Print This Page

Review of Occupational Exposure Limits in Ontario:
Current and Proposed Exposure Limits


Proposed changes based on the 2014 ACGIH recommendations

Proposed Changes to Occupational Exposure Limits for Substances Regulated Under Regulation 833, Control of Exposure to Biological or Chemical Agents and O. Reg. 490/09 - Designated Substances
Current Substance Current
TWA
Current
STEL/C
Proposed Substance Proposed
TWA
Proposed
STEL/C
Change
Atrazine [1912-24-9] (and related symmetrical triazines) 5 mg/m3   Atrazine [1912-24-9] (and related symmetrical triazines) 2 mg/m3 (I)   OEL developed for inhalable fraction.
Barium sulfate
[7727-43-7]
10 mg/m3   Barium sulfate
[7727-43-7]
5 mg/m3 (I)(E)   OEL developed for inhalable fraction.
1-Bromopropane
[106-94-5]
10 ppm   1-Bromopropane
[106-94-5]
0.1 ppm   TWA reduced.
Ethylidene norbornene [16219-75-3]   5 ppm C Ethylidene norbornene
[16219-75-3]
2 ppm 4 ppm Ceiling limit (C) removed. TWA and STEL added.
Ethyl isocyanate
[109-90-0] – Skin
No specific listing No specific listing Ethyl isocyanate
[109-90-0] – Skin
0.02 ppm 0.06 ppm Specific listing and OELs added for this substance.
Substance previously regulated under Section 17 of O. Reg. 490/09.
Methomyl
[16752-77-5]
2.5 mg/m3   Methomyl
[16752-77-5] – Skin
0.2 mg/m3 (IFV)   OEL developed for inhalable fraction and vapour. Skin notation added.
Methyl isocyanate
[624-83-9] – Skin
0.02 ppm   Methyl isocyanate
[624-83-9] – Skin
0.02 ppm 0.06 ppm STEL added.
Naphthalene
[91-20-3] – Skin
10 ppm 15 ppm Naphthalene
[91-20-3] – Skin
10 ppm   STEL removed.
Nickel carbonyl
[13463-39-3], as Ni
0.05 ppm   Nickel carbonyl
[13463-39-3], as Ni
  0.05 ppm C TWA removed. Ceiling value added.
Pentachlorophenol
[87-86-5] – Skin
0.5 mg/m3   Pentachlorophenol
[87-86-5] – Skin
0.5 mg/m3 (IFV) 1 mg/m3 (IFV) TWA developed for inhalable fraction and vapour. STEL added for inhalable fraction and vapour.
Pentane, all isomers
[78-78-4; 109-66-0; 463-82-1]
600 ppm   Pentane, all isomers
[78-78-4; 109-66-0; 463-82-1]
1000 ppm   TWA increased.
Peracetic acid [79-21-0] No listing No listing Peracetic acid [79-21-0]   0.4 ppm (IFV) Substance new to regulation.
Trichloroacetic acid
[76-03-9]
1 ppm   Trichloroacetic acid
[76-03-9]
0.5 ppm   TWA reduced.

Proposed changes based on the 2015 ACGIH recommendations

Proposed Changes to Occupational Exposure Limits for Substances Regulated Under Regulation 833, Control of Exposure to Biological or Chemical Agents and O. Reg. 490/09 - Designated Substances
Current Substance Current
TWA
Current
STEL/C
Proposed Substance Proposed
TWA
Proposed
STEL/C
Change
Acetone [67-64-1] 500 ppm 750 ppm Acetone [67-64-1] 250 ppm 500 ppm TWA and STEL reduced.
Cyanogen bromide
[506-68-3]
No listing No listing Cyanogen bromide
[506-68-3]
  0.3 ppm C Addition of substance to regulation.
Lithium hydride
[7580-67-8]
0.025 mg/m3   Lithium hydride
[7580-67-8]
  0.05 mg/m3 (I) C TWA removed. Ceiling (C) added for inhalable fraction.
Methyl formate
[107-31-3]
100 ppm 150 ppm Methyl formate
[107-31-3] – Skin
50 ppm 100 ppm TWA and STEL reduced. Skin notation added.
Oxalic acid [144-62-7] 1 mg/m3 2 mg/m3 Oxalic acid, anhydrous [144-62-7] and dihydrate [6153-56-6] 1 mg/m3 2 mg/m3 Addition of oxalic acid dihydrate [6153-56-6] to substance listing.
Phenyl isocyanate
[103-71-9]
No listing No listing Phenyl isocyanate
[103-71-9] – Skin
0.005 ppm 0.015 ppm Specific listing and OELs added for this substance. Substance previously regulated under Section 17 of
O. Reg. 490/09.
1,2,3-Trichloropropane [96-18-4] – Skin 10 ppm   1,2,3-Trichloropropane [96-18-4] 0.005 ppm   TWA reduced. Skin notation removed.
Triethylamine
[121-44-8] – Skin
1 ppm 3 ppm Triethylamine
[121-44-8] – Skin
0.5 ppm 1 ppm TWA and STEL reduced.

Endnotes and Abbreviations

TWA or time-weighted average limit means the time-weighted average airborne concentration of a biological or chemical agent to which a worker may be exposed in a work day or work week.

STEL or short-term exposure limit means the maximum airborne concentration of a biological or chemical agent to which a worker may be exposed in any 15-minute period;

C or ceiling limit means the maximum airborne concentration of a biological or chemical agent to which a worker may be exposed at any time;

(E) This value is for particulate matter containing no asbestos and < 1% crystalline silica.

(I) Inhalable fraction

(IFV) means inhalable fraction and vapour

(R) Respirable fraction