Monomeric Diisocyanates

Monomeric Diisocyanates are reactive chemicals that must only be handled under very restricted conditions. They are strongly irritating to the skin, eyes and the respiratory tract (nose, throat, lung). Delayed appearance of the complaints and development of hypersensitivity (difficult breathing, coughing, asthma) are possible. Monomeric Diisocyanates act as skin and respiratory tract/lung sensitizers. Long term overexposure can result in a loss of lung function. Results from animal tests with repeated exposures indicate that the respiratory tract is the primary target of Monomeric Diisocyanates, other organs are not significantly affected. Available information does not provide evidence that Monomeric Diisocyanates might either be mutagenic, carcinogenic or toxic to reproduction. All Monomeric Diisocyanates are classified as toxic by inhalation.

For all Monomeric Diisocyanates occupational exposure limits (OELs) have been established worldwide. However, hypersensitive persons may suffer from the sensitizing effects of aliphatic diisocyanates even at concentrations below established OELs. Personnel who work with Monomeric Diisocyanates should have a pre-placement medical examination and periodic examinations thereafter, including a pulmonary function test. Anyone with a medical history of chronic respiratory disease, asthmatic or bronchial attacks, indications of allergic responses, recurrent exzema or sensitization conditions of the skin should not handle or work with Monomeric Diisocyanates. Anyone who develops chronic respiratory distress when working with Monomeric Diisocyanates should be removed from exposure and examined by a physician. Further exposure must be avoided if a sensitivity to diisocyanates has developed.

All Monomeric Diisocyanates are not readily biodegradable. However, due to other elimination mechanisms (photodegradation, hydrolysis, adsorption), long retention times in water are not to be expected. Within the limits of water solubility, Monomeric Diisocyanates have a low to moderate toxicity for aquatic organisms.

More details can be found in the following safety information sheets:
  • HDI (Hexamethylene Diisocyanate)
  • H12MDI (4,4'-Methylenebis (cyclohexyl isocyanate)
  • IPDI (Isophorone diisocyanate)