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Overview on isocyanatesStockholm
(03.04.1998 - Rolf Ählberg*) Exposure to
isocyanates is a more serious health hazard than has previously been realised, according
to recent findings by scientists Gunnar Skarping, Marianne Dalene and their colleagues at
Lund University Hospital in Sweden.
Nordic Metal (the confederation of metalworker unions in the Nordic
countries) is working to fight these problems in a European context by seeking regulations
on the use of products containing or discharging isocyanates. What are isocyanates? Isocyanates are basic chemicals. They are mainly used in producing polyurethane foam, polyurethane elastomers, polyurethane adhesives and polyurethane varnish.
Isocyanates are found in chemical products such as
When does exposure to isocyanates occur? The industrial manufacture of polyurethane or any processing of polyurethane products involving heating can cause exposure to isocyanates. Such risks occur in
How many people are exposed and to what quantities? The production and use of isocyanates has been increasing for many years. In Western Europe, polyurethane production increased from 994,000 tons in 1983 to 1,687,000 tons in 1992 and this increase has continued. It is difficult to estimate the number of people whose health is at risk in their workplaces because of isocyanates, but they can be counted by the thousand. Most western European countries apply the same safety limits (0.005 ppm) and this value is also applied in the USA and Canada. Strict regulations apply to the use of isocyanates as such. The problem is that the methods so far used to measure exposure have failed to reveal the true extent of the problem.
The methods used for many years to measure isocyanates have turned out to be inadequate, untrustworthy and inaccurate. The limitations of the principal methods have meant that symptoms have not been linked to exposure to isocyanates. New measurement methods make it possible to study the decomposition products of polyurethanes. Other constituents of technical isocyanate products can also be determined. New measuring instruments providing direct readouts have been
developed and this has made it possible to trace isocyanate levels over a period of time
and also to register short processes, thus enabling us to identify critical manufacturing
operations. New methods for analysing urine and blood samples have also been developed. What symptoms are linked to working with products with a high isocyanate content? The following are some of the symptoms that can arise. Runny noses, stuffy noses, sneezing and/or itching in the nose, nose bleeds, soreness or dryness in the throat, wheezing, breathlessness and/or a tight feeling in the chest, pain, irritable coughs, breathing problems, asthma and loss of lung capacity, irritation of the eyes and skin problems ranging from redness to eczema-like changes. Isocyanate asthma is the most common form of workplace asthma in contemporary Sweden. These symptoms may appear long after the work has been finished and may also disappear during long periods of absence from work such as holidays.
Isocyanates are found almost everywhere. 1. THE ELECTRONICS INDUSTRY
2. MANUFACTURING DOMESTIC APPLIANCES
3. MANUFACTURING PLASTIC GOODS
5. CAR AND VEHICLE WORKSHOPS
6. CASTING
7. WELDING INVOLVING
8. WORK INVOLVING PLASTIC FOAM OR INSULATION FOAM
9. WORK INVOLVING PAINTING/VARNISHING
10. WORK INVOLVING ADHESIVES OR GLUED COMPONENTS OR PRODUCTS
11. WORK INVOLVING MINERAL WOOL (ROCK WOOL, GULL FIBRE ETC.)
12. WORK INVOLVING BAKELITE AND WOOD GLUE
Besides measures at national level, Nordic Metal also proposes European regulations on the use of products containing or capable of discharging isocyanates. Irrespective of the form of European regulations, they should at least cover the following areas:
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