CONTROL OF SILICA DUST IN CONSTRUCTION 

Handheld Grinders for Mortar Removal 

(Tuckpointing)

The use of a handheld grinder to remove mortar when tuckpointing can generate 

respirable crystalline silica dust. When inhaled, the small particles of silica can 

irreversibly damage the lungs. This fact sheet describes control measures to 

minimize the amount of airborne dust when using handheld grinders to remove 

mortar between brick, stone, and concrete blocks as listed in Table 1 of the 

Respirable Crystalline Silica Standard for Construction, 29 CFR 1926.1153.

Engineering Control Method: Vacuum Dust Collection System

Vacuum Dust Collection System (VDCS)

A VDCS can be used to capture the dust 

generated when removing mortar with a 

handheld grinder. Employers can comply with 

Table 1 in the silica standard by using a:

• Commercially available shroud on the grinding 

wheel designed to fit 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 and 

removing mortar. 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.

The grinder and dust collector must be 

operated and maintained in accordance with 

the manufacturer’s instructions to minimize 

dust emissions. VDCSs are most effective when 

workers are properly trained and use good work 

practices, including:

• 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 needed. 

Do not overfill the bag.

• Set a regular schedule for maintenance and 

filter cleaning of the grinder and VDCS.

• Avoid exposure to dust when changing 

vacuum bags and cleaning or replacing 

air filters.

Photo courtesy of OSHA

Worker grinding mortar from between bricks 

(tuckpointing) with a handheld grinder equipped 

with a shroud and dust collection system using 

respiratory protection. 

FactSheet
Proper handling of the handheld grinder is very 

important. Ensure the following occurs:

• Place one side of the shroud against the 

working surface before inserting the blade into 

the mortar joint. This directs the dust into the 

shroud as the blade cuts into the mortar joint.

• Keep the shroud tight against the working 

surface. This cuts down on dust that would 

otherwise escape from the collection system.

• Move the grinder counter to the direction of 

blade rotation to minimize escaping dust.

• Back off the cutting pressure of the blade a 

short distance before removing it from the 

slot so the vacuum can have enough time to 

clear any dust buildup.

• Do not move the grinder back and forth along 

the slot, as this will create a gap that increases 

dust escape. For better results, move the 

grinder in one direction, making a second 

pass only if necessary.

• Use only enough cutting force to operate the 

tool effectively and keep the leading tool edge 

flush against the working surface. Do not leave a 

large gap between the shroud and uncut mortar.

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 with a HEPA filter-equipped 

vacuum or by wet methods.

Indoors or in Enclosed Areas

Using a VDCS indoors or in an enclosed area 

may not reliably keep exposure low, so extra 

ventilation may be needed to reduce visible 

airborne dust. Extra ventilation can be supplied 

by using:

• Exhaust trunks

• Portable exhaust fans

• Air ducts

• Other means of mechanical ventilation

Photo courtesy of OSHA

Worker is showing a handheld grinder 

equipped with shroud. 

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.

Respiratory Protection

In addition to using a VDCS, respiratory 

protection with a minimum Assigned Protection 

Factor (APF) of 10 is also required whenever a 

handheld grinder for mortar removal is used for 

4 hours or less per shift. Respiratory protection 

with a minimum APF of 25 is required whenever 

a handheld grinder for mortar removal is used 

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.
DSG FS-3632 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.

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.

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.