TABLE 1: SPECIFIED EXPOSURE CONTROL METHODS WHEN WORKING
WITH MATERIALS CONTAINING CRYSTALLINE SILICA
Equipment / Task
Required Respiratory
Protection and Minimum Assigned
Protection Factor (APF)
Engineering and Work Practice
Control Methods
(xi) Handheld grinders for uses
other than mortar removal Use grinder equipped with commercially available shroud and dust collection system.
Operate and maintain tool in accordance with manufacturer’s instructions to minimize
dust emissions. Dust collector must provide 25 cubic feet per minute (cfm) or greater
of airflow per inch of wheel diameter and have a filter with 99% or greater efficiency and
a cyclonic pre-separator or filter-cleaning mechanism.
(xii) Walk-behind milling
machines and floor grinders. Use machine equipped with integrated water delivery system that continuously
feeds water to the cutting surface. Operate and maintain tool in accordance with
manufacturer’s instructions to minimize dust emissions.
OR
Use machine equipped with dust collection system recommended by the manufacturer.
Operate and maintain tool in accordance with manufacturer’s instructions to minimize dust
emissions. Dust collector must provide the air flow recommended by the manufacturer,
or greater, and have a filter with 99% or greater efficiency and a filter-cleaning mechanism.
When used indoors or in an enclosed area, use a HEPA-filtered vacuum to remove
loose dust in between passes.
< 4 hours /shift > 4 hours /shift
APF 10 APF 25
None None
None None
(xiii) Small drivable milling machines
(less than half-lane) Use a machine equipped with supplemental water sprays designed
to suppress dust. Water must be combined with a surfactant. Operate and maintain
machine to minimize dust emissions. None None
(xiv) Large drivable milling machines
(half-lane and larger) For cuts of any depth on asphalt only: Use machine equipped with exhaust ventilation
on drum enclosure and supplemental water sprays designed to suppress dust. Operate
and maintain machine to minimize dust emissions. For cuts of four inches in depth or less on
any substrate: Use machine equipped with exhaust ventilation on drum enclosure
and supplemental water sprays designed to suppress dust. Operate and maintain
machine to minimize dust emissions.
OR
Use a machine equipped with supplemental water spray designed to suppress dust.
Water must be combined with a surfactant. Operate and maintain machine to
minimize dust emissions. None None
(xv) Heavy equipment and utility
vehicles used to abrade or fracture
silica-containing materials (e.g., hoe-
ramming, rock ripping) or used during
demolition activities involving silica-
containing materials. Operate equipment from within an enclosed cab
When employees outside of the cab are engaged in the task, apply water
and/or dust suppressants as necessary to minimize dust emissions. None None
(xvi) Heavy equipment and utility
vehicles for tasks such as grading
and excavating but not including:
Demolishing, abrading, or fracturing
silica-containing materials. For cuts of any depth on asphalt only: Use machine equipped with exhaust ventilation
on drum enclosure and supplemental water sprays designed to suppress dust. Operate
and maintain machine to minimize dust emissions. For cuts of four inches in depth or less on
any substrate: Use machine equipped with exhaust ventilation on drum enclosure
and supplemental water sprays designed to suppress dust. O