Silica Dust Control

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This Tech Tip is a reproduction of the 2017 OSHA Fact Sheet “Control of Silica Dust In Construction”


Heavy Equipment and Utility Vehicles Used for Grading and Excavating Tasks

Using heavy equipment and utility vehicles for earth moving tasks such as grading and excavating does not in most cases generate hazardous levels of respirable crystalline silica dust. However, in dry conditions hazardous exposures can occur. This fact sheet describes methods to minimize the amount of airborne dust when using heavy equipment or utility vehicles for earth moving tasks such as grading and excavating soil, as listed in Table 1 of the Respirable Crystalline Silica Standard for Construction, 29 CFR 1926.1153. A separate fact sheet covers dust controls for heavy equipment used for abrading, or fracturing silica-containing materials during demolition activities.

Engineering Control Methods: Enclosed cab (when only the operator is exposed) OR water sprays and/or dust surfactants (a dust suppressant)

The application of water and/or dust suppressants can help to reduce exposure to dust when operating heavy equipment or utility vehicles for tasks such as grading and excavating. If the equipment operator is the only worker engaged in the task, the employer can choose to apply water and/or dust suppressants to minimize dust emissions or can require the operator to stay within an enclosed cab. However, if there are other workers engaged in the task, then water and/or dust suppressants must be applied as needed to minimize their exposure to airborne dust.


Wet Methods
Wet methods for heavy equipment and utility vehicle operators include the use of any method that will suppress dust emissions and be compatible to the job task.

These include using:

Water must be applied at flow rates sufficient to minimize the release of visible dust. Too much water can create mud slurry that can cause hazards. Too little water will not effectively control dust emissions.


Operator Isolation

When operators rely on enclosed cabs for protection against silica dust, the cab must:

Modern heavy equipment often comes equipped with enclosed, filtered cabs that meet the requirements of the silica standard in Table 1 (linked below). Retrofit equipment is available for older equipment.

Respiratory Protection
When properly used, an enclosed cab or wet methods can effectively control airborne silica dust. Therefore, Table 1 in the silica standard for construction does not require the use of respirators when wet methods are used for dust suppression, or for the operator when operating heavy equipment or utility vehicles from within an enclosed cab.

Resources
OSHA Silica Resource Web Page
https://www.osha.gov/dsg/topics/silicacrystalline/construction.html

OSHA Table 1 Tasks
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_
table=STANDARDS&p_id=1270

 

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