CONTROL OF SILICA DUST IN CONSTRUCTION 

Heavy Equipment and Utility Vehicles 

Used for Grading and Excavating Tasks

Using heavy equipment and utility vehicles for earthmoving 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 earthmoving 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:

• Tank trucks equipped with hoses and nozzles 

that spray water or other dust suppressants 

over large areas to wet the materials disturbed 

during earthmoving tasks, including haul 

roads and job sites in general.

• A worker who assists the operator by applying 

water or other types of dust suppressants to 

materials being moved.

• Large atomized misting devices.

• Spray equipment attached directly to the 

vehicle.

• Nozzles adjusted so that water spray is 

directed at the work areas where dust 

suppression is required.

• Timing the application of the water or other 

dust suppressants to ensure that the materials 

are still damp when they are disturbed.

Photo courtesy of International Union of Operating Engineers

 Backhoe with enclosed cab. 

FactSheet
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:

• Be well-sealed and well-ventilated using 

positive pressure.

• Have door jambs, window grooves, power line 

entries and other joints that work properly and 

are tightly sealed.

• Have heating and air conditioning, so that 

operators can keep windows and doors 

closed.

• Use an intake air filter with a minimum MERV16 rating (at least 95 percent efficient in the 

0.3-10.0 μm range).

• Be kept free from settled dust by regular 

cleaning and maintenance to prevent dust 

from become airborne inside the enclosure.

Modern heavy equipment often comes 

equipped with enclosed, filtered cabs that 

meet the requirements of the silica standard 

in Table 1. 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.

Additional Information

For more information, visit www.osha.gov/silica

and see the OSHA Fact Sheet on the Crystalline 

Silica Rule for Construction, and the Small Entity 

Compliance Guide for the Respirable Crystalline 

Silica Standard for Construction.

OSHA can provide compliance assistance 

through a variety of programs, including 

technical assistance about effective safety and 

health programs, workplace consultations, 

and training and education. OSHA’s On-Site 

Consultation Program offers free, confidential 

occupational safety and health services 

to small and medium-sized businesses in 

all states and several territories across the 

country, with priority given to high-hazard 

worksites. On-Site consultation services are 

separate from enforcement and do not result 

in penalties or citations. To locate the OSHA 

On-Site Consultation Program nearest you, 

visit www.osha.gov/consultation.

How to Contact OSHA

Under the Occupational Safety and Health Act 

of 1970, employers are responsible for providing 

safe and healthful workplaces for their employees. 

OSHA’s role is to ensure these conditions for 

America’s working men and women by setting 

and enforcing standards, and providing training, 

education and assistance. For more information, 

visit www.osha.gov or call OSHA at 1-800-321-

OSHA (6742), TTY 1-877-889-5627.

DSG FS-3937 12/2017

This is one in a series of informational fact sheets highlighting OSHA programs, policies or 

standards. It does not impose any new compliance requirements. For a comprehensive list of 

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal 

Regulations. This information will be made available to sensory-impaired individuals upon request. 

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.