Recommendation of occupational exposure limits (2021–2022)

Abstract

The Japan Society for Occupational Health (JSOH) recommends the Occupational Exposure Limits (OELs) as reference values for preventing adverse health effects on workers caused by occupational exposure to chemical substances, continuous or intermittent noise, impulsive or impact noise, heat stress, cold stress, whole-body vibration, hand-arm vibration and time-varying electric, magnetic and electromagnetic fields and ultraviolet and ionizing radiation.

Characteristics of OELs and Instructions for Users

1. OELs should be applied by individuals well-trained and experienced in occupational health.

2. OELs cannot be applied in cases where exposure duration or work intensity exceeds the prerequisite conditions for setting an OEL.

3. OELs are set based on various information obtained from experiences in industries and experiments on humans and animals. However, the quantity and quality of information used in setting OELs is not always the same.

4. Types of health effects considered in setting OELs depend on the substances involved; an explicit health impairment provides the basis for OELs in certain substances, while health effects such as discomfort, irritation or CNS suppressive effects afford the basis in others. Thus, OELs cannot be used simply as a relative scale of toxicity.

5. Due to the variance in individual susceptibilities, discomfort, deterioration of pre-existing ill health or occupational disease may be induced at levels of exposure below the OELs, even though the chances of this should be remote.

6. Because OELs do not represent a definitive borderline between safe and hazardous conditions, it is not correct to conclude that working environments above OEL are the direct and sole cause of health impairment in workers, or vice versa.

7. OELs cannot be applied as reference values in non-occupational environments.

8. OELs will be revised when JSOH considers it necessary.

9. JSOH welcomes the submission, by concerned parties or individuals, of opinions based on scientific aspects of OELs.

10. In the reproduction of any Tables and/or Figures of OELs, JSOH requires that the full text of OELs be quoted to prevent misunderstanding and misuse.

I. Occupational Exposure Limits for Chemical Substances

1. Definitions

Exposure concentration is defined as the concentration of a chemical substance in air which will be inhaled by a worker during a job without the use of protective respiratory equipment.

Occupational Exposure Limit-Mean (OEL-M) for mean concentration of a chemical substance is defined as the reference value to the mean exposure concentration at or below which adverse health effects caused by the substance do not appear in most workers working for 8 hours a day, 40 hours a week under a moderate work-load. Exposure above OEL-M should be avoided even where duration is short or work intensity is light. If mean levels and duration of exposure corresponding to segments of various jobs can be measured or estimated, then an overall exposure concentration can be determined as the time-weighted average concentration.

Occupational Exposure Limit-Ceiling (OEL-C) of occupational exposure to a chemical substance is defined as the reference value to the maximal exposure concentration of the substance during a working day at or below which adverse health effects do not appear in most workers. The main reason why OEL-C is recommended for some substances is that the toxicity in question can induce immediate adverse effects such as irritation or CNS suppressive effects. However, it is quite difficult in practice to measure the momentary maximal exposure concentration. Short-term measurement lasting for 5 minutes or less at the time when the highest exposure concentration is expected may be used as a substitute for the measurement of maximal exposure concentration.

2. Variability of exposure concentration

Exposure concentration fluctuates around the mean value. OEL-M should be referred to only when the fluctu-ation is not large. Allowable range of fluctuation depends on the substance. In practical terms, the mean exposure concentration for a period of 15 minutes during which maximum exposure concentration is expected should not exceed 1.5 times OEL-M, unless otherwise notified.

3. Skin absorption

“S” marks in Tables I-1 and I-2 show that a significant dose from the view of systemic health effects or absorption of the substance concerned may be absorbed through the skin when the substance is in contact with the skin. OELs are set at conditions under which no skin absorption will take place.

Table I-1. Occupational exposure limits for chemical substances

Substance [CAS No.]	OEL		Skin absorption	Class of carcino- genicity	Class of sensitizing potential		Reproductive Toxicants	Year of proposal
	ppm	mg/m3			Airway	Skin
Acetaldehyde [75-07-0]	(Table I-2)			2B				ʼ21
Acetic acid [64-19-7]	10	25						ʼ78
Acetic anhydride [108-24-7]	5*	21*						ʼ90
Acetone [67-64-1]	200	475						ʼ72
Acrylaldehyde [107-02-8]	0.1	0.23						ʼ73
Acrylamide [79-06-1]	—	0.1	S	2A		2	2	ʼ04
Acrylonitrile [107-13-1]	2	4.3	S	2Aψ				ʼ88
Allyl alcohol [107-18-6]	1	2.4	S					ʼ78
2-Aminoethanol [141-43-5]	3	7.5						ʼ65
Ammonia [7664-41-7]	25	17						ʼ79
Aniline [62-53-3]	1	3.8	S			1		ʼ88
o-Anisidine [90-04-0]	0.1	0.5	S	2B				ʼ96
p-Anisidine [104-94-9]	0.1	0.5	S					ʼ96
Antimony and compounds (as Sb except stibine) [7440-36-0]	—	0.1						(ʼ13)
Arsenic and compounds (as As) [7440-38-2]	(Table III-2)			1			1	ʼ00
Arsine [7784-42-1]	0.01	0.032						ʼ92
	0.1*	0.32*
Atrazine [1912-24-9]		2					3	ʼ15
Benomyl [17804-35-2]		1				2	2#	ʼ18
Benzene [71-43-2]	(Table III-2)		S	1				ʼ97
Benzyl alcohol [100-51-6]	—	25*				2		’19
Beryllium and compounds (as Be) [7440-41-7]	—	0.002		1ψ	1	2		ʼ63
Boron trifluoride [7637-07-2]	0.3	0.83						ʼ79
Bromine [7726-95-6]	0.1	0.65						ʼ64
Bromoform [75-25-2]	1	10.3						ʼ97
1-Bromopropane [106-94-5]	0.5	2.5		2B			2	ʼ12
2-Bromopropane [75-26-3]	(Table I-2)		S	2B†			1	ʼ21
Buprofezin [69327-76-0]	—	2						ʼ90
Butane (all isomers) [106-97-8]	500	1,200						ʼ88
1-Butanol [71-36-3]	50*	150*	S					ʼ87
2-Butanol [78-92-2]	100	300						ʼ87
Butyl acetate [123-86-4]	100	475						ʼ94
t-Butyl alcohol [75-65-0]	50	150						ʼ87
Butylamine [109-73-9]	5*	15*	S					(ʼ94)
n-butyl-2,3-epoxy-propyl ether [2426-08-6]	0.25	1.3		2B		2	3	ʼ16
Cadmium and compounds (as Cd) [7440-43-9]	—	0.05		1ψ			1	ʼ76
Calcium cyanide (as CN) [592-01-8]	—	5*	S					ʼ01
Carbaryl [63-25-2]	—	5	S					ʼ89
Carbon dioxide [124-38-9]	5,000	9,000						ʼ74
Carbon disulfide [75-15-0]	1	3.13	S				1#	ʼ15
Carbon monoxide [630-08-0]	50	57					1	ʼ71
Carbon tetrachloride [56-23-5]	5	31	S	2B				ʼ91
Chlorine [7782-50-5]	0.5*	1.5*						ʼ99
Chlorobenzene [108-90-7]	10	46						ʼ93
Chlorodifluoromethane [75-45-6]	1,000	3,500					2	ʼ87
Chloroethane [75-00-3]	100	260						ʼ93
Chloroform [67-66-3]	3	14.7	S	2B				ʼ05
Chloromethane [74-87-3]	50	100					2	ʼ84
Chloromethyl methyl ether (technical grade) [107-30-2]	—	—		2A				ʼ92
Chloropicrin [76-06-2]	0.1	0.67						ʼ68
Chromium and compounds (as Cr) [7440-47-3]					2	1	3	ʼ89
Chromium metal	—	0.5
Chromium (III) compounds	—	0.5
Chromium (VI) compounds	—	0.05
Certain chromium (VI) compounds	—	0.01		1
Cobalt and compounds (without tungsten carbide) [7440-48-4]	—	0.05		2B	1	1		ʼ92
Cresol (all isomers)	5	22	S					ʼ86
Cumene [98-82-8]	10	50	S	2B				ʼ19
Cyclohexane [110-82-7]	150	520						ʼ70
Cyclohexanol [108-93-0]	25	102						ʼ70
Cyclohexanone [108-94-1]	25	100						ʼ70
Diazinon [333-41-5]	—	0.1	S	2B				ʼ89
Diborane [19287-45-7]	0.01	0.012						ʼ96
Dibutyl phthalate [84-74-2]	—	5				2		ʼ96
o-Dichlorobenzene [95-50-1]	25	150						ʼ94
p-Dichlorobenzene [106-46-7]	10	60		2B			3	ʼ98
1,4-Dichloro-2-butene [764-41-0]	0.002			2B				ʼ15
3,3’-Dichloro-4,4’-diaminodiphenylmethane (MBOCA) [101-14-4]	—	0.005	S	2Aψ				ʼ12
Dichlorodifluoromethane [75-71-8]	500	2,500						ʼ87
1,1-Dichloroethane [75-34-3]	100	400						ʼ93
1,2-Dichloroethane [107-06-2]	10	40		2B				ʼ84
2,2’-Dichloroethyl ether [111-44-4]	15	88	S					ʼ67
1,2-Dichloroethylene [540-59-0]	150	590						ʼ70
Dichloromethane [75-09-2]	50	173	S	2A				ʼ99
	100*	347*
2,4-Dichlorophenoxyacetic acid (2,4-D) [94-75-7]	—	2	S				2	’19
1,2-Dichloropropane [78-87-5]	1	4.6		1		2		ʼ13
2,2-Dichloro-1,1,1-trifluoroethane [306-83-2]	10	62						ʼ00
Diethylamine [109-89-7]	10	30						ʼ89
Di(2-ethylhexyl) phthalate [117-81-7]	—	5		2B			1#	ʼ95
Diethyl phthalate [84-66-2]	—	5						ʼ95
N,N-Dimethyl acetamide [127-19-5]	10	36	S	2B			2	ʼ90
Dimethylamine [124-40-3]	2	3.7					3	ʼ16
N,N-Dimethylaniline [121-69-7]	5	25	S					ʼ93
N,N-Dimethylformamide (DMF) [68-12-2]	10	30	S	2A			2	ʼ74
Dimethyl sulfate [77-78-1]	0.1	0.52	S	2Aψ				ʼ80
Dimethyl terephthalate [120-61-6]		8						ʼ20
1,2-Dinitrobenzene [528-29-0]	0.15	1	S					ʼ94
1,3-Dinitrobenzene [99-65-0]	0.15	1	S					ʼ94
1,4-Dinitrobenzene [100-25-4]	0.15	1	S					ʼ94
1,4-Dioxane [123-91-1]	1	3.6	S	2B				ʼ15
Diphenylmethane-4,4’-diiso-cyanate (MDI) [101-68-8]	—	0.05			1			ʼ93
Dusts			(Table I-3)
2,3-Epoxypropyl methacrylate (Glycidyl methacrylate, GMA) [106-91-2]	0.01	0.06	S	2A		2	3	ʼ18
Ethyl acetate [141-78-6]	200	720						ʼ95
Ethylamine [75-04-7]	10	18						ʼ79
Ethylbenzene [100-41-4]	20	87	S	2B			2	ʼ20
Ethylenediamine [107-15-3]	10	25	S		2	2		ʼ91
Ethylene glycol monobutyl ether [111-76-2]	20*	97*	S				2	ʼ17
Ethylene glycol monoethyl ether [110-80-5]	5	18	S				2	ʼ85
Ethylene glycol monoethyl ether acetate [111-15-9]	5	27	S				2	ʼ85
Ethylene glycol monomethyl ether [109-86-4]	0.1	0.31	S				1	ʼ09
Ethylene glycol monomethyl ether acetate [110-49-6]	0.1	0.48	S				1	ʼ09
Ethylene oxide [75-21-8]	1	1.8		1ψ		2	1	ʼ90
Ethylenimine [151-56-4]	0.05	0.09	S	2B			3	ʼ18
Ethyl ether [60-29-7]	400	1,200						(ʼ97)
2-Ethy1-1-hexanol [104-76-7]	1	5.3					3†	ʼ16
Ethylidene norbornene [16219-75-3]	2	10					3	ʼ18
Etofenprox [80844-07-1]	—	3						ʼ95
Fenitrothion [122-14-5]	—	1	S					ʼ81
Fenobucarb [3766-81-2]	—	5	S					ʼ89
Fenthion [55-38-9]	—	0.2	S					ʼ89
Flutolanil [66332-96-5]	—	10						ʼ90
Formaldehyde [50-00-0]	0.1	0.12		2A	2	1		ʼ07
	0.2*	0.24*
Formic acid [64-18-6]	5	9.4						ʼ78
Fthalide [27355-22-2]	—	10						ʼ90
Furfural [98-01-1]	2.5	9.8	S					(ʼ89)
Furfuryl alcohol [98-00-0]	5	20		2B				ʼ78
Gasoline [8006-61-9]	100b	300b		2B				ʼ85
Glyphosate [1071-83-6]	(Table I-2)			2B†			3†	’21
Glutaraldehyde [111-30-8]	0.03*				1	1		ʼ06
Heptane [142-82-5]	200	820						ʼ88
Hexachlorobutadiene [87-68-3]	0.01	0.12	S					ʼ13
Hexane [110-54-3]	40	140	S					ʼ85
Hexane-1,6-diisocyanate (HDI) [822-06-0]	0.005	0.034			1			ʼ95
Hydrazine (anhydrous) and Hydrazine hydrate [302-01-2/7803-57-8]	0.1	0.13 and 0.21	S	2A		1		ʼ98
Hydrogen chloride [7647-01-0]	2*	3.0*						ʼ14
Hydrogen cyanide [74-90-8]	5	5.5	S					ʼ90
Hydrogen fluoride [7664-39-3]	3*	2.5*	S					(ʼ20)
Hydrogen selenide [7783-07-5]	0.05	0.17						ʼ63
Hydrogen sulfide [7783-06-4]	5	7						ʼ01
Indium and compounds [7440-74-6]	(Table II-1)			2A				ʼ07
Iodine [7553-56-2]	0.1	1				2		ʼ68
Isobutyl alcohol [78-83-1]	50	150						ʼ87
Isopentyl alcohol [123-51-3]	100	360						ʼ66
Isoprene [78-79-5]	3	8.4		2B				ʼ17
Isopropyl acetate [108-21-4]	100							ʼ17
Isopropyl alcohol [67-63-0]	400*	980*						ʼ87
Isoprothiolane [50512-35-1]	—	5						ʼ93
Lead and compounds (as Pb except alkyl lead compounds) [7439-92-1]	—	0.03		2B			1#	ʼ16
Lithium hydroxide [1310-65-2]	—	1						ʼ95
Malathion [121-75-5]	—	10	S	2B				ʼ89
Maleic anhydride [108-31-6]	0.1	0.4			2	2		(ʼ15)
	0.2*	0.8*
Manganese and its compounds (as Mn except organic compounds) [7439-96-5]	(Table I-2)						2	ʼ21
Man-made mineral fibers**								ʼ03
Ceramic fibers, Micro glass fibers	—	—		2B
Continuous filament glass fibers,		1 (fiber/ml)
Glass wool fibers, Rock wool fibers, Slag wool fibers
Mepronil [55814-41-0]	—	5						ʼ90
Mercury vapor [7439-97-6]	—	0.025					2	ʼ98
Methacrylic acid [79-41-4]	2	7.0						ʼ12
Methanol [67-56-1]	200	260	S				2	ʼ63
Methyl acetate [79-20-9]	200	610						ʼ63
Methyl acrylate [96-33-3]	2	7		2B		2		ʼ04
Methylamine [74-89-5]	5	6.5						ʼ19
Methyl bromide [74-83-9]	1	3.89	S					ʼ03
Methyl n-butyl ketone [591-78-6]	5	20	S					ʼ84
Methylcyclohexane [108-87-2]	400	1,600						ʼ86
Methylcyclohexanol [25639-42-3]	50	230						ʼ80
Methylcyclohexanone [1331-22-2]	50	230	S					ʼ87
Methyl methacrylate [80-62-6]		8.3			2	2		ʼ12
4,4’-Methylenedianiline [101-77-9]	—	0.4	S	2B				ʼ95
Methyl ethyl ketone [78-93-3]	200	590						ʼ64
Methyl isobutyl ketone [108-10-1]	50	205		2B				ʼ84
N-Methyl-2-pyrrolidone [872-50-4]	1	4	S					ʼ02
Methyltetrahydrophthalic anhydride [11070-44-3]	0.007	0.05			1			ʼ02
	0.015*	0.1*
Nickel [7440-02-0]	—	1			2	1	3	ʼ11
Nickel carbonyl [13463-39-3]	0.001	0.007						ʼ66
Nickel compounds (total dusts) (as Ni) [7440-02-0],				2B			3	ʼ11
Nickel compounds, soluble		0.01						ʼ11
Nickel compounds, not soluble		0.1						ʼ11
Nickel smelting dusts [7440-02-0]	(Table III-2)			1				ʼ11
Nitric acid [7697-37-2]	2	5.2						ʼ82
p-Nitroaniline [100-01-6]	—	3	S					ʼ95
Nitrobenzene [98-95-3]	1	5	S	2B				(ʼ88)
p-Nitrochlorobenzene [100-00-5]	0.1	0.64	S					ʼ89
Nitrogen dioxide [10102-44-0]	(pending)							ʼ61
Nitroglycerin [55-63-0]	0.05*	0.46*	S					ʼ86
Nitroglycol [628-96-6]	0.05	0.31	S					ʼ86
Nonane [111-84-2]	200	1,050						ʼ89
Octane [111-65-9]	300	1,400						ʼ89
Oil mist, mineral	—	3		1ψ				ʼ77
Ozone [10028-15-6]	0.1	0.2						ʼ63
Parathion [56-38-2]	—	0.1	S					(ʼ80)
Pentachlorophenol [87-86-5]	—	0.5	S				2	(ʼ89)
Pentane [109-66-0]	300	880						ʼ87
Pentyl acetate, all isomers [628-63-7; 123-92-2; 626-38-0; 620-11-1; 625-16-1; 624-41-9; 926-41-0]	50	266.3						ʼ08
	100*	532.5*
Perfluorooctanoic acid [335-67-1]		0.005c		2B			1#	ʼ08
Phenol [108-95-2]	5	19	S				3	ʼ78
m-Phenylenediamine [108-45-2]	—	0.1				3		ʼ99
o-Phenylenediamine [95-54-5]	—	0.1		2B		3		ʼ99
p-Phenylenediamine [106-50-3]	—	0.1				1		ʼ97
Phosgene [75-44-5]	0.1	0.4						ʼ69
Phosphine [7803-51-2]	0.3*	0.42*						ʼ98
Phosphoric acid [7664-38-2]	—	1						(ʼ90)
Phosphorus (yellow) [7723-14-0]	—	0.1						(ʼ88)
Phosphorus pentachloride [10026-13-8]	0.1	0.85						ʼ89
Phosphorus trichloride [7719-12-2]	0.2	1.1						ʼ89
Phthalic anhydride [85-44-9]	0.33*	2*			1			ʼ98
o-Phthalodinitrile [91-15-6]	0.01	S						ʼ09
Picric acid	—	—				2		ʼ14
Platinum, soluble salts (as Pt) [7440-06-4]	—	0.001			1	1		ʼ00
Polychlorobiphenyls	—	0.01	S	1ψ			1	ʼ06
Potassium cyanide (as CN) [151-50-8]	—	5*	S					ʼ01
Potassium hydroxide [1310-58-3]	—	2*						ʼ78
Propyl acetate [109-60-4]	200	830						ʼ70
Propyleneimine (2-Methylaziridine)	0.2	0.45	S	2B				ʼ17
Pyridaphenthion [119-12-0]	—	0.2	S					ʼ89
Rhodium (soluble compounds, as Rh) [7440-16-6]	—	0.001				2		ʼ07
Selenium and compounds (as Se, except SeH2 and SeF6) [7782-49-2]	—	0.1						ʼ00
Silane [7803-62-5]	100*	130*						ʼ93
Silicon carbide whisker [409-21-2; 308076-74-6]	—	0.1 (fiber/ml)		2A				’19
Silver and compounds (as Ag) [7440-22-4]	—	0.01						ʼ91
Sodium cyanide (as CN) [143-33-9]	—	5*	S					ʼ01
Sodium hydroxide [1310-73-2]	—	2*						ʼ78
Styrene [100-42-5]	20	85	S	2B			2	ʼ99
Sulfur dioxide [7446-09-5]	(pending)							ʼ61
Sulfuric acid [7664-93-9]	—	1*						ʼ00
Sulfur monochloride [10025-67-9]	1*	5.5*						ʼ76
1,1,2,2-Tetrachloroethane [79-34-5]	1	6.9	S	2B				ʼ84
Tetrachloroethylene [127-18-4]	(pending)		S	2B			3	ʼ72
Tetraethoxysilane [78-10-4]	10	85						ʼ91
Tetraethyl lead (as Pb) [78-00-2]	—	0.075	S					ʼ65
Tetrahydrofuran [109-99-9]	50	148	S	2B				ʼ15
Tetramethoxysilane [681-84-5]	1	6						ʼ91
Thiuram [137-26-8]		0.1				1		ʼ08
Titanium dioxide (nanoparticle, as Ti) [13463-67-7]	—	0.3		2B				ʼ13
Toluene [108-88-3]	50	188	S				1	(ʼ13)
Toluene diisocyanates [26471-62-5]	0.005	0.035		2B	1	2		ʼ92
	0.02*	0.14*
Trichlorhon [52-68-6]		0.2	S					ʼ10
o-Toluidine [95-53-4]	1	4.4	S	1ψ				ʼ91
1,1,1-Trichloroethane [71-55-6]	200	1,090						ʼ74
1,1,2-Trichloroethane [79-00-5]	10	55	S					(ʼ78)
Trichloroethylene [79-01-6]	25	135		1ψ		1	3	ʼ15
Trichlorofluoromethane [75-69-4]	1,000*	5,600*						ʼ87
1,1,2-Trichloro-1,2,2-trifluoroethane [76-13-1]	500	3,800						ʼ87
Tricyclazole [41814-78-2]	—	3						ʼ90
Trimellitic anhydride [552-30-7]		0.0005	S		1			ʼ15
		0.004*
1,2,3-Trimethylbenzene [526-73-8]	25	120						ʼ84
1,2,4-Trimethylbenzene [95-63-6]	25	120						ʼ84
1,3,5-Trimethylbenzene [108-67-8]	25	120						ʼ84
Trinitrotoluene (all isomers)	—	0.1	S					ʼ93
Turpentine	50	280				1		ʼ91
Vanadium compounds							2
Ferrovanadium dust [12604-58-9]	—	1						ʼ68
Vanadium pentoxide [1314-62-1]	—	0.05		2B				ʼ03
Vinyl chloride [75-01-4]	(Table III-2)			1ψ				ʼ17
Xylene (all isomers and their mixture)	50	217						ʼ01
Xylene for industrial use							2
Xylene (ortho-, meta-, para-xylene and their mixture)							3
Zinc oxide nanoparticle [1314-13-2]	(Table I-2)							ʼ21

1. ppm: parts of vapors and gases per million of substance in air by volume at 25°C and atmospheric pressure (760 torr, 1,013 hPa); OELs in ppm are converted to those in mg/m³, in which the values are rounded off to 2 significant digits.

2. ( ) in the year of proposal column indicates that revision was done in the year without change of the OEL value.

3. *: Occupational Exposure Limit-Ceiling; exposure concentration must be kept below this level.

 **: Fibers longer than 5 μm and with an aspect ratio equal to or greater than 3:1 as determined by the membrane filter method at 400×magnification phase contrast illumination.

 ^ψ: Substance whose OEL is set based on non-carcinogenic health effects; see III.

 ^a: Exposure concentration should be kept below a detectable limit though OEL is set at 2.5 ppm provisionally.

 ^b: OEL for gasoline is 300 mg/m³, and an average molecular weight is assumed to be 72.5 for conversion to ppm units.

 ^c: Not applicable to women of child bearing potential.

 ^#: Precaution should be taken for exposure lower than the OEL-M or OEL-B. As for reproductive toxicity, it is generally known that there is a sensitive period, during pregnancy for example, and such effects of this substance have been identified.

 ^†: Provisional.

Table I-2. Occupational exposure limits for chemical substances (Provisional values)

Substance [CAS No.]	OEL		Skin absorption	Class of carcinogenicity	Class of sensitizing potential		Reproductive Toxicants	Year of proposal
	ppm	mg/m3			Airway	Skin
Acetaldehyde [75-07-0]	10*	18*		2B‡				’21
2-Bromopropane [75-26-3]	0.5	2.5	S‡	2B			1‡	’21
Glyphosate [1071-83-6]		1.5		2B			3	’21
Manganese and its compounds (as Mn except organic compounds) [7439-96-5]		0.02 (respirable particulate matter) 0.1 (Total particulate matter)					2‡	’21
Zinc oxide nanoparticle [1314-13-2]		0.5						’21

Note: see Table I-1

^‡: Not provisional

Table I-3. Occupational exposure limits for dusts^a

I. Respirable crystalline silicaψ, *  OEL-C 0.03 mg/m3 II. Dusts other than I
	Dusts	OEL (mg/m3)
		Respirable dust*	Total dust**
Class 1	Activated charcoal, Alumina, Aluminum, Bentonite, Diatomite, Graphite, Kaolinite, Pagodite, Pyrites, Pyrite cinder, Talc	0.5	2
Class 2	Dusts containing less than 3% cry stalline silica, Bakelite, Carbon black, Coal, Cork dust, Cotton dust, Iron oxide, Grain dust, Joss stick material dust, Marble, Portland cement, Titanium oxide, Zinc oxide	1	4
Class 3	Limestone‡, Inorganic and organic dusts other than Classes 1 and 2b	2	8
Asbestos***		(Table III-2)

1. a, OELs for dusts are set to prevent from Class 2 pneumoconiosis, while no other toxicities are considered

 b, OEL for ‘inorganic and organic dusts other than Classes 1 and 2’ is a reference value assigned for dusts that are insoluble or poorly soluble in water to prevent from pneumoconiosis caused by inhaling large amount of those; thus, be aware that unknown toxocity may be developed even below this value

2.*: Respirable crystalline silica and respirable dust consist of particles captured by the following collection efficiency, R (d_ae).

 R (d_ae)=0.5[1+exp (–0.06d_ae)] [1–F (x)]

 d_ae: aerodynamic diameter of particle (μm), F (x): cumulative distribution function of the standardized normal variable

   x=ln(d_ae/Γ)/ln(Σ), ln natural logarithm, Γ=4.25 μm, Σ=1.5

 **: Total dust comprises particles with a flow speed of 50 to 80 cm/sec at the entry of a particle sampler.

 ***: Fibers longer than 5 μm and with an aspect ratio equal to or greater than 3:1 as determined by the membrane filter method at 400×magnification (4 mm objective) phase contrast illumination.

3. ^‡: Do not include asbestos nor ≥1% crystalline silica.

4. ^ψ: Substance whose OEL is set based on non-carcinogenic health effects; see III.

5. OEL for wood dust is under consideration.

4. Interaction with other working conditions

Other working conditions, such as work intensity, heat stress and abnormal atmospheric pressure, must be considered, since their co-existence could cause an increase in the inhaled dose of a chemical substance, thereby intensifying its effects on workers’ health.

5. OEL for exposure to mixture of chemical substances

OEL-M values listed in Table I-1 and I-2 are applicable in cases where the substance exists alone. When workers are exposed to a mixture of chemical substances and there is no reliable evidence to the contrary that the effects of the chemicals are assumed to be additive, the effects should be assumed as additive.

The users should refer not to each OEL-M value, but rather to the following equation:

I=C₁/T₁+C₂/T₂+...+C_i/T_i+...+C_n/T_n

C_i=mean exposure concentration for each component i

T_i=OEL-M for each component i

Any value of I exceeding 1 indicates an exposure that is above OEL.

II. Occupational Exposure Limits Based on Biological Monitoring

1. Definition

Biological monitoring in the occupational setting consists of (1) measuring the concentration of a chemical substance or its metabolite (s) in biological specimens, and/or (2) determining early health effects by using biological specimens which are predictors or warning signs of the occurrence of adverse health effects.

Occupational Exposure Limit Based on Biological Monitoring (OEL-B) is defined as the reference values to the data obtained by biological monitoring at or below (depending on agents, above) which the adverse health effects do not appear in most workers who are exposed to the chemical substances.

2. Characteristics of OEL-B

(1) In setting OEL-B, consideration is given to the exposure-effect and/or exposure-response relationships between biological monitoring values and health effects, or to the relationship between biological monitoring values and OEL-Ms.

(2) There is a possibility that exposure concentration of chemical substances in the workplace will not closely associate with biological monitoring values due to various factors, e.g., intra- and inter-individual variation in metabolism, social habits such as smoking and alcohol consumption, working conditions, working time, skin absorption, use of personal protective equipment, and possible exposure to the substances outside the workplace. Biological monitoring values could exceed OEL-B even though exposure to the chemical substances is below OEL-M, and vice versa. Both OEL-M and OEL-B must be satisfied at the workplace.

(3) Biological specimens should be collected at the time that is most likely to represent the particular exposure to the substances concerned, or at the time most likely to predict occurrence of the particular adverse health effects. Only biological monitoring values measured under this condition can be referred to OEL-B.

(4) OEL-B is applied to cases of single-substance absorption. For exposure to a mixture of substances, interactions in terms of absorption, metabolism, accumulation, excretion and health effects must also be considered.

Table II-1. Occupational exposure limits based on biological monitoring

Substance	Assay material	Parameter	OEL-B	Sampling time	Year of proposal
Acetone	urine	Acetone	40 mg/l	Within 2 h prior to end of shift	ʼ01
2-Butoxyethanol and 2-Butoxyethyl acetate	urine	Butoxyacetic acid	200 mg/g·Cr	End of shift	ʼ08
Cadmium and its compounds	blood	Cadmium	5 µg/l†	Not critical	’21
	urine	Cadmium	5 µg/g·Cr†	Not critical	’21
Carbon disulfide	urine	2-Thiothiazolidine-4-carboxylic acid	0.5 mg/g·Cr	End of shift (Avoid sizable intake of brassica vegetables)	ʼ15
Cobalt and inorganic compounds (except cobalt oxides)	blood	Cobalt	3 μg/l	Within 2 h prior to end of shift at end of work week	ʼ05
	urine	Cobalt	35 μg/l	Within 2 h prior to end of shift at end of work week	ʼ05
Chlorobenzene	urine	4-Chlorocatechol (hydrolysis)	120 mg/g·Cr	End of shift	ʼ08
3,3’-Dichloro-4,4’-diaminodiphenyl-methane (MBOCA)	urine	total MBOCA	50 μg/g·Cr	End of shift at end of workweek	ʼ94
Dichloromethane	urine	Dichloromethane	0.2 mg/l	End of shift	ʼ05
Ethylbenzene	urine	Mandelic acid	150 mg/g·Cr†	End of shift	’21
	urine	Mandelic acid+ Phenylglyoxylic acid	200 mg/g·Cr†	End of shift at end of workweek	’21
	urine	Ethylbenzene	15 µg/l†	End of shift	’21
Hexane	urine	2,5-Hexanedione	3 mg/g·Cr (after acid hydrolysis)	End of shift at end of workweek	ʼ94
	urine	2,5-Hexanedione	0.3 mg/g·Cr (without acid hydrolysis)	End of shift at end of workweek	ʼ94
Indium and compounds	serum	Indium	3 μg/l	Not critical	ʼ07
Lead and compounds (except alkyl lead compounds)	blood	Lead	15 μg/100 ml	Not critical	ʼ13
	blood	Protoporphyrin	200 μg/100 ml·RBC	Not critical	ʼ94
			80 μg/100 ml·blood	(After one month or more since consecutive exposure)	ʼ94
	urine	δ-Aminolevulinic acid	5 mg/l	Not critical	ʼ94
				(After one month or more since consecutive exposure)
Mercury and compounds (except alkyl mercury compounds)	urine	total inorganic mercury	35 μg/g·Cr	Not critical	ʼ93
Methanol	urine	Methanol	20 mg/l	End of shift	ʼ10
Methylethylketone	urine	Methylethylketone	5 mg/l	End of shift or A few hours after high exposure	ʼ06
Methyl isobutyl ketone	urine	Methyl isobutyl ketone	1.7 mg/l	End of shift	ʼ07
Phenol	urine	Phenol	250 mg/g·Cr	End of shift	ʼ08
Polychlorobiphenyls (PCBs)	blood	total PCB	25 μg/l	Not critical	ʼ06
Styrene	urine	Mandelic acid + Phenylglyoxylic acid	430 mg/l	End of shift at end of work week	ʼ07
	blood	Styrene	0.2 mg/l	End of shift at end of work week	ʼ07
Tetrahydrofuran	urine	Tetrahydrofuran	2 mg/l	End of shift	(ʼ15)
Toluene	blood	Toluene	0.6 mg/l	Within 2 h prior to end of shift at end of work week	ʼ99
	urine	Toluene	0.06 mg/l		ʼ99
Trichloroethylene	urine	total trichloro-compounds	150 mg/l	Within 2 h prior to end of shift at end of work week	ʼ99
	urine	Trichloroethanol	100 mg/l		ʼ99
	urine	Trichloroacetic acid	50 mg/l
Xylene	urine	total (o-, m-, p-) methylhippuric acid	800 mg/l	End of shift at end of work week	ʼ06

^†: Provisional

See the JSOH website for brief summary of OEL documentation at http://sanei.or.jp/oel-eng

III. Occupational Carcinogens

JSOH classifies the occupational carcinogens based primarily on the epidemiological evidences¹⁾, but the results of the animal experiments and their extrapolation to human are also considered. The classification is made by strength of the evidence, but does not reflect the carcinogenic potency.

JSOH considers that the classification of occupational carcinogens proposed by the International Agency for Research on Cancer (IARC)²⁾ is appropriate in principle. JSOH also discussed the classification of several agents based on other information sources and finalized the list of occupational carcinogens in Table III-1a, b, and c. Group 1 includes agents that are carcinogenic to humans. Group 2 indicates the agents which are probably or possibly carcinogenic to humans, classifying them into two sub-groups on the basis of degree of evidence: Group 2A is assigned to the agents with more sufficient evidence (probably carcinogenic to humans), Group 2B to those with less (possibly carcinogenic to humans).

Table III-1a. Group 1 carcinogens

Substance	CAS No.	Year of proposal
4-Aminobiphenyl	92-67-1	ʼ81, ʼ86
Arsenic and inorganic arsenic compounds*	7440-38-2	ʼ81, ʼ86, (ʼ00)
Asbestos	1332-21-4	ʼ81, ʼ86, (ʼ00)
Benzene	71-43-2	ʼ81, ʼ86, (ʼ97), (ʼ19)
Benzidine	92-87-5	ʼ81, ʼ86
Benzo [a] pyrene	50-32-8	ʼ86, ʼ17
Benzotrichloride	98-07-7	ʼ81, ʼ86, (ʼ01)
Beryllium and compounds*	7440-41-7	ʼ86, ʼ16
Bis (chloromethyl) ether	542-88-1	ʼ81, ʼ86
1,3-Butadiene	106-99-0	ʼ91, ʼ95, ʼ01
Cadmium and compounds*	7440-43-9	ʼ86, ʼ91, ʼ96
Chromium (VI) compounds	18540-29-9	ʼ81, ʼ86
Coal-tar pitch volatiles	—	ʼ81, ʼ86, (ʼ04)
Coal-tars	8007-45-2	ʼ81, ʼ86, (ʼ04)
1,2-Dichloropropane	78-87-5	ʼ13, ʼ14
Erionite	12510-42-8	ʼ91
Ethylene oxide	75-21-8	ʼ86, ʼ90, ʼ96
Ionizing radiation	—	ʼ12
Mineral oils (untreated and mildly treated)	—	ʼ81, ʼ86, ʼ91
2-Naphthylamine	91-59-8	ʼ81, ʼ86
Nickel smelting dusts*	7440-02-0	ʼ81, ʼ86, ʼ91, (ʼ09)
Polychlorinated biphenyls (PCB)	1336-36-3, 53469-21-9, 11097-69-1	ʼ86, ʼ91, ʼ16
Shale oils	68308-34-9	ʼ95
Silica (crystalline)	14808-60-7	ʼ91, ʼ01
Soots	—	ʼ81, ʼ86
Sulphur dichlorodiethyl	505-60-2	ʼ86
Talc containing asbestiform fibers	14807-96-6	ʼ91
2,3,7,8-Tetrachlorodibenzo-p-dioxin	1746-01-6	ʼ86, ʼ00
Tobacco smoke	—	ʼ10
o-Toluidine	95-53-4	ʼ86, ʼ95, ʼ01, ʼ16
Trichloroethylene	79-01-6	ʼ96, ʼ15
UV radiation from welding†	—	’21
Vinyl chloride	75-01-4	ʼ81, ʼ86
Welding fume†	—	’21
Wood dust	—	ʼ98

*Evaluation does not necessarily apply to all individual chemicals within the group.

( ) in the year of proposal indicates year of reconsideration resulting in no classification change.

^† Provisional

Table III-1b. Group 2A carcinogens

Substance	CAS No.	Year of proposal
Acrylamide	79-06-1	ʼ91, ʼ95, (ʼ04)
Acrylonitrile	107-13-1	ʼ86
Benzal chloride	98-87-3	ʼ91, ʼ01
Benzyl chloride	100-44-7	ʼ91, ʼ01
Chloromethyl methyl ether (technical grade)	107-30-2	ʼ92, (ʼ01)
4-Chloro-o-toluidine	95-69-2	ʼ91, ʼ01
CI Direct Black 38**	1937-37-7	ʼ86, ʼ91, ʼ95, ʼ01, (ʼ15)
CI Direct Blue 6**	2602-46-2	ʼ86, ʼ91, ʼ95, ʼ01, (ʼ15)
CI Direct Brown 95**	16071-86-6	ʼ86, ʼ91, ʼ95, ʼ01, (ʼ15)
Cobalt metal with tungsten carbide	7440-48-4, 12070-12-1	ʼ16
Creosotes	8001-58-9	ʼ91
1,2-Dibromoethane	106-93-4	ʼ86, ʼ95, ʼ01
3,3’-Dichloro-4,4’-diaminodiphenylmethane (MBOCA)	101-14-4	ʼ93, (ʼ12)
Dichloromethane	75-09-2	ʼ91, ʼ14, ʼ15
Diethyl sulphate	64-67-5	ʼ86
N,N-Dimethylformamide	68-12-2	’91, ’20
Dimethyl sulphate	77-78-1	ʼ86
Dimethylcarbamoyl chloride	79-44-7	ʼ86, ʼ91
Epichlorohydrin	106-89-8	ʼ86, ʼ91
2,3-Epoxypropyl methacrylate (Glycidyl methacrylate, GMA)	106-91-2	ʼ18
Formaldehyde	50-00-0	ʼ86, ʼ91, (ʼ07), (ʼ17)
Glycidol	556-52-5	ʼ01
Hydrazine (Hydrazine anhydrous and Hydrazine hydrate)	302-01-2, 7803-57-8	’86, (ʼ98), ʼ19
Indium and compounds (inorganic, hardly, soluble)	7440-74-6	ʼ13, (ʼ17)
2-Nitrotoluene	88-72-2	ʼ18
PAHs (Cyclopenta [c,d] pyrene, Dibenz [a,h] anthracene, Dibenz [a,j] acridine, Dibenzo [a,l] pyrene, 1-Nitropyrene, 6-Nitrochrysene)	27208-37-3, 53-70-3, 224-42-0, 191-30-0, 5522-43-0, 7496-02-8	ʼ16
1,3-Propane sultone	1120-71-4	ʼ91, ʼ17
Silicon carbide whisker	409-21-2, 308076-74-6	ʼ19
Styrene oxide	96-09-3	ʼ92, (ʼ18)
1,2,3-Trichloropropane	96-18-4	ʼ01
Tris (2,3-dibromopropyl) phosphate	126-72-7	ʼ91
Vinyl bromide	593-60-2	ʼ91
Vinyl fluoride	75-02-5	ʼ98

**Dyes metabolized to benzidine.

^†Provisional

( ) in the year of proposal indicates year of reconsideration resulting in no classification change.

Table III-1c. Group 2B carcinogens

Substance	CAS No.	Year of proposal
Acetamide	60-35-5	ʼ91
Acetoaldehyde	75-07-0	ʼ91
Acrylic acid methyl	96-33-3	ʼ19
o-Aminoazotoluene	97-56-3	ʼ91
p-Aminoazobenzene	60-09-3	ʼ91
2-Amino-4-chlorophenol	95-85-2	ʼ19
Amitrole	61-82-5	ʼ86
Antimony trioxide	1309-64-4	ʼ91, (ʼ13)
o-Anisidine	90-04-0	ʼ91, (ʼ96)
Anthraquinone	84-65-1	ʼ15
Auramine (technical grade)	492-80-8	ʼ86
Benzofuran	271-89-6	ʼ15
Benzophenone	119-61-9	ʼ15
Benzoyl chloride	98-88-4	ʼ16
Benzyl violet 4B	1694-09-3	ʼ91
2,2-Bis (bromomethyl) propane-1,3-diol	3296-90-0	ʼ01
Bitumens	8052-42-4	ʼ91
1-Bromo-3-chloropropane	109-70-6	’20
Bromodichloromethane	75-27-4	ʼ95
1-Bromopropane	106-94-5	ʼ17
2-Bromopropane†	75-26-3	’21
1-tert-Butoxy-2-propanol	57018-52-7	ʼ18
n-Butyl-2,3-epoxypropyl ether	2426-08-6	ʼ16
β-Butyrolactone	3068-88-0	ʼ95
Carbon black	1333-86-4	ʼ91
Carbon tetrachloride	56-23-5	ʼ86
Catechol	120-80-9	ʼ01
Chlordane	57-74-9	ʼ01
Chlordecone (Kepone)	143-50-0	ʼ01
Chlorendic acid	115-28-6	ʼ91
Chlorinated paraffins	—	ʼ91
p-Chloroaniline	106-47-8	ʼ95
4-Chlorobenzotrifluoride	98-56-6	’20
Chloroform	67-66-3	ʼ86, (ʼ05)
1-Chloro-2-methylpropene	513-37-1	ʼ01
3-Chloro-2-methylpropene	563-47-3	ʼ01, (ʼ17)
Chlorophenoxy acetic acid herbicides*	—	ʼ86
p-Chloro-o-phenylenediamine	95-83-0	ʼ91
Chloroprene	126-99-8	ʼ01
Chlorothalonil	1897-45-6	ʼ01
CI acid red 114	6459-94-5	ʼ95
CI basic red 9	569-61-9	ʼ95
CI direct blue 15	2429-74-5	ʼ95
CI direct blue 218†	28407-37-6	’21
Citrus red No.2	6358-53-8	ʼ91
Cobalt and compounds (without tungsten carbide)*	7440-48-4	ʼ95, (ʼ16)
p-Cresidine	120-71-8	ʼ91
Crotonaldehyde†	4170-30-3	’21
Cumene	98-82-8	ʼ15, (ʼ19)
Dantron	117-10-2	ʼ15
N,N’-Diacetyl benzidine	613-35-4	ʼ91
2,4-Diaminoanisole	615-05-4	ʼ91
4,4’-Diaminodiphenyl ether	101-80-4	ʼ91
2,4-Diaminotoluene	95-80-7	ʼ91
Diazinon	333-41-5	ʼ18
1,2-Dibromo-3-chloropropane	96-12-8	ʼ91
2,3-Dibromopropan-1-ol	96-13-9	ʼ01
p-Dichlorobenzene	106-46-7	ʼ91, (ʼ98)
3,3’-Dichlorobenzidine	91-94-1	ʼ86
1,4-Dichloro-2-butene	764-41-0	ʼ15
3,3’-Dichloro-4,4’-diaminodiphenyl ether	28434-86-8	ʼ91
1,2-Dichloroethane	107-06-2	ʼ91
1,4-Dichloro-2-nitrobenzene	89-61-2	ʼ19
2,4-Dichloro-1-nitrobenzene	611-06-3	ʼ19
1,3-Dichloropropene (technical grade)	542-75-6	ʼ91
1,3-Dichloro-2-propanol	96-23-1	ʼ15
Dichlorvos	62-73-7	ʼ01
Diepoxybutane	1464-53-5	ʼ91
Diethanolamine	111-42-2	ʼ15
Di (2-ethylhexyl) phthalate	117-81-7	ʼ91
1,2-Diethylhydrazine	1615-80-1	ʼ91
Diglycidyl resorcinol ether	101-90-6	ʼ91
Diisopropyl sulfate	2973-10-6	ʼ95
N,N-Dimethylacetamide	127-19-5	ʼ19
p-Dimethylaminoazobenzene	60-11-7	ʼ91
2,6-Dimethylaniline	87-62-7	ʼ95
3,3’-Dimethylbenzidine (o-Tolidine)	119-93-7	ʼ91
1,1-Dimethylhydrazine	57-14-7	ʼ91
N,N-Dimethyl-p-toluidine	99-97-8	ʼ17
3,3’-Dimethoxybenzidine (o-Dianisidine)	119-90-4	ʼ86
2,4-(or 2,6-) Dinitrotoluene	121-14-2	ʼ98
1,4-Dioxane	123-91-1	ʼ86, (ʼ15)
Disperseblue 1	2475-45-8	ʼ91
DDT	50-29-3	ʼ86, (ʼ17)
1,2-Epoxybutane	106-88-7	ʼ01
Ethyl acrylate	140-88-5	ʼ91, (ʼ19)
Ethylbenzene	100-41-4	ʼ01, (ʼ20)
2-Ethylhexyl acrylate	103-11-7	ʼ19
Ethyl methanesulphonate	62-50-0	ʼ91
Ethylene thiourea	96-45-7	ʼ86
Ethylenimine	151-56-4	ʼ01, (ʼ18)
(2-Formylhydrazino)-4-(5-nitro-2-furyl) thiazole	3570-75-0	ʼ91
Furan	110-00-9	ʼ01
Furfuryl alcohol	98-00-0	ʼ19
Gasoline	8006-61-9	ʼ01
Glycidaldehyde	765-34-4	ʼ91
Glyphosate†	1071-83-6	’21
Hexachlorocyclohexanes	319-84-6	ʼ91
HC blue No. 1	2784-94-3	ʼ95
Heptachlor	76-44-8	ʼ01
Hexamethylphosphoramide	680-31-9	ʼ01
Isoprene	78-79-5	ʼ95, (ʼ17)
Lead and compounds (except alkyl lead)*	7439-92-1	ʼ91, (ʼ16)
Magenta (containing CI basic red 9)	632-99-5	ʼ95
Magnetic fields, extremely low-frequency	—	ʼ15
Malathion	121-75-5	ʼ18
Man-made mineral fibers (Ceramic fibers, Micro glass fibers)	—	ʼ91, ʼ03
Melamine	108-78-1	ʼ19
2-Mercaptobenzothiazole	149-30-4	ʼ19
4,4’-Methylene bis (2-methylaniline)	838-88-0	ʼ91
4,4’-Methylenedianiline	101-77-9	ʼ91, (ʼ95)
Methyl isobutyl ketone	108-10-1	ʼ15
Methyl mercuries	7439-97-6	ʼ95
2-Methyl-1-nitroanthraquinone	129-15-7	ʼ91
N-Methyl-N-nitrosourethane	615-53-2	ʼ91
α-Methylstyrene	98-83-9	ʼ15
Mirex	2385-85-5	ʼ01
Molybdenum trioxide	1313-27-5	ʼ17
β-Myrcene	123-35-3	ʼ18
Naphthalene	91-20-3	ʼ15
Nickel compounds (except nickel carbonyl and nickel smelting dusts)*	7440-02-0	ʼ81, ʼ86, ʼ91, (ʼ09)
2-Nitroanisole	91-23-6	ʼ98
4-Nitroanisole	100-17-4	ʼ19
Nitrobenzene	98-95-3	ʼ98
o-Nitrochlorobenzene	88-73-3	ʼ19
p-Nitrochlorobenzene	100-00-5	ʼ19
Nitrilotriacetic acid and its salts	139-13-9	ʼ91
Nitrogen mustard-N-oxide	126-85-2	ʼ91
5-Nitroacenaphtene	602-87-9	ʼ91
Nitromethane	75-52-5	ʼ01
2-Nitropropane	79-46-9	ʼ91
N-Nitrosodiethanolamine	1116-54-7	ʼ01
N-Nitroso-N-phenylhydroxylamine ammonium salt (Cupferron)†	135-20-6	’21
N-Nitrosomorpholine	59-89-2	ʼ91
Oil orange SS	2646-17-5	ʼ91
PAHs (Benz[a]anthracene, Benz[j]aceanthrylene, Benzo[b]fluoranthene, Benzo[c]phenanthrene, Benzo[j]fluoranthene, Benzo[k]fluoranthene, Chrysene, Dibenz[a, h]acridine, Dibenz[c, h]acridine, Dibenzo[a, h]pyrene, Dibenzo[a, i]pyrene, 7H-Dibenzo[c, g]carbazole, 1,3-Dinitropyrene, 1, 6- Dinitropyrene, 1,8-Dinitropyrene, 5-Methylchrysene, 3-Nitrobenzanthrone, 4-Nitropyrene)	56-55-3, 202-33-5, 205-99-2, 195-19-7, 205-82-3, 207-08-9, 218-01-9, 226-36-8, 224-53-3, 189-64-0, 189-55-9, 194-59-2, 75321-20-9, 42397-64-8, 42397-65-9, 3697-24-3, 17117-34-9, 57835-92-4	ʼ16
Perfluorooctanoic acid	335-67-1	ʼ17
Phenyl glycidyl ether	122-60-1	ʼ91
o-Phenylenediamine and its dihydrochloride	95-54-5, 615-28-1	ʼ19
Polybrominated biphenyls	59536-65-1	ʼ91, (ʼ17)
Polychlorophenols (technical grades)	—	ʼ86
Ponceau 3R	3564-9-8	ʼ91
Ponceau MX	3761-53-3	ʼ91
β-Propiolactone	57-57-8	ʼ91
Propylene imine (2-Methylaziridine)	75-55-8	ʼ91, (ʼ17)
Propylene oxide	75-56-9	ʼ91, ʼ95
Pyridine	110-86-1	ʼ18
Quinoline	91-22-5	ʼ18
Radiofrequency electromagnetic fields	—	ʼ15
Styrene	100-42-5	ʼ91
1,1,2,2-Tetrachloroethane	79-34-5	ʼ15
Tetrachloroethylene	127-18-4	ʼ91, (ʼ01)
Tetrafluoroethylene	116-14-3	ʼ01, (ʼ17)
2,4,6-Trichlorophenol	88-06-2	ʼ18
Tetrabromobisphenol A	79-94-7	ʼ19
Tetrahydrofuran	109-99-9	ʼ19
Tetranitromethane	509-14-8	ʼ98
4,4’-Thiodianiline	139-65-1	ʼ91
Thiourea	62-56-6	ʼ95
Titanium dioxide	13463-67-7	ʼ15
Toluene diisocyanates (TDI)	26471-62-5	ʼ91
Trimethylolpropane Triacrylate (technical grade)	15625-89-5	ʼ19
Trypane blue	72-57-1	ʼ91
Urethane	51-79-6	ʼ91
Vanadium pentoxide	1314-62-1	ʼ15
Vinylidene chloride	75-35-4	ʼ18
Vinyl acetate	108-05-4	ʼ98
4-Vinylcyclohexene	100-40-3	ʼ95
4-Vinylcyclohexene diepoxide	106-87-6	ʼ95

^*Evaluation does not necessarily apply to all individual chemicals within the group.

^†Provisional

( ) in the year of proposal indicates year of reconsideration resulting in no classification change.

N,N-dimethylformamide is proposed to be excluded from Group 2B^†

Only when scientifically reasonable information is available, JSOH will estimate a reference value corresponding to an individual excess lifetime risk of cancer due to exposure to a Group I carcinogen, and show it in Table III-2. JSOH does not recommend either the reference value as a safe exposure level or the individual excess lifetime risk as an acceptable risk level. The reference value should be applied only by experts well-trained and well-experienced in occupational health to avoid or minimize the risk of occupational cancer.

Table III-2. Reference values corresponding to an individual excess lifetime risk of cancer

Substance	Individual excess lifetime risk of cancer	Reference value		Method of estimation	Year of estimation
Arsenic and inorganic arsenic compounds	10–3	3	μg/m3	Average relative risk model	ʼ00
	10–4	0.3	μg/m3
Asbestos
chrysotile	10–3	0.15	fibers/ml	Average relative risk model	ʼ00
	10–4	0.015	fibers/ml
containing asbestos fibers	10–3	0.03	fibers/ml
other than chrysotile	10–4	0.003	fibers/ml
Benzene	10–3	1	ppm	Average relative risk model	ʼ97, (ʼ19)
	10–4	0.1	ppm
Ionizing radiation	(Table III-3)				ʼ12
Nickel smelting dusts (as Ni)	10–3	10	μg/m3	Average relative risk model	ʼ09
	10–4	1	μg/m3
Vinyl chloride	10–3	1.5	ppm	Average relative risk model	ʼ17
	10–4	0.15	ppm

The occupational carcinogens may have OEL in Table I-1. These values must be used with caution. Some substances had epidemiological or experimental evidences that carcinogenicity was observed only at significantly higher concentrations than those for non-carcinogenic health effects, but the others did not. For the latter case, the substance is indicated as ψ in Table I-1³⁾.

1)  Epidemiological evidences include serum epidemiology and molecular epidemiology

2)  Including mechanistic evidences^†

3)  See Table I-1 for Group 1 and Group 2A carcinogens.

†  Provisional

Table III-3 indicates reference values corresponding to an individual excess lifetime risk of cancer for ionizing radiation. A series of the reference values, i.e. unit risk doses of ionizing radiation, are shown as Radiation Exposure Induced Death (REID) levels of 100, 50, 10, 1 for 1,000 population with stratified by sex, age, and exposure situation (single, repeated). Dose and dose-rate effectiveness factor (DDREF) of 1 is being adopted primarily, and REID levels with DDREF of 2 are also calculated for comparison. The reference values here are calculated based on exposure-response relationship of low LET radiation, indicating that the values should not be applied in the case that internal exposure is considered.

Table III-3. Unit risk doses of ionizing radiation: Risk of Exposure-Induced Death (REID) levels of 100, 50, 10, 1, for 1,000 population

Single exposure (mSV) DDREF=1
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	892.2	1,075.5	1,342.1	1,760.8	2,441.8		10−1	762.9	939.2	1,204.2	1,628.9	2,320.5
5×10−2	440.8	535.2	676.9	911.2	1,325.0		5×10−2	374.1	462.3	597.7	821.7	1,207.9
10−2	87.4	106.8	136.7	189.0	291.6		10−2	73.7	91.4	119.0	166.0	251.9
10−3	8.7	10.7	13.7	19.1	30.0		10−3	7.3	9.1	11.9	16.6	25.5
10−4	0.9	1.1	1.4	1.9	3.0		10−4	0.7	0.9	1.2	1.7	2.6
Repeated exposure until age 68 (from first exposure age to the end of age 67) (mSv/year) DDREF=1
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	34.1	50.8	83.5	160.2	412.8		10−1	28.6	42.7	70.1	133.0	342.4
5×10−2	16.4	24.5	40.3	77.5	203.9		5×10−2	13.8	20.7	33.9	64.5	167.5
10−2	3.2	4.8	7.8	15.1	40.4		10−2	2.7	4.0	6.6	12.6	33.0
10−3	0.3	0.5	0.8	1.5	4.0		10−3	0.3	0.4	0.7	1.3	3.3
10−4	0.03	0.05	0.08	0.15	0.40		10−4	0.03	0.04	0.07	0.13	0.33
Repeated 10 year exposure, (10 years from first exposure age) (mSv/year) DDREF=1
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	101.7	126.8	168.1	245.8	412.8		10−1	85.5	108.2	145.3	211.0	342.4
5×10−2	49.2	61.4	81.4	119.6	203.9		5×10−2	41.5	52.5	70.5	102.6	167.5
10−2	9.6	12.0	15.9	23.4	40.4		10−2	8.1	10.3	13.8	20.1	33.0
10−3	1.0	1.2	1.6	2.3	4.0		10−3	0.8	1.0	1.4	2.0	3.3
10−4	0.10	0.12	0.16	0.23	0.40		10−4	0.08	0.10	0.14	0.20	0.33
Repeated 5 year exposure, (5 years from first exposure age) (mSv/year) DDREF=1
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	192.5	236.8	306.4	430.4	673.3		10−1	161.8	202.3	266.4	376.7	581.4
5×10−2	93.3	115.0	149.3	211.4	337.9		5×10−2	78.6	98.3	129.7	184.1	287.1
10−2	18.2	22.5	29.3	41.7	68.0		10−2	15.4	19.2	25.4	36.2	56.9
10−3	1.8	2.2	2.9	4.2	6.8		10−3	1.5	1.9	2.5	3.6	5.7
10−4	0.18	0.22	0.29	0.42	0.68		10−4	0.15	0.19	0.25	0.36	0.57
Single exposure (mSv) DDREF=2
(a) Male							(b) Female
REID	Age 18	28	38	48	58		REID	Age 18	28	38	48	58
10−1	1,541.0	1,801.1	2,139.4	2,599.6	3,245.9		10−1	1,403.1	1,692.1	2,084.0	2,646.2	3,436.8
5×10−2	797.0	946.9	1,153.4	1,455.7	1,911.2		5×10−2	707.5	862.9	1,085.7	1,425.2	1,940.6
10−2	165.1	199.8	251.4	335.9	486.3		10−2	142.8	176.1	226.6	309.8	453.4
10−3	16.7	20.3	25.8	35.1	53.3		10−3	14.3	17.7	22.9	31.7	47.7
10−4	1.7	2.0	2.6	3.5	5.4		10−4	1.4	1.8	2.3	3.2	4.8
Repeated exposure until age 68 (from first exposure age to the end of age 67) (mSv/year) DDREF=2
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	63.5	93.4	150.2	276.5	650.5		10−1	54.9	81.4	131.9	244.7	596.9
5×10−2	30.7	45.3	73.2	136.8	337.3		5×10−2	26.6	39.5	64.2	120.1	301.3
10−2	6.0	8.8	14.4	27.2	70.2		10−2	5.2	7.7	12.6	23.7	60.9
10−3	0.6	0.9	1.4	2.7	7.1		10−3	0.5	0.8	1.3	2.4	6.1
10−4	0.06	0.09	0.14	0.27	0.71		10−4	0.05	0.08	0.13	0.24	0.61
Repeated 10 year exposure, (10 years from first exposure age) (mSv/year) DDREF=2
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	191.2	235.3	304.2	424.7	650.5		10−1	165.2	207.5	274.3	387.7	596.9
5×10−2	93.2	115.1	149.9	212.5	337.3		5×10−2	80.5	101.2	134.4	191.7	301.3
10−2	18.3	22.6	29.7	42.6	70.2		10−2	15.8	19.9	26.5	38.0	60.9
10−3	1.8	2.3	3.0	4.3	7.1		10−3	1.6	2.0	2.6	3.8	6.1
10−4	0.18	0.23	0.30	0.43	0.71		10−4	0.16	0.20	0.26	0.38	0.61
Repeated 5 year exposure, (5 years from first exposure age) (mSv/year) DDREF=2
(a) Male							(b) Female
REID	age at first exposure						REID	age at first exposure
	18	28	38	48	58			18	28	38	48	58
10−1	358.0	433.6	545.5	726.9	1,032.7		10−1	310.9	385.1	497.8	681.2	989.7
5×10−2	176.0	214.5	272.8	371.6	550.8		5×10−2	152.1	189.1	246.1	341.5	510.3
10−2	34.8	42.6	54.7	76.1	118.5		10−2	29.9	37.3	48.8	68.6	105.3
10−3	3.5	4.3	5.5	7.7	12.1		10−3	3.0	3.7	4.9	6.9	10.6
10−4	0.35	0.42	0.55	0.77	1.21		10−4	0.30	0.37	0.49	0.69	1.06

IV. Occupational Sensitizers

This table is the list of occupational sensitizers to the airway and skin (Table IV). The sensitizers are classified into Group 1 substances which induce allergic reactions in humans, Group 2 substances which probably induce allergic reactions in humans, and Group 3 substances which are considered possibly to induce allergic reactions in humans based on animal experiments.

Table IV. Occupational sensitizers

Airway

Group 1

Beryllium*, Cobalt*, Colophony (Rosin)*, Diphenylmethane-4,4’-diisocyanate (MDI), Glutaraldehyde, Hexane-1,6-diisocyanate, Methyltetrahydrophthalic anhydride, o-Phthalaldehyde†, Phthalic anhydride, Platinum*, Toluene diisocyanates*, Trimellitic anhydride

Group 2

Chlorothalonil, Chromium*, Ethylenediamine, Formaldehyde, Maleic anhydride, Methyl methacrylate, Nickel*, Piperazine

Skin

Group 1

Aniline, Benzoyl peroxide, Benzyl alcohol, Chlorothalonil, Chromium*, Cobalt*, Colophony (Rosin)*, 2,4-Dinitrochlorobenzene (DNCB), Epichlorohydrin, Formaldehyde, Glutaraldehyde, Hydrazine*, Mercury*, Methacrylic acid 2-hydroxyethyl ester (2-Hydroxyethyl methacrylate), 4,4’-Methylenedianiline, Nickel*, p-Phenylenediamine, o-Phthalaldehyde†, Platinum*, Resorcinol, Sodium ethylmercury 2-Sulfidobenzoate (Thimerosal), Thiuram, Trichloroethylene, Tri (propylene glycol) diacrylate, N,N’,N’’-Tris (β-hydroxyethyl)-hexahydro-1,3,5-triazine, Turpentine*, m-Xylylendiamine

Group 2

Acrylamide, Benomyl, Benzyl alcohol, Beryllium*, Buthyl acrylate, N-butyl-2,3-epoxy-propyl ether, Copper*, Dibutyl phthalate, Dichloropropane, Dicyclohexylcarbodiimide, Diethanolamine, 2,3-Epoxypropyl methacrylate (Glycidyl methacrylate, GMA), Ethyl acrylate, Ethylenediamine, Ethylene glycol dimethacrylate†, Ethylene oxide, 1,6-Hexanediol diacrylate†, Hydroquinone, 2-Hydroxyethyl methacrylate, Iodine*, Maleic anhydride, Methyl acrylate, Methyl methacrylate, Picric acid, Polyvinyl chloride plasticizers*, Rodium*, Toluene diamine*, Toluene diisocyanates*, Usnic acid

Group 3

m-Chloroaniline, Dimethylamine, Isophoronediisocyanate, o-Phenylenediamine, m-Phenylenediamine

*Evaluation does not necessarily apply to all individual chemicals within the group. ^†Provisional.

The revised definition of “Occupational sensitizer” has been applied to the substances proposed in 1998 or later, and the substances listed before 1998 are not fully re-examined at this time; please note that OEL values are not necessarily recommended to all the substances listed here. See JSOH web site for brief summary of OEL documentation at http://sanei.or.jp/oel-eng

Recommendation of occupational exposure limits for the occupational sensitizers does not necessarily consider either prevention of sensitization or allergic reaction. Any substance which is not included in the list does not indicate that the substance is not a sensitizer.

V. Reproductive Toxicants

The Japan Society for Occupational Health (JSOH) classifies reproductive toxicants on the basis of evidence of reproductive toxicity obtained from epidemiological studies and other studies in humans, as well as that from experimental studies in animals. The classification is made based on the strength of the evidence for adverse effects on reproduction in humans, but does not reflect the potency of such adverse effects. Namely, the classification does not necessarily indicate that exposures to the classified substances at the present Occupational Exposure Limit (OEL-M) levels induce adverse effects on reproduction. The definition of reproductive toxicity and the classification criteria for judgment are as follows.

1. Definition of reproductive toxicity

Reproductive toxicity includes adverse effects on reproductive functions in males and females, as well as on the offspring. Effects on functions such as fertility, pregnancy, delivery, and lactation in women, and fertility/insemination in men are within the scope of the definition. Substances that have adverse effects on reproductive organs are also included within the classification criteria if it is suspected that the reproductive functions referred to above are affected. In the case of offspring, reproductive toxicity is defined as the effects on the development of the embryo/fetus including teratogenic insults by prenatal exposure to the substance and/or the effects on the infant by postnatal exposure via lactation due to transfer in breast milk. If effects on post-weaning growth, behavior, function, sexual maturation, carcinogenesis, accelerated aging, and other processes are clearly demonstrated in the offspring as a result of parental exposure, then such effects are considered as reproductive toxicity.

2. Classification and judgment criteria

1) Classification of reproductive toxicants:

Reproductive toxicants shall be classified in Group 1, Group 2, or Group 3, defined as follows.

Group 1: Substances known to cause reproductive toxicity in humans.

Group 2: Substances presumed to cause reproductive toxicity in humans.

Group 3: Substances suspected to cause reproductive toxicity in humans.

2) Judgment criteria for the classification of reproductive toxicity:

Group 1: Substances for which sufficient evidence in humans has been obtained from epidemiological studies and other human studies shall be classified.

Sufficient evidence that demonstrates reproductive toxicity in humans is required, where sufficient means two or more reports of epidemiological studies conducted in an appropriate manner. A single epidemiological study can be used as the evidence for classification to this group if any of the following conditions are satisfied: a) the study takes into consideration both dose-response relationships and co-exposure to other substances or potential confounding factors, in an appropriate manner; b) the study is supported by many non-epidemiological study reports on, for example, clinical cases or accidental exposures, indicating reproductive toxicity and it can therefore be decided overall that there is sufficient evidence of toxicity in humans. Animal experimental data are considered as supportive information.

Group 2: Substances for which sufficient evidence demonstrating reproductive toxicity has been obtained in appropriate animal experiments, and thus presumed to cause reproductive toxicity in humans, shall be classified.

Judgment shall be made on the basis of animal experiments, namely, evidence showing obvious adverse effects on reproduction in animals, identified by appropriately conducted animal experimental studies, and thus reasonably indicating that the substance causes reproductive toxicity in humans. When judgment is made from the results of animal experiments, it is required that the observed effects should not be the consequences of secondary non-specific effects of other general toxicities, and that the identified mechanism of action be non-species-specific and therefore relevant for extrapolation to humans. In addition, if the observed changes are small and exert only non-significant effects on the life or function of the subject, then such changes are considered as not satisfying the requirement.

Group 3: Substances for which limited evidence has been demonstrated shall be classified.

Substances are allocated into this group when reproductive toxicities are suspected from reports in humans or from animal experiments. If information for reproductive toxicity is obtained from epidemiological studies, other human studies, and/or animal experiments, but such evidence is not considered to be sufficient for allocating the substance to Group 1 or Group 2, then classification in Group 3 should be considered.

3. Classified reproductive toxicants

Table V. lists the substances classified in each reproductive toxicant group according to the judgment criteria referred to above. The judgment is made for substances for which OEL is recommended by JSOH based on information described in the documentation for Recommendation of Occupational Exposure Limits by JSOH and other relevant information; this does not mean that substances not included in the table do not meet the classification criteria of reproductive toxicity. There may be some substances for which reproductive toxicity might be observed below the level of OEL-M or OEL-B; in such cases, precautionary notice is given by adding a symbol (#) next to the substances in Table V.

Table V. Reproductive toxicants

Group 1

Arsenic and compounds, 2-Bromopropane, Cadmium and compounds, Carbon disulfide, Carbon monoxide#, Di (2-ethylhexyl) phthalate#, Ethylene glycol monomethyl ether, Ethylene glycol monomethyl ether acetate, Ethylene oxide, Lead and compounds#, Perfluorooctanoic acid (PFOA)#, Polychlorobiphenyls (PCB), Toluene

Group 2

Acrylamide, Benomyl#, 1-Bromopropane, Chlorodifluoromethane, Chloromethane, 2,4-Dichlorophenoxyacetic acid (2,4-D), N,N-Dimethylacetamide, N,N-Dimethylformamide (DMF), Ethyl benzene, Ethylene glycol monobutyl ether, Ethylene glycol monoethyl ether, Ethylene glycol monoethyl ether acetate, Inorganic mercury (including mercury vapor), Manganese and its compounds (as Mn except organic manganese compounds), Methanol, Pentachlorophenol (PCP), Styrene, Vanadium and compounds, Xylene for industrial use

Group 3

Atrazine, n-Butyl-2,3-epoxypropylether, Chromium and compounds, p-Dichlorobenzene, 2,3-Epoxypropyl methacrylate (Glycidyl methacrylate, GMA), Ethyleneimine, 2-Ethyl-1-hexanol, Ethylidene norbornene, Glyphosate†, Nickel and compounds, Phenol, Tetrachloroethylene, Trichloroethylene, Xylene (ortho-, meta-, para-xylene and their mixture)

Not all substances that may exert reproductive toxicity are identified.

^#: Precaution should be given for lower exposure than OEL-M or OEL-B. As for reproductive toxicity, it is generally known that there is a sensitive period, during pregnancy for example, and such effects of this substance have been identified.

^†Provisional

See JSOH web site for brief summary of OEL documentation at http://sanei.or.jp/oel-eng

VI. Occupational Exposure Limits for Continuous or Intermittent Noise

Occupational exposure limits (OELs) for continuous or intermittent noise exposure are recommended as follows to protect against noise-induced hearing loss.

1. OELs for continuous or intermittent noise

Values in Fig. VI or Table VI-1 show OELs, at or below which noise-induced permanent threshold shift (NIPTS) is expected to be below 10 dB at or below a frequency of 1 kHz, below 15 dB at 2 kHz, and below 20 dB at or more than 3 kHz after more than 10 years of continuous or intermittent noise exposure for 8 hours a day in most workers.

Fig. VI.

Occupational exposure limits for continuous or intermittent noise.

Table VI-1. Occupational exposure limits for continuous or intermittent noise

Center frequency (Hz)	OELs by octave-band level (dB)
	480 min	240 min	120 min	60 min	40 min	30 min
250	98	102	108	117	120	120
500	92	95	99	105	112	117
1000	86	88	91	95	99	103
2000	83	84	85	88	90	92
3000	82	83	84	86	88	90
4000	82	83	85	87	89	91
8000	87	89	92	97	101	105

2. Applicable noise

OELs can be applied to wide and narrow-band noise with band width below 1/3 octave. OELs are temporarily applicable to pure tones regarded as narrow-band noise. Impulsive or impact noise is excluded from the application (see Section VII).

3. Application method

(1) In the case of continuous noise exposure throughout the work-time, OELs corresponding to the exposure duration should be taken from Fig. VI or Table VI-1.

(2) In the case of intermittent noise exposure, an equivalent exposure duration is considered to be the sum of exposure duration throughout the work-time minus an effective resting duration, and OELs corresponding to the equivalent exposure duration should be taken from Fig. VI or Table VI-1. The effective resting duration is the duration when the noise levels are below 80 dB.

(3) In the case that noise is analyzed by an octave band filter, OELs corresponding to exposure duration are the values at the left ordinate of Fig. VI or in Table VI-1. In the case that noise is analyzed by a narrower band filter with a band width of 1/3 octave or less, OELs are the values at the right ordinate of Fig. VI or the values subtracted 5 from the figures in Table VI-1.

4. OELs by A-weighted sound pressure level

Basically, frequency analysis of noise is recommended. In the case of evaluating with an A-weighted sound pressure level, OELs in Table VI-2 should be used.

Table VI-2. Occupational exposure limits for continuous or intermittent noise by A-weighted sound pressure level

Exposure duration (hours-minutes)	OELs by A-weighted sound pressure level (dB)	Exposure duration (hours-minutes)	OELs by A-weighted sound pressure level (dB)
24−00	80	2−00	91
20−09	81	1−35	92
16−00	82	1−15	93
12−41	83	1−00	94
10−04	84	0−47	95
8−00	85	0−37	96
6−20	86	0−30	97
5−02	87	0−23	98
4−00	88	0−18	99
3−10	89	0−15	100
2−30	90

5. Noise measurement

For measurement methods, refer to ‘Japan Industrial Standard (JIS) Z 8731–1999 Acoustics-Description and measurement of environmental noise’.

VII-i. Occupational Exposure Limits for Impulsive or Impact Noise

Occupational Exposure Limits (OELs) for impulsive or impact noise exposure in the workplace are recommended as follows to protect against noise-induced hearing loss.

1. OELs for impulsive or impact noise

In the case that total frequency of exposure to impulsive or impact noise is at or below 100 times a day, the peak sound pressure level shown in Fig. VII-1 is recommended as the OEL corresponding to the duration of impulsive or impact noise explained in “3. Measurement method”.

In the case that total number of exposures to impulsive or impact noise is above 100 times a day, the sum of the peak sound pressure level in Fig. VII-1 with the adjustment value in Fig. VII-2 to cerrect the difference of exposure frequency is recommended as OEL. At or below these limits, NIPTS is expected to be below 10 dB at or below a frequency of 1 kHz, below 15 dB at 2 kHz, and below 20 dB at or more than 3 kHz after more than 10 years of impulsive or impact noise exposure in most workers.

Fig. VII-1.

Occupational exposure limits for impulsive or impact noise.

Fig. VII-2.

Correction values corresponding to exposure frequency a day.

2. Applicable noise

These OELs are applicable to impulsive or impact noise only. In the case of mixed exposure to both impulsive or impact noise and continuous or intermittent noise, both OELs should be satisfied.

3. Measurement method

Impulsive or impact noises are classified by their oscilloscope-measured wave forms into two groups, as shown in Fig. VII-3 (A) and (B). In Fig. VII-3 (A), A duration is defined as the duration between T_O and T_D. In Fig. VII-3 (B), B duration is defined as either the duration between T₀ and T_D’ if no reflection sound exists, or the sum of durations between T₀ and T_D’ and between T₀’’ and T_D’’ if reflection sound dose exists. In the case of (B), T_D’ or T_D’’ is determined by the intersection of a wave envelope indicating sound pressure change with a line indicating a sound pressure 20 dB below peak sound pressure. This method is also applicable in the case of multiple reflection sounds.

Fig. VII-3.

Measurement for impulsive or impact noise.

VII-ii. Occupational Exposure Limit for Impulsive or Impact Noise by A-Weighted Sound Pressure Level

1. Occupational exposure limit (OEL)

In the case that total frequency of exposure to impulsive or impact noise is at or below 100 times a day, OEL is 120 dB at A-weighted sound pressure level. In the case that total frequency of exposure to impulsive or impact noise is above 100 times a day, the adjustment value in Fig. VII-2 corresponding to frequency of exposure should be added for OEL determination.

2. Application

OEL is applicable to type B wave in Fig. VII-3 only.

3. Measurement method

Maximum values should be measured by the Sound Level Meter (JIS C 1509-1-2005) with use of an A-weighted frequency response and fast dynamic characteristic.

VIII. Occupational Exposure Limits for Heat Stress

1. Occupational Exposure Limits

Permissible heat exposure limits were proposed as Table VIII-1 on the presumption that any unfavorable physiological response should not be caused by the heat stress.

Table VIII-1. Occupational Exposure Limits for heat stress

Work load	OELs
	WBGT (°C)
RMR ~1 (Very Light, ~130 kcal/h)	32.5
RMR ~2 (Light, ~ 190 kcal/h)	30.5
RMR ~3 (Moderate, ~ 250 kcal/h)	29.0
RMR ~4 (Moderate, ~ 310 kcal/h)	27.5
RMR ~5 (Heavy, ~ 370 kcal/h)	26.5

2. Application

These exposure limits show the condition for which the workers work without health impairment or decrease in work efficiency for one hour of continuous work or two hours of intermittent work. The workers mentioned here are healthy adult male workers, adapted themselves to hot environment, well used to the work, wearing usual summer clothes, and taking enough water and salt.

Hot environment means the condition in which the regulation of body temperature is mainly performed by the evaporation responding to the complex of ambient temperature, humidity, and heat radiation.

Adaptation is the effect of the vicarious physiological change of the worker working under hot environment.

The thermal adaptation is obtained by usually working for one week under hot environment. If hot environment exposure is ceased, the adaptation effect is lost immediately and usually disappears in two weeks. Therefore, it is necessary to pay attention to the workers’ condition when their adaptation is not enough or when they return to work after two or more days off.

The unfavorable physiological response is the state that physiological burdens such as increase of the heart rate, a rise in temperature, the increase of the quantity of water loss continue increasing.

Therefore, if the physiological burden on worker continues increasing under hot environment, some engineering measures should be taken or other measures like wearing cool clothes and reducing work load should be performed to decrease heat strain. The heat stress consists of factors such as environmental thermal condition, heat production through metabolism and heat exposure time.

The work load means metabolic energy used at the work. We expressed the degree in Relative Metabolic Rate (RMR) and classified in five categories as shown in Table VIII-2. RMR is calculated by the following expression.   

$$\text{RMR}=\frac{\begin{array}{c}\text{(energy consumption on exertion)−}\\ \text{(energy consumption at rest)}\end{array}}{\text{(basal metabolic rate)}}$$

Table VIII-2. Work load and metabolic energy (kcal/h)

Work load	Metabolic energy (kcal/h)
RMR ~1 (Very Light, ~130 kcal/h)	~130
RMR ~2 (Light, ~ 190 kcal/h)	~190
RMR ~3 (Moderate, ~ 250 kcal/h)	~250
RMR ~4 (Moderate, ~ 310 kcal/h)	~310
RMR ~5 (Heavy, ~ 370 kcal/h)	~370

RMR values according to common movements are displayed in Table VIII-3. This table should be referred to estimate the work load.

Table VIII-3. Classification of RMR by work

RMR	Principal motion sites	Motion	Examples of works
0−0.5 0.5−1.0	hand	moving mechanically	call handling (seated) 0.4, data entry 0.5, gauge monitoring (seated) 0.5,
		moving consciously	straightening (hammer tapping, 98 times/min) 0.9, vehicle driving 1.0
1.0−2.0 2.0−3.0	hand movement with some upper limb movement	hand movement with some forearm movement forearm	lathe work (pairing, 0.83 minutes/unit) 1.1, surveillance work (standing) 1.2, walking slowly on level ground (45 m/min) 1.5
		hand movement with some upper arm movement	walking (ordinary, 71 m/min) 2.1, concrete polishing (lightly) 2.0, circular saw work 2.5, stair walking (down, 50 m/min) 2.6
3.0−4.0	upper limb	normal movement	chinning grinder (grinding 150 kg parts, 6 min. / unit) 3.0, riding bicycle (level ground, 170 m/min) 3.4, walking (fast, 95 m/min) 3.5
4.0−5.5		relatively big movement with power	riveting (1.3 /min) 4.2, filing (36 cm file, 150 times /min.) 4.2, rough saw 5.0
5.5−6.5	whole body lifting, turning, pulling, pushing, throwing, moving up-and-down, scraping	normal movement	tapping (poking 7 kg, 16-20 times/min) 5.7, shoveling (6 kg, 18 times/min) 6.5, stair walking (up, 45 m/min) 6.5
6.5−8.0		relatively big movement with equal power especially momentary	hammering (6.8 kg, 26 times/min.) 7.8
8.0−9.5			pile up (15 kg, 10 times/min) 9.0
10.0− 12.0	whole body (same as above)	physically strenuous work with a bit of leeway; may continue for sometime	pushing at full power 10.0 pickaxe (concrete bursts) 10.5 shovel (72 times/min.) 11.0
12.0−	physically strenuous work such as construction work	concentrate on whole body movement and can tolerate only for less than one minute	hammering (4.5 kg, 29 times/min) 19.3

In an ordinary industrial setting, many of the works are manually performed continuously with the work load of around RMR 1.0. And most of the work loads are not more than RMR 2. However, it is considered possible to work continuously for one hour by the work load of RMR 4, we set one hour continuous work as the basic work unit for the work load up to RMR 4. Furthermore, although the work exceeding RMR 4 may exist, we assumed those work must be performed intermittently, as it is difficult to continue for one hour.

Therefore, regarding the working hour mentioned here, we classify the work into continuous work or intermittent work. We assumed one-hour work as the evaluation unit for continuous work and proposed the method of evaluating the environment in one-hour continuous work for normal eight hours. Likewise, we assumed two-hour work as the evaluation unit for intermittent work and proposed the method of evaluating the environment in two-hour intermittent work similarly. We adopted these methods in order to make it applicable to the real industrial workshop and to make it possible to evaluate in a short time.

3. Thermal index and method for measuring workload

We decided to use the environmental index corresponding to the physiological response by the heat stress for an evaluation of the hot environment. As the best method now, we adopted Wet Bulb Globe Temperature (WBGT) as the simple and practical index for the thermal condition.

Calculation of thermal index

Methods for the measurement of thermal index are described elsewhere. WBGT is calculated as follows.

Calculation of WBGT

(1) Inside the room or outdoors without sunlight radiation

WBGT = 0.7NWB + 0.3GT

(2) Outdoors with sunlight radiation

WBGT = 0.7NWB + 0.2GT + 0.1DB

NWB (natural wet bulb temperature): Wet bulb temperature (without breathing forcibly and not surrounding the bulb part to prevent heat radiation) measured with being exposed to natural air flow

GT (globe thermometer temperature): Temperature measured by globe thermometer of 6 inches in diameters

DB (dry bulb temperature): Dry bulb temperature measured by covering the bulb part to prevent the direct effect of heat radiation without interfering spontaneous air flow

At measurement, it is important to comprehensively evaluate the thermal load affected by the ambient thermal condition and artificial heat production in the workplace. The actual situation including the workers’ condition should be fully understood such as the work position, the work intensity, the time and frequency of the heat exposure. We estimate the actual work condition as follows.

In the case of continuous work, the thermal condition of the workplace should be defined as the highest one-hour value of WBGT in a daily working hour.

In the case of two-hour intermittent work, the thermal condition of the workplace should be defined by two-hour time-weighted value of WBGT.

Two-hour time-weighted value of WBGT = (WBGT₁ × t₁ + WBGT₂ × t₂ +... + WBGT_n × t_n) /120 minutes WBGT₁, WBGT₂... WBGT_n: Each value of WBGT at work or at break

t₁, t₂... t_n: Each value of time at work or at break (minute)

The method to calculate work load of two-hour intermittent work is as follows.

If the workers are engaged in heavy/moderate work load for more than one hour, we define it as moderate workload.

If the workers are engaged in light work load for more than one hour, and the rest in moderate workload, we define it as light work load.

If the workers are engaged in light work load for more than one hour, and the rest in heavy workload, we define it as moderate work load.

When each of the work load is of concern, we calculate the two-hour load average of the work load as follows.

Two-hour load average of the work load = (WL₁ × t₁ + WL₂ × t₂ + … + WL_n × t_n) /120 minutes

WL₁, WL₂ … WLn: Each value of work load at each work or at break

t₁, t₂... t_n: Each time at work or at break (minute)

4. Year of proposal: 1982

IX. Occupational Exposure Limits for Cold Stress

Workers should wear appropriate clothing to protect themselves from cold stress in cold environments. The values of thermal insulation of the combination of clothing are shown in Table IX-1.

Table IX-1. Thermal performance of clothing

Combination of clothing	clo value
Underwear (top /bottom), shirt, trousers, coat, vest, socks, shoes	1.11
Underwear (top /bottom), thermal jumper, thermal trousers, socks, shoes	1.40
Underwear (top /bottom), shirt, trousers, coat, over jacket, cap, gloves, socks, shoes	1.60
Underwear (top /bottom), shirt, trousers, coat, over jacket, over trousers, socks, shoes	1.86
Underwear (top /bottom), shirt, trousers, coat, over jacket, over trousers, cap, gloves, socks, shoes	2.02
Underwear (top /bottom), over jacket, over trousers, thermal jumper, thermal trousers, socks, shoes	2.22
Underwear (top /bottom), over jacket, over trousers, thermal jumper, thermal trousers, cap, gloves, socks, shoes	2.55
Cold protective clothing	3~4.5
Sleeping bag	3~8

Recommendations about clothing: Wear several layers of loose clothing. Layering provides better insulation. Make sure to protect the ears, face, hands, and feet in extremely cold weather. Boots should be waterproof and insulated. Avoid touching cold metal surfaces with bare skin.

The gloves are necessary to prevent frostbite of the hands. The appropriate gloves should be chosen, depending on work, and waterproof gloves in some cases. If the degree of the chilliness is severer, mittens are more effective.

The relationship between equivalent temperature and thermal insulation of clothing, during both light and moderate workloads is presented in Table IX-2.

Table IX-2. Occupational exposure limits for cold stress (Maximal work duration in a 4-hour shift)

Temperature	Work load	Maximal work duration (min)
−10~–25°C	Light work (RMR~2)	~ 50
	Moderate work (RMR~3)	~ 60
−26~–40°C	Light work (RMR~2)	~ 30
	Moderate work (RMR~3)	~ 45
−41~–55°C	Light work (RMR~2)	~ 20
	Moderate work (RMR~3)	~ 30

When air temperature is lower, the worker should wear clothing with higher thermal insulation power. And also, when a workload is low, the worker should wear higher thermal insulation clothing, because the internal heat produced by the body is lower than in the case of a higher workload.

In the cold environment, the wind velocity becomes a critical factor as well as air temperature.

An equivalent chill temperature chart relating the air temperature and the wind velocity is presented in Table IX-3.

Table IX-3. Cooling power of wind on exposed body areas air expressed as equivalent chill temperature

wind velocity (m/sec)	air temperature (°C)
	0	−5	−10	−15	−20	−25	−30	−35	−40	−45	−50
	equivalent chill temperature (°C)
calm	0	−5	−10	−15	−20	−25	−30	−35	−40	−45	−50
2	−1	−6	−11	−16	−21	−27	−32	−37	−42	−47	−52
3	−4	−10	−15	−21	−27	−32	−38	−44	−49	−55	−60
5	−9	−15	−21	−28	−34	−40	−47	−53	−59	−66	−72
8	−13	−20	−27	−34	−41	−48	−55	−62	−69	−76	−83
11	−16	−23	−31	−38	−46	−53	−60	−68	−75	−83	−90
15	−18	−26	−34	−42	−49	−57	−63	−73	−80	−88	−96
20	−20	−28	−36	−44	−52	−60	−68	−76	−84	−92	−100

Maximum work period recommended for properly clothed workers, working 4-hour shifts, at air temperatures and workloads are shown in Table IX-4. The workload is expressed in RMR (Relative Metabolic Rate) with the identical case of occupational exposure limits for heat stress. Light workload is less than RMR 2, (less than 190 kca1/h, metabolic energy), and moderate workload is RMR 2-3 (about 250 kca1/h, metabolic energy).

Table IX-4. Occupational exposure limits for cold stress (Maximum work period recommended working 4-hour shift)

Air temperature	Work lord		Maximum work period (min)
−10~−25°C	light work lord.	(RMR~2)	~50
	moderate work load	(RMR~3)	~60
−26~−40°C	light work load	(RMR~2)	~30
	moderate work load	(RMR~3)	~45
−41~−55°C	light workload	(RMR~2)	~20
	moderate work load	(RMR~3)	~30

Wind velocity is below 0.5 m/sec, in an almost windless environment.

The standard work conditions are for four hours by shift work taking a rest in a recovery room for at least 30 minutes after one work sequel to.

There is much continuous light work (RMR l-2) and moderate work of RMR 3 in some cases. In the workload of these levels, physical loads to thermoregulation system by the cold stress, are bigger than the load to breathing and the circulatory system in the body function by the work.

The standard work conditions are for four hours shift work, taking a rest for at least 30 minutes after each shift work, wearing adequate cold-protective clothing to work in an almost windless environment.

Physical effects by cold chill index and equivalent temperature are shown in Table IX-5.

Table IX-5. Physical effects by cold chill index and equivalent temperature

Cold chill index	Equivalent air temperature (°C)	Physical effects
1,000	−14	Very cold
1,200	−22	Extremely cold
1,400~1,550	−30~−38	Frostbite of exposed skin in one hour
1,700~1,900	−45~−53	Dangerous outside activity such as walking, frostbite occurs on exposed part of the face in one minute
2,000~2,300	−61~−69	Frostbite occurs on exposed part of the face in 30 seconds

In cold environments, skin temperatures decrease particularly in the tip of the hands and feet. Body temperatures decrease, when heat production in the body is less than the heat radiation on the equilibrium of the internal heat balance.

Tremors and unconsciousness appear by hypothermia. Core temperature such as rectal temperature should keep above 36°C. Outbreak of more intense tremors is the danger signal that temperature is decreasing more, and one should promptly stop exposure to the cold.

Work efficiency decreases and is unsafe due to pain, tightening, and the chilliness of the peripheral parts such as hands and feet. Furthermore, the skin temperature of the toes is approximately 13°C, and 10°C at the fingers. Pain and numbness by cold is a danger signal leading to frostbite.

X. Occupational Exposure Limits for Whole Body Vibration

0.35 m/s²A_sum (8)

XI. Occupational Exposure Limits for Hand-Arm Vibration

Fig. XI.

Occupational exposure limits for hand-arm vibration using vibration total value of frequency-weighted r.m.s. acceleration.

Table XI. Occupational exposure limits for hand-arm vibration using vibration total value of frequency-weighted r.m.s. acceleration

Exposure time (min)	Vibration total value of frequency-weighted r.m.s. acceleration (m/s2 r.m.s.)
≤6	25.0
10	19.4
15	15.8
30	11.2
60	7.92
90	6.47
120	5.60
150	5.01
180	4.57
210	4.23
240	3.96
270	3.73
300	3.54
330	3.38
360	3.23
390	3.11
420	2.99
450	2.89
480	2.80

XII. Occupational Exposure Limits for Time-Varying Electric, Magnetic and Electromagnetic Fields (up to 300 GHz)

Table XII-1. Static magnetic fields (Frequency: 0~0.25 Hz)

	OEL-M	OEL-C
Head, trunk	200 mT (1.63×105 Am–1)	2T
Extremities	500 mT (4.08×105 Am–1)	5T

Table XII-2. Low frequency time-varying electric and magnetic fields (Frequency: 0.25 Hz~100 kHz)

Frequency (f)	EF*	Magnetic flux density	MF†
0.25~1.0 Hz		50/f mT	4.08 × 104/f Am−1
1.0~25 Hz	20 kVm−1	50/f mT	4.08 × 104/f Am−1
25~500 Hz	500/f kVm−1	50/f mT	4.08 × 104/f Am−1
500~814 Hz	500/f kVm−1	0.1 mT	81.4 Am−1
0.814~60 kHz	614 Vm−1	0.1 mT	81.4 Am−1
60~100 kHz	614 Vm−1	6/f mT	4,880/f Am−1

*EF: electric field, ^†MF: magnetic field

Table XII-3. Radio-frequency electromagnetic fields (Frequency: 0.1 MHz~300 GHz)

Frequency (f)	EF*	Magnetic flux density	MF†	Power density
0.1~3.0 MHz	614Vm−1	6/f μT	4.88/f Am−1
3.0~30 MHz	1,842/f Vm−1	6/f μT	4.88/f Am−1
30~400 MHz	61.4Vm−1	0.2 μT	0.163Am−1	10Wm−2
400~2000 MHz	3.07f0.5Vm−1	0.01f0.5 μT	8.14f0.5mAm−1	f/40 Wm−2
2~300 GHz	137Vm−1	0.447 μT	0.364Am−1	50Wm−2

*EF: electric field, ^†MF: magnetic field

Fig. XII-1.

OEL-Ms of time-varying electric fields

Fig. XII-2.

OEL-Ms of static and time-varying magnetic fields

XIII. Occupational Exposure Limit for Ultraviolet Radiation

Occupational Exposure Limit for ultraviolet radiation with wavelengths between 180 nm and 400 nm is recommended to be 30 J/m² as effective irradiance integrated over 8 hours a day, to avoid acute effects on eye (cornea or conjunctiva) or the skin. This value is not applicable to laser radiation.

Effective irradiance is defined as follows:   

$${\text{E}}_{eff}=\sum _{\lambda =180\text{nm}}^{400\text{nm}}{E}_{\lambda }S(\lambda )\mathrm{\Delta }\lambda$$

where: E_eff = effective irradiance

E_λ = spectral irradiance at exposure

S (λ) = relative spectral effectiveness (Table XIII)

Δλ = band width

Table XIII. Ultraviolet radiation and relative spectral effectiveness

Wavelength (nm)	Relative spectral effectiveness	Wavelength (nm)	Relative spectral effectiveness	Wavelength (nm)	Relative spectral effectiveness
180	0.012	280	0.880	325	0.00050
190	0.019	285	0.770	328	0.00044
200	0.030	290	0.640	330	0.00041
205	0.051	295	0.540	333	0.00037
210	0.075	297	0.460	335	0.00034
215	0.094	300	0.300	340	0.00027
220	0.120	303	0.120	345	0.00023
225	0.150	305	0.060	350	0.00020
230	0.190	308	0.025	355	0.00016
235	0.230	310	0.015	360	0.00013
240	0.300	313	0.006	365	0.00011
245	0.360	315	0.003	370	0.000094
250	0.430	316	0.0023	375	0.000077
254	0.500	317	0.0020	380	0.000064
255	0.520	318	0.0016	385	0.000053
260	0.650	319	0.0012	390	0.000044
265	0.810	320	0.0010	395	0.000036
270	1.000	322	0.00067	400	0.000030
275	0.970	323	0.00054

Members of the Committee for Recommendation of Occupational Exposure Limits (2020–2021)

Chairperson

Tetsuo Nomiyama (Matsumoto)

Members

Kenichi Azuma (Osaka), Tetsuhito Fukushima (Fukushima), Kunio Hara (Kita-Kyusyu), Hajime Hori (Kita-Kyusyu), Seichi Horie (Kita-Kyusyu), Masayoshi Ichiba (Saga), Gaku Ichihara (Chiba), Tatsuya Ishitake (Kurume), Akiyoshi Ito (Kawasaki), Satoko Iwasawa (Tokorozawa), Michihiro Kamijima (Nagoya), Kanae Karita (Tokyo), Takahiko Katoh (Kumamoto), Toshihiro Kawamoto (Tokyo), Shinji Kumagai (Sakai), Yukinori Kusaka (Shimane), Muneyuki Miyagawa (Tokyo), Hiroyuki Miyauchi (Kita-Kyusyu), Yasuo Morimoto (Kita-Kyusyu), Hirokazu Okuda (Kanagawa), Kazuyuki Omae (Tokyo), Tomotaka Sobue (Suita), Toru Takebayashi (Tokyo), Tatsuya Takeshita (Wakayama), Yuko Yamano (Tokyo), Kazuhito Yokoyama (Tokyo)

Drafting members

Atsuko Araki (Sapporo), Kouji Harada (Kyoto), Hyogo Horiguchi (Sagamihara), Yuki Ito (Nagoya), Takeyasu Kakamu (Fukushima), Akiko Matsumoto (Saga), Hisao Naito (Nagoya), Makiko Nakano (Tokyo), Masayuki Okuda (Yamaguchi), Kazuhiro Sato (Fukui), Yasushi Suwazono (Chiba), Akito Takeuchi (Osaka), Ayano Takeuchi (Tokyo), Mayumi Tsuji (Kita-Kyusyu), Teruomi Tsukahara (Matsumoto), Susumu Ueno (Kita-Kyusyu), Jun Ueyama (Nagoya), Yumi Umeda (Kanagawa), Kenya Yamamoto (Kawasaki), Takenori Yamauchi (Tokyo)

Advisory members

Ginji Endo (Osaka), Yoko Endo (Osaka), Toshio Kawai (Osaka), Reiko Kishi (Sapporo), Kasuke Nagano (Kanagawa), Tamie Nakajima (Kasugai), Shigeru Tanaka (Saitama), Eiji Yano (Tokyo)