DEPARTMENT OF LICENSING AND REGULATORY AFFAIRS  
DIRECTOR'S OFFICE  
OCCUPATIONAL HEALTH STANDARDS  
(By authority conferred on the director of the department of licensing and regulatory  
affairs by sections 14 and 24 of 1974 PA 154, MCL 408.1014 and 408.1024, and  
Executive Reorganization Order Nos. 1996-1, 1996-2, 2003-1, 2008-4, and 2011-4, MCL  
330.3101, 445.2001, 445.2011, 445.2025 and 445.2030.)  
PART 523 ABRASIVE BLASTING  
R 325.50251 Scope.  
Rule 1. These rules apply to all operations where an abrasive is forcibly applied to a  
surface by pneumatic or hydraulic pressure, or by centrifugal force. These rules do not  
apply to steam blasting or steam cleaning, or hydraulic-cleaning methods where work is  
done without the aid of abrasives.  
History: 2001 AACS; 2016 AACS.  
R 325.50252 Adoption of standards.  
Rule 2. (1) The following standards are adopted by reference in these rules and are  
available from IHS Global, 15 Inverness Way East, Englewood, Colorado, 80112, USA,  
telephone number: 1-800-854-7179 or via the internet at website: http://global.ihs.com; at  
a cost as of the time of adoption of these rules, as stated in this subrule:  
(a) American National Standards Institute Standard ANSI Z9.3 “Spray Finishing  
Operations: Safety Code for Design, Construction , and Ventilation,” 1985 edition. Cost:  
$25.00.  
(b) ANSI Z33.1 “Blower and Exhaust Systems for Dust, Stock and Vapor Removal  
or Conveying,” 1961 edition. Cost: $25.00.  
(c) National Fire Protection Association NFPA 68 “Standard on Explosion  
Protection by Deflagration Venting,” 1954 edition. Cost: $38.00.  
(2) The standards adopted in these rules are available for inspection at the  
Department of Licensing and Regulatory Affairs, MIOSHA Regulatory Services Section,  
530 West Allegan Street, P.O. Box 30643, Lansing, Michigan, 48909-8143.  
(3) Copies of the standards adopted in these rules may be obtained from the  
publisher or may be obtained from the Department of Licensing and Regulatory Affairs,  
MIOSHA Regulatory Services Section, 530 West Allegan Street, P.O. Box 30643,  
Lansing, Michigan, 48909-8143, at the cost charged in this rule, plus $20.00 for shipping  
and handling.  
(4) The following Michigan occupational safety and health standards (MIOSHA) are  
referenced in these rules. Up to 5 copies of these standards may be obtained at no charge  
from the Michigan Department of Licensing and Regulatory Affairs, MIOSHA  
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Regulatory Services Section, 530 West Allegan Street, P.O. Box 30643, Lansing,  
Michigan, 48909-8143 or via the internet at website:  
www.michigan.gov/mioshastandards. For quantities greater than 5, the cost, at the time of  
adoption of these rules, is 4 cents per page.  
(a) General Industry Safety Standard Part 39 “Design Safety Standards for Electrical  
Systems,” R 408.13901 to R 408.13905.  
(b) Occupational Health Standard Part 301 “Air Contaminants for General  
Industry,” R 325.51101 to R 325.51108.  
(c) Occupational Health Standard Part 451 “Respiratory Protection,” R 325.60051 to  
R 325.60052.  
(5) Appendix A is informational only and is not intended to create any additional  
obligations or requirements not otherwise imposed or to detract from any established  
obligations or requirements.  
History: 2001 AACS; 2016 AACS.  
R 325.50253 Definitions.  
Rule 3. (1) "Abrasive" means a solid substance used in an abrasive-blasting  
operation.  
(2) "Abrasive-blasting respirator" means a respirator constructed so that it covers the  
wearer's head, neck, and shoulders to protect the wearer from rebounding abrasive.  
(3) "Blast-cleaning barrel" means a complete enclosure that rotates on an axis, or  
that has an internal moving tread to tumble the parts, in order to expose various surfaces  
of the parts to the action of an automatic blast spray.  
(4) "Blast-cleaning room" means a complete enclosure in which blasting operations  
are performed and where the operator works inside of the room to operate the blasting  
nozzle and direct the flow of the abrasive material.  
(5) "Blasting cabinet" means an enclosure where the operator stands outside and  
operates the blasting nozzle through an opening or openings in the enclosure.  
(6) "Clean air" means air that will not cause harm or discomfort to an individual if it  
is inhaled for extended periods of time.  
(7) "Dust collectors" means a device or combination of devices for separating dust  
from the air handled by an exhaust ventilation system.  
(8) "Exhaust ventilation system" means a system for removing contaminated air  
from a space that is comprised of 2 or more of the following elements:  
(a) An enclosure or hood.  
(b) Duct work.  
(c) Dust-collecting equipment.  
(d) Exhauster.  
(e) Discharge stack.  
(9) "Particulate-filter respirator" means an air-purifying respirator, commonly  
referred to as a dust or a fume respirator, that removes most of the dust or fume from the  
air passing through the device.  
(10) "Respirable dust" means airborne dust in sizes capable of passing throughout  
the upper respiratory system to reach the lower lung passages.  
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(11) "Rotary blast-cleaning table" means an enclosure where the pieces to be  
cleaned are positioned on a rotating table and are passed automatically through a series of  
blast sprays.  
(12) "Abrasive blasting" means the forcible application of an abrasive to a surface  
by pneumatic pressure, hydraulic pressure, or centrifugal force.  
History: 2001 AACS; 2016 AACS.  
R 325.50254 Dust hazards from abrasive blasting.  
Rule 4. (1) Abrasives and the surface coatings on the materials blasted are shattered  
and pulverized during blasting operations and the dust formed will contain particles of  
respirable size. An employer shall consider the composition and toxicity of the dust from  
these sources in making an evaluation of the potential health hazards.  
(2) An employer shall ensure that the concentration of respirable dust or fume in the  
breathing zone of the abrasive-blasting operator or any other worker is kept below the  
exposure levels specified in Occupational Health Standard Part 301 “Air Contaminants  
for General Industry,” as referenced in R 325.50252.  
(3) An employer shall ensure that only organic abrasives that are combustible are  
used in automatic systems. If flammable or explosive dust mixtures may be present, then  
the construction of the equipment, including the exhaust system and all electric wiring,  
shall conform to the requirements of ANSI Z33.1 “Blower and Exhaust Systems for Dust,  
Stock, and Vapor Removal or Conveying,” 1961 edition, as adopted in R 325.50252; and  
General Industry Safety Standard Part 39 “Design Safety Standards for Electrical  
Systems,” as referenced in R 325.50252.  
(4) An employer shall ensure that the blast nozzle is bonded and grounded to prevent  
the buildup of static charges. If flammable or explosive dust mixtures are present, then  
the abrasive blasting enclosure, the ducts, and the dust collector shall be constructed with  
loose panels or explosion venting areas, located on sides away from any occupied area, to  
provide for pressure relief in case of explosion, following the principles set forth in the  
NFPA 68 “Standard on Explosion Protection by Deflagration Venting,” 1954 edition, as  
adopted in R 325.50252.  
(5) With respect to operational procedures and general safety, dust shall not be  
permitted to accumulate on the floor or on ledges outside of an abrasive-blasting  
enclosure, and dust spills shall be cleaned up promptly. Aisles and walkways shall be  
kept clear of steel shot or similar abrasive that may create a slipping hazard.  
History: 2001 AACS; 2016 AACS.  
R 325.50255 Blast-cleaning enclosures.  
Rule 5. (1) An employer shall ensure that blast-cleaning enclosures are exhaust  
ventilated so that a continuous inward flow of air will be maintained at all openings in the  
enclosure during the blasting operation.  
(2) An employer shall ensure that all air inlets and access openings are baffled or  
arranged so that, by combining inward air flow and baffling, the escape of abrasive or  
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dust particles into an adjacent work area will be minimized and visible spurts of dust will  
not be observed.  
(3) The rate of exhaust shall be sufficient to provide prompt clearance of dust-laden  
air within the enclosure after the cessation of blasting.  
(4) Before the enclosure is opened, the blast shall be turned off and the system shall  
be run for a sufficient period of time to remove the dusty air within the enclosure.  
(5) Where hard deep-cutting abrasives are used, an employer shall ensure that safety  
glass protected by screening is used in observation windows.  
(6) Slit abrasive-resistant baffles shall be installed in multiple sets of all small access  
openings where dust might escape and shall be inspected regularly and replaced when  
needed.  
(7) Doors on blast-cleaning enclosures shall be flanged and tight when closed.  
(8) An employer shall ensure that doors on blast-cleaning rooms are operable from  
both inside and outside, except that where there is a small operator access door, the large  
work access door may be closed or opened from the outside only.  
History: 2001 AACS; 2016 AACS.  
R 325.50256 Exhaust ventilation systems.  
Rule 6. (1) An employer shall ensure that the construction, installation, inspection,  
and maintenance of exhaust systems conform to the principles and requirements set forth  
in ANSI Z9.3 “Spray Finishing Operations: Safety Code for Design, Construction, and  
Ventilation,” 1985 edition, and ANSI Z33.1 “Blower and Exhaust Systems for Dust,  
Stock and Vapor Removal or Conveying,” 1961 edition, as adopted in R 325.50252.  
(2) If dust leaks are noted, then repairs shall be made as soon as possible.  
(3) The static pressure drop at the exhaust ducts leading from the equipment shall be  
checked when the installation is completed and periodically thereafter to assure continued  
satisfactory operation. If an appreciable change in the pressure drop indicates a partial  
blockage, then the system shall be cleaned and returned to normal operating condition.  
(4) In installations where the abrasive is recirculated, the exhaust ventilation system  
for the blasting enclosure shall not be relied upon for the removal of fines from the spent  
abrasive instead of an abrasive separator. An abrasive separator shall be provided for this  
purpose.  
(5) The air exhausted from blast-cleaning equipment shall be discharged through  
dust-collecting equipment. Dust collectors shall be set up so that the accumulated dust  
can be emptied and removed without contaminating other working areas.  
History: 2001 AACS; 2016 AACS.  
R 325.50257 Respiratory protection.  
Rule 7. (1) An employer shall implement a respiratory protection program in  
accordance with Occupational Health Standard Part 451 “Respiratory Protection,” as  
referenced in R 325.50252, when respirators are required by this rule.  
(2) Abrasive-blasting respirators shall be worn by all abrasive-blasting operators in  
all of the following situations:  
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(a) When working inside blast-cleaning rooms.  
(b) When using silica sand in manual blasting operations where the nozzle and blast  
are not physically separated from the operator in an exhaust-ventilated enclosure.  
(c) Where concentrations of toxic dust dispersed by the abrasive blasting may  
exceed the exposure limits set in Occupational Health Standard Part 301 “Air  
Contaminants for General Industry,” as referenced in R 325.50252, and the nozzle and  
blast are not physically separated from the operator in an exhaust-ventilated enclosure.  
(3) Employers may use properly fitted particulate-filter respirators, commonly  
referred to as dust-filter respirators, for short, intermittent, or occasional dust exposures  
such as cleanup, dumping of dust collectors, or unloading shipments of sand at a  
receiving point when it is not feasible to control the dust by enclosure, exhaust  
ventilation, or other means. The respirator used shall be for protection against the specific  
type of dust encountered.  
(4) Dust-filter respirators may be used to protect the operator of outside abrasive  
blasting operations where nonsilica abrasives are used on materials that have low  
toxicities.  
(5) Dust-filter respirators shall not be used for continuous protection if silica sand is  
used as the blasting abrasive or if toxic materials are blasted.  
History: 2001 AACS; 2016 AACS.  
R 325.50258 Air supply and air compressors.  
Rule 8. An employer shall ensure that air for abrasive-blasting respirators is free of  
harmful quantities of dusts, mists, or noxious gases, and meets the requirements for  
supplied-air quality and use specified in Occupational Health Standard Part 451  
“Respiratory Protection,” as referenced in R 325.50252.  
APPENDIX A  
APPLICABLE MIOSHA STANDARDS  
The following table provides links to several MIOSHA standards (not all-inclusive)  
that may contain requirements that apply to abrasive blasting operations. For example,  
the removal of lead paint by abrasive blasting will likely require employers to follow  
provisions of the MIOSHA lead standards. MIOSHA standards listed in this appendix  
provide employers and workers with information that may be useful for safely conducting  
abrasive blasting.  
GENERAL INDUSTRY  
CONSTRUCTION INDUSTRY  
OH Part 520 Ventilation Control for  
General Industry  
OH Part 301 Air Contaminants for  
General Industry  
OH Part 620 Ventilation Control for  
Construction  
OH Part 601 Air Contaminants for  
Construction  
OH Part 603 Lead Exposure in  
Construction  
OH Part 310 Lead  
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GENERAL INDUSTRY  
OH Part 308 Inorganic Arsenic  
OH Part 309 Cadmium  
CONSTRUCTION INDUSTRY  
OH Part 308 Inorganic Arsenic  
OH Part 309 Cadmium  
OH Part 315 Chromium (VI) in  
General Industry  
OH Part 604 Chromium (VI) in  
Construction  
OH Part 451 Respiratory Protection  
OH Part 308 Inorganic Arsenic  
OH Part 451 Respiratory Protection  
OH Part 308 Inorganic Arsenic  
OH Part 430 Hazard Communication  
OH Part 430 Hazard Communication  
OH Part 433 Personal Protective  
Equipment  
CS Part  
Equipment  
6
Personal Protective  
OH Part 474 Sanitation  
CS Part 1 General Rules  
History: 2001 AACS; 2016 AACS.  
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