Silicosis

Silicosis Introduction

Of all the dust diseases, or pnuemoconioses, silicosis produces the largest number of victims according to NIOSH. According to the World Health Organization, Silicosis, one of the oldest occupational diseases, still kills thousands of people every year, everywhere in the world. It is an incurable lung disease caused by inhalation of dust containing free crystalline silica. It is irreversible and, moreover, the disease progresses even when exposure stops. Extremely high exposures are associated with much shorter latency and more rapid disease progression.

Free crystalline silica, SiO2, is one of the most common minerals on earth. Silica appears in sand, many rocks such as granite, sandstone, flint and slate, and in some coal and metallic ores. The three most common forms are quartz, tridymite and cristobalite.

The International Agency for Research on Cancer (IARC) classifies inhaled crystalline silica (in the form of quartz or crystobalite) from occupational sources as a Group 1 human lung carcinogen.

Harmful silica dust is invisible to the naked eye and is so light that it can remain airborne for hours; thus affecting workers in trades far from the point of origin.

Frequently overlooked or misdiagnosed, silicosis causes progressive asphyxiation, often complicated by tuberculosis and infection. Over a million American workers are exposed to silicosis-producing dust in the 21st century and more than 50,000 will develop disease, even though methods to prevent the disease have been known to employers since Ancient Greece.