OSHA has announced a new National Emphasis Program for occupational exposure to chemical hazards.  One such chemical compound is isocyanates, which can cause occupational asthma, irritation of the skin, eyes, nose and throat, and possibly cancer.  

What are isocyanates? These chemicals are used in materials including paints, varnishes, auto body repair, and building insulation.  Spray-on polyurethane products containing isocyanates have been created for a wide range of retail, commercial, and industrial uses to protect cement, wood, fiberglass, steel and aluminum, including protective coatings for truck beds, trailers, boats, foundations, and decks.  Other jobs that have exposure to these chemicals are the manufacture of mattresses and car seats. 

Polyurethanes were a creation of America’s post World War II science and technology – the time when hundreds of so-called wonder chemicals were invented.  Polyurethanes or plasticizers are produced in three forms:

  1. As rigid foams primarily for building insulation, support elements, and decoration, and:
  2. As flexible or soft foams used for cushioning, and:
  3. As elasto-plastics used for automobile body panels, coatings, adhesives, sealants, and as a substitute for rubber.  Because of easy application and versatility, manufacturers and employers consider polyurethanes to be invaluable.

Polyurethanes are formed by combining a variety of chemicals: the most important ingredient is the family of isocyanates, which is made up of a number of chemicals: Toluene Diisocyanate (TDI), Methylene Bisphenyl Diisocyanate (MDI), Hexamethylene Diisocyanate (HDI), Naphthalene Diisocyanate (NDI), and Diisocyanate Dicyclohexyl Urethane.  

Telecommunications and automotive manufacturing members work with and are exposed to isocyanate products.  This work involves the use of polyurethane products used as foam plugs to weatherproof and seal telephone cable splices in the telecommunication business.  In the automotive manufacturing industry, polyurethane products are used in the plastics and related materials. 

Hazardous Exposures: 

Health effects of isocyanates include irritation of skin and mucous membranes, chest tightness, and difficulty breathing.  These chemicals include compounds known as potential human carcinogens, known to cause cancer in animals.  TDI exposure causes serious upper respiratory health problems that involve the throat, nose, esophagus and lungs.  It can also cause acute irritation, (such as a burn inside the nose, throat or lungs.)  This exposure can be so damaging that the body loses its ability to fight infections.  Before or as soon as possible after working with TDI, affected workers should have a complete work up and medical history, including, chest x-ray, lung function test, and blood tests.  This is very important for those workers who have a history of upper respiratory/lung allergies, previously weakened lungs, or lung/throat problems at the time of exposure. 

Controlling Hazards: 

The best way, of course, to control the hazard is to remove it from the workplace.  Some less toxic and more acceptable substitutes should be used.  Isocyanate products can be effectively controlled with the use of engineering controls, such as enclosed systems or methods, as well as local exhaust ventilation.  It is up the employer to ensure that their workers are not exposed to harmful levels of these chemicals.  If affected workers can smell the TDI substance (smells like fruit), they should leave the area immediately and notify the supervisor.  If, after implementing engineering and administrative controls, the workers are still exposed to harmful levels, employees must be given the appropriate personal protective equipment.  In addition to gloves, goggles, and protective clothing, the workers must also be given the correct type of respirator. 

Good hygiene by the workers is also a must.  They should not smoke or eat in TDI work areas.  Also, they should never wear contaminated work clothing home.  The employer should collect such clothing and arrange for it to be cleaned.  If TDI gets in the eyes, they need to be flushed with water for at least 15 minutes.  Affected workers should contact his/her physician.

If the chemical is inhaled, get the worker to fresh air, and call a physician immediately.  Trained personnel should give oxygen treatment to the patient.  If breathing stops, artificial respiration should immediately be given.