Occurs after 15-20 years of exposure to moderate to low levels of silica dust.

When the organic rubber is exposed to fire, it burns to ash and leaves behind the silica dust with which the product started.

First, the patient history should reveal exposure to sufficient silica dust to cause this illness.

Simple chronic silicosis - results from long-term exposure (more than 20 years) to low amounts of silica dust.

People who work in jobs where they are exposed to silica dust are at risk.

Inhalation of silica dust can lead to the serious lung disease, silicosis.

To be eligible, workers have to register themselves within two years of exposure to silica dust.

As a result of the exposure to silica dust, many workers developed silicosis, a debilitating lung disease.

Respirators are required to prevent inhalation of powdered silica dust.

Suspected chemical toxins include trichloroethylene in well water and silica dust.