Health and Safety Executive

Health and Safety Executive

Gaynor Guthrie

Medical Inspector

Silica Dust:

You Are More At Risk Than You May Think

“It’s only dust you know!”

What is the Problem?

Why is it a Problem?

• Particles need to be “respirable” to cause harm

• Issue is Respirable Crystalline Silica or RCS

• RCS particles can penetrate to deep lung

Why is it a Problem?• A micron is one millionth of a meter. • Human hair varies between 40 to 100 m thick. • Respirable dust = 10 m or less

Silicosis

• ?10 to 20% construction workers exposed

• Silicosis usually follows at least 10 years of exposure to RCS

• It causes stiffening and scarring of the lungs. Nodules visible on X-Ray

• Symptoms are coughing and breathlessness

• Progressive, even after exposure stops

Silicosis

Irreversible

• Increased risk of Tuberculosis (TB)

• After 15 years of exposure to RCS at the WEL of 0.1mg/m3, the risk of developing silicosis is 1 in 40

• Silicosis is under-reported.

Normal chest X-Ray

Tuberculosis

Lung cancer

• There is an association between silicosis and lung cancer

• Over 500 silica related lung cancer deaths in construction in 2004 – Over 10 a week

• Silica is the second most important cause of occupational lung cancer after asbestos

Lung cancer

Lung cancer

Second commonest cancer in men after prostate

Symptoms: cough (phlegm and blood), pain on breathing or coughing, shortness of breath, weight loss

Only 7% men survive 5 years after diagnosis

Chronic Obstructive Pulmonary Disease (COPD)

• Persistent obstruction of airflow into lungs

• Irreversible (unlike asthma)

• Progressive

• Main cause is smoking

• Silica exposure associated with COPD

• Construction workers 2 to 3 times risk

• Symptoms: breathlessness, cough with phlegm

Health Surveillance

• G404 Health surveillance for RCS

• Use a health professional

• Risk based

• Symptom enquiry (COPD, TB)

• Lung function test

• Chest X-Ray

How Much is a Problem?

COSHH sets WEL for dust:

General Dust

• 10 mg.m-3 (inhalable)

• 4 mg.m-3 (respirable)

Respirable Silica

• 0.1 mg.m-3 (8-hour TWA)