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cas_number
stringlengths
7
10
osha_pel_twa
float64
0.05
5k
niosh_rel
float64
0.01
5k
acgih_tlv_twa
float64
0.01
5k
uk_wel_twa_eh40
float64
0.02
5k
eu_ioelv
float64
0.1
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units
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2 values
notes
stringlengths
81
392
Acetone
67-64-1
1,000
250
250
500
500
ppm
OSHA PEL from 29 CFR 1910.1000 Table Z-1. ACGIH TLV 2024. UK WEL EH40. EU IOELV 2017/164/EU Annex I.
Ammonia
7664-41-7
50
25
25
25
20
ppm
OSHA PEL Table Z-1. NIOSH REL 10-h TWA. ACGIH TLV 2024. UK WEL EH40 4th ed. EU IOELV 2017/164/EU.
Benzene
71-43-2
1
0.1
0.5
1
0.5
ppm
OSHA PEL 29 CFR 1910.1028 (substance-specific standard). NIOSH REL = lowest feasible; 0.1 ppm used here. ACGIH TLV-TWA 2024 (A1 carcinogen). UK WEL EH40 with notation 'Sk'. EU IOELV 2017/164/EU 0.5 ppm. All values approximate — verify against current source before use.
Carbon dioxide
124-38-9
5,000
5,000
5,000
5,000
5,000
ppm
OSHA PEL Table Z-1. NIOSH REL. ACGIH TLV 2024. UK WEL EH40. EU IOELV 2017/164/EU.
Carbon monoxide
630-08-0
50
35
25
20
20
ppm
OSHA PEL Table Z-1 50 ppm. NIOSH REL 35 ppm (10-h TWA) with ceiling 200 ppm. ACGIH TLV-TWA 2024 25 ppm. UK WEL EH40 20 ppm. EU IOELV 2019/1831/EU 20 ppm.
Chlorine
7782-50-5
1
null
0.5
0.5
0.5
ppm
OSHA PEL Table Z-1 1 ppm ceiling. NIOSH REL is a ceiling of 0.5 ppm — not directly comparable as a TWA; left blank. ACGIH TLV-C 0.5 ppm (ceiling, not TWA). UK WEL EH40 0.5 ppm. EU IOELV 2017/164/EU.
Formaldehyde
50-00-0
0.75
0.016
0.1
2
0.3
ppm
OSHA PEL 29 CFR 1910.1048 action level 0.5 ppm / PEL 0.75 ppm TWA. NIOSH REL = ceiling 0.016 ppm (15-min). ACGIH TLV-C 0.1 ppm (ceiling). UK WEL EH40 2 ppm (8-h) — verify against current EH40. EU IOELV 2019/130/EU 0.3 ppm. Values differ substantially across frameworks; verify before use.
Hexane (n-hexane)
110-54-3
500
50
50
20
null
ppm
OSHA PEL Table Z-1 500 ppm (all hexane isomers). NIOSH REL and ACGIH TLV-TWA 2024 are 50 ppm for n-hexane specifically (neurotoxin). UK WEL EH40 20 ppm for n-hexane. EU IOELV not established for n-hexane as of 2024 — verify current status.
Hydrogen cyanide
74-90-8
10
null
4.7
0.9
null
ppm
OSHA PEL Table Z-2 10 ppm ceiling. NIOSH: no TWA REL — ceiling 4.7 ppm (10-min). ACGIH TLV-C 4.7 ppm ceiling; not directly a TWA. UK WEL EH40 0.9 ppm (8-h TWA) with Sk notation. EU IOELV not confirmed — left blank.
Hydrogen sulfide
7783-06-4
20
null
1
1
5
ppm
OSHA PEL Table Z-2 ceiling 20 ppm / peak 50 ppm. NIOSH REL 10-h TWA 1 ppm. ACGIH TLV-TWA 2024 1 ppm. UK WEL EH40 1 ppm. EU IOELV Directive 2017/164/EU 5 ppm — verify amendment status.
Isocyanates (MDI)
101-68-8
null
0.005
0.005
0.02
null
mg/m3
MDI = methylene diphenyl diisocyanate. OSHA PEL not established as substance-specific TWA for MDI — verify 29 CFR 1910.1000 Table Z. NIOSH REL 0.005 mg/m3 (10-h TWA). ACGIH TLV-TWA 2024 0.005 mg/m3. UK WEL EH40 0.02 mg/m3 (as NCO) — verify current EH40. EU IOELV not confirmed — left blank.
Lead
7439-92-1
0.05
null
0.05
0.15
null
mg/m3
OSHA PEL 29 CFR 1910.1025 (lead standard) 0.05 mg/m3 TWA. ACGIH TLV-TWA 2024 0.05 mg/m3. UK WEL EH40 0.15 mg/m3. EU IOELV not yet in force for general industry as at 2024 — verify Council Directive 98/24/EC status. All as inorganic lead dust/fume.
Mercury (vapour)
7439-97-6
null
0.05
0.025
0.02
null
mg/m3
OSHA PEL for mercury vapour from Table Z-2 (0.1 mg/m3 ceiling) — TWA PEL uncertain; left blank. NIOSH REL 0.05 mg/m3 (10-h TWA). ACGIH TLV-TWA 2024 0.025 mg/m3. UK WEL EH40 0.02 mg/m3. EU IOELV not confirmed — left blank.
Methanol
67-56-1
200
200
200
200
260
ppm
OSHA PEL Table Z-1 200 ppm. NIOSH REL 200 ppm with Sk. ACGIH TLV-TWA 2024 200 ppm Sk. UK WEL EH40 200 ppm. EU IOELV 2017/164/EU 260 ppm — verify current directive.
Nitric acid
7697-37-2
2
2
2
1
null
ppm
OSHA PEL Table Z-1 2 ppm. NIOSH REL 2 ppm (1-h ceiling). ACGIH TLV-TWA 2024 2 ppm. UK WEL EH40 1 ppm — verify. EU IOELV not confirmed — left blank.
Nitrogen dioxide
10102-44-0
5
1
0.2
0.5
0.5
ppm
OSHA PEL Table Z-1 5 ppm ceiling. NIOSH REL 1 ppm (15-min ceiling). ACGIH TLV-TWA 2024 0.2 ppm. UK WEL EH40 0.5 ppm. EU IOELV 2017/164/EU 0.5 ppm.
Ozone
10028-15-6
0.1
0.1
0.05
0.2
0.2
ppm
OSHA PEL Table Z-1 0.1 ppm. NIOSH REL 0.1 ppm (2-h TWA for heavy work). ACGIH TLV-TWA 2024 0.05 ppm (light work, 8-h). UK WEL EH40 0.2 ppm. EU IOELV 2017/164/EU 0.2 ppm. Note: ACGIH value depends on work intensity.
Respirable crystalline silica (quartz)
14808-60-7
0.05
null
0.025
0.1
0.1
mg/m3
OSHA PEL 0.05 mg/m3 (29 CFR 1910.1053 silica standard, 2016). NIOSH REL 0.05 mg/m3 recommended; NIOSH considers any exposure a risk — 0.025 mg/m3 action level used by some. ACGIH TLV-TWA 2024 0.025 mg/m3 (respirable fraction). UK WEL EH40 0.1 mg/m3. EU IOELV 2017/2398/EU 0.1 mg/m3 (transition periods apply).
Styrene
100-42-5
100
50
20
100
20
ppm
OSHA PEL Table Z-2 100 ppm TWA / ceiling 200 ppm. NIOSH REL 50 ppm (10-h TWA). ACGIH TLV-TWA 2024 20 ppm (A4, possible carcinogen). UK WEL EH40 100 ppm. EU IOELV 2019/1831/EU 20 ppm.
Sulfur dioxide
7446-09-5
5
0.5
0.25
0.5
0.5
ppm
OSHA PEL Table Z-1 5 ppm. NIOSH REL 0.5 ppm (10-h TWA). ACGIH TLV-TWA 2024 0.25 ppm. UK WEL EH40 0.5 ppm. EU IOELV 2017/164/EU 0.5 ppm.
Sulfuric acid mist
7664-93-9
1
null
0.2
0.1
null
mg/m3
OSHA PEL Table Z-1 1 mg/m3. ACGIH TLV-TWA 2024 0.2 mg/m3 (thoracic fraction; A2 suspected human carcinogen). UK WEL EH40 0.1 mg/m3 (inhalable). EU IOELV not confirmed — left blank. NIOSH REL not confirmed as a TWA — left blank.
Toluene
108-88-3
200
100
20
50
50
ppm
OSHA PEL Table Z-2 200 ppm (300 ppm ceiling / 500 ppm peak). NIOSH REL 100 ppm (10-h TWA). ACGIH TLV-TWA 2024 20 ppm. UK WEL EH40 50 ppm. EU IOELV 2017/164/EU 50 ppm.
Trichloroethylene
79-01-6
100
1
10
10
10
ppm
OSHA PEL Table Z-2 100 ppm. NIOSH: suspected occupational carcinogen — REL 1 ppm (lowest feasible). ACGIH TLV-TWA 2024 10 ppm (A2). UK WEL EH40 10 ppm. EU IOELV Directive 2017/164/EU 10 ppm. Regulatory status evolving — verify current limits.
Welding fume (total inhalable)
null
null
0.1
1
1
null
mg/m3
No single CAS number; values for generic welding fume. OSHA PEL for fume components varies; no single Table Z total fume PEL — left blank. NIOSH REL 0.1 mg/m3 as recommended limit. ACGIH TLV-TWA 2024 1 mg/m3 (total inhalable fume). UK WEL EH40 1 mg/m3 (total inhalable). EU IOELV not established for generic welding fume...
Wood dust (hard/oak/beech)
null
null
1
1
3
null
mg/m3
No single CAS. OSHA PEL varies by wood type — no OSHA PEL specifically for hardwood dust as a category in Table Z — left blank. NIOSH REL 1 mg/m3 (hardwood). ACGIH TLV-TWA 2024 1 mg/m3 (inhalable; A1 carcinogen for hardwood). UK WEL EH40 3 mg/m3 (hardwood; note reduction under review — verify current EH40). EU IOELV Di...
Xylene (all isomers)
1330-20-7
100
100
100
50
50
ppm
OSHA PEL Table Z-1 100 ppm. NIOSH REL 100 ppm (10-h TWA). ACGIH TLV-TWA 2024 100 ppm. UK WEL EH40 50 ppm. EU IOELV 2017/164/EU 50 ppm.
Acetylene
74-86-2
null
null
null
null
1,000
ppm
OSHA PEL: not listed as a toxicity limit in Table Z-1 (simple asphyxiant above flammable levels) — left blank. NIOSH REL: simple asphyxiant — no TWA — left blank. ACGIH: simple asphyxiant designation — no TLV-TWA — left blank. UK WEL: no WEL published (asphyxiant). EU IOELV 2017/164/EU 1000 ppm. Flammability limits (2....
Ethyl acetate
141-78-6
400
400
400
200
400
ppm
OSHA PEL Table Z-1 400 ppm. NIOSH REL 400 ppm (10-h TWA). ACGIH TLV-TWA 2024 400 ppm. UK WEL EH40 200 ppm. EU IOELV 2017/164/EU 400 ppm.

Occupational Exposure Limits Crosswalk 2026 — OSHA PEL / NIOSH REL / ACGIH TLV / UK WEL / EU IOELV

Side-by-side OEL crosswalk for 28 priority substances across OSHA 29 CFR 1910.1000, NIOSH REL, ACGIH TLV, UK EH40 WEL, and EU IOELV (2024 directive).

Details

Citation

SmartQHSE Ltd (2026). Occupational Exposure Limits Crosswalk 2026 — OSHA PEL / NIOSH REL / ACGIH TLV / UK WEL / EU IOELV [dataset]. Zenodo. https://doi.org/10.5281/zenodo.20446747

Disclaimer

Published for reference, training, and research. Consult authoritative sources before operational or compliance decisions. SmartQHSE Ltd accepts no liability for errors or omissions.

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