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May 07, 2024

According to Decree 280-2024 published on February 28, 2024, in the Gazette officielle du Québec, the amendment to the Appendix 1 of the Regulation respecting occupational health and safety (RSST, RLRQ, c. S-2.1, r. 13) will come into force on March 14, 2024. These regulatory changes have not yet been incorporated into the current Substance Data Sheets of the Sampling Guide for Air Contaminants in the Workplace. An update is currently underway and will be available as soon as possible. Consequently, the information contained in the data sheets of substances modified or added in Decree 280-2024 is partially inaccurate or incomplete. Please consult our infoLABO (in French only) for more details. Please contact our client service: [email protected] for further information.

Methylene bis (4-phenyl isocyanate) (MDI)

French name in the regulation: Diisocyanate-4,4' de diphénylméthane (MDI)
CAS : 101-68-8
Synonyms: Isocyanic acid, methylenedi-p-phenylene ester; Desmodur 44; Hylene M50; Isonate; MDI; Rubinate 44

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)
ppm mg/m3 f/cc Notes
TWAEV 0,005 0,051 - -
STEV - - - -
Ceiling - - - -
Simple asphyxiant Percutaneous
Minimum exposure Sensitizer S
Prohibited use Prohibited recirculation
Carcinogenicity

TWA adjustment for unusual work schedules

III : Weekly adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Methylene bis (4-phenyl isocyanate) (MDI)

Analysis:

Diisocyanate-4,4' de diphénylméthane (MDI)

Method: IRSST - 376

Sampling device:
Sampling media required:
#IRSSTDescription
917 Impregnated GF filter in series with teflon filter and vial

Parameters:
Flow rate: 1 L/min
TWA sampling volume: 15 L
STEL sampling volume: -
Remarks: Refer to the sampling guidelines supplied with the equipment. For surface wipe test, contact Laboratory Customer Service.

Principle: High performance liquid chromatography with UV detection (HPLC-UV)
Precision (%): 10
Remarks: The two filters in the sampling cassette allow specific analysis of monomer isocyanate in vapour form and in aerosol form and the result of each form is supplied. It should be noted that only the result representing the sum of the two forms, also reported in the analytical report (total monomer), must be used for comparison to a PEV. Determination of the corresponding oligomers is also done during the analysis. The sampling time can be longer than 15 minutes if the isocyanate is present in vapour form only. RMV for MDI monomer vapour is 0.018 µg. RMV for MDI monomer aerosol is 0.041 µg.

IRSST. "Détermination de la fraction monomèrique des isocyanates sous forme vapeur et aérosol dans l'air des lieux de travail". Méthode 376. Non publiée.

MDI à haute sensibilité

Method: IRSST - 366

Sampling device:
Sampling media required:
#IRSSTDescription
970 Impregnated GF filter

Parameters:
Flow rate: 1,0 L/min
TWA sampling volume: 15 L
STEL sampling volume: -
Remarks: The recommended volume is 15 litres; however the sampling time can be up to 8 hours. Store the samples in a refrigerator before and after sampling.

Principle: High performance liquid chromatography with mass spectrometry (HPLC-MS)
Precision (%): 5,0
Minimum reported value: 0,0007 µg
Remarks: Four isocyanates can be requested at the same time: HDI, TDI, MDI and IPDI. The analysis is done for the isocyanates present in vapour form only and the result is expressed as a monomer concentration.

IRSST. "Analyse des isocyanates à haute sensibilité". Méthode 366. Non publiée.

Diisocyanate-4,4' de diphénylméthane (MDI)

Method: IRSST - 376

Sampling device:
Sampling media required:
#IRSSTDescription
1415 Glass midget Impinger for isocyantes

Parameters:
Flow rate: 1 L/min
TWA sampling volume: 15 L
STEL sampling volume: -
Remarks: Refer to the sampling guidelines supplied with the equipment. For surface wipe test, contact Laboratory Customer Service. An impinger must be used for sampling if the process applied in the workplace involves a very fast isocyanate reaction, such as the application of MDI-based insulation for building insulation. Impinger sampling can only be done at a fixed station. Use equipment code 981 if small diameter particles are suspected (<2µm) and equipment code 1415 if only large particles are anticipated (>2µm). Determination of corresponding oligomers is also done during the analysis. The sampling time for impingers may be longer than 15 minutes.

Principle: High performance liquid chromatography with UV detection (HPLC-UV)
Precision (%): 8,8
Minimum reported value: 0,041 µg

IRSST. "Détermination de la fraction monomèrique des isocyanates sous forme vapeur et aérosol dans l'air des lieux de travail". Méthode 376. Non publiée.

Diisocyanate-4,4' de diphénylméthane (MDI)

Method: IRSST - 376

Sampling device:
Sampling media required:
#IRSSTDescription
981 Isocyanates glass midget impinger and filter

Parameters:
Flow rate: 1 L/min
TWA sampling volume: 15 L
STEL sampling volume: -
Remarks: Refer to the sampling guidelines supplied with the equipment. For surface wipe test, contact Laboratory Customer Service. An impinger must be used for sampling if the process applied in the workplace involves a very fast isocyanate reaction, such as the application of MDI-based insulation for building insulation. Impinger sampling can only be done at a fixed station. Use equipment code 981 if small diameter particles are suspected (<2µm) and equipment code 1415 if only large particles are anticipated (>2µm). Determination of corresponding oligomers is also done during the analysis. The sampling time for impingers may be longer than 15 minutes.

Principle: High performance liquid chromatography with UV detection (HPLC-UV)
Precision (%): 8,8
Minimum reported value: 0,041 µg

IRSST. "Détermination de la fraction monomèrique des isocyanates sous forme vapeur et aérosol dans l'air des lieux de travail". Méthode 376. Non publiée.
Following the amendment of Appendix 1 of the Quebec Regulation respecting occupational health and safety (RSST, RLRQ, c. S-2.1, r. 13), part of Quebec Occupational Health and Safety Act, which came into effect on March 26, 2020, the TWAEV, STEL and Ceiling values for certain substances are now expressed in ppm. For these substances, the IRSST performed the conversion calculations to express these TWAEV, TWA and Ceiling values in mg/m3, which thus appears in its Sampling Guide for Air Contaminants in the Workplace (Guide d'échantillonnage des contaminants de l'air en milieu de travail ) and the associated Substance Data Sheets. However, it is imperative to refer to the values expressed in the RSST which are legally binding.