Course:SPPH381B/TermProject/Alkaline battery- Samin/Track ballast/Silicosis

Recognition

Workers exposed to silica dust during the process of track ballast while making railroads

Silica is a very common mineral found in sand and rocks such as granite, sandstone, flint and slate, which can be found in ballast. When these rocks are cut, broken, drilled or crushed a fine silica dust can be produced which is hazardous to health when inhaled. Employees who work with these materials are at potential risk of developing silicosis as a result of their exposure to silica. Silicosis is a completely preventable but incurable respiratory disease

If this dust is inhaled, small particles of it can become embedded into parts of the lung and cannot be cleared by mucous or coughing. The dust is toxic to the lining of the lungs causing a strong inflammatory reaction. Eventually, this causes the lung tissue to become irreversibly thickened and scarred - a condition known as fibrosis. This scar tissue prevents the lungs from taking in oxygen properly. Exposure to very high levels of silica can cause disease within a year, but it usually takes at least 10 - 15 years of exposure before symptoms occur. The longer the interval between exposure and the onset of symptoms, the slower the disease tends to progress. All types of silicosis cause damage to the lung tissue. Symptoms include a cough, which is sometimes dry, fatigue, shortness of breath, chest tightness and pain and loss of appetite. Patients may lose weight, have severe trouble breathing and cough up blood as the disease progresses. People who have silicosis are also more susceptible to other respiratory diseases such as tuberculosis. There may also be an increased risk of lung cancer in workers who have been exposed to silica.

Evaluation

Workers who may be exposed to crystalline silica dust should have regular medical exams. They should be examined before they begin their jobs and at least every three years thereafter. Examinations should include medical and work histories, chest X-rays, and tuberculosis evaluations. Medical examinations should supplement air monitoring.

Control

Elimination or substitution

Eliminating the hazard by substituting a safer process or material, where possible, is the most effective control. Some questions to consider:

• Can a less hazardous material be used (for example, garnet instead of silica in sand-blasting operations)?
• Can formwork be designed more carefully to reduce the amount of concrete finishing required?
• Can a process that generates less dust be used (for example, splitting rather than sawing concrete pavers)?

Engineering controls

Making physical modifications to facilities, equipment, and processes can reduce exposure. Some questions to consider:

• Can local exhaust ventilation be used on all equipment that generates silica dust?
• Can water be used to prevent dust from becoming airborne?
• Can the areas that generate large amounts of dust be enclosed, and have proper ventilation to clean the air?

Administrative controls

These involve changing work practices and work policies. Providing awareness tools and training also count as administrative controls. All can limit the risk of silica dust exposure. Some questions to consider:

• Have you developed a written exposure control plan for silica?
• Can warning signs be posted in the work area?
• Can crews be scheduled to work as far away from silica dust-generating processes as possible?
• Have you provided adequate washing facilities on site?
• Have you developed safe work procedures for dealing with silica dust?
• How will worker exposure to silica be monitored?

Personal protective equipment

This is the least effective control. When used, there must always be at least one other control in place as well. Some questions to consider:

• Do workers have the proper respirators, eye wear, and protective clothing?
• Has personal protective equipment been tested to make sure it is working properly?