By Liz White, editor, UT International
Seoul - In a recent accident in China, drums containing TDI (toluene diisocyanate)fell off a truck and landed close to a stream, causing complete chaos to the drinking water supply for many thousands of local people. But this disruption could have been avoided had the expertise and data collected by the III (International Isocyanates Institute) been drawn on.
This story, from Dr Michael Collins, scientific director of the UK-based isocyanates study group, highlights the dangers inherent in over-regulating, he told assembled delegates, in his introductory lecture at the International Polyurethane forum 2007 in Seoul on 22 May. The meeting, organised by the Polyurethane Society of Korea, attracted 200 delegates, including a group from China and one from India.
The Chinese authorities have classified TDI as a "hyper-toxic chemical," based on "one single short rat study," Collins pointed out, and this has led to "quite restrictive transport regulations."
Had the Chinese government looked at III's studies of the ecological effects of isocyanate spillage into water, and at experience by one of III's member producers of a closely monitored spillage into marshy woodland, they would have seen no evidence of any diamine formation with toxicological problems.
III has carried out a 'mecocosm' study in a simulated water environment on the effects of isocyanate spillage into an artificial pond complete with fish and zooplankton, which showed that "there are no severe or long-lasting ecological problems."
One reason for this lack of environmental hazard is that, despite conventional wisdom about isocyanates reacting with water in a "very fast and aggressive," manner ... "in practice the reaction is rather slow because the isocyanates are hydrophobic and insoluble," Collins explained. The main reaction is a surface one to form solid polyurea, he added. Hence, with isocyanates, "a spill into the environment is not a disaster," the isocyanates expert concluded. PIC: Collins speaking at the Korean forum."