CONTROL OF SILICA DUST IN CONSTRUCTION 

Handheld Grinders for Tasks Other Than 

Mortar Removal

The use of a handheld grinder to smooth or cut the surfaces of concrete, masonry 

or other silica containing materials can generate respirable crystalline silica dust. 

When inhaled, the small particles of silica can irreversibly damage the lungs. This 

fact sheet describes dust control that can be used to minimize the amount of 

airborne dust when using handheld grinders for uses other than mortar removal as 

listed in Table 1 of the Respirable Crystalline Silica Standard for Construction, 29 

CFR 1926.1153.

Engineering Control Method: Water applied continuously to the grinding wheel OR Vacuum Dust 

Collection System

Two methods for controlling dust when operating 

handheld grinders for smoothing or cutting 

surfaces, and uses other than mortar removal 

are: (1) use a grinder equipped with an integrated 

water delivery system (outdoors only); or (2) use 

a grinder equipped with a commercially available 

shroud and vacuum dust collection system. The 

grinder must be operated and maintained in 

accordance with the manufacturer’s instructions 

to minimize dust emissions.

Wet Methods

Grinders equipped with an integrated water 

delivery system can be used to control dust when 

cutting, grinding, or polishing granite, concrete 

or other materials containing crystalline silica 

outdoors. A water faucet or pressurized container 

can be used to supply a constant spray of water to 

the grinding wheel. When used outdoors, waterfed grinders can control dust on uneven surfaces 

and near corners and edges more effectively than 

vacuum dust collection systems.

Electrical Safety. Where water is used 

to control dust, electrical safety is a 

particular concern. Use ground-fault circuit 

interrupters (GFCIs) and watertight, sealable 

electrical connectors for electric tools and 

equipment on construction sites.

Photo courtesy of OSHA

Example of a handheld grinder with 

integrated water delivery system. 

Make sure to:

• Check that hoses are securely connected and 

are not cracked or broken.

• Adjust nozzles so that water goes to the 

grinding surface or cut point. Water flow rates 

must be sufficient to minimize the release of 

visible dust.

• Set a regular schedule for maintenance and 

cleaning of the tool and control.

FactSheet
Clean up any slurry produced to prevent the 

slurry from drying and releasing silica dust into 

the air. Wet slurry can be cleaned up using, for 

example, shovels or a wet vacuum equipped 

with a HEPA filter.

Vacuum Dust Collection System (VDCS)

Employers can also comply with Table 1 in the 

silica standard by using a VDCS to control dust 

when using a handheld grinder. Use a:

• Commercially available shroud and dust 

collection system on the grinding wheel 

appropriate for the grinder and wheel size.

• Vacuum that provides at least 25 cubic feet 

per minute (cfm) of airflow per inch of blade 

to capture dust at the point of grinding. For 

example, a 5” grinding wheel would require 

a rating of 125 cfm of air flow or more for 

effective capture.

• Vacuum equipped with a cyclonic preseparator or filter- cleaning mechanism with a 

filter that has 99 percent or greater collection 

efficiency for respirable-sized particles.

• Vacuum exhaust hose capable of providing 

the airflow recommended by the tool 

manufacturer. A 1.5” to 2” diameter vacuum 

exhaust hose is typically adequate.

Make sure to:

• Keep the vacuum hose clear and free of 

debris, kinks, and tight bends.

• Follow the equipment manufacturer’s 

directions on how to reduce dust buildup on 

the filter.

• Change vacuum-collection bags as directed 

by the manufacturer. Do not overfill the bag.

• Set a regular schedule for maintenance and 

filter cleaning of the drill and VDCS.

• Avoid exposure to dust when changing vacuum 

bags and cleaning or replacing air filters.

Illustration courtesy of NIOSH

Detail of grinder with vacuum dust collection system attachment. 

Respiratory Protection

When properly used, wet methods can 

effectively control exposure to silica dust. 

Therefore, Table 1 does not require the use of 

respiratory protection when operating handheld 

grinders outdoors using wet methods.

When using a VDCS, respiratory protection with 

a minimum Assigned Protection Factor (APF) of 

10 is required whenever handheld grinders are 

used indoors or in enclosed areas for more than 

4 hours per shift.

When respirators are required, employers must 

put in place a written respiratory protection 

program in accordance with OSHA’s Respiratory 

Protection Standard 29 CFR 1910.134.

Use of Compressed Air: Unless there is a 

ventilation system that effectively captures 

the dust cloud, do not use compressed air 

or blowers to clean surfaces, clothing or 

filters because it can increase exposure to 

silica. Instead, clean only with a HEPA filterequipped vacuum or by wet methods.

Indoors or in Enclosed Areas

Using a handheld grinder with a VDCS indoors 

or in an enclosed area may not be relied on to 

keep exposure low, so extra ventilation may be 

needed to reduce visible airborne dust. Extra 

ventilation can be supplied by using:

• Exhaust trunks

• Portable fans

• Air ducts

• Other means of mechanical ventilation

Ensure air flow is not impeded by the 

movements of employees during work, or by 

the opening or closing of doors and windows. 

Position the ventilation to move contaminated air 

away from the workers’ breathing zones.

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 
DSG FS-3628 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.

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.

Workers’ Rights

Workers have the right to:

• Working conditions that do not pose a risk of 

serious harm.

• Receive information and training (in a 

language and vocabulary the worker 

understands) about workplace hazards, 

methods to prevent them, and the OSHA 

standards that apply to their workplace.

• Review records of work-related injuries and 

illnesses.

• File a complaint asking OSHA to inspect their 

workplace if they believe there is a serious 

hazard or that their employer is not following 

OSHA’s rules. OSHA will keep all identities 

confidential.

• Exercise their rights under the law without 

retaliation, including reporting an injury or 

raising health and safety concerns with their 

employer or OSHA. If a worker has been 

retaliated against for using their rights, they 

must file a complaint with OSHA as soon as 

possible, but no later than 30 days.

For additional information, see OSHA’s Workers 

page.

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.