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OSHA has recently developed a new respirable crystalline silica standard for the construction, general and maritime industries. Among other things the rule requires employers to use a variety of engineering controls to protect workers and also provide training for their employees.

OSHA Construction Silica Rule – Fact Sheet
OSHA General and Maritime Industry Rule – Fact Sheet


OSHA issued the final silica standard on March 24th, 2016. Since the rule has been amended it will now take effect for the construction industry on September 23rd, 2017 (please see “compliance schedule” for other industry compliance dates. By this date all employers affected by the rule are obligated to comply with the new federal standard.

OSHA has split the final silica standard into two standards:
  • Construction
  • General and Maritime

Construction Standard

The new OSHA silica standard allows employers to choose between two methods of controlling silica exposure:

  • Use Specified exposure control methods
  • Use alternative exposure control methods
    • PEL
    • Exposure Assessment
    • Methods of Compliance

In other words, you may either follow the specified exposure control methods listed in Table 1 or establish a PEL, keep exposure to workers below the PEL and periodically assess worker exposure to crystalline silica dust.

Note: Any individuals whose exposure does not surpass 25 ug/m3 as an 8-hour time weighted average is not covered by the rule

Specified Exposure Control Methods
  • Table 1 in the construction standard matches 18 tasks with effective dust control methods and, in some cases, respirator requirements.
  • Employers that fully and properly implement controls on Table 1 do not have to:
    • Comply with the PEL
    • Conduct exposure assessments for employees engaged in those tasks

For each employee engaged in a task identified on Table 1, the employer shall implement engineering controls, work practices, and respiratory protection specified for the task on Table 1. If the employer assesses that the limit of exposure to employees is below the permissible exposure limit.

General and Maritime Industries

Who is affected by the general industry and maritime standard ?

About 295,000 workers are exposed to respirable crystalline silica in over 75,000 general industry and maritime workplaces. Exposure to respirable crystalline silica can cause silicosis, lung cancer, other respiratory diseases, and kidney disease. Some of the affected industries are shown below.

  • Measure the amount of silica that workers are exposed to if it may be at or above an action level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an 8-hour day;
  • Protect workers from respirable crystalline silica exposures above the permissible exposure limit of 50 μg/m3, averaged over an 8-hour day;
  • Limit workers’ access to areas where they could be exposed above the PEL;
  • Use dust controls to protect workers from silica exposures above the PEL;
  • Provide respirators to workers when dust controls cannot limit exposures to the PEL;
  • Restrict housekeeping practices that expose workers to silica where feasible alternativesare available;
  • Establish and implement a written exposure control plan that identifies tasks that involveexposure and methods used to protect workers;
  • Offer medical exams — including chest X-rays and lung function tests — every three years for workers exposed at or above the action level 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 medical exams hat does the standard require?
Compliance Schedule
  • Construction Industry: September 23, 2017 – OSHA made the decision to delay enforcement in order to supply additional support services. Please see the memorandum for more guidance.
  • General Industry: June 23, 2018
  • Hydraulic Fracturing: June 23, 2018 – All provisions except engineering controls which will go into effect June 23rd, 2021

For more information on staying in compliance with OSHA’s Respirable Crystalline Silica Rule please check out the Silica Small Entity Compliance Guide for construction.

For more information on relating to general and maritime industries please see the General and Maritime Small Entity Compliance Guide for crystalline silica

Key Revisions

  • Reduce the permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter of air, averaged over an 8-hour shift
  • Requires the use of engineering controls (such as ventilation and water) to limit worker exposure to silica dust to below the PEL
  • Provides medical examinations for highly exposed individuals
  • Requires training for all workers that may be exposed to crystalline silica dust.

Reasons for the Rule

  • Previous permissible exposure limits (PEL)s and formulas that many find hard to understand
  • Construction / Shipyard PELs are obsolete particle count limits
  • General industry formula PEL is about equal to 100 uh.m3; Construction/Shipyard formulas are about 250 ug/m3
  • Previous PELs do not adequately protect workers from exposure
  • Exposure to respirable crystalline has been linked to:
    • Silicosis
    • Lung cancer
    • Chronic obstructive pulmonary disease
    • Kidney disease
  • Extensive epidemiologic evidence that lung cancer and silicosis occur at exposure levels below 100 ug/m3

Health benefits of the rule

OSHA estimates that once the effects of the rule are fully initialized, it will prevent:

  • More than 600 deaths per year
  • More than 900 new silicosis cases per year

About Crystalline Silica

Crystalline silica is a basic component of soil, sand, granite, and many other materials. One of the most common forms of crystalline silica is Quartz. These forms of crystalline silica only become dangerous when there particles are small enough to enter the lungs.

Crystalline is found in 3 forms:
  • Quartz
  • Crystobalite
  • Tridymite

Exposures arise from chipping, cutting, sawing, drilling, grinding, sanding, and crushing of concrete, brick block, rock, and stone products (such as in construction operations)

Exposures from using sand products (such as glass manufacturing, foundries, and sand blasting)

Industries and Operations with exposures
  • Construction
  • Glass manufacturing
  • Pottery products
  • Structural clay products
  • Concrete products
  • Foundries
  • Dental laboratories
  • Paintings and coatings
  • Jewelry production
  • Refractory products
  • Asphalt products
  • Landscaping
  • Ready-mix concrete
  • Cut stone and stone products
  • Abrasive blasting in:
    • Maritime work
    • Construction
    • General industry
  • Refractory Furnace Installation repair
  • Railroads
  • Hydraulic fracturing for gas and oil

Knowing the Hazard

Although it’s not well known, silica exposure is a serious threat to nearly 2 million workers in the United States including the 100,000 workers who participate in high risk jobs such as abrasive blasting, foundry work, and tunneling.

  • 2.3 million workers:
    • Construction: 2 million
    • General industry and Maritime: 300,000
  • 676,000 establishments
    • Construction: 600,000
    • General industry and Maritime: 76,000
Want to learn more about silica dust hazards?
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