[Code of Federal Regulations]
[Title 29, Volume 6]
[Revised as of July 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.1000]

[Page 5-19]
 
                             TITLE 29--LABOR
 
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT 
                                OF LABOR
 
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED)--Table of 
Contents
 
                Subpart Z_Toxic and Hazardous Substances
 
Sec.  1910.1000  Air contaminants.




  --------------------------------------------------------------------
Part                                                                Page
1910            Occupational Safety and Health Standards 
                    (Continued).............................           7
                Subject Index for 29 CFR Part 1910--
                    Occupational Safety and Health Standards         497

[[Page 7]]





                Subpart Z_Toxic and Hazardous Substances

Sec.
1910.1000 Air contaminants.
1910.1001 Asbestos.
1910.1002 Coal tar pitch volatiles; interpretation of term.
1910.1003 13 Carcinogens (4-Nitrobiphenyl, etc.).
1910.1004 alpha-Naphthylamine.
1910.1005 [Reserved]
1910.1006 Methyl chloromethyl ether.
1910.1007 3,'--Dichlorobenzidine (and its salts).
1910.1008 bis-Chloromethyl ether.
1910.1009 beta-Naphthylamine.
1910.1010 Benzidine.
1910.1011 4-Aminodiphenyl.
1910.1012 Ethyleneimine.
1910.1013 beta-Propiolactone.
1910.1014 2-Acetylaminofluorene.
1910.1015 4-Dimethylaminoazobenzene.
1910.1016 N-Nitrosodimethylamine.
1910.1017 Vinyl chloride.
1910.1018 Inorganic arsenic.
1910.1020 Access to employee exposure and medical records.
1910.1025 Lead.
1910.1026 Chromium (VI).
1910.1027 Cadmium.
1910.1028 Benzene.
1910.1029 Coke oven emissions.
1910.1030 Bloodborne pathogens.
1910.1043 Cotton dust.
1910.1044 1,2-dibromo-3-chloropropane.
1910.1045 Acrylonitrile.
1910.1047 Ethylene oxide.
1910.1048 Formaldehyde.
1910.1050 Methylenedianiline.
1910.1051 1,3-Butadiene.
1910.1052 Methylene Chloride.
1910.1096 Ionizing radiation.
1910.1200 Hazard communication.
1910.1201 Retention of DOT markings, placards and labels.
1910.1450 Occupational exposure to hazardous chemicals in laboratories.

Subject Index for 29 CFR Part 1910--Occupational Safety and Health 
          Standards


    Authority: Sections 4, 6, 8 of the Occupational Safety and Health 
Act of 1970 (29 U.S.C. 653, 655, 657: Secretary of Labor's Order No. 12-
71 (36 FR 8754), 8-76 (41 FR 25059), 9-83 (48 FR 35736), 1-90 (55 FR 
9033), 6-96 (62 FR 111), 3-2000 (65 FR 50017), or 5-2002 (67 FR 65008), 
as applicable; and 29 CFR part 1911.
    All of subpart Z issued under section 6(b) of the Occupational 
Safety and Health Act, except those substances that have exposure limits 
listed in Tables Z-1, Z-2, and Z-3 of 29 CFR 1910.1000. The latter were 
issued under section 6(a) (29 U.S.C. 655(a)).
    Section 1910.1000, Tables Z-1, Z-2 and Z-3 also issued under 5 
U.S.C. 553, Section 1910.1000 Tables Z-1, Z-2, and Z-3 but not under 29 
CFR part 1911 except for the arsenic (organic compounds), benzene, 
cotton dust, and chromium (VI) listings.
    Section 1910.1001 also issued under section 107 of the Contract Work 
Hours and Safety Standards Act (40 U.S.C. 3704) and 5 U.S.C. 553.
    Section 1910.1002 also issued under 5 U.S.C. 553 but not under 29 
U.S.C. 655 or 29 CFR part 1911.
    Sections 1910.1018, 1910.1029 and 1910.1200 also issued under 29 
U.S.C. 653.
    Section 1910.1030 also issued under Pub. L. 106-430, 114 Stat. 1901.

    Source: 39 FR 23502, June 27, 1974, unless otherwise noted. 
Redesignated at 40 FR 23072, May 28, 1975.


    An employee's exposure to any substance listed in Tables Z-1, Z-2, 
or Z-3 of this section shall be limited in accordance with the 
requirements of the following paragraphs of this section.
    (a) Table Z-1--(1) Substances with limits preceded by ``C''--Ceiling 
Values. An employee's exposure to any substance in Table Z-1, the 
exposure limit of which is preceded by a ``C'', shall at no time exceed 
the exposure limit given for that substance. If instantaneous monitoring 
is not feasible, then the ceiling shall be assessed as a 15-minute time 
weighted average exposure which shall not be exceeded at any time during 
the working day.
    (2) Other substances--8-hour Time Weighted Averages. An employee's 
exposure to any substance in Table Z-1, the exposure limit of which is 
not preceded by a ``C'', shall not exceed the 8-hour Time Weighted 
Average given for that substance in any 8-hour work shift of a 40-hour 
work week.
    (b) Table Z-2. An employee's exposure to any substance listed in 
Table Z-2 shall not exceed the exposure limits specified as follows:
    (1) 8-hour time weighted averages. An employee's exposure to any 
substance

[[Page 8]]

listed in Table Z-2, in any 8-hour work shift of a 40-hour work week, 
shall not exceed the 8-hour time weighted average limit given for that 
substance in Table Z-2.
    (2) Acceptable ceiling concentrations. An employee's exposure to a 
substance listed in Table Z-2 shall not exceed at any time during an 8-
hour shift the acceptable ceiling concentration limit given for the 
substance in the table, except for a time period, and up to a 
concentration not exceeding the maximum duration and concentration 
allowed in the column under ``acceptable maximum peak above the 
acceptable ceiling concentration for an 8-hour shift.''
    (3) Example. During an 8-hour work shift, an employee may be exposed 
to a concentration of Substance A (with a 10 ppm TWA, 25 ppm ceiling and 
50 ppm peak) above 25 ppm (but never above 50 ppm) only for a maximum 
period of 10 minutes. Such exposure must be compensated by exposures to 
concentrations less than 10 ppm so that the cumulative exposure for the 
entire 8-hour work shift does not exceed a weighted average of 10 ppm.
    (c) Table Z-3. An employee's exposure to any substance listed in 
Table Z-3, in any 8-hour work shift of a 40-hour work week, shall not 
exceed the 8-hour time weighted average limit given for that substance 
in the table.
    (d) Computation formulae. The computation formula which shall apply 
to employee exposure to more than one substance for which 8-hour time 
weighted averages are listed in subpart Z of 29 CFR part 1910 in order 
to determine whether an employee is exposed over the regulatory limit is 
as follows:
    (1)(i) The cumulative exposure for an 8-hour work shift shall be 
computed as follows:

E = (Ca Ta+Cb Tb+. . 
    .Cn Tn)/8

Where:

E is the equivalent exposure for the working shift.
C is the concentration during any period of time T where the 
concentration remains constant.
T is the duration in hours of the exposure at the concentration C.

The value of E shall not exceed the 8-hour time weighted average 
specified in subpart Z of 29 CFR part 1910 for the substance involved.

    (ii) To illustrate the formula prescribed in paragraph (d)(1)(i) of 
this section, assume that Substance A has an 8-hour time weighted 
average limit of 100 ppm noted in Table Z-1. Assume that an employee is 
subject to the following exposure:

Two hours exposure at 150 ppm
Two hours exposure at 75 ppm
Four hours exposure at 50 ppm

    Substituting this information in the formula, we have

(2x150+2x75+4x50)/8=81.25 ppm

    Since 81.25 ppm is less than 100 ppm, the 8-hour time weighted 
average limit, the exposure is acceptable.

    (2)(i) In case of a mixture of air contaminants an employer shall 
compute the equivalent exposure as follows:

Em=(C1/L1+C2/
    L2)+. . .(Cn/Ln)

Where:

Em is the equivalent exposure for the mixture.
C is the concentration of a particular contaminant.
L is the exposure limit for that substance specified in subpart Z of 29 
CFR part 1910.

The value of Em shall not exceed unity (1).

    (ii) To illustrate the formula prescribed in paragraph (d)(2)(i) of 
this section, consider the following exposures:

------------------------------------------------------------------------
                                                  Actual
                                              concentration
                  Substance                     of 8-hour     8-hour TWA
                                                 exposure     PEL (ppm)
                                                  (ppm)
------------------------------------------------------------------------
B...........................................           500         1,000
C...........................................            45           200
D...........................................            40           200
------------------------------------------------------------------------

    Substituting in the formula, we have:

Em=500/1,000+45/200+40/200
Em=0.500+0.225+0.200
Em=0.925

Since Em is less than unity (1), the exposure combination is 
within acceptable limits.

    (e) To achieve compliance with paragraphs (a) through (d) of this 
section, administrative or engineering controls must first be determined 
and implemented whenever feasible. When such controls are not feasible 
to achieve full compliance, protective equipment or any other protective 
measures shall be used to keep the exposure of employees to air 
contaminants within the limits

[[Page 9]]

prescribed in this section. Any equipment and/or technical measures used 
for this purpose must be approved for each particular use by a competent 
industrial hygienist or other technically qualified person. Whenever 
respirators are used, their use shall comply with 1910.134.

                                     Table Z-1--Limits for Air Contaminants
----------------------------------------------------------------------------------------------------------------
                                                                          mg/m\3\ (b)
                 Substance                    CAS No. (c)    ppm (a) \1\      \1\           Skin designation
----------------------------------------------------------------------------------------------------------------
Acetaldehyde..............................         75-07-0       200          360
Acetic acid...............................         64-19-7        10           25
Acetic anhydride..........................        108-24-7         5           20
Acetone...................................         67-64-1      1000         2400
Acetonitrile..............................         75-05-8        40           70
2-Acetylaminofluorine; see 1910.1014......         53-96-3
Acetylene dichloride; see 1,2-
 Dichloroethylene.
Acetylene tetrabromide....................         79-27-6         1           14
Acrolein..................................        107-02-8         0.1          0.25
Acrylamide................................         79-06-1  ............        0.3    X
Acrylonitrile; see 1910.1045..............        107-13-1
Aldrin....................................        309-00-2  ............        0.25   X
Allyl alcohol.............................        107-18-6         2            5      X
Allyl chloride............................        107-05-1         1            3
Allyl glycidyl ether (AGE)................        106-92-3     (C)10        (C)45
Allyl propyl disulfide....................       2179-59-1         2           12
alpha-Alumina.............................       1344-28-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Aluminum, metal (as Al)...................       7429-90-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
4-Aminodiphenyl; see 1910.1011............         92-67-1
2-Aminoethanol; see Ethanolamine.
2-Aminopyridine...........................        504-29-0         0.5          2
Ammonia...................................       7664-41-7        50           35
Ammonium sulfamate........................       7773-06-0
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
n-Amyl acetate............................        628-63-7       100          525
sec-Amyl acetate..........................        626-38-0       125          650
Aniline and homologs......................         62-53-3         5           19      X
Anisidine (o-, p-isomers).................      29191-52-4  ............        0.5    X
Antimony and compounds (as Sb)............       7440-36-0  ............        0.5
ANTU (alpha Naphthylthiourea).............         86-88-4  ............        0.3
Arsenic, inorganic compounds (as As); see        7440-38-2
 1910.1018.
Arsenic, organic compounds (as As)........       7440-38-2  ............        0.5
Arsine....................................       7784-42-1         0.05         0.2
Asbestos; see 1910.1001...................           (\4\)
Azinphos-methyl...........................         86-50-0  ............        0.2    X
Barium, soluble compounds (as Ba).........       7440-39-3  ............        0.5
Barium sulfate............................       7727-43-7
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Benomyl...................................      17804-35-2
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Benzene; see 1910.1028....................         71-43-2

    See Table Z-2 for the limits
     applicable in the operations or
     sectors excluded in 1910.1028 \d\

Benzidine; see 1910.1010..................         92-87-5
p-Benzoquinone; see Quinone.
Benzo(a)pyrene; see Coal tar pitch
 volatiles..
Benzoyl peroxide..........................         94-36-0  ............        5
Benzyl chloride...........................        100-44-7         1            5
Beryllium and beryllium compounds (as Be).       7440-41-7  ............    (\2\)
Biphenyl; see Diphenyl.
Bismuth telluride, Undoped................       1304-82-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Boron oxide...............................       1303-86-2
    Total dust............................  ..............  ............       15
Boron trifluoride.........................       7637-07-2      (C)1         (C)3
Bromine...................................       7726-95-6         0.1          0.7
Bromoform.................................         75-25-2         0.5          5      X
Butadiene (1,3-Butadiene); See 29 CFR             106-99-0  1 ppm/5 ppm
 1910.1051; 29 CFR 1910.19(l).                                  STEL

[[Page 10]]


Butanethiol; see Butyl mercaptan.
2-Butanone (Methyl ethyl ketone)..........         78-93-3       200          590
2-Butoxyethanol...........................        111-76-2        50          240      X
n-Butyl-acetate...........................        123-86-4       150          710
sec-Butyl acetate.........................        105-46-4       200          950
tert-Butyl acetate........................        540-88-5       200          950
n-Butyl alcohol...........................         71-36-3       100          300
sec-Butyl alcohol.........................         78-92-2       150          450
tert-Butyl alcohol........................         75-65-0       100          300
Butylamine................................        109-73-9      (C)5        (C)15      X
tert-Butyl chromate (as CrO3); see               1189-85-1
 1910.1026 \6\.
n-Butyl glycidyl ether (BGE)..............       2426-08-6        50          270
Butyl mercaptan...........................        109-79-5        10           35
p-tert-Butyltoluene.......................         98-51-1        10           60
Cadmium (as Cd); see 1910.1027............       7440-43-9
Calcium carbonate.........................       1317-65-3
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Calcium hydroxide.........................       1305-62-0
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Calcium oxide.............................       1305-78-8  ............        5
Calcium silicate..........................       1344-95-2
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Calcium sulfate...........................       7778-18-9
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Camphor, synthetic........................         76-22-2  ............        2
Carbaryl (Sevin)..........................         63-25-2  ............        5
Carbon black..............................       1333-86-4  ............        3.5
Carbon dioxide............................        124-38-9      5000         9000
Carbon disulfide..........................         75-15-0  ............    (\2\)
Carbon monoxide...........................        630-08-0        50           55
Carbon tetrachloride......................         56-23-5  ............    (\2\)
Cellulose.................................       9004-34-6
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Chlordane.................................         57-74-9  ............        0.5    X
Chlorinated camphene......................       8001-35-2  ............        0.5    X
Chlorinated diphenyl oxide................      55720-99-5  ............        0.5
Chlorine..................................       7782-50-5      (C)1         (C)3
Chlorine dioxide..........................      10049-04-4         0.1          0.3
Chlorine trifluoride......................       7790-91-2      (C)0.1       (C)0.4
Chloroacetaldehyde........................        107-20-0      (C)1         (C)3
a-Chloroacetophenone (Phenacyl chloride)..        532-27-4         0.05         0.3
Chlorobenzene.............................        108-90-7        75          350
o-Chlorobenzylidene malononitrile.........       2698-41-1         0.05         0.4
Chlorobromomethane........................         74-97-5       200         1050
2-Chloro-1,3-butadiene; see beta-
 Chloroprene.
Chlorodiphenyl (42% Chlorine) (PCB).......      53469-21-9  ............        1      X
Chlorodiphenyl (54% Chlorine) (PCB).......      11097-69-1  ............        0.5    X
1-Chloro-2,3-epoxypropane; see
 Epichlorohydrin.
2-Chloroethanol; see Ethylene
 chlorohydrin.
Chloroethylene; see Vinyl chloride.
Chloroform (Trichloromethane).............         67-66-3     (C)50       (C)240
bis(Chloromethyl) ether; see 1910.1008....        542-88-1
Chloromethyl methyl ether; see 1910.1006..        107-30-2
1-Chloro-1-nitropropane...................        600-25-9        20          100
Chloropicrin..............................         76-06-2         0.1          0.7
beta-Chloroprene..........................        126-99-8        25           90      X
2-Chloro-6-(trichloromethyl) pyridine.....       1929-82-4
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Chromium (II) compounds.
    (as Cr)...............................       7440-47-3  ............        0.5
Chromium (III) compounds.
    (as Cr)...............................       7440-47-3  ............        0.5
Chromium (VI) compounds; See 1910.1026 \5\
Chromium metal and insol. salts (as Cr)...       7440-47-3  ............        1
Chrysene; see Coal tar pitch volatiles.
Clopidol..................................       2971-90-6

[[Page 11]]


    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Coal dust (less than 5% SiO2), respirable   ..............  ............    (\3\)
 fraction.
Coal dust (greater than or equal to 5%      ..............  ............    (\3\)
 SiO2), respirable fraction.
Coal tar pitch volatiles (benzene soluble       65966-93-2  ............        0.2
 fraction), anthracene, BaP, phenanthrene,
 acridine, chrysene, pyrene.
Cobalt metal, dust, and fume (as Co)......       7440-48-4  ............        0.1
Coke oven emissions; see 1910.1029.
Copper....................................       7440-50-8
    Fume (as Cu)..........................  ..............  ............        0.1
    Dusts and mists (as Cu)...............  ..............  ............        1
Cotton dust \e\; see 1910.1043............  ..............  ............        1
Crag herbicide (Sesone)...................        136-78-7
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Cresol, all isomers.......................       1319-77-3         5           22      X
Crotonaldehyde............................       123-73-9;         2            6
                                                 4170-30-3
Cumene....................................         98-82-8        50          245      X
Cyanides (as CN)..........................           (\4\)  ............        5      X
Cyclohexane...............................        110-82-7       300         1050
Cyclohexanol..............................        108-93-0        50          200
Cyclohexanone.............................        108-94-1        50          200
Cyclohexene...............................        110-83-8       300         1015
Cyclopentadiene...........................        542-92-7        75          200
2,4-D (Dichlorophenoxyacetic acid)........         94-75-7  ............       10
Decaborane................................      17702-41-9         0.05         0.3    X
Demeton (Systox)..........................       8065-48-3  ............        0.1    X
Diacetone alcohol (4-Hydroxy-4-methyl-2-          123-42-2        50          240
 pentanone).
1,2-Diaminoethane; see Ethylenediamine.
Diazomethane..............................        334-88-3         0.2          0.4
Diborane..................................      19287-45-7         0.1          0.1
1,2-Dibromo-3-chloropropane (DBCP); see            96-12-8
 1910.1044.
1,2-Dibromoethane; see Ethylene dibromide.
Dibutyl phosphate.........................        107-66-4         1            5
Dibutyl phthalate.........................         84-74-2  ............        5
o-Dichlorobenzene.........................         95-50-1     (C)50       (C)300
p-Dichlorobenzene.........................        106-46-7        75          450
3,'-Dichlorobenzidine; see 1910.1007......         91-94-1
Dichlorodifluoromethane...................         75-71-8      1000         4950
1,3-Dichloro-5,5-dimethyl hydantoin.......        118-52-5  ............        0.2
Dichlorodiphenyltrichloroethane (DDT).....         50-29-3  ............        1      X
1,1-Dichloroethane........................         75-34-3       100          400
1,2-Dichloroethane; see Ethylene
 dichloride.
1,2-Dichloroethylene......................        540-59-0       200          790
Dichloroethyl ether.......................        111-44-4     (C)15        (C)90      X
Dichloromethane; see Methylene chloride.
Dichloromonofluoromethane.................         75-43-4      1000         4200
1,1-Dichloro-1-nitroethane................        594-72-9     (C)10        (C)60
1,2-Dichloropropane; see Propylene
 dichloride.
Dichlorotetrafluoroethane.................         76-14-2      1000         7000
Dichlorvos (DDVP).........................         62-73-7  ............        1      X
Dicyclopentadienyl iron...................        102-54-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Dieldrin..................................         60-57-1  ............        0.25   X
Diethylamine..............................        109-89-7        25           75
2-Diethylaminoethanol.....................        100-37-8        10           50      X
Diethyl ether; see Ethyl ether.
Difluorodibromomethane....................         75-61-6       100          860
Diglycidyl ether (DGE)....................       2238-07-5      (C)0.5       (C)2.8
Dihydroxybenzene; see Hydroquinone.
Diisobutyl ketone.........................        108-83-8        50          290
Diisopropylamine..........................        108-18-9         5           20      X
4-Dimethylaminoazobenzene; see 1910.1015..         60-11-7
Dimethoxymethane; see Methylal.
Dimethyl acetamide........................        127-19-5        10           35      X
Dimethylamine.............................        124-40-3        10           18
Dimethylaminobenzene; see Xylidine........
Dimethylaniline (N,N-Dimethylaniline).....        121-69-7         5           25      X
Dimethylbenzene; see Xylene.

[[Page 12]]


Dimethyl-1,2-dibromo-2,2-dichloroethyl            300-76-5  ............        3
 phosphate.
Dimethylformamide.........................         68-12-2        10           30      X
2,6-Dimethyl-4-heptanone; see Diisobutyl
 ketone.
1,1-Dimethylhydrazine.....................         57-14-7         0.5          1      X
Dimethylphthalate.........................        131-11-3  ............        5
Dimethyl sulfate..........................         77-78-1         1            5      X
Dinitrobenzene (all isomers)..............  ..............  ............        1      X
    (ortho)...............................        528-29-0
    (meta)................................         99-65-0
    (para)................................        100-25-4
Dinitro-o-cresol..........................        534-52-1  ............        0.2    X
Dinitrotoluene............................      25321-14-6  ............        1.5    X
Dioxane (Diethylene dioxide)..............        123-91-1       100          360      X
Diphenyl (Biphenyl).......................         92-52-4         0.2          1
Diphenylmethane diisocyanate; see
 Methylene bisphenyl isocyanate.
Dipropylene glycol methyl ether...........      34590-94-8       100          600      X
Di-sec octyl phthalate (Di-(2-ethylhexyl)         117-81-7  ............        5
 phthalate).
Emery.....................................      12415-34-8
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Endrin....................................         72-20-8  ............        0.1    X
Epichlorohydrin...........................        106-89-8         5           19      X
EPN.......................................       2104-64-5  ............        0.5    X
1,2-Epoxypropane; see Propylene oxide.
2,3-Epoxy-1-propanol; see Glycidol.
Ethanethiol; see Ethyl mercaptan.
Ethanolamine..............................        141-43-5         3            6
2-Ethoxyethanol (Cellosolve)..............        110-80-5       200          740      X
2-Ethoxyethyl acetate (Cellosolve acetate)        111-15-9       100          540      X
Ethyl acetate.............................        141-78-6       400         1400
Ethyl acrylate............................        140-88-5        25          100      X
Ethyl alcohol (Ethanol)...................         64-17-5      1000         1900
Ethylamine................................         75-04-7        10           18
Ethyl amyl ketone (5-Methyl-3-heptanone)..        541-85-5        25          130
Ethyl benzene.............................        100-41-4       100          435
Ethyl bromide.............................         74-96-4       200          890
Ethyl butyl ketone (3-Heptanone)..........        106-35-4        50          230
Ethyl chloride............................         75-00-3      1000         2600
Ethyl ether...............................         60-29-7       400         1200
Ethyl formate.............................        109-94-4       100          300
Ethyl mercaptan...........................         75-08-1     (C)10        (C)25
Ethyl silicate............................         78-10-4       100          850
Ethylene chlorohydrin.....................        107-07-3         5           16      X
Ethylenediamine...........................        107-15-3        10           25
Ethylene dibromide........................        106-93-4  ............    (\2\)
Ethylene dichloride (1,2-Dichloroethane)..        107-06-2  ............    (\2\)
Ethylene glycol dinitrate.................        628-96-6      (C)0.2       (C)1      X
Ethylene glycol methyl acetate; see Methyl
 cellosolve acetate.
Ethyleneimine; see 1910.1012..............        151-56-4
Ethylene oxide; see 1910.1047.............         75-21-8
Ethylidene chloride; see 1,1-
 Dichloroethane.
N-Ethylmorpholine.........................        100-74-3        20           94      X
Ferbam....................................      14484-64-1
    Total dust............................  ..............  ............       15
Ferrovanadium dust........................      12604-58-9  ............        1
Fluorides (as F)..........................           (\4\)  ............        2.5
Fluorine..................................       7782-41-4         0.1          0.2
Fluorotrichloromethane                             75-69-4      1000         5600
 (Trichlorofluoromethane).
Formaldehyde; see 1910.1048...............         50-00-0
Formic acid...............................         64-18-6         5            9
Furfural..................................         98-01-1         5           20      X
Furfuryl alcohol..........................         98-00-0        50          200
Grain dust (oat, wheat, barley)...........  ..............  ............       10
Glycerin (mist)...........................         56-81-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Glycidol..................................        556-52-5        50          150
Glycol monoethyl ether; see 2-
 Ethoxyethanol.
Graphite, natural, respirable dust........       7782-42-5  ............    (\3\)
Graphite, synthetic.......................

[[Page 13]]


    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Guthion; see Azinphos methyl.
Gypsum....................................      13397-24-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Hafnium...................................       7440-58-6  ............        0.5
Heptachlor................................         76-44-8  ............        0.5    X
Heptane (n-Heptane).......................        142-82-5       500         2000
Hexachloroethane..........................         67-72-1         1           10      X
Hexachloronaphthalene.....................       1335-87-1  ............        0.2    X
n-Hexane..................................        110-54-3       500         1800
2-Hexanone (Methyl n-butyl ketone)........        591-78-6       100          410
Hexone (Methyl isobutyl ketone)...........        108-10-1       100          410
sec-Hexyl acetate.........................        108-84-9        50          300
Hydrazine.................................        302-01-2         1            1.3    X
Hydrogen bromide..........................      10035-10-6         3           10
Hydrogen chloride.........................       7647-01-0      (C)5         (C)7
Hydrogen cyanide..........................         74-90-8        10           11      X
Hydrogen fluoride (as F)..................       7664-39-3  ............    (\2\)
Hydrogen peroxide.........................       7722-84-1         1            1.4
Hydrogen selenide (as Se).................       7783-07-5         0.05         0.2
Hydrogen sulfide..........................       7783-06-4  ............    (\2\)
Hydroquinone..............................        123-31-9  ............        2
Iodine....................................       7553-56-2      (C)0.1       (C)1
Iron oxide fume...........................       1309-37-1  ............       10
Isoamyl acetate...........................        123-92-2       100          525
Isoamyl alcohol (primary and secondary)...        123-51-3       100          360
Isobutyl acetate..........................        110-19-0       150          700
Isobutyl alcohol..........................         78-83-1       100          300
Isophorone................................         78-59-1        25          140
Isopropyl acetate.........................        108-21-4       250          950
Isopropyl alcohol.........................         67-63-0       400          980
Isopropylamine............................         75-31-0         5           12
Isopropyl ether...........................        108-20-3       500         2100
Isopropyl glycidyl ether (IGE)............       4016-14-2        50          240
Kaolin....................................       1332-58-7
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Ketene....................................        463-51-4         0.5          0.9
Lead, inorganic (as Pb); see 1910.1025....       7439-92-1
Limestone.................................       1317-65-3
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Lindane...................................         58-89-9  ............        0.5    X
Lithium hydride...........................       7580-67-8  ............        0.025
L.P.G. (Liquefied petroleum gas)..........      68476-85-7      1000         1800
Magnesite.................................        546-93-0
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Magnesium oxide fume......................       1309-48-4
    Total particulate.....................  ..............  ............       15
Malathion.................................        121-75-5
    Total dust............................  ..............  ............       15      X
Maleic anhydride..........................        108-31-6         0.25         1
Manganese compounds (as Mn)...............       7439-96-5  ............     (C)5
Manganese fume (as Mn)....................       7439-96-5  ............     (C)5
Marble....................................       1317-65-3
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Mercury (aryl and inorganic) (as Hg)......       7439-97-6  ............    (\2\)
Mercury (organo) alkyl compounds (as Hg)..       7439-97-6  ............    (\2\)
Mercury (vapor) (as Hg)...................       7439-97-6  ............    (\2\)
Mesityl oxide.............................        141-79-7        25          100
Methanethiol; see Methyl mercaptan.
Methoxychlor..............................         72-43-5
    Total dust............................  ..............  ............       15
2-Methoxyethanol (Methyl cellosolve)......        109-86-4        25           80      X
2-Methoxyethyl acetate (Methyl cellosolve         110-49-6        25          120      X
 acetate).
Methyl acetate............................         79-20-9       200          610
Methyl acetylene (Propyne)................         74-99-7      1000         1650
Methyl acetylene-propadiene mixture (MAPP)  ..............      1000         1800

[[Page 14]]


Methyl acrylate...........................         96-33-3        10           35      X
Methylal (Dimethoxy-methane)..............        109-87-5      1000         3100
Methyl alcohol............................         67-56-1       200          260
Methylamine...............................         74-89-5        10           12
Methyl amyl alcohol; see Methyl isobutyl
 carbinol.
Methyl n-amyl ketone......................        110-43-0       100          465
Methyl bromide............................         74-83-9     (C)20        (C)80      X
Methyl butyl ketone; see 2-Hexanone.
Methyl cellosolve; see 2-Methoxyethanol.
Methyl cellosolve acetate; see 2-
 Methoxyethyl acetate.
Methyl chloride...........................         74-87-3  ............    (\2\)
Methyl chloroform (1,1,1-Trichloroethane).         71-55-6       350         1900
Methylcyclohexane.........................        108-87-2       500         2000
Methylcyclohexanol........................      25639-42-3       100          470
o-Methylcyclohexanone.....................        583-60-8       100          460      X
Methylene chloride........................         75-09-2  ............    (\2\)
Methyl ethyl ketone (MEK); see 2-Butanone.
Methyl formate............................        107-31-3       100          250
Methyl hydrazine (Monomethyl hydrazine)...         60-34-4      (C)0.2       (C)0.35   X
Methyl iodide.............................         74-88-4         5           28      X
Methyl isoamyl ketone.....................        110-12-3       100          475
Methyl isobutyl carbinol..................        108-11-2        25          100      X
Methyl isobutyl ketone; see Hexone.
Methyl isocyanate.........................        624-83-9         0.02         0.05   X
Methyl mercaptan..........................         74-93-1     (C)10        (C)20
Methyl methacrylate.......................         80-62-6       100          410
Methyl propyl ketone; see 2-Pentanone.
alpha-Methyl styrene......................         98-83-9    (C)100       (C)480
Methylene bisphenyl isocyanate (MDI)......        101-68-8      (C)0.02      (C)0.2
Mica; see Silicates.
Molybdenum (as Mo)........................       7439-98-7
    Soluble compounds.....................  ..............  ............        5
 Insoluble compounds.
       Total dust.........................  ..............  ............       15
Monomethyl aniline........................        100-61-8         2            9      X
Monomethyl hydrazine; see Methyl
 hydrazine.
Morpholine................................        110-91-8        20           70      X
Naphtha (Coal tar)........................       8030-30-6       100          400
Naphthalene...............................         91-20-3        10           50
alpha-Naphthylamine; see 1910.1004........        134-32-7
beta-Naphthylamine; see 1910.1009.........         91-59-8
Nickel carbonyl (as Ni)...................      13463-39-3         0.001        0.007
Nickel, metal and insoluble compounds (as        7440-02-0  ............        1
 Ni).
Nickel, soluble compounds (as Ni).........       7440-02-0  ............        1
Nicotine..................................         54-11-5  ............        0.5    X
Nitric acid...............................       7697-37-2         2            5
Nitric oxide..............................      10102-43-9        25           30
p-Nitroaniline............................        100-01-6         1            6      X
Nitrobenzene..............................         98-95-3         1            5      X
p-Nitrochlorobenzene......................        100-00-5  ............        1      X
4-Nitrodiphenyl; see 1910.1003............         92-93-3
Nitroethane...............................         79-24-3       100          310
Nitrogen dioxide..........................      10102-44-0      (C)5         (C)9
Nitrogen trifluoride......................       7783-54-2        10           29
Nitroglycerin.............................         55-63-0      (C)0.2       (C)2      X
Nitromethane..............................         75-52-5       100          250
1-Nitropropane............................        108-03-2        25           90
2-Nitropropane............................         79-46-9        25           90
N-Nitrosodimethylamine; see 1910.1016.
Nitrotoluene (all isomers)................  ..............         5           30      X
    o-isomer..............................         88-72-2
    m-isomer..............................         99-08-1
    p-isomer..............................         99-99-0
Nitrotrichloromethane; see Chloropicrin.
Octachloronaphthalene.....................       2234-13-1  ............        0.1    X
Octane....................................        111-65-9       500         2350
Oil mist, mineral.........................       8012-95-1  ............        5
Osmium tetroxide (as Os)..................      20816-12-0  ............        0.002
Oxalic acid...............................        144-62-7  ............        1
Oxygen difluoride.........................       7783-41-7         0.05         0.1
Ozone.....................................      10028-15-6         0.1          0.2

[[Page 15]]


Paraquat, respirable dust.................      4685-14-7;  ............        0.5    X
                                                1910-42-5;
                                                 2074-50-2
Parathion.................................         56-38-2  ............        0.1    X
Particulates not otherwise regulated
 (PNOR) \f\.
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
PCB; see Chlorodiphenyl (42% and 54%
 chlorine).
Pentaborane...............................      19624-22-7         0.005        0.01
Pentachloronaphthalene....................       1321-64-8  ............        0.5    X
Pentachlorophenol.........................         87-86-5  ............        0.5    X
Pentaerythritol...........................        115-77-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Pentane...................................        109-66-0      1000         2950
2-Pentanone (Methyl propyl ketone)........        107-87-9       200          700
Perchloroethylene (Tetrachloroethylene)...        127-18-4  ............    (\2\)
Perchloromethyl mercaptan.................        594-42-3         0.1          0.8
Perchloryl fluoride.......................       7616-94-6         3           13.5
Petroleum distillates (Naphtha) (Rubber     ..............       500         2000
 Solvent).
Phenol....................................        108-95-2         5           19      X
p-Phenylene diamine.......................        106-50-3  ............        0.1    X
Phenyl ether, vapor.......................        101-84-8         1            7
Phenyl ether-biphenyl mixture, vapor......  ..............         1            7
Phenylethylene; see Styrene.
Phenyl glycidyl ether (PGE)...............        122-60-1        10           60
Phenylhydrazine...........................        100-63-0         5           22      X
Phosdrin (Mevinphos)......................       7786-34-7  ............        0.1    X
Phosgene (Carbonyl chloride)..............         75-44-5         0.1          0.4
Phosphine.................................       7803-51-2         0.3          0.4
Phosphoric acid...........................       7664-38-2  ............        1
Phosphorus (yellow).......................       7723-14-0  ............        0.1
Phosphorus pentachloride..................      10026-13-8  ............        1
Phosphorus pentasulfide...................       1314-80-3  ............        1
Phosphorus trichloride....................       7719-12-2         0.5          3
Phthalic anhydride........................         85-44-9         2           12
Picloram..................................       1918-02-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Picric acid...............................         88-89-1  ............        0.1    X
Pindone (2-Pivalyl-1,3-indandione)........         83-26-1  ............        0.1
Plaster of Paris..........................      26499-65-0
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Platinum (as Pt)..........................       7440-06-4
    Metal.................................
    Soluble salts.........................  ..............  ............        0.002
Portland cement...........................      65997-15-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Propane...................................         74-98-6      1000         1800
beta-Propriolactone; see 1910.1013........         57-57-8
n-Propyl acetate..........................        109-60-4       200          840
n-Propyl alcohol..........................         71-23-8       200          500
n-Propyl nitrate..........................        627-13-4        25          110
Propylene dichloride......................         78-87-5        75          350
Propylene imine...........................         75-55-8         2            5      X
Propylene oxide...........................         75-56-9       100          240
Propyne; see Methyl acetylene.
Pyrethrum.................................       8003-34-7  ............        5
Pyridine..................................        110-86-1         5           15
Quinone...................................        106-51-4         0.1          0.4
RDX; see Cyclonite.
Rhodium (as Rh), metal fume and insoluble        7440-16-6  ............        0.1
 compounds.
Rhodium (as Rh), soluble compounds........       7440-16-6  ............        0.001
Ronnel....................................        299-84-3  ............       15
Rotenone..................................         83-79-4  ............        5
Rouge.....................................
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Selenium compounds (as Se)................       7782-49-2  ............        0.2
Selenium hexafluoride (as Se).............       7783-79-1         0.05         0.4

[[Page 16]]


Silica, amorphous, precipitated and gel...     112926-00-8  ............    (\3\)
Silica, amorphous, diatomaceous earth,          61790-53-2  ............    (\3\)
 containing less than 1% crystalline
 silica.
Silica, crystalline cristobalite,               14464-46-1  ............    (\3\)
 respirable dust.
Silica, crystalline quartz, respirable          14808-60-7  ............    (\3\)
 dust.
Silica, crystalline tripoli (as quartz),         1317-95-9  ............    (\3\)
 respirable dust.
Silica, crystalline tridymite, respirable       15468-32-3  ............    (\3\)
 dust.
Silica, fused, respirable dust............      60676-86-0  ............    (\3\)
Silicates (less than 1% crystalline
 silica).
    Mica (respirable dust)................      12001-26-2  ............    (\3\)
    Soapstone, total dust.................  ..............  ............    (\3\)
    Soapstone, respirable dust............  ..............  ............    (\3\)
    Talc (containing asbestos); use         ..............  ............    (\3\)
     asbestos limit; see 29 CFR 1910.1001.
    Talc (containing no asbestos),              14807-96-6  ............    (\3\)
     respirable dust.
 Tremolite, asbestiform; see 1910.1001.
Silicon...................................       7440-21-3
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Silicon carbide...........................        409-21-2
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Silver, metal and soluble compounds (as          7440-22-4  ............        0.01
 Ag).
Soapstone; see Silicates.
Sodium fluoroacetate......................         62-74-8  ............        0.05   X
Sodium hydroxide..........................       1310-73-2  ............        2
Starch....................................       9005-25-8
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Stibine...................................       7803-52-3         0.1          0.5
Stoddard solvent..........................       8052-41-3       500         2900
Strychnine................................         57-24-9  ............        0.15
Styrene...................................        100-42-5  ............    (\2\)
Sucrose...................................         57-50-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Sulfur dioxide............................       7446-09-5         5           13
Sulfur hexafluoride.......................       2551-62-4      1000         6000
Sulfuric acid.............................       7664-93-9  ............        1
Sulfur monochloride.......................      10025-67-9         1            6
Sulfur pentafluoride......................       5714-22-7         0.025        0.25
Sulfuryl fluoride.........................       2699-79-8         5           20
Systox; see Demeton.
2,4,5-T (2,4,5-trichlorophenoxyacetic              93-76-5  ............       10
 acid).
Talc; see Silicates.
Tantalum, metal and oxide dust............       7440-25-7  ............        5
TEDP (Sulfotep)...........................       3689-24-5  ............        0.2    X
Tellurium and compounds (as Te)...........      13494-80-9  ............        0.1
Tellurium hexafluoride (as Te)............       7783-80-4         0.02         0.2
Temephos..................................       3383-96-8
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
TEPP (Tetraethyl pyrophosphate)...........        107-49-3  ............        0.05   X
Terphenyls................................      26140-60-3      (C)1         (C)9
1,1,1,2-Tetrachloro-2,2-difluoroethane....         76-11-9       500         4170
1,1,2,2-Tetrachloro-1,2-difluoroethane....         76-12-0       500         4170
1,1,2,2-Tetrachloroethane.................         79-34-5         5           35      X
Tetrachloroethylene; see
 Perchloroethylene.
Tetrachloromethane; see Carbon
 tetrachloride.
Tetrachloronaphthalene....................       1335-88-2  ............        2      X
Tetraethyl lead (as Pb)...................         78-00-2  ............        0.075  X
Tetrahydrofuran...........................        109-99-9       200          590
Tetramethyl lead (as Pb)..................         75-74-1  ............        0.075  X
Tetramethyl succinonitrile................       3333-52-6         0.5          3      X
Tetranitromethane.........................        509-14-8         1            8
Tetryl (2,4,6-                                    479-45-8  ............        1.5    X
 Trinitrophenylmethylnitramine).
Thallium, soluble compounds (as Tl).......       7440-28-0  ............        0.1    X
4,4'-Thiobis (6-tert, Butyl-m-cresol).....         96-69-5
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Thiram....................................        137-26-8  ............        5
Tin, inorganic compounds (except oxides)         7440-31-5  ............        2
 (as Sn).

[[Page 17]]


Tin, organic compounds (as Sn)............       7440-31-5  ............        0.1
Titanium dioxide..........................      13463-67-7
    Total dust............................  ..............  ............       15
Toluene...................................        108-88-3  ............    (\2\)
Toluene-2,4-diisocyanate (TDI)............        584-84-9      (C)0.02      (C)0.14
o-Toluidine...............................         95-53-4         5           22      X
Toxaphene; see Chlorinated camphene.
Tremolite; see Silicates.
Tributyl phosphate........................        126-73-8  ............        5
1,1,1-Trichloroethane; see Methyl
 chloroform.
1,1,2-Trichloroethane.....................         79-00-5        10           45      X
Trichloroethylene.........................         79-01-6  ............    (\2\)
Trichloromethane; see Chloroform.
Trichloronaphthalene......................       1321-65-9  ............        5      X
1,2,3-Trichloropropane....................         96-18-4        50          300
1,1,2-Trichloro-1,2,2-trifluoroethane.....         76-13-1      1000         7600
Triethylamine.............................        121-44-8        25          100
Trifluorobromomethane.....................         75-63-8      1000         6100
2,4,6-Trinitrophenol; see Picric acid.
2,4,6-Trinitrophenylmethylnitramine; see
 Tetryl.
2,4,6-Trinitrotoluene (TNT)...............        118-96-7  ............        1.5    X
Triorthocresyl phosphate..................         78-30-8  ............        0.1
Triphenyl phosphate.......................        115-86-6  ............        3
Turpentine................................       8006-64-2       100          560
Uranium (as U)............................       7440-61-1
    Soluble compounds.....................  ..............  ............        0.05
    Insoluble compounds...................  ..............  ............        0.25
Vanadium..................................       1314-62-1
    Respirable dust (as V2 O5)............  ..............  ............     (C)0.5
    Fume (as V2 O5).......................  ..............  ............     (C)0.1
Vegetable oil mist........................
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Vinyl benzene; see Styrene.
Vinyl chloride; see 1910.1017.............         75-01-4
Vinyl cyanide; see Acrylonitrile.
Vinyl toluene.............................      25013-15-4       100          480
Warfarin..................................         81-81-2  ............        0.1
Xylenes (o-, m-, p-isomers)...............       1330-20-7       100          435
Xylidine..................................       1300-73-8         5           25      X
Yttrium...................................       7440-65-5  ............        1
Zinc chloride fume........................       7646-85-7  ............        1
Zinc oxide fume...........................       1314-13-2  ............        5
Zinc oxide................................       1314-13-2
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Zinc stearate.............................        557-05-1
    Total dust............................  ..............  ............       15
    Respirable fraction...................  ..............  ............        5
Zirconium compounds (as Zr)...............       7440-67-7  ............        5
----------------------------------------------------------------------------------------------------------------
\1\ The PELs are 8-hour TWAs unless otherwise noted; a (C) designation denotes a ceiling limit. They are to be
  determined from breathing-zone air samples.
(a) Parts of vapor or gas per million parts of contaminated air by volume at 25 [deg]C and 760 torr.
(b) Milligrams of substance per cubic meter of air. When entry is in this column only, the value is exact; when
  listed with a ppm entry, it is approximate.
(c) The CAS number is for information only. Enforcement is based on the substance name. For an entry covering
  more than one metal compound, measured as the metal, the CAS number for the metal is given--not CAS numbers
  for the individual compounds.
(d) The final benzene standard in 1910.1028 applies to all occupational exposures to benzene except in some
  circumstances the distribution and sale of fuels, sealed containers and pipelines, coke production, oil and
  gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures; for the
  excepted subsegments, the benzene limits in Table Z-2 apply. See 1910.1028 for specific circumstances.
(e) This 8-hour TWA applies to respirable dust as measured by a vertical elutriator cotton dust sampler or
  equivalent instrument. The time-weighted average applies to the cottom waste processing operations of waste
  recycling (sorting, blending, cleaning and willowing) and garnetting. See also 1910.1043 for cotton dust
  limits applicable to other sectors.
(f) All inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance
  name are covered by the Particulates Not Otherwise Regulated (PNOR) limit which is the same as the inert or
  nuisance dust limit of Table Z-3.
\2\ See Table Z-2.
\3\ See Table Z-3.
\4\ Varies with compound.
\5\ See Table Z-2 for the exposure limit for any operations or sectors where the exposure limit in Sec.
  1910.1026 is stayed or is otherwise not in effect.
\6\ If the exposure limit in Sec.   1910.1026 is stayed or is otherwise not in effect, the exposure limit is a
  ceiling of 0.1 mg/m\3\.


[[Page 18]]


                                                    Table Z-2
----------------------------------------------------------------------------------------------------------------
                                                                            Acceptable maximum peak above the
                                                                         acceptable ceiling concentration for an
           Substance                 8-hour time     Acceptable ceiling                 8-hr shift
                                  weighted average      concentration   ----------------------------------------
                                                                            Concentration      Maximum duration
----------------------------------------------------------------------------------------------------------------
Benzene \a\ (Z37.40-1969)......  10 ppm............  25 ppm............  50 ppm............  10 minutes.
Beryllium and beryllium          2 [micro]g/m\3\...  5 [micro]g/m\3\...  25 [micro]g/m\3\..  30 minutes.
 compounds (Z37.29-1970).
Cadmium fume \b\ (Z37.5-1970)..  0.1 mg/m\3\.......  0.3 mg/m\3\.......
Cadmium dust \b\ (Z37.5-1970)..  0.2 mg/m\3\.......  0.6 mg/m\3\.......
Carbon disulfide (Z37.3-1968)..  20 ppm............  30 ppm............  100 ppm...........  30 minutes.
Carbon tetrachloride (Z37.17-    10 ppm............  25 ppm............  200 ppm...........  5 min. in any 4
 1967).                                                                                       hrs.
Chromic acid and chromates       ..................  1 mg/10m\3\.......
 (Z37.7-1971) (as CrO3)\c\.
Ethylene dibromide (Z37.31-      20 ppm............  30 ppm............  50 ppm............  5 minutes.
 1970).
Ethylene dichloride (Z37.21-     50 ppm............  100 ppm...........  200 ppm...........  5 min. in any 3
 1969).                                                                                       hrs.
Fluoride as dust (Z37.28-1969).  2.5 mg/m\3\.......
Formaldehyde; see 1910.1048....
Hydrogen fluoride (Z37.28-1969)  3 ppm.............
Hydrogen sulfide (Z37.2-1966)..  ..................  20 ppm............  50 ppm............  10 mins. once, only
                                                                                              if no other meas.
                                                                                              exp. occurs.
Mercury (Z37.8-1971)...........  ..................  1 mg/10m\3\.......
Methyl chloride (Z37.18-1969)..  100 ppm...........  200 ppm...........  300 ppm...........  5 mins. in any 3
                                                                                              hrs.
Methylene Chloride: See Sec.
 1919.52..
Organo (alkyl) mercury (Z37.30-  0.01 mg/m\3\......  0.04 mg/m\3\......
 1969).
Styrene (Z37.15-1969)..........  100 ppm...........  200 ppm...........  600 ppm...........  5 mins. in any 3
                                                                                              hrs.
Tetrachloroethylene (Z37.22-     100 ppm...........  200 ppm...........  300 ppm...........  5 mins. in any 3
 1967).                                                                                       hrs.
Toluene (Z37.12-1967)..........  200 ppm...........  300 ppm...........  500 ppm...........  10 minutes.
Trichloroethylene (Z37.19-1967)  100 ppm...........  200 ppm...........  300 ppm...........  5 mins. in any 2
                                                                                              hrs.
----------------------------------------------------------------------------------------------------------------
\a\ This standard applies to the industry segments exempt from the 1 ppm 8-hour TWA and 5 ppm STEL of the
  benzene standard at 1910.1028.
\b\ This standard applies to any operations or sectors for which the Cadmium standard, 1910.1027, is stayed or
  otherwise not in effect.
\c\ This standard applies to any operations or sectors for which the exposure limit in the Chromium (VI)
  standard, Sec.   1910.1026, is stayed or is otherwise not in effect.


                        Table Z-3--Mineral Dusts
------------------------------------------------------------------------
                   Substance                     mppcf \a\     mg/m\3\
------------------------------------------------------------------------
Silica:
Crystalline
                                                  250 \b\     10 mg/m\3\
                                                                 \e\
    Quartz (Respirable).......................   ----------   ----------
                                                  %SiO2+5     % SiO2 + 2

                                                ...........   30 mg/m\3\
    Quartz (Total Dust).......................  ...........   ----------
                                                              % SiO2 + 2

  Cristobalite: Use \1/2\ the value calculated
   from the count or mass formulae for quartz
  Tridymite: Use \1/2\ the value calculated
   from the formulae for quartz
                                                ...........   80 mg/m\3\
Amorphous, including natural diatomaceous                20   ----------
 earth........................................                  %SiO2

Silicates (less than 1% crystalline silica):
  Mica........................................           20
  Soapstone...................................           20
  Talc (not containing asbestos)..............       20 \c\
  Talc (containing asbestos) Use asbestos
   limit......................................
  Tremolite, asbestiform (see 29 CFR
   1910.1001).................................
  Portland cement.............................           50

Graphite (Natural)............................           15

Coal Dust:

  Respirable fraction less than 5% SiO2.......  ...........  2.4 mg/m\3\
                                                                 \e\

[[Page 19]]



                                                ...........   10 mg/m\3\
                                                                 \e\
  Respirable fraction greater than 5% SiO2....  ...........   ----------
                                                               %SiO2+2

Inert or Nuisance Dust: \d\
  Respirable fraction.........................           15    5 mg/m\3\
  Total dust..................................           50   15 mg/m\3\
------------------------------------------------------------------------
Note--Conversion factors - mppcf x 35.3 = million particles per cubic
  meter = particles per c.c.

\a\ Millions of particles per cubic foot of air, based on impinger
  samples counted by light-field techniques.
\b\ The percentage of crystalline silica in the formula is the amount
  determined from airborne samples, except in those instances in which
  other methods have been shown to be applicable.
\c\ Containing less than 1% quartz; if 1% quartz or more, use quartz
  limit.
\d\ All inert or nuisance dusts, whether mineral, inorganic, or organic,
  not listed specifically by substance name are covered by this limit,
  which is the same as the Particulates Not Otherwise Regulated (PNOR)
  limit in Table Z-1.
\e\ Both concentration and percent quartz for the application of this
  limit are to be determined from the fraction passing a size-selector
  with the following characteristics:


------------------------------------------------------------------------
                                                        Percent passing
      Aerodynamic diameter (unit density sphere)            selector
------------------------------------------------------------------------
2....................................................                 90
2.5..................................................                 75
3.5..................................................                 50
5.0..................................................                 25
10...................................................                  0
------------------------------------------------------------------------
The measurements under this note refer to the use of an AEC (now NRC)
  instrument. The respirable fraction of coal dust is determined with an
  MRE; the figure corresponding to that of 2.4 mg/m\3\ in the table for
  coal dust is 4.5 mg/m\3K\.


[58 FR 35340, June 30. 1993; 58 FR 40191, July 27, 1993, as amended at 
61 FR 56831, Nov. 4, 1996; 62 FR 1600, Jan. 10, 1997; 62 FR 42018, Aug. 
4, 1997; 71 FR 10373, Feb. 28, 2006; 71 FR 16673, Apr. 3, 2006; 71 FR 
36008, June 23, 2006]