A widely used farm chemical that is a key ingredient in a new herbicide developed by Dow AgroSciences "possibly" causes cancer in humans, a World Health Organization research unit has determined.
The classification of the weed killer, 2,4-dichlorophenoxyacetic acid, known as 2,4-D, was made by the WHO's International Agency for Research on Cancer (IARC).
The IARC said it reviewed the latest scientific literature and decided to classify 2,4-D as "possibly carcinogenic to humans." That is a step below the more definitive "probably carcinogenic" category but two steps above the "probably not carcinogenic" category.
IARC's findings on 2,4-D have been awaited by environmental and consumer groups that are lobbying U.S. regulators to tightly restrict its use, as well as by farm groups and others that defend 2,4-D as an important agent in food production that does not need more restrictions.