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Toluene-2,4-Diisocyanate (TDI)

General Description

  • Synonyms: 2,4-Diisocyanato-1-methylbenzene; TDI; 2,4-TDI; 2,4-Toluene diisocyanate
  • OSHA IMIS Code Number: 2470

    (IMIS Name History: Toluene-2,4-Diisocyanate prior to 9/1/89)

  • Chemical Abstracts Service (CAS) Registry Number: 584-84-9
  • NIOSH Registry of Toxic Effects (RTECS) Identification Number: CZ6300000
  • Department of Transportation Regulation Number (49 CFR 172.101) and Emergency Response Guidebook: 2078 156
  • NIOSH Pocket Guide to Chemical Hazards - Toluene-2,4-Diisocyanate: Chemical description, physical properties, potentially hazardous incompatibilities, and more
  • U.S. Environmental Protection Agency (EPA) Hazard Summary - Toluene-2,4-Diisocyanate: Uses, sources and potential exposure, acute and chronic health hazard information, and more

Exposure Limits and Health Effects

Exposure Limit

Limit Values

HE Codes

Health Factors and Target Organs

OSHA Permissible Exposure Limit (PEL) - General Industry See 29 CFR 1910.1000 Table Z-1

0.02 ppm
(0.14 mg/m3) Ceiling

HE9

Allergic sensitization of respiratory tract; asthma

OSHA PEL - Construction Industry
See 29 CFR 1926.55 Appendix A

0.02 ppm
(0.14 mg/m3) Ceiling

HE9

Allergic sensitization of respiratory tract; asthma

OSHA PEL - Shipyard Employment
See 29 CFR 1915.1000 Table Z-Shipyards

0.02 ppm
(0.14 mg/m3) Ceiling

HE9

Allergic sensitization of respiratory tract; asthma

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL)
See Appendix A

Lowest Feasible Concentration

Ca

HE2

Carcinogenicity (pancreas, liver, skin, mammary glands, and circulatory system)

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) (2004)*

0.005 ppm (0.036 mg/m3) TWA

0.02 ppm
(0.14 mg/m3) STEL

A4; SEN

HE9

Allergic sensitization of respiratory tract; asthma

HE11

Bronchitis, pneumonitis, pulmonary edema

HE14

Eye, mucous membrane, and respiratory irritation

CAL/OSHA PELs

0.005 ppm (0.04 mg/m3) TWA

0.02 ppm Ceiling

0.02 ppm (0.15 mg/m3) STEL

HE9

Allergic sensitization of respiratory tract; asthma

HE11

Bronchitis, pneumonitis, pulmonary edema

HE14

Eye, mucous membrane, and respiratory irritation

*In the ACGIH 2012 Notice of Intended Changes, ACGIH proposed the following limit values and notations: 0.001 ppm TWA (inhalable fraction); 0.003 ppm STEL (inhalable fraction); Skin; SEN; A3; basis: asthma.

  • National Toxicology Program (NTP) carcinogenic classification: Reasonably anticipated to be a human carcinogen (PDF)
  • International Agency for Research on Cancer (IARC) carcinogenic classification: Group 2B (PDF) (possibly carcinogenic to humans)
  • EPA carcinogenic classification: Not listed
  • EPA Inhalation Reference Concentration (RfC): Not established
  • Agency for Toxic Substances and Disease Registry (ATSDR) Inhalation Minimal Risk Level (MRL): Not established
  • NIOSH Immediately Dangerous to Life or Health (IDLH) concentration: 2.5 ppm
  • Notes on Other Potential Health Effects and Hazards
    1. Toluene-2, 4-diisocyanate is combustible and can give off toxic fumes in a fire (NIOSH/IPCS 1995).
    2. Death from severe asthma in sensitized workers has been reported (NIOSH 1996).
    3. Once sensitized, workers may continue to exhibit the health effects of TDI several years after exposure has ended (ACGIH 2004).
    4. Individuals sensitized to TDI may develop a chronic-like syndrome that includes coughing, wheezing, tightness or congestion in the chest, and shortness of breath (ACGIH 2004).
  • Date Last Revised: 9/6/2012
  • Literature Basis

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):
  • Coated Glass Fiber Filter (37 mm open face) Coated with 1.0 mg 1-(2-Pyridyl)piperazine
  • maximum volume: 240 Liters
  • maximum flow rate: 1.0 L/min (TWA)
  • maximum volume: 15 Liters
  • maximum flow rate: 1.0 L/min (STEL)
  • maximum volume: 15 Liters
  • maximum flow rate: 1.0 L/min (Ceiling)
  • current analytical method: High Performance Liquid Chromatography; HPLC/UV/FLU
  • analytical solvent: 90/10 (v/v) Acetonitrile/Dimethyl Sulfoxide
  • method reference: OSHA Manual of Analytical Methods (OSHA 42)
  • method classification: Fully Validated
  • note: OSHA personnel may obtain filters from Salt Lake Technical Center (SLTC) and refrigerate until used.
On-Site Sampling Techniques/Methods:
  • Detector Tube
  • manufacturer: Dräger
  • model/type: Toluene Diisocyanate 0.02/a, order no. 67 24501
  • sampling information: 25 strokes
  • upper measurement limit: 0.2 ppm
  • detection limit: approx. 0.02 ppm
  • standard deviation: ±30%
  • method reference: on-site air secondary (manufacturer)

** All Trademarks are the property of their respective owners.

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