Hazards at Work: Silica Exposure

If you or someone you know works in mining, construction, or sand blasting, an occupational hazard you should be aware of is exposure to crystalline silica, which can develop into life threatening conditions.

According to the U.S. Department of Labor, jobs which create high risk for silica exposure include rock drilling, stonecutting, foundry and quarry work, and abrasive blasting. Over 100,000 people today work in these fields and they are part of the approximately two million American workers exposed to silica.

Minerals and materials such as granite, sand and soil all contain crystalline silica, the most common form of which is quartz. Other forms include tridymite and cristobalite. These three forms of silica can be inhaled as particles as a result of drilling, cutting or chipping silica-containing objects.

Silica dust, when breathed in through the lungs, creates thick scar tissue, which makes the lungs less flexible and hinders their ability to take in oxygen and may put them at higher risk for tuberculosis.

Breathing in silica may also result in disabling or fatal silicosis. There are three kinds of silicosis: chronic, accelerated and acute.

• Chronic silicosis may only occur after nearly two decades of low or moderate exposure to silica. Because symptoms of the chronic form may not be easily detected, a chest x-ray would be necessary to determine the extent of damage to the lungs. Some later symptoms could include shortness of breath, fatigue and chest pain. Respiratory failure is also possible in the chronic form.
• High exposure of silica for up to ten years can result in accelerated silicosis. Symptoms may be also shortness of breath coupled with weight loss or weakness.
• Even higher levels of silica exposure may result in acute silicosis, the onset of which can appear only months after exposure. Symptoms include shortness of breath to a disabling degree, weakness and death resulting from extreme weight loss.

Currently, the U.S. Occupational Safety and Health Administration has defined an amount of silica exposure per eight-hour work day that is not to be exceeded. Aside from this, both employees and employers can take measures to reduce silica exposure including using non-silica materials as much as possible, making sure respirator equipment fits properly, and diligently participating in safety training.

Links:

http://www.cdc.gov/niosh/topics/silica/default.html

http://www.osha.gov/Publications/osha3176.html