The role of isocyanates in fire toxicity

Abstract

Isocyanates are a group of low molecular weight, highly reactive compounds with a functional isocyanate group. The main human exposure route is via inhalation of airborne isocyanates, although dermal exposure has also been reported. The inhalation of isocyanates is associated with severely adverse health effects such as asthma, inflammation in the respiratory tract and cancer. During thermal degradation of polyurethane materials, airborne isocyanates can be sampled in the fire effluent. This paper discusses the reactivity and commercial applications of isocyanates and the generation of airborne isocyanates during thermal degradation, the human health effects as well as the environmental fate of some of the most commercially important isocyanates. This is followed by a review of the generation of isocyanates from large-scale fire testing and bench-scale test methods as well as sampling techniques and derivatisation agents necessary to stabilise the isocyanates and analysis.

Fire toxicity – The elephant in the room?

“…Isocyanates: The potent respiratory sensitisers, isocyanates, triggering asthma, and sometimes death after a single exposure, have been identified in fire effluents [65,66]. Isocyanates are widely used in the manufacturing of flexible polyurethane (PU) foams for soft furniture and rigid PU foams for insulation in buildings as well as fridges and freezers.…”

Investigation of epoxy‐based wood adhesives

“…PURs are isocyanate‐based adhesives whose use requires a good ventilation. It is well documented that the combustion of PURs generates toxic fumes such as hydrogen cyanide . Therefore, it is desirable to develop isocyanate‐free and formaldehyde‐free cold‐set wood adhesives for production of thick wood‐based composite panels.…”

High levels of isocyanic acid in smoke generated during hot iron cauterization

“…[1][2][3] ICA is a strong organic acid that, together with other pollutants, has been found in fire smoke, diesel emissions and in emissions from heated products that contain urea-formaldehyde resins as binders. [4][5][6][7][8][9] ICA and hydrogen cyanide (HCN) have been shown during high-temperature pyrolysis of biofuels with a nitrogen content that varied between 2.9 and 15.5%. The formation of ICA did then increased proportionally with the nitrogen content of the fuel and no ICA was found from bark with only 0.4% nitrogen.…”