Wikipedia
Nitrofen
Nitrofen is an herbicide of the diphenyl ether class. Because of concerns about its carcinogenicity, the use of nitrofen has been banned in the European Union and in the United States since 1996.
In 2002 Nitrofen was detected in organic feed, organic eggs, and organic poultry products in Germany prompting a scandal which caused a decline in all organic meat sales in Europe to slip.
Nitrofen is listed as an IARC Group 2B carcinogen, meaning it is "possibly carcinogenic to humans".