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. 2025 Aug 26;7(1):ROEL2025. doi: 10.1539/eohp.ROEL2025

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

Substance [CAS No.] Assay material Parameter OEL-B Sampling time Year of proposal
Acetone [67-64-1] urine Acetonea 40 mg/l Within 2 h prior to end of shift ʼ01
2-Butoxyethanol and 2-Butoxyethyl acetate
[111-76-2, 112-07-2]
urine Butoxyacetic acida 200 mg/g·Cr End of shift ʼ08
Cadmium and compounds
[7440-43-9]
blood Cadmiumb 5 µg/l Not critical ’21
urine Cadmiumb 5 µg/g·Cr Not critical ’21
Carbon disulfide
[75-15-0]
urine 2-Thiothiazolidine-4-carboxylic acida 0.5 mg/g·Cr End of shift (Avoid sizable intake of brassica vegetables) ʼ15
Cobalt and inorganic compounds (Except cobalt oxides)
[7440-48-4]
blood Cobalta 3 μg/l Within 2 h prior to end of shift at end of work week ʼ05
urine Cobalta 35 μg/l Within 2 h prior to end of shift at end of work week ʼ05
Chlorobenzene
[108-90-7]
urine 4-Chlorocatechol (hydrolysis)a 120 mg/g·Cr End of shift ʼ08
3,3’-Dichloro-4,4’-diaminodiphenylmethane (MBOCA, MOCA)
[101-14-4]
urine total MOCAa 10 μg/g·Cr End of shift ʼ23
Dichloromethane
[75-09-2]
urine Dichloromethanea 0.2 mg/l End of shift ʼ05
N,N-Dimethylacetamide [127-19-5] urine N-Methylacetamide 25 mg/g·Cr End of shift at end of
workweek
ʼ25
Ethylbenzene
[100-41-4]
urine Mandelic acida 150 mg/g·Cr End of shift ’21
urine Mandelic acid+
Phenylglyoxylic acida
200 mg/g·Cr End of shift at end of workweek ’21
urine Ethylbenzenea 15 µg/l End of shift ’21
Hexane [110-54-3] urine 2,5-Hexanedionea 3 mg/g·Cr (After acid hydrolysis) End of shift at end of workweek ʼ94
urine 2,5-Hexanedionea 0.3 mg/g·Cr (Without acid hydrolysis) End of shift at end of workweek ʼ94
Indium and compounds
[7440-74-6]
serum Indiumb 3 μg/l Not critical ʼ07
Lead and compounds (Except alkyl lead compounds)
[7439-92-1]
blood Leadb 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 2 mg/g·Cr Not critical ʼ24
Mercury and compounds (Except alkyl mercury compounds)
[7439-97-6]
urine total inorganic mercuryb 35 μg/g·Cr Not critical ʼ93
Methanol [67-56-1] urine Methanola 20 mg/l End of shift ʼ10
Methyl ethyl ketone
[78-93-3]
urine Methyl ethyl ketonea 5 mg/l End of shift or a few hours after high exposure ʼ06
Methyl isobutyl ketone [108-10-1] urine Methyl isobytyl ketonea 0.7 mg/l End of shift ʼ25
Phenol [108-95-2] urine Phenola 250 mg/g·Cr End of shift ʼ08
Polychlorinated biphenyls (PCBs)
[53469-21-9, 11097-69-1, 1336-36-3]
blood total PCBsb 25 μg/l Not critical ʼ06
Styrene [100-42-5] urine Styrenea 20 µg/l End of shift at end of workweek ’22
urine Mandelic acid +
Phenylglyoxylic acida
160 mg/g·Cr End of shift at end of workweek ’22
Tetrachloroethylene
[127-18-4]
blood Tetrachloroethylene 0.3 mg/l Prior to end of shift at end of workweek ʼ25
end-exhaled air Tetrachloroethylene 3 ppm Immediately after end of shift at end of workweek ʼ25
urine Tetrachloroethylene 40 µg/l After end of shift at end of workweek ʼ25
Tetrahydrofuran
[109-99-9]
urine Tetrahydrofurana 2 mg/l End of shift (ʼ15)
Toluene [108-88-3] blood Toluenea 0.6 mg/l Within 2 h prior to end of shift at end of work week ʼ99
urine Toluenea 0.06 mg/l ʼ99
Trichloroethylene
[79-01-6]
urine Trichloroacetic acidb 10 mg/l End of shift at end of workweek ’22
blood Trichloroethylene Semi-quantitative End of shift at end of workweek ’22
end-exhaled air Trichloroethylene Semi-quantitative End of shift at end of workweek ’22
Xylene [95-47-6, 108-38-3, 106-42-3, 1330-20-7] urine total (o-, m-, p-) methylhippuric acida 800 mg/l End of shift at end of work week ʼ05

1. In setting OEL-B, consideration is given to either:

 a, The relationship between biological monitoring values and OEL-Ms.

 b, The exposure-effect and/or exposure-response relationships between biological monitoring values and health effects.

2. : Provisional

3. See the JSOH website for a brief summary of OEL documentation at https://www.sanei.or.jp/english/oels/index.html