DEPARTMENT OF CONSUMER AND INDUSTRY SERVICES  
DIRECTOR'S OFFICE  
OCCUPATIONAL HEALTH STANDARDS  
(By authority conferred on the director of the department of consumer and industry  
services by sections 14 and 24 of 1974 PA 154 and Executive Reorganization  
Orders Nos. 1996-1 and 1996-2, MCL 408.1014, 408.1024, 330.3101, and 445.2001)  
PART 700. AGRICULTURE  
R 325.2401 Scope.  
Rule 1. These rules apply only to places of employment.  
History: 1979 AC; 2003 AACS.  
R 325.2402 General definitions.  
Rule 2. As used in these rules:  
(a) "Aerosol" means particulate matter suspended in air.  
(b) "Contaminant" means an airborne material capable of causing  
occupational disease or significant physiological disturbances to a person, and includes,  
but is not limited to, the substances listed in R 325.2413 to R 325.2419.  
(c) "Director" means the director of the department of consumer and industry  
services or the designee of the director.  
(d) "Employer" means an individual or type of organization which has in its  
employ 1 or more individuals performing services for it.  
(e) "Gas" means a normally formless fluid which occupies a space or enclosure  
and which can be changed to the liquid or solid state by the effect of increased pressure  
or decreased temperature, or both.  
(f) "Inert gas" means a gas or vapor which acts primarily as a simple asphyxiant  
without other significant physiological effect, recognizing that an inert gas may have  
flammable or explosive characteristics.  
(g) "Inert particulate" means an aerosol which does not produce significant  
organic disease or toxic effect in a lung-tissue reaction from any of the following:  
(i) The architecture of the air spaces remains intact.  
(ii) Collagen (scar tissue) is not formed to a significant extent.  
(iii) The tissue reaction is potentially reversible.  
(h) "Particulate matter" means fine solid or liquid particles.  
(i) "Physical agent" means a form of energy transmitted directly or through the  
air from the point of emission to the receiver.  
(j) "Vapor" means the gaseous state of a substance.  
History: 1979 AC; 2003 AACS.  
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R 325.2403 Definitions pertaining to contaminants.  
Rule 3. As used in these rules:  
(a) "Maximum allowable concentration" or "MAC" means the threshold limit  
value or the time-weighted average 8-hour airborne concentration of a contaminant  
to which a person may be safely exposed. R 325.2413 to R 325.2419, tables 1 to 7,  
refer to the MAC of a particular contaminant.  
(b) "Mg/M3" means milligrams of particulate per cubic meter of air.  
(c) "Mppcf" means millions of particulates per cubic foot of air based on impinger  
samples counted by light field microscopic techniques.  
(d) "Non-respirable atmosphere" means an atmosphere which contains  
insufficient oxygen, or an elevated level of contaminants, which may render a person  
incapable of self-rescue.  
(e) "Ppm" means parts of vapor or gas per million parts of air by volume at 25  
degrees Celsius and 760 millimeters of mercury pressure.  
(f) "Source" means a process or equipment which releases a contaminant into the  
air in concentrations exceeding the MAC.  
History: 1979 AC; 2003 AACS.  
R 325.2404 Definitions pertaining to noise.  
Rule 4. As used in these rules:  
(a) "Auditory protective equipment" means ear plugs, muffs, or other protective  
devices worn by an exposed person to attenuate airborne noise pressure in the ear  
canal.  
(b) "Broad-band noise" means noise generally distributed throughout the sound  
frequency spectrum.  
(c) "Continuous noise" means an uninterrupted noise or more than 60 noises per  
minute.  
(d) "dBA" means the airborne sound pressure level measured with the "A"  
weighting network of a sound level meter.  
(e) "Decibel" or "dB" means a dimensionless unit expressing the ratio of 2 sound  
quantities in logarithmic form, 1 of which quantities is a reference level of 0.0002  
microbar.  
(f) "Impact noise meter" means an instrument used for the measurement of peak  
sound pressures of impulse.  
(g) "Impulse noise" means a single noise or 60 or less noises per minute.  
(h) "Noise" means airborne sound in the frequency range from 20 to 20,000 hertz  
or cycles per second.  
(i) "Sound level meter" means an instrument, whose characteristics comply with  
those specified in the American standards association, standard S1.4-1961, used for  
the measurement of the airborne sound pressure level.  
History: 1979 AC; 2003 AACS.  
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R 325.2405 Definitions pertaining to respirators.  
Rule 5. As used in these rules:  
(a) "Atmosphere immediately dangerous to life or health" means  
nonrespirable atmosphere.  
a
(b) "Canister" means a container filled with air-purifying media to remove gases  
and vapors from air drawn through the container. The canister may also contain an  
aerosol filter to remove solid or liquid particulate matter.  
(c) "Cartridge" means a canister having reduced air-purifying capacity.  
(d) "Facepiece" means that portion of a respirator that is designed to make a  
gastight or dusttight fit with the face and includes the headbands, exhalation valves,  
and connections for an air-purifying device or respirable-gas source. A half-mask  
facepiece covers the wearer's nose and mouth. A full-mask facepiece covers the  
wearer's nose, mouth, and eyes.  
(e) "Filter" means a media used in a respirator to remove solid or liquid particulate  
matter from air drawn through the respirator.  
(f) "Respiratory protective equipment" means a device or system designed to  
protect the wearer from inhalation of unhealthful atmospheres.  
(g) "Respirator" means a type of respiratory protective equipment.  
History: 1979 AC; 2003 AACS.  
R 325.2410 Definitions pertaining to controls.  
Rule 10. As used in these rules:  
(a) "Control" means the limitation of worker exposure to contaminate levels not  
exceeding the MAC.  
(b) "Controlled process" means an arrangement of equipment to control the  
contaminant by means of suitable design measures.  
(c) "Enclosure" means a room, booth, or exhaust hood that confines  
contaminants at their sources.  
(d) "General ventilation" means the supply and removal of air from a space to dilute  
or remove contaminants.  
(e) "Local exhaust ventilation system" means an arrangement of exhaust hoods,  
ducts, and fans that removes air to control a contaminant at its source.  
(f) "Process space" means a tunnel, process equipment, shaft, or enclosed space.  
(g) "Supply ventilation system" means an arrangement of inlet openings or  
equipment to introduce outside air into the working environment.  
History: 1979 AC; 2003 AACS.  
R 325.2411 Contaminants; exposure; MACs.  
Rule 11. (1) An employer shall not allow the exposure of a person to  
concentrations of a contaminant in excess of the limit expressed by the contaminant's  
MAC as established in R 325.2412 to R 325.2419.  
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(2) An employer shall not allow the exposure of a person to a contaminant or  
combination of contaminants in concentrations which are hazardous or injurious to  
the person's health.  
History: 1979 AC; 2003 AACS.  
R 325.2412 Maximum allowable concentrations.  
Rule 12. (1) Maximum allowable concentrations of air contaminants based on a  
repeated 8-hour work day exposure are in tables 1 to 7 in R 325.2413 to R 325.2419.  
(2) A substance in tables 1 to 6 in R 325.2413 to R 325.2418, which is preceded  
by A, C, or S, is an especially hazardous contaminant and all of the following precautions  
shall be taken:  
(a) If the substance is preceded by "A," then the employer shall not allow a person  
or any part of his or her anatomy to be exposed to or come in contact with the  
substance by any respiratory, oral, or skin route.  
(b) If the substance is preceded by "C," then its MAC means the highest  
concentration at which an employer may allow a person to be exposed at any time.  
(c) If the substance is preceded by "S," then an employer shall provide necessary  
precautions against skin absorption of the contaminant by a person.  
History: 1979 AC; 2003 AACS.  
R 325.2413 Maximum allowable concentrations for substances A and B.  
Rule 13. Table 1 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2414 Maximum allowable concentrations for substances C and D.  
Rule 14. Table 2 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2415 Maximum allowable concentrations for substances E to H.  
Rule 15. Table 3 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2416 Maximum allowable concentrations for substances I to M.  
Rule 16. Table 4 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2417 Maximum allowable concentrations for substances N to P.  
Rule 17. Table 5 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2418 Maximum allowable concentrations for substances Q to Z.  
Rule 18. Table 6 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2419 Maximum allowable concentrations for mineral dusts.  
Rule 19. Table 7 reads as follows:  
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History: 1979 AC; 2003 AACS.  
R 325.2421 Continuous, broad-band noise.  
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Rule 21. (1) The following are maximum permissible levels of continuous, broad-  
band noise based on daily exposure time in places of employment:  
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History: 1979 AC; 2003 AACS.  
R 325.2422 Impulse noise.  
Rule 22. The maximum permissible level for impulse noise shall be 140 dB as  
measured with a cathode-ray oscilloscope system or with other equipment  
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such as the impact noise meter capable of indicating the maximum-instantaneous  
peak noise level.  
History: 1979 AC; 2003 AACS.  
R 325.2424 Illumination.  
Rule 24. The level of illumination shall be adequate as determined by the director  
for the performance of the task.  
History: 1979 AC; 2003 AACS.  
R 325.2429 Control methods for enclosures and controlled processes.  
Rule 29. (1) An enclosure shall be provided at a stationary source unless the  
omission of the enclosure does not impair control.  
(2) A controlled process shall be designed and regulated to prevent the creation of  
a hazard to health or life. If the director determines that there may be an immediate  
danger to health or life due to the failure of the process design or regulatory device, then  
he or she may require that the process fail-safe in such manner to avert the hazard.  
History: 1954 ACS 61, Eff. Feb. 16, 1970; 1979 AC; 2003 AACS.  
R 325.2430 Rescinded.  
History: 1979 AC; 1993 AACS.  
R 325.2431 Inert gas or foam systems.  
Rule 31. If an inert gas or foam system is provided in an occupied area for the  
prevention or extinguishment of fire or explosion, then the affected area shall be  
conspicuously posted to call attention to the potential creation of a nonrespirable  
atmosphere. The actuating of an audible and visible alarm before the system is  
activated shall be provided. The system shall incorporate a sufficient time-delay to  
permit the egress of persons within the affected area. After the activation of the  
system, an audible and visible warning that a nonrespirable atmosphere has been created  
within the area shall continue until the nonrespirable atmosphere has been purged or  
diluted with air to safe breathing levels.  
History: 1979 AC; 2003 AACS.  
R 325.2434 Supply ventilation systems.  
Rule 34. (1) A supply ventilation system shall be provided to ensure a flow of air  
into the working environment to replace the volume of air exhausted.  
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(2) A mechanical air supply system shall be provided if its absence will result in  
building negative pressures sufficient to cause back-drafting of vents from fuel-fired  
equipment or ineffective control.  
(3) Mechanical air supply volumes shall be heated to maintain a minimum air  
temperature of 65 degrees Fahrenheit measured at the point of air discharge to the  
space. Exceptions to this requirement are refrigerated storage rooms, special process  
rooms, and similar locations where lower air temperatures are essential to the  
preservation of the product or service, or, if in the opinion of the director, a lower air  
temperature will not be  
harmful to the health of the persons affected.  
History: 1979 AC; 2003 AACS.  
R 325.2435 Direct-fired air heaters.  
Rule 35. (1) A direct-fired air heater, wherein combustion products are released in  
the supply air stream, may be installed in buildings of industrial occupancy,  
garages, laundries, and commercial kitchens. They shall not be installed in offices,  
schools, hospitals, and places of public assembly.  
(2) A direct-fired air heater shall have an inlet duct connected directly to the out-of-  
doors. Room air shall not be circulated across the burner.  
(3) A direct-fired air heater shall deliver air which contains not more than 10 ppm  
of carbon monoxide and is free from odors of combustion products. Permissible  
concentrations of other contaminants in the delivered air may be established by the  
director pursuant to their MAC and the degree of exposure to a person.  
(4) The air volume supplied to the building by a direct-fired air heater shall not  
exceed 110% of the total air volume exhausted. The director may require interlocking  
of a heater control system with an exhaust ventilation system if necessary to ensure that  
the exhaust systems are operating.  
(5) A direct-fired air heater shall have both of the following:  
(a) A pre-ignition purge of fresh air.  
(b) A positive fuel supply closure in the event of fuel supply failure, ignition  
failure, flame failure, power failure or interruption, or air flow reduction below 50% of  
its rated capacity.  
History: 1979 AC; 2003 AACS.  
R 325.2436 Exhaust ventilation systems.  
Rule 36. The minimum rate of exhaust ventilation for places of  
manufacturing, processing, assembling, maintenance and repair, or storage of material  
shall be 1 cubic foot of air per minute per square foot of floor area. This amount of  
exhaust ventilation may be provided by local exhaust, general exhaust, or both. The  
director may permit a variance if contaminant control can be accomplished at a lesser  
rate of ventilation.  
History: 1979 AC; 2003 AACS.  
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R 325.2437 Local exhaust ventilation.  
Rule 37. (1) Local exhaust ventilation shall be provided at all stationary  
sources. The director may allow a variance from this requirement if control is  
accomplished with general ventilation.  
(2) If a local exhaust system is used, then the exhaust air volume shall create an  
indraft air volume at an enclosure, hood, duct, or fan sufficient to control the  
contaminant.  
(3) A local exhaust system shall be designed to capture and control the  
contaminant. Distribution of exhaust air between various exhaust points may be  
accomplished by balanced duct design. If balancing gates are used, then they shall be  
locked permanently in place after final adjustment.  
(4) The design and construction of a local exhaust ventilation system shall be  
adequate for the contaminant and conditions of service. A listing of practical ventilation  
texts and references shall be available from the director upon request. Technical  
information and experience regarding specific contaminants and control measures may  
be obtained from the director.  
History: 1979 AC; 2003 AACS.  
R 325.2438 General ventilation system.  
Rule 38. A general ventilation system may be used for contaminant control. The  
ventilation air volume shall be sufficient to dilute the airborne contaminant to levels  
not exceeding the MAC.  
History: 1979 AC; 2003 AACS.  
R 325.2439 Exhaust system discharge locations.  
Rule 39. The discharge locations of local exhaust or general exhaust systems  
shall not permit exhausted air to re-enter a workroom or other buildings directly, or  
indirectly, through air supply systems without substantial dilution.  
History: 1979 AC; 2003 AACS.  
R 325.2440 Recirculation of air from exhaust systems.  
Rule 40. (1) The recirculation of air containing a contaminant whose MAC is at  
least 1000 ppm, 15 mg/m3, or 50 mppcf, shall be permitted if the exhaust ventilation  
system is equipped with an air cleaning device capable of reducing the contaminant  
concentrations to 10% or less of their MAC in the returned air.  
(2) The director may allow the recirculation of air containing a contaminant  
whose MAC is less than 1000 ppm, 15 mg/m3 or 50 mppcf, if the toxicity of the  
contaminant and the degree of air cleaning to be achieved create an environment which  
will not impair the health of the workers, and if  
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the contaminant concentrations in the returned air do not exceed 10% of its MAC.  
(3) A recirculation system shall include an alternate air duct connection to  
discharge the returned air outside of the building if necessary to protect the workers'  
health.  
History: 1979 AC; 2003 AACS.  
R 325.2441 Air pollution control.  
Rule 41. A local exhaust and general exhaust ventilation system shall comply  
with rules adopted by the Michigan Department of Environmental Quality, being R  
336.1101 to R 336.1910.  
History: 1979 AC; 2003 AACS.  
R 325.2442 Respiratory protective equipment; selection and use.  
Rule 42. (1) Respiratory protective equipment for the safeguarding of the workers'  
health shall be provided by the employer if other methods do not control the  
contaminants.  
(2) Respiratory protective equipment for the safeguarding of a worker's health  
may be used in place of other control measures in intermittent or temporary work  
situations.  
(3) Respiratory protective equipment shall be of a type approved for protection  
against the contaminant and degree of exposure to be encountered. A listing of approved  
types of respiratory protective equipment shall be available from the director.  
(4) Responsibility for equipment selection, issuance, use, training, and  
maintenance shall be vested in a qualified individual who shall have sufficient  
knowledge of the subject.  
(5) A worker shall be trained in the use of the equipment and shall have an  
opportunity to become familiar with it, have it fitted properly, and test its facepiece to  
face seal. If a worker needs to wear corrective lenses, then the facepiece and lenses  
shall be fitted by a qualified individual.  
(6) A worker shall use the equipment in accordance with instructions, shall  
report any malfunctioning of the equipment to the person responsible, and shall guard  
the equipment against damage.  
(7) If the equipment is to be used in an atmosphere immediately dangerous to life  
or health, then the worker shall use it in normal air for a reasonable familiarity  
period.  
(8) Emergency equipment shall be readily accessible at all times and its location  
shall be clearly marked.  
History: 1979 AC; 2003 AACS.  
R 325.2442a Respiratory protective equipment; maintenance.  
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Rule 42a. (1) Respiratory protective equipment shall be maintained in clean and  
effective condition.  
(2) Routinely used equipment shall be cleaned, inspected, and sanitized as  
frequently as necessary to ensure that proper protection is provided for the wearer.  
(3) Emergency equipment that is not routinely used shall be inspected, cleaned,  
and sanitized after each use and inspected at least monthly to ensure that it is in  
effective working condition. A record shall be kept of inspection dates and findings.  
(4) Equipment inspection shall include a check of the tightness of connections  
and the proper functioning of all parts.  
(5) Replacement or repairs shall be made by trained persons with parts  
designated for the specific equipment. Reducing valves or regulators shall be returned  
to the manufacturer or to a trained technician for adjustment or repair.  
(6) Equipment shall be stored to protect against dust, sunlight, heat, extreme cold,  
excessive moisture, or damaging chemicals.  
History: 1979 AC; 2003 AACS.  
R 325.2442b Respiratory protective equipment; types for certain hazards.  
Rule 42b. The following equipment shall be used in any of the following hazards:  
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History: 1979 AC; 2003 AACS.  
R 325.2442c Respiratory protective equipment; supplies and components.  
Rule 42c. (1) Compressed or liquid oxygen used with respiratory protective  
equipment shall be of high purity. Compressed oxygen shall not be used in supplied-air  
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respirators or in open-circuit self-contained breathing apparatus that have previously  
used compressed air.  
(2) Air may be supplied to equipment from cylinders or air compressors with  
proper pressure regulation and control. Air shall contain 19-23% oxygen and not more  
than 20 ppm carbon monoxide and 5 mg/m3 oil mist.  
(3) A compressor or compressor air intake shall be situated so as to prevent  
entry of contaminants into the system in amounts which may be injurious to the  
health of an exposed person.  
(4) An oil lubricated compressor shall incorporate suitable inline air purifying  
sorbents and filters, temperature regulators, and high-temperature cut-off to assure  
breathing air quality. An oil lubricated compressor shall not use vegetable oil lubricants.  
(5) An air-line coupling or connector shall be incompatible with outlets for other  
gas systems to prevent connection with nonrespirable gases or oxygen.  
(6) A self-contained breathing apparatus and universal type gas mask shall  
incorporate an audible or visible alarm or window to indicate impending failure of the  
device to provide respirable air. It is recommended that warning be given when 20-  
25% of rated service time remains.  
History: 1979 AC; 2003 AACS.  
R 325.2443 Variances.  
Rule 43. Variances as provided in R 325.2436 and R 325.2437(1) may be  
granted by the director upon written request. Variances granted by the director shall  
be in writing and shall consider the potential health hazard and the control measures to  
be employed.  
History: 1979 AC; 2003 AACS.  
R 325.2444 Hearing procedures.  
Rule 44. (1) The director shall serve a written notice upon an employer alleged to  
be in violation of these rules. The notice shall describe the alleged violation and set a  
date, time, and place for a hearing to determine whether a violation exists. The notice  
shall be delivered at least 15 days before the hearing date.  
(2) Evidence and testimony may be introduced at the hearing and all interested  
parties shall be given the full opportunity to present evidence and to cross-examine  
witnesses.  
(3) If a violation is found to exist, the director shall issue an order directing the  
person, firm, or corporation to correct the violation before a specified correction date.  
The correction date shall be established with consideration to the health hazard  
involved and the difficulty of eliminating the violation.  
(4) At the time of the hearing, or within 30 days after receipt of an order from  
the director, the person, firm, or corporation may request an extension of the  
correction date. The director may grant an extension of the correction date, with  
consideration to the health hazard and the difficulty of correction, for a reasonable time  
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if it is shown that the violation can and will be corrected before the extended correction  
date.  
(5) If a violation is not eliminated within the time specified, then the director shall  
issue a final order directing the person, firm, or corporation to cease the operation of the  
source that is in violation.  
History: 1979 AC; 2003 AACS.  
R 325.2445 Emergency procedure.  
Rule 45. If the director knows there is an immediate and serious hazard from  
exposure to a contaminant and he or she believes that a delay of 15 days would be  
prejudicial to the health or life of exposed persons, then the director shall notify the  
employer by written notice to  
discontinue immediately the exposure to the  
contaminant. Within 15 days the director shall provide the employer the opportunity to  
be heard and to present any proof that exposure to the contaminant does not constitute  
a danger to the health or life of the exposed persons.  
History: 1979 AC; 2003 AACS.  
R 325.2446 Appeals.  
Rule 46. An employer aggrieved by a decision of the director may appeal the  
decision pursuant to sections 101 to 106 of 1969 PA 306, MCL 24.301 to 24.306.  
History: 1979 AC; 2003 AACS.  
R 325.2447 Amendments; revisions.  
Rule 47. (1) If the director has knowledge that rule revision is required for the  
prevention of occupational disease or significant physiological disturbance, or after  
consideration of a request by any person, he may proceed to amend these rules in  
accordance with the administrative procedures act.  
(2) If the director believes that there is a significant hazard to the health of  
exposed persons, he may proceed to amend these rules and provide for the immediate  
effect of the amendment in accordance with the administrative procedures act.  
History: 1979 AC; 2003 AACS.  
R 325.2448 Rescission.  
Rule 48. The rules entitled "Basic Guides for Control of Exposure to  
Atmospheric Contaminants in Places of Employment," being R 325.1351 to R  
325.1355 of the Michigan Administrative Code and appearing on pages 2592 to 2599 of  
the 1962 Annual Supplement to the Code, are rescinded.  
History: 1979 AC; 2003 AACS.  
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;