ICI has pulled out of the controversial US project to spray vast areas of Colombia with herbicides in an attempt to eradicate its cocaine and heroin trade.
The British chemicals company's decision, which came after an Observer investigation revealed its involvement, will be a major embarrassment to the US government and will dent the credibility of the plan.
ICI does not want its name dragged into such a program, particularly as there have been reports of children in Colombia who have inhaled the chemicals falling ill.
The $1 billion program, instigated by former President Bill Clinton, will also be hit by revelations that an individual working for the US company fumigating the coca and opium plants has been suspected of smuggling heroin back into the US.
According to an official document from the US Drug Enforcement Administration obtained by The Observer, on 12 May last year Colombian police intercepted a parcel sent from Dyncorp's Colombia offices to its base in Florida. The police found two small bottles of a thick liquid which, when tested, was found to be laced with heroin worth more than $100,000.
A Dyncorp spokeswoman said the company had investigated the issue and found no evidence of wrongdoing.
ICI's decision to refuse to allow its products to be used is likely to worry the US government. Hospitals in sprayed areas have reported increases in skin rashes, diarrhea, stomach aches and respiratory problems. Food crops have also been destroyed and livestock poisoned.
In January, the US State Department claimed the only chemical used in the aerial eradication is glyphosate. This pesticide, commonly known as 'Round Up', is made by the biotech corporation Monsanto.
However, the department was forced to admit it was mixing the glyphosate in an untested brew with another chemical called Cosmo Flux, a sticky soap-like substance which helps the pesticides stick to the leaves of plants. One of its key ingredients is made by ICI.
ICI was forced to admit its products were being used when presented with documents from The Observer obtained by Colombian scientist Dr Elsa Nivía of the Pesticides Action Network.
Ed Hammond of the US campaigning group Sunshine Project said: 'Massive spraying in Colombia has been a hostile act against the environment and people that live there. The decision by ICI not to have anything to do with this program is sensible and will be a wake-up call to Washington.'
© Guardian Newspapers Limited 2001