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Health and Environment

Hazards

Acute (Short-Term) Health Effects

  • The inhalation of TDIs causes severe irritation of the skin and eyes, and affects the respiratory, gastrointestinal, and central nervous systems. Exposure to high levels of 2,4-TDI can cause pulmonary edema (fluid build-up in the lungs) and at 2.5 parts per million (ppm) 2,4-TDI is immediately dangerous to life and health.
  • Contact with TDIs can cause severe skin and eye irritation and burns. Prolonged contact with 2,4-TDI can cause eye damage.

Chronic (Long-Term) Health Effects

  • TDIs are possible carcinogens. The International Agency for Research on Cancer (IARC) classifies 2,4-TDI, 2,6-TDI, and TDI mixed isomers as Group 2B carcinogens, possible carcinogens. 2,4-TDI has been shown to cause pancreas, liver, and breast cancer and TDI mixed isomers have been shown to cause cancer of the pancreas, liver, and heart in animals.
  • There is limited evidence that 2,4-TDI may be a reproductive hazard; it has caused temporary impotence in males. It is a mutagen, causing genetic changes.
  • 2,4-TDI and 2,6-TDI may cause an asthma-like allergy,where future exposure to very low levels of TDI result in asthma attacks with shortness of breath, wheezing, coughing, or chest tightness.
  • Chronic exposure to 2,4-TDI at high concentrations may cause memory and concentration problems.

Life-Cycle Hazards
Manufacturers produce TDI using the "phosgenation process," where phosgene is an intermediary in the manufacture of TDI. Phosgene is a lethal gas at very low concentrations and is considered a "more hazardous chemical" by the Massachusetts Toxics Use Reduction Science Advisory Board. To avert exposing workers to phosgene, manufacturers of TDI continuously monitor operating areas and employ a variety of alarm and shutdown systems.

Exposure Routes

Worker Health
Facilities using TDIs must minimize worker exposure.

  • Use TDIs in a closed system. If a closed production system is infeasible, enclose operations and use local exhaust ventilation. If 2,4-TDI exposure may exceed 0.005 ppm, use a Mine Safety and Health Administration/National Institute for Occupational Safety and Health approved supplied-air respirator with a full facepiece.
  • Take precautions to avoid contact with TDIs. If TDIs contact skin or eyes, immediately wash and transport the victim to a hospital for treatment.

Public Health
Products are the primary source of public exposure to TDIs.

  • Residual amounts of unreacted TDI are often found in polyurethane products. The unreacted TDI seeps out of products ("off-gases"), exposing people to small concentrations of TDI. Indoor products that may release TDI monomer include polyurethane coatings, cushions, pads, cement sealers, and mastic sealants.
  • The public may also be exposed to TDIs through the use of household products, including polyurethane foam kits.

Endnotes:
The data for this section were collected from the following sources: Environmental Defense Fund (EDF), 1999, "Chemical Profile: Toluene-2,6-Diisocyanate", "Chemical Profile: Toluene-2,4-Diisocyanate", and "Chemical Profile: Toluene Diisocyanate (Mixed Isomers)" (New York: EDF; see webpage: http:/www.scorecard.org/chemical-profiles/); Richard J. Lewis, Sr. (ed.), 1993, Hazardous Chemicals Desk Reference (New York: Van Nostrand Reinhold); National Institute for Environment, Health, and Safety (NIEHS), National Toxicology Program (NTP), "NTP Chemical Repository (Radian Corporation, August 29, 1991), Toluene Diisocyanate," (see webpage: http://ntp-db.niehs.nih.gov/NTP_Reports/NTP_Chem_H&S/NTP_Chem2/Radian26471-62-5.txt) and "NTP Chemical Repository (Radian Corporation, August 29, 1991), Toluene-2,6-Diisocyanate," (see webpage:http://ntp-db.niehs.nih.gov/NTP_Reports/NTP_Chem_H&S/NTP_Chem9/Radian91-08-7.txt) and New Jersey Department of Health and Senior Services, 1996, "Hazardous Substance Fact Sheet: Toluene-2,6-Diisocyanate" and "Hazardous Substance Fact Sheet: Toluene-2,4-Diisocyanate" (Trenton, New Jersey; see webpage: http://www.state.nj.us/health/eoh/rtkweb/rtkhsfs.htm); and U.S. EPA, Office of Air Quality Planning and Standards, 1998, "Toluene-2,4-Diisocyanate" (Washington, D.C.: U.S. EPA; see webpage: http://www.epa.gov/ttn/uatw/hlthef/toluene2.html); Stanford Research Institute (SRI) International, Chemical Economics Handbook, "Diisocyanates and Polyisocyanates" (1998) and "Phosgene" (1997) (Palo Alto, California: SRI).