I work for a government contractor writing technical manuals for the Navy after retiring from the Navy. In the technical manuals that we write that have the potential to expose people to Isocyanates, here's what the WARNINGs say:
"Isocyanates are typically used to form polyurethane materials. Sawing, grinding, abrading, or other operations on cured [polyurethane materials] that heat the material may generate low levels of free isocyanate in the dust particles. These operations may also liberate an isocyanate vapor. Low levels of free isocyanate are also present during the mixing and application of [polyurethane] paint."
"Isocyanates are toxic materials that can cause short-term health effects and in some cases, long-term health effects. Short-term health effects include irritation of the eyes, respiratory tract, and skin. If exposure is severe, bronchitis and fluid in the lung may develop. Extended contact of liquid isocyanate with skin can also cause redness, swelling and blistering."
"Sensitization to isocyanates, although not common, is a potential long-term health effect. Sensitization results in a reaction similar to asthma, with the development of wheezing, shortness of breath and coughing. Individuals who become sensitized will likely not be able to work with isocyanate materials without developing asthma-like symptoms."
"Workers assigned to [handle polyurethane materials] should be medically screened by local medical/industrial hygiene authorities and cleared for working with isocyanate containing materials. If an individual indicates sensitivity to any of the SHT materials, the worker shall be removed immediately from this work and referred to the medical department."
The
Naval Ships Technical Manual 631 - Preservation of Ships In Service is the tech manual that contains all of the requirements for handling isos, among lots of other things. If you want to learn how the Navy keeps their ships from rusting, read this (it's 304 pages, if that's any clue how important it is).