounded nodules, often in the upper lungs, and sometimes eggshell calcification of lymph nodes. Read by specially trained B readers for surveillance.
3. High-resolution CT scan: more sensitive for early disease.
4. Lung function tests: may show restriction, obstruction or reduced gas transfer.
5. Tests for TB and autoimmune disease as indicated.
6. Biopsy only if the diagnosis is unclear.

Treatment

There is no treatment that reverses silicosis. Management focuses on slowing progression and treating complications:

• Stop all further silica exposure, which may mean changing jobs; seek advice on workers' compensation.
• Stop smoking.
• Screen for and treat tuberculosis, including latent TB.
• Vaccinations: flu, COVID-19, pneumococcal and RSV as recommended.
• Inhalers for airway obstruction.
• Oxygen therapy for low oxygen levels.
• Pulmonary rehabilitation.
• Lung transplant for selected people with advanced disease.
• Lung cancer screening where eligible.

Antifibrotic medicines used for other lung scarring are being studied but are not proven for silicosis.

Prevention

Silicosis is completely preventable with proper controls:

• Wet cutting and water spray to suppress dust
• Local exhaust ventilation and vacuum dust collection
• Respirators properly fitted and rated for silica, as part of a respiratory protection program
• Using lower-silica materials where possible
• Medical surveillance with chest X-rays and lung function tests
• Compliance with exposure limits: OSHA's permissible exposure limit is 50 micrograms per cubic meter averaged over 8 hours
• No dry sweeping or compressed-air cleaning of dust

Frequently asked questions

What causes silicosis?

Silicosis is caused by breathing in fine crystalline silica dust released when cutting, grinding, drilling or blasting stone, sand, concrete, brick, tile or engineered stone. The dust scars the lungs. It is almost always work-related.

What are the symptoms of silicosis?

Common symptoms are a persistent cough, shortness of breath, fatigue, chest tightness and weight loss. Early silicosis may cause no symptoms. Fever, night sweats and worsening cough may signal tuberculosis, a common complication.

Is silicosis curable?

No. The lung scarring is permanent and can continue to worsen even after exposure stops. Stopping exposure, avoiding smoking, treating complications such as tuberculosis, oxygen, rehabilitation and lung transplant for advanced disease help manage it.

Why are countertop workers getting silicosis?

Engineered stone contains very high levels of crystalline silica, often over 90 percent. Cutting and polishing it, especially dry and without ventilation or respirators, releases large amounts of dust, causing severe silicosis in young workers after only a few years.