Hesperian Health Guides

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Isocyanates

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HealthWiki > Workers' Guide to Health and Safety > APPENDIX B: Common chemicals and materials > Isocyanates


Isocyanates are liquids used in glues, rubber, and coatings in shoe manufacturing. Isocyanate (water-based) glues were once considered safer than solvent-based glues, but more and more health problems in workers show that these glues are not safe. The most common and dangerous isocyanates are diisocyanates. In the chart belowe we only list diisocyanates.

Mixing isocyanates and water or acids in a closed container can be very dangerous. It can create high pressure that might explode the container.

Isocyanates are often combined with other chemicals such as alcohols, acids, and polyurethanes. They are mixed with alcohols to create polyurethane plastic and with acids to make polyurea coatings. See more information on alcohols, acids, and polyurethane.

One of the biggest health problems caused by working with isocyanates is asthma. If you feel chest tightness, difficulty breathing, or begin to have asthma attacks, leave the work area and stop working with the isocyanates. If you continue to work with isocyanates, you might have a more serious asthma attack that could kill you. Talk to a health worker and try to transfer to a different job in your factory.

The charts include only some of the isocyanates that exist. See Learn about chemicals used in your factory and how to find information about other isocyanates. See the Index of chemical names to find alternative names for isocyanates.

Prevent or reduce exposure:

  • Use ventilation systems that extract fumes and replace or dilute dirty air with clean air (see Chapter 17: Ventilation).
  • Enclose equipment where possible.
  • Do not mix or pour isocyanates by hand.
  • Wear butyl rubber gloves. Wear correct respirators that fit you. (See Chapter 18: Personal protective equipment.)
  • Have an emergency plan that includes first aid treatment and protective equipment for spills, splashes, and exposures. Keep necessary emergency supplies at the worksite, well stocked, and accessible to workers.
  • Work areas where isocyanates are used, stored, and mixed need to be controlled for heat and monitored for concentration of fumes and vapors. The work areas should also have alarms, fire extinguishers, and a fire emergency plan (see Chapter 11: Fire).


Isocyanates


Isophorone diisocyanate (IPDI) CAS No. 4098-71-9

fire or explosive





Methylene bisphenyl diisocyanate (MDI, 4,4-diphenylmethane diisocyanate) CAS No. 101-68-8






Naphthalene diisocyanate (NDI, 1,5-naphthylene diisocyanate) CAS No. 3173-72-6

fire or explosive





Toluene diisocyanate (TDI, Toluene-2,4-diisocyanate) CAS No. 26471-62-5


Might harm reproductive health




Hexamethylene diisocyanate (HDI, 1,6-diisocyanatohexane) CAS No. 822-06-0

fire or explosive




WHAT ARE THEY?
Isocyanates are clear, colorless, or slightly yellow liquids that have a strong, fruity smell. If you can smell them, they can harm you.
DO YOU WORK WITH THEM?
Isocyanates are used in shoe making in glues, rubber, and finish coatings.
WHEN THEY COME IN CONTACT WITH YOUR BODY
SKIN

They irritate and burn the skin. You may develop a rash, redness, and dryness. Your skin might start peeling, itching, and cracking. Your skin may become so sensitive that even a very small amount causes skin irritation. See First Aid.

EYES

They irritate and burn your eyes. They cause conjunctivitis: watery eyes and discomfort. High amounts of isocyanate can permanently damage your eyes. See First Aid.

NOSE/LUNGS

The fumes can irritate your nose, throat, and lungs, causing congestion, coughing, wheezing, shortness of breath, and chest tightness. The longer you are exposed, the more sensitive you become, which can lead to severe asthma attacks. Inhaling a lot of isocyanate fumes can create buildup of fluid in the lungs, called lung edema. See First Aid.

MOUTH/BELLY
They can irritate your gastrointestinal tract, and cause nausea and vomiting. See First Aid and seek medical help.
WHEN YOU ARE EXPOSED OVER TIME:

Isocyanates can make your nose and lungs sensitive and cause chronic asthma and pneumonitis. After some time you may develop chronic asthma that continues even if you stop working with isocyanates.

Toluene diisocyanate may cause cancer.
IF YOU ARE AT RISK OF EXPOSURE:

Use elbow-length, butyl rubber gloves, an apron, and eye/face protection (see Chapter 18: Personal protective equipment).

Use a supplied-air respirator. Negative pressure air-purifying respirators are not recommended for isocyanates.
SAFER SUBSTITUTES:
Methylene bisphenyl diisocyanate and naphthalene diisocyanate are safer than other isocyanates because they evaporate more slowly.



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