RESPIRABLE CRYSTALLINE SILICA
Respirable crystalline silica (RCS) is one of the major hazards in the construction industry. It is generated from sand, concrete, rock, bricks, blocks, etc. Silica is found in nature most commonly as quartz.
Respirable crystalline silica is a major hazard in construction industry because of the construction activities that is being carried out on daily basis in our construction sites. These activities includes: Concrete cutting, Sandblasting, Drilling, Chiseling, Grinding, Cleaning, etc.
Studies has shown that orally ingested silica is non-toxic with LD50 (Lethal dose) of 5000mg/kg.
Moreover, inhaling crystalline silica can lead to Silicosis, Bronchitis or Cancer. These defects are caused when silica dust settles in the lungs and continuously irritate the lungs tissue, thereby reducing the lungs functionality.
Any activity that generates dust can expose workers to airborne silica. Silica exposure has a chronic effect which takes a long time before it manifests. Exposure to silica dust destroys the lungs tissue gradually, until the effect becomes irreversible. When the lung is destroyed, the patient will cause severe shortness of breath, severe coughing, body weakness, etc.
It is due to this harmful health effect of silica that its exposure limit was set at 50µg/m3.
HOW TO PREVENT/REDUCE UNNECESSARY EXPOSURE TO RESPIRABLE CRYSTALLINE SILICA
- Reduce exposure radius: The hazard radius should be reduced leading to a reduced number of people exposed to it. This can be done by choosing an appropriate task site where fewer workers will be exposed. Or shielding the silica generation area.
- Adequate training should be implemented: Any worker assign to carry out a task which could lead to the generation of crystalline silica should pass through adequate training. The training should cover, hazard awareness, personal hygiene, proper use of PPE, etc.
- Reducing exposure time: One worker should not be assigned to do any task that generates crystalline silica continuously. More than one worker should be trained for the task, so that when one person is on the task, the other can use that time for natural recovery.
- Provision of welfare facility: Welfare facilities like washing site, hand wash, changing room, etc, should be in place. This will prevent unnecessary exposure of other workers to the hazard.
Choice of equipment could help to either eliminate the crystalline silica or reduce its generation.
Like in cutting, a cutting equipment that will favour wet cutting can be used. This will eliminate the crystalline dust generation in its entirety.
PERSONAL PROTECTIVE EQUIPMENT:
Personal protective equipment (PPE) as we all know is our last line of defense when every other control measures fail. When carrying out a task that involves generation of respirable crystalline silica, the use of adequate respirator is necessary, good disposable work clothing and other relevant protective devices.
Some job sites give their workers involved in cutting Peak milk at the end of every task, do we think that peak milk has something to do with neutralizing the effect of the inhaled dust?
See more on silica control by NIOSH