DEPARTMENT OF LABOR AND ECONOMIC OPPORTUNITY  
DIRECTOR'S OFFICE  
CONSTRUCTION SAFETY AND HEALTH STANDARD  
(By authority conferred on the director of the department of labor and economic  
opportunity by sections 14, 16, 19, 21, and 24 of the Michigan occupational safety and  
health act, 1974 PA 154, MCL 408.1014, 408.1016, 408.1019, 408.1021, and 408.1024,  
and Executive Reorganization Order Nos. 1996-1, 1996-2, 2003-1, 2008-4, 2011-4, and  
2019-3, MCL 330.3101, 445.2001, 445.2011, 445.2025, 445.2030, and 125.1998)  
PART 601. AIR CONTAMINANTS FOR CONSTRUCTION  
R 325.60151 Scope, application, and availability of standards.  
Rule 1. (1) An employer shall ensure that employee exposures to inhalation, ingestion,  
skin absorption, or contact with any material or substance at a concentration above those  
specified in the "Threshold Limit Values of Airborne Contaminants for 1970" of the  
American Conference of Governmental Industrial Hygienists, as listed in R 325.60154 to  
R 325.60161, are avoided.  
(2) To achieve compliance with subrule (1) of this rule, an employer shall ensure that  
administrative or engineering controls are implemented whenever feasible. If  
administrative or engineering controls are not feasible to achieve full compliance, then  
protective equipment or other protective measures must be used to keep the exposure of  
employees to air contaminants within the limits prescribed in this rule. Any equipment  
and technical measures used for this purpose must first be approved for each particular  
use by a competent industrial hygienist or other technically qualified person. Respirators  
must be used in a manner that is in compliance with Occupational Health Standard Part  
451. “Respiratory Protection.”  
(3) General Industry Safety and Health Standard Part 302 “Vinyl Chloride,” applies to  
the exposure of every employee to vinyl chloride in every employment and place of  
employment covered by these rules in place of any different standard on exposure to  
vinyl chloride that would otherwise be applicable under subrule (1) of this rule.  
(4) The “Threshold Limit Values (TLV) of the American Conference of Governmental  
Industrial Hygienists (A.C.G.I.H.) for 1970” appear in R 325.60153 to R 325.60161. The  
Threshold Limit Values identified in these rules as Maximum Allowable Concentrations  
(MAC) are specified in these rules.  
(5) These rules do not apply to the following types of employment:  
(a) Agriculture.  
(b) Domestic.  
(c) Mining.  
(d) General industry work.  
Page 1  
(6) Exposure to air contaminants in general industry work is covered by General  
Industry Safety and Health Standard Part 301. “Air Contaminants for General Industry.”  
(7) The following Michigan Occupational Safety and Health Administration (MIOSHA)  
standards are referenced in these rules. Up to 5 copies of these standards may be  
obtained at no charge from the Michigan Department of Labor and Economic  
Opportunity, MIOSHA Regulatory Services Section, 530 West Allegan Street, P.O. Box  
30643, Lansing, Michigan, 48909-8143 or via the internet at the following website:  
www.michigan.gov/mioshastandards. For quantities greater than 5, the cost, as of the  
time of adoption of these rules, is 4 cents per page.  
(a) General Industry Safety and Health Standard Part 301. “Air Contaminants for  
General Industry,” R 325.51101 to R 325.51108.  
(b) General Industry Safety and Health Standard Part 302. “Vinyl Chloride,”  
R 325.51401 to R 325.51414.  
(c) General Industry and Construction Safety and Health Standard Part 304. “Ethylene  
Oxide,” R 325.51151 to R 325.51177.  
(d) General Industry and Construction Safety and Health Standard Part 306.  
“Formaldehyde,” R 325.51451 to R 325.51477.  
(e) General Industry and Construction Safety and Health Standard Part 307.  
“Acrylonitrile,” R 325.51501 to R 325.51527.  
(f) General Industry and Construction Safety and Health Standard Part 308. “Inorganic  
Arsenic,” R 325.51601 to R 325.51628.  
(g) General Industry and Construction Safety and Health Standard Part 311.  
“Benzene,” R 325.77101 to R 325.77115.  
(h) Occupational Health Standard Part 312. “1,3-Butadiene,” R 325.50091 to  
R 325.50093.  
(i) Occupational Health Standard Part 313. “Methylene Chloride,” R 325.51651 to  
R 325.51653.  
(j) General Industry and Construction Safety and Health Standard Part 314. “Coke  
Oven Emissions,” R 325.50100 to R 325.50136.  
(k) Occupational Health Standard Part 451. “Respiratory Protection,” R 325.60051 to  
R 325.60052.  
(l) Occupational Health Standard Part 602. “Asbestos Standards for Construction,”  
R 325.51301 to R 325.51302.  
(m) Construction Safety and Health Standard Part 603. “Lead Exposure in  
Construction,” R 325.51983 to R 325.51993.  
(n) Occupational Health Standard Part 604. “Chromium (VI) in Construction,”  
R 325.51995 to R 325.51997.  
(o) Construction Safety and Health Standard Part 605. “Methylenedianiline (MDA) in  
Construction,” R 325.60501 to R 325.60501.  
(p) Construction Safety and Health Standard Part 609. “Cadmium in Construction,”  
R 325.60901 to R 325.60901.  
(q) Occupational Health Standard Part 690. “Silica in Construction,” R 325.69001 to  
R 325.69015.  
History: 2002 AACS; 2013 AACS; 2017 AACS; 2019 AACS.  
Page 2  
R 325.60151a Rescinded.  
History: 2013 AACS; 2017 AACS; 2019 AACS.  
R 325.60152 Definitions.  
Rule 2. (1) "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.  
(2) "Mg/m3" means milligrams of particulate per cubic meter of air.  
(3) "Mppcf" means millions of particulates per cubic foot of air based on impinger  
samples counted by light field microscopic techniques.  
(4) "Non-respirable atmosphere" means an atmosphere that contains insufficient  
oxygen, or an elevated level of contaminants that may render a person incapable of self-  
rescue.  
(5) "Ppm" means parts of vapor or gas per million parts of air by volume at 25 degrees  
Celsius and 760 millimeters of mercury pressure.  
(6) "Source" means a process or equipment that releases a contaminant into the air in  
concentrations exceeding the MAC.  
History: 2002 AACS; 2017 AACS.  
R 325.60153 Contaminants; exposures; MAC.  
Rule 3. (1) An employer shall not allow an employee to be exposed to a contaminant  
at concentrations in excess of the MAC as listed in R 325.60154 to R 325.60161.  
(2) An employer shall not allow an employee to be exposed to a contaminant or  
combination of contaminants in concentrations that are hazardous or injurious to the  
person's health.  
History: 2002 AACS.  
R 325.60154 Maximum allowable concentrations.  
Rule 4. (1) Maximum allowable concentrations of air contaminants based on a repeated  
8-hour work day exposure are listed in tables 1 to 7 in R 325.60155 to R 325.60161.  
(2) A substance in tables 1 to 6 that is preceded by the letter A, C, S, or STEL is an  
especially hazardous contaminant and all the following precautions shall be taken:  
(a) If the substance is preceded by the letter "A", then an employer shall ensure that an  
employee or any part of an employee’s anatomy is not exposed to, or allowed to come in  
contact with, the substance by means of any respiratory, oral, or skin route.  
(b) If the substance is preceded by the letter "C", then its MAC means the highest  
concentration at which an employer may allow a person to be exposed at any time unless  
noted otherwise. This concentration is commonly referred to as a “ceiling.”  
(c) If the substance is preceded by the letter "S", then an employer shall ensure that  
precautions are taken to prevent skin absorption.  
Page 3  
(d) If the substance is preceded by “STEL”, then it means the STEL listed. For  
example, an employee's 15-minute, time-weighted average exposure, shall not be  
exceeded at any time during a work day. The STEL is commonly referred to as the  
"short-term exposure limit."  
History: 2002 AACS; 2013 AACS.  
R 325.60155 Maximum allowable concentrations for substances; A and B.  
Rule 5. Table 1 for substances A and B, are as follows:  
TABLE 1  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; A AND B  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
Abate  
3383-96-8  
75-07-0  
64-19-7  
108-24-7  
67-64-1  
75-05-8  
---  
200  
10  
15  
360  
25  
Acetaldehyde  
Acetic acid  
Acetic anhydride  
Acetone  
5
20  
1,000  
40  
2,400  
70  
Acetonitrile  
Acetylene  
Inert gas  
Acetylene dichloride  
Acetylene tetrabromide  
Acrolein  
See 1,2-Dichloroethylene  
79-27-6  
1
14  
0.25  
0.3  
107-02-8  
0.1  
---  
S
S
S
S
Acrylamide  
79-06-1  
Acrylonitrile  
See GI & CS 307. Acrylonitrile*  
Aldrin  
309-00-2  
107-18-6  
107-05-1  
106-92-3  
2179-59-1  
---  
2
0.25  
5
Allyl alcohol  
Allyl chloride  
1
3
C
Allyl glycidyl ether (AGE)  
Allyl propyl disulfide  
Alundum (Al203)  
2-Aminoethanol  
2-Aminopyridine  
Ammonia  
10  
2
45  
12  
Inert dust  
See Ethanolamine  
504-29-0  
0.5  
50  
---  
2
7664-41-7  
35  
15  
Ammonium sulfamate (amate)  
7773-06-0  
Page 4  
TABLE 1  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; A AND B  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
n-Amyl acetate  
628-63-7  
626-38-0  
62-53-3  
100  
125  
5
525  
650  
19  
sec-Amyl acetate  
S
S
Aniline  
Anisidine (o- and p-isomers)  
Antimony and compounds (as Sb)  
ANTU (alpha naphthylthiourea)  
Argon  
29191-52-4  
7440-36-0  
86-88-4  
---  
---  
---  
0.5  
0.5  
0.3  
Inert gas  
Arsenic, inorganic compounds  
Arsenic, organic compounds (as As)  
Arsine  
See GI & CS 308. Inorganic Arsenic*  
7440-38-2  
7784-42-1  
---  
0.05  
---  
0.5  
0.2  
0.2  
0.5  
S
Azinphos-methyl  
86-50-0  
Barium (soluble compounds)  
Benzene (benzol)  
7440-39-3  
---  
See GI & CS 311. Benzene*  
92-87-5  
A, S Benzidine  
p-Benzoquinone  
---  
---  
See Quinone  
94-36-0  
Benzoyl peroxide  
Benzyl chloride  
---  
1
5
5
100-44-7  
MAC/Ceiling/STEL  
STEL  
MAC  
ppm  
---  
mg/m3  
mg/m3  
Beryllium and beryllium compounds (as  
Be)  
0.0002  
7440-41-7  
7440-41-7  
(0.2 μg/m3)  
Beryllium and beryllium compounds (as  
Be)  
0.002  
STEL  
(2.0 μg/m3)  
Biphenyl  
See Diphenyl  
Bisphenol A  
See Diglycidyl ether  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
Boron oxide  
1303-86-2  
---  
1
15  
10  
Boron tribromide  
10294-33-4  
Page 5  
TABLE 1  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; A AND B  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
C
S
Boron trifluoride  
7637-07-2  
7726-95-6  
1
3
Bromine  
0.1  
0.1  
0.5  
0.7  
0.7  
5
Bromine pentafluoride  
Bromoform  
7789-30-2  
75-25-2  
Butadiene (1,3-butadiene)  
Butanethiol  
See OH 312. 1,3-Butadiene*  
See Butyl mercaptan  
2-Butanone  
78-93-3  
111-76-2  
123-86-4  
105-46-4  
540-88-5  
71-36-3  
78-92-2  
75-65-0  
109-73-9  
200  
50  
590  
240  
710  
950  
950  
300  
450  
300  
15  
S
2-Butoxy ethanol (butyl cellosolve)  
Butyl acetate (n-butyl acetate)  
sec-Butyl acetate  
tert-Butyl acetate  
Butyl alcohol  
150  
200  
200  
100  
150  
100  
5
sec-Butyl alcohol  
tert-Butyl alcohol  
S, C Butylamine  
tert-Butyl chromate (as Cr+6)  
See OH 604. Chromium (VI) in Construction*, **  
n-Butyl glycidyl ether (BGE)  
Butyl mercaptan  
p-tert-Butyltoluene  
2426-08-6  
109-79-5  
98-51-1  
50  
0.5  
10  
270  
1.5  
60  
The CAS number is for information only. Enforcement is based on the substance name. For  
an entry covering more than 1 metal compound measured as the metal, the CAS number for  
the metal is given - not the CAS number for the individual compounds.  
See R 325.60154(2)(a).  
See R 325.60154(2)(b).  
See R 325.60154(2)(c).  
1
A
C
S
STEL See R 325.60154(2)(d).  
*
Caution--these rules contain extensive requirements for exposure to these substances.  
If the exposure limit in OH 604. Chromium (VI) in Construction is stayed or is otherwise not  
in effect, the exposure limit is a ceiling of 0.1 mg/m3 and has an "S" notation.  
All MIOSHA Standards shown in this table  
**  
are referenced in R 325.60151.  
History: 2002 AACS; 2013 AACS; 2017 AACS; 2019 AACS.  
Page 6  
R 325.60156 Maximum allowable concentrations for substances; C and D.  
Rule 6. Table 2 for substances C and D, are as follows:  
TABLE 2  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; C AND D  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
Cadmium and cadmium compounds  
Calcium arsenate  
Calcium carbonate  
Calcium oxide  
See CS 609. Cadmium in Construction*  
---  
1
1317-65-3  
1305-78-8  
76-22-2  
Inert dust  
---  
2
5
---  
Camphor (synthetic)  
Carbaryl (Sevin®)  
Carbon black  
63-25-2  
---  
5
1333-86-4  
124-38-9  
75-15-0  
---  
3.5  
9,000  
60  
Carbon dioxide  
5,000  
20  
S
Carbon disulfide  
Carbon monoxide  
630-08-0  
56-23-5  
50  
55  
S, C Carbon tetrachloride  
Cellulose (paper fiber)  
10  
65  
9004-34-6  
57-74-9  
Inert dust  
S
S
Chlordane  
---  
---  
0.5  
0.5  
Chlorinated camphene  
8001-35-2  
55720-99-5  
or  
Chlorinated diphenyl oxide  
---  
0.5  
31242-93-0  
Chlorine  
7782-50-5  
10049-04-4  
7790-91-2  
107-20-0  
532-27-4  
108-90-7  
2698-41-1  
74-97-5  
1
3
0.3  
0.4  
3
Chlorine dioxide  
0.1  
0.1  
1
C
C
Chlorine trifluoride  
Chloroacetaldehyde  
alpha-Chloroacetophenone (Phenacyl chloride)  
Chlorobenzene (mono chlorobenzene)  
o-Chlorobenzylidene malononitrile (OCBM)  
Chlorobromomethane  
0.05  
75  
0.3  
350  
0.4  
1,050  
0.05  
200  
2-Chloro-1,3-butadiene  
See Chloroprene  
S
S
Chlorodiphenyl (42% Chlorine)  
Chlorodiphenyl (54% Chlorine)  
1-Chloro-2,3-epoxy propane  
53469-21-9  
11097-69-1  
---  
---  
1
0.5  
See Epichlorohydrin  
Page 7  
TABLE 2  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; C AND D  
MAC/Ceiling/STEL  
SUBSTANCE  
2-Chloroethanol  
CAS No.1  
ppm  
mg/m3  
See Ethylene chlorohydrin  
See Vinyl chloride  
67-66-3  
Chloroethylene  
C
S
Chloroform (Trichloromethane)  
1-Chloro-1-nitropropane  
Chloropicrin  
50  
20  
0.1  
25  
240  
100  
0.7  
90  
600-25-9  
76-06-2  
Chloroprene (2-chloro-1,3-butadiene)  
126-99-8  
Chromic acid and chromates  
(as Cr03 )  
See OH 604. Chromium (VI) in Construction*, ***  
See OH 604. Chromium (VI) in Construction*, ***  
Chromium (VI) compounds  
Chromium  
Varies with  
compound  
sol. chromic and chromous salts (as Cr)  
Metal and insol. Salts  
---  
---  
0.5  
1
7440-47-3  
Coal tar pitch volatiles  
(benzene soluble fraction: anthracene, BaP,  
phenanthrene, acridine, chrysene, pyrene)  
65996-93-2  
7440-48-4  
---  
0.2  
0.1  
Cobalt, metal fume and dust  
Coke oven emissions  
Copper  
See GI & CS 314. Coke Oven Emissions*  
Fume  
---  
0.1  
1
7440-50-8  
---  
Dusts and mists  
Corundum (Al203)  
Cotton dust (raw)  
Crag® herbicide  
Cresol (all isomers)  
Inert dust  
---  
---  
5
1
136-78-7  
1319-77-3  
15  
22  
S
123-73-9  
4170-30-3  
Crotonaldehyde  
Cumene  
2
6
245  
5
S
S
98-82-8  
50  
---  
Varies with  
compound  
Cyanide (as CN)  
Cyanogen  
460-19-5  
110-82-7  
108-93-0  
10  
300  
50  
---  
Cyclohexane  
Cyclohexanol  
1,050  
200  
Page 8  
TABLE 2  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; C AND D  
MAC/Ceiling/STEL  
SUBSTANCE  
Cyclohexanone  
CAS No.1  
ppm  
50  
mg/m3  
200  
1,015  
200  
10  
108-94-1  
110-83-8  
542-92-7  
94-75-7  
50-29-3  
Cyclohexene  
300  
75  
Cyclopentadiene  
2,4-D  
---  
S
DDT (Dichlorodiphenyl-trichloroethane)  
---  
1
DDVP  
See Dichlorvos  
S
S
Decaborane  
Demeton®  
17702-41-9  
8065-48-3  
0.05  
---  
0.3  
0.1  
Diacetone alcohol  
(4-hydroxy-4-methyl-2-pentanone)  
123-42-2  
50  
240  
1,2-Diainoethane  
Diazomethane  
Diborane  
See Ethylenediamine  
334-88-3  
19287-45-7  
106-93-4  
0.2  
0.1  
25  
0.4  
0.1  
190  
5
S, C 1,2-Dibromoethane (ethylene dibromide)  
Dibutyl phosphate  
107-66-4  
1
Dibutyl phthalate  
84-74-2  
---  
5
C
C
Dichloroacetylene  
7572-29-4  
95-50-1  
0.1  
50  
0.4  
300  
450  
4,950  
0.2  
400  
200  
790  
90  
o-Dichlorobenzene  
p-Dichlorobenzene  
106-46-7  
75  
Dichlorodifluoromethane  
1,3-Dichloro-5, 5-dimethyl hydantoin  
1,1-Dichloroethane  
75-71-8  
1,000  
---  
118-52-5  
75-34-3  
100  
50  
1,2-Dichloroethane  
107-06-2  
1,2-Dichloroethylene  
540-59-0  
200  
15  
S, C Dichloroethyl ether  
Dichloromethane  
111-44-4  
See Methylene chloride  
75-69-4  
Dichloromonofluoromethane  
1,000  
10  
4,200  
60  
C
S
1,1-Dichloro-1-nitroethane  
1,2-Dichloropropane  
594-72-9  
See Propylene dichloride  
76-14-2  
Dichlorotetrafluoroethane  
Dichlorvos (DDVP)  
1,000  
---  
7,000  
1
62-73-7  
Page 9  
TABLE 2  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; C AND D  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
---  
mg/m3  
0.25  
75  
S
S
Dieldrin  
60-57-1  
109-89-7  
100-37-8  
111-40-0  
Diethylamine  
25  
Diethylamino, ethanol  
10  
50  
S, C Diethylene triamine  
Diethyl ether  
10  
42  
See Ethyl ether  
Difluorodibromomethane  
75-61-6  
100  
0.5  
860  
2.8  
C
Diglycidyl ether (DGE)  
Dihydroxybenzene  
2238-07-5  
See Hydroquinone  
108-83-8  
Diisobutyl ketone  
50  
5
290  
20  
S
S
Diisopropylamine  
108-18-9  
Dimethoxymethane  
Dimethyl acetamide  
Dimethylamine  
See Methylal  
127-19-5  
124-40-3  
10  
10  
35  
18  
Dimethylaminobenzene  
Dimethylaniline (N-dimethylaniline)  
Dimethylbenzene  
See Xylidene  
See Xylene  
S
121-69-7  
5
25  
Dimethyl-1, 2-dibromo- 2,  
2-dichloroethyl phosphate (Dibrom®)  
300-76-5  
68-12-2  
---  
10  
3
S
S
Dimethylformamide  
2,6-Dimethylheptanone  
1,1-Dimethylhydrazine  
Dimethylphthalate  
30  
See Diisobutyl ketone  
57-14-7  
0.5  
---  
1
1
5
5
131-11-3  
S
S
Dimethyl sulfate  
77-78-1  
99-65-0  
528-29-0  
100-25-4  
Dinitrobenzene (all isomers)  
---  
1
S
S
S
Dinitro-o-cresol  
534-52-1  
25321-14-6  
123-91-1  
92-52-4  
---  
---  
0.2  
1.5  
360  
1
Dinitrotoluene  
Dioxane (diethylene dioxide)  
Diphenyl  
100  
0.2  
---  
Diphenylamine  
122-39-4  
10  
Diphenylmethane diisocyanate  
See Methylene bisphenyl isocyanate (MDI)  
Page 10  
TABLE 2  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; C AND D  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
100  
mg/m3  
S
Dipropylene glycol methyl ether  
34590-94-8  
117-81-7  
600  
Di-sec-octyl phthalate  
(di-2-ethylhexylphthalate)  
---  
5
The CAS number is for information only. Enforcement is based on the substance name. For  
an entry covering more than 1 metal compound measured as the metal, the CAS number for  
the metal is given - not the CAS number for the individual compounds.  
1
A
See R 325.60154(2)(a).  
C B See R 325.60154(2)(b).  
S C See R 325.60154(2)(c).  
STEL See R 325.60154(2)(d).  
*
Caution--these rules contain extensive requirements for exposure to these substances.  
If the exposure limit in OH 604. Chromium (VI) in Construction is stayed or is otherwise not  
*** in effect, the exposure limit is 0.1 mg/m3 for chromic acid and chromates (Cr03) as an 8-hour  
TWA.  
All MIOSHA Standards shown in is this table  
are referenced in R 325.60151.  
History: 2002 AACS; 2013 AACS; 2017 AACS; 2019 AACS.  
R 325.60157 Maximum allowable concentrations for substances; E to H.  
Rule 7. Table 3 for substances E to H, are as follows:  
TABLE 3  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; E TO H  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
mg/m3  
Emery  
Inert dust  
S
S
S
S
Endosulfan (Thiodan®)  
Endrin  
115-29-7  
72-20-8  
---  
---  
5
0.1  
0.1  
19  
Epichlorohydrin  
EPN  
106-89-8  
2104-64-5  
---  
0.5  
1,2-Epoxypropane  
See Propylene oxide  
Page 11  
TABLE 3  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; E TO H  
MAC/Ceiling/STEL  
SUBSTANCE  
2,3-Epoxy-1-propanol  
CAS No.1  
ppm  
mg/m3  
See Glycidol  
Ethane  
Inert gas  
Ethanethiol  
See Ethyl mercaptan  
141-43-5  
Ethanolamine  
3
200  
100  
400  
25  
6
S
S
2-Ethoxyethanol  
2-Ethoxyethyl acetate (cellosolve acetate)  
Ethyl acetate  
110-80-5  
111-15-9  
141-78-6  
140-88-5  
64-17-5  
75-04-7  
541-85-5  
100-41-4  
74-96-4  
106-35-4  
75-00-3  
60-29-7  
109-94-4  
75-08-1  
78-10-4  
740  
540  
1,400  
100  
1,900  
18  
S
Ethyl acrylate  
Ethyl alcohol (ethanol)  
Ethylamine  
1,000  
10  
Ethyl sec-amyl ketone (5-methyl-3-heptanone)  
Ethyl benzene  
25  
130  
435  
890  
230  
2,600  
1,200  
300  
1
100  
200  
50  
Ethyl bromide  
Ethyl butyl ketone (3-heptanone)  
Ethyl chloride  
1,000  
400  
100  
0.5  
Ethyl ether  
Ethyl formate  
Ethyl mercaptan  
Ethyl silicate  
100  
850  
Ethylene  
Inert gas  
S
Ethylene chlorohydrin  
Ethylenediamine  
107-07-3  
107-15-3  
5
16  
25  
10  
Ethylene dibromide  
Ethylene dichloride  
See 1,2-Dibromoethane  
See 1,2-Dichloroethane  
628-96-6  
S, C Ethylene glycol dinitrate  
0.2  
1
1
Ethylene glycol monomethyl ether acetate  
See Methyl cellosolve acetate  
151-56-4 0.5  
S
S
Ethyleneimine  
Ethylene oxide  
Ethylidine chloride  
N-Ethylmorpholine  
Ferbam  
See GI & CS 304. Ethylene Oxide*  
See 1,1-Dichloroethane  
100-74-3  
20  
---  
94  
15  
14484-64-1  
Page 12  
TABLE 3  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; E TO H  
MAC/Ceiling/STEL  
SUBSTANCE  
Ferrovanadium dust  
CAS No.1  
ppm  
---  
mg/m3  
12604-58-9  
1
Fibrous glass  
Inert dust  
Varies with  
compound  
Fluoride (as F)  
---  
2.5  
Fluorine  
7782-41-4  
75-69-4  
0.1  
0.2  
Fluorotrichloromethane  
Formaldehyde  
Formic acid  
1,000  
5,600  
C
S
See GI & CS 306. Formaldehyde*  
64-18-6  
98-01-1  
98-00-0  
5
5
9
Furfural  
20  
Furfuryl alcohol  
50  
200  
Gasoline (limits will be based on aromatic hydrocarbons in mixture)  
Glycerine mist  
Inert mist  
Glycidol (2,3-epoxy-1-propanol)  
Glycol monoethyl ether  
Graphite (synthetic)  
Guthion®  
556-52-5  
50  
---  
150  
See 2-Ethoxyethanol  
Inert dust  
Inert dust  
Inert gas  
See Azinphos-methyl  
13397-24-5  
Gypsum  
Hafnium  
7440-58-6  
0.5  
0.5  
Helium  
S
Heptachlor  
76-44-8  
142-82-5  
67-72-1  
---  
500  
1
Heptane (n-heptane)  
Hexachloroethane  
Hexachloronaphthalene  
Hexane (n-hexane)  
2-Hexanone  
2,000  
10  
S
S
1335-87-1  
110-54-3  
591-78-6  
108-10-1  
108-84-9  
302-01-2  
---  
0.2  
500  
100  
100  
50  
1,800  
410  
410  
300  
1.3  
Hexone (methyl isobutyl ketone)  
sec-Hexyl acetate  
Hydrazine  
S
1
Hydrogen  
Inert gas  
Hydrogen bromide  
Hydrogen chloride  
10035-10-6  
7647-01-0  
3
5
10  
7
C
Page 13  
TABLE 3  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; E TO H  
MAC/Ceiling/STEL  
SUBSTANCE  
Hydrogen cyanide  
CAS No.1  
ppm  
10  
3
mg/m3  
S
74-90-8  
7664-39-3  
7722-84-1  
7783-07-5  
7783-06-4  
123-31-9  
11  
Hydrogen fluoride  
Hydrogen peroxide  
Hydrogen selenide  
Hydrogen sulfide  
Hydroquinone  
2
1
1.4  
0.2  
15  
0.05  
10  
---  
2
The CAS number is for information only. Enforcement is based on the substance name. For  
an entry covering more than 1 metal compound measured as the metal, the CAS number for  
the metal is given - not the CAS number for the individual compounds.  
1
A
See R 325.60154(2)(a).  
C B See R 325.60154(2)(b).  
S C See R 325.60154(2)(c).  
STEL See R 325.60154(2)(d).  
*
Caution--these rules contain extensive requirements for exposure to these substances.  
All MIOSHA Standards shown in is this table  
are referenced in R 325.60151.  
History: 2002 AACS; 2013 AACS; 2017 AACS; 2019 AACS 2019.  
R 325.60158 Maximum allowable concentrations for substances; I to M.  
Rule 8. Table 4 for substances I to M, are as follows:  
TABLE 4  
MAXIMUM ALLOWABLE CONCENTRATIONS FOR SUBSTANCES; I TO M  
MAC/Ceiling/STEL  
SUBSTANCE  
CAS No.1  
ppm  
10  
mg/m3  
Indene  
95-13-6  
45  
Indium and compounds (as In)  
Iodine  
7440-74-6  
7553-56-2  
1309-37-1  
---  
0.1