Silica on the Jobsite

OSHA’s final rule for Respirable Crystalline Silica (1926.1153) reduces the permissible exposure limit (PEL) for respirable crystalline silica to 50 micrograms per cubic meter (50µg/m3) of air, averaged over a continuous 8-hour period. That’s a total of a little less than 1 gram (about 840µg) of silica per workday, according to calculations performed by Joel Guth in a series of blogs for iQ Power Tools. Guth’s math also shows that cutting a single 2x4x8-inch paver in half using a 1/8-inch blade produces about 9,000,000µg of silica dust. In other words, the OSHA PEL is so small that almost any activity involving silica dust will require special protective measures.

To comply by the June 23, 2017, deadline, remodelers can either measure exposure levels and decide what steps to take to meet the PEL (an impractical choice for most small companies), or they can follow OSHA’s Table 1, which prescribes “engineering controls” (such as wet-sawing or ventilation) for a list of construction tasks, plus use of employer-provided respirators where those controls are inadequate (see sample below). Most Table 1 measures are commonsense methods that many contractors are already using.

In addition, every company must do the following, according to the OSHA Fact Sheet for the silica rule:

• Establish a written exposure control plan that identifies methods to protect workers performing tasks involving silica exposure, including restricting access to work areas where high exposures may occur.
• Designate a competent person to implement the written exposure control plan.
• Restrict housekeeping practices, such as dry sweeping, that expose workers to silica where feasible alternatives are available.
• Offer medical exams (including chest x-rays and lung-function tests) every three years for workers who are required to wear a respirator for 30 or more days per year.
• Train workers on work operations that result in silica exposure and ways to limit exposure.
• Keep records of workers’ silica exposure and their medical exams.

For more information and links to the full text of the final rule, including Table 1, go to osha.gov/silica.

More articles on jobsite dust control:

• The Dirt on Dust - Part 1
• The Dirt on Dust – Part 2 
• Dust-Control Products and Equipment
• Doing the Math for Silica
• The Dust-Free Jobsite Is Overdue
• The Body’s Defenses Against Breathing Dusty Air