Masonry Magazine November 2002 Page. 12
Government Affairs
Silica, Silicosis and the
Department of Labor
▼By Marian Marshall
Director, MCAA Government Affairs
Construction workers are exposed to a wide variety of occupational hazards each year and existing silica regulations have not been revised in quite some time. Accordingly, due to pressure from labor organizations and increased concerns about overexposure and the resulting health problems in the construction industry, The Department of Labor has been forced to do research and feasibility studies to determine how to develop a new formula for measuring exposure limits of respirable dust. Although a proposal is not imminent, I thought it might be useful to give our readers a general overview of some of the issues associated with new silica standards.
Silicosis is a permanent, disabling and sometimes fatal lung disease caused by breathing dust containing extremely fine particles of crystalline silica. When concrete, masonry and rock are made into a fine dust-through abrasive blasting of concrete, demolition of concrete and masonry structures, or chipping, hammering, drilling, sawing, and grinding of concrete or masonry - and suspended in the air, breathing in these fine particles can produce lung damage.
The U.S. Department of Labor reports that more than one million U.S. workers, in all industries, are exposed to crystalline silica each year. More than 250 American workers die with silicosis each year, yet only a very small percentage of those fatalities are attributable to occupational exposures in the construction industry.
While there is no cure for silicosis, it is 100 percent preventable if employers, workers and health professionals work together to reduce exposures. Working in any dusty environment where crystalline silica is present generally can increase a person's chances of getting silicosis.
As one might imagine, screening and monitoring for silicosis can be very expensive. More importantly, although exposure to silica can lead to other diseases such as bronchitis, tuberculosis and lung cancer, contractors must be leery of whether or not those illnesses can definitely be linked to on-the-job performance. Smoking and predisposition to allergies or bronchial problems are just a few of the many real complex problems with reducing exposure limits to silica for those in the masonry industry.
Crystalline silica is regulated by a number of OSHA standards, all of which employers should understand. In order to comply with established OSHA permissible exposure limits, the employer must first implement engineering or administrative controls whenever possible. Administrative control methods include job rotation to minimize exposure and protect workers. Also, when sawing concrete or masonry, workers can use saws that provide water to the blade. Second, during rock drilling, use water through the drain stem to reduce the amount of dust in the air and, third, use dust collection systems where possible.
OSHA established Permissible Exposure Limits (PELs) for many substances, including airborne crystalline silica. PEL is the maximum amount of a contaminant in the air to which workers may be exposed over a given time period. (The OSHA PEL for crystalline silica in general industry is listed in the Code of Federal Regulations, 29 CFR 1910.1000, "Air Contaminants," under Table Z-3, "Mineral Dusts.")
This is a time-weighted average amount that cannot be legally exceeded for an eight-hour shift during a 40-hour week. OSHA has published general industry PELs for three different forms of crystalline silica. Cristobalite and tridymite are forms of crystalline silica, less abundant than quartz, that have lower PELs than quartz. OSHA PELs for respirable crystalline silica, expressed in milligrams of respirable dust per cubic meter of air (mg/m³) are as follows: