On Tuesday 22nd of March 2005 Sarah Hull, a spokeswoman for the international agrochemical and GMO company Syngenta announced that farmers in four U.S. states planted 37,000 acres (15.000 ha) with the experimental Bt10 corn variety from 2001 through 2004. She refused to say which four states. "All current plantings and seed stock have been identified and either destroyed or isolated for future destruction," she said in a prepared statement. While most of the corn produced from the Bt10 seeds, engineered to act as a pesticide, likely went into animal feed, some of it may have entered the human food supply, Hull said. She also said the Bt10 corn could have been exported to countries that have approved the Bt11 variety. That list includes Canada, Argentina, Japan, South Africa, Uruguay, the European Union, Switzerland, Australia, New Zealand, Taiwan, the Philippines, China, Russia, and South Korea. Jeff Stein, Syngenta's director of regulatory affairs for North America, said the primary difference between Bt10 and Bt11 is that the same DNA was inserted into different portions of the plant's genome, but the proteins created by the process remained identical.

Hull said Syngenta informed the U.S. government about the mix-up between the Bt10 and Bt11 corn varieties in "mid-December," but did not inform the public because "this is not a food safety issue whatsoever." A teleconference was arranged to talk to media after the story was published on Tuesday on the Website of Nature magazine. A spokesman for the US Department of Agriculture (USDA) said that Syngenta could be fined up to $500,000 for the mistake.

Thursday, 24th March: The EU Commission announced that they had only been informed about the problem by Syngenta and US authorities on the 23rd of March. Japanese and South Korean authorities announced they would require testing for "Bt10" in US maize imports.

Thursday, 31st March: Syngenta admitted that "Bt10" also contained an antibiotic resistance gene (ampicillin) but claims it was not active in the construct. It was also admitted that Bt10 was shipped to the EU as well as provided for planting experiments in Spain and France.

Thursday, 31st March: Genetic ID, a private testing company offered a PCR detection method specific for "Bt10".

Friday, 1st April: The EU Commission issued a press release and "deplored" the accident asking for full information in letters to Syngenta and the US embassy.

Monday, 4th April: The Commission announced they had no means to test for the presence of bt10 in maize feed and food as Syngenta had not provided a test so far.

Friday, 8th April: Syngenta annouces it has settled with the US Department of Agriculture to pay a $375,000  fine over the scandal.

Tuesday 12th April: The EU Member States Standing Committee on the Food Chain and Animal Health discussed the issue in Brussels. The representatives concluded that there was no imminent health threat associated with Bt10. They also endorsed a Commission proposal to require laboratory certification for maize imports from the US to be free of Bt10.

Friday, 15th April: The EU Member States voted in favour of a Commission proposal to adopt an emergency measure requiring imports of corn gluten feed and brewers grain from the United States of America to be certified as free of the unauthorised GMO Bt10, as these are the imported products considered most likely to be contaminated. Syngenta welcomes the decision and commissions a test to the testing company "GeneScan", which is to be applied from April 18th on outgoing cargos from the US.

Thursday, 21st April: The Commission decision to require independent certification of US corn gluten feed and brewers grains not to contain Bt10 is published in the Official Journal.

Wednesday, 27th April: The US Environmental Protection Agency and the US Food and Drug Administration for the first time publish statements of their risk assessment of Bt10. The assessments do not include any event specific considerations but simply state that the expressed protein of Bt10 and Bt11 was the same.

Wednesday, 11th May: Syngenta informs NGO representatives about the case but insists that the full sequence of Bt10 would not be made public and reference material for testing will be exclusively provided only to a single laboratory, GeneScan, under the company's contract.

Wednesday, 25th May: A first US shipment of maize feed contaminated with Bt10 is impounded by Irish authorities.

Wednesday, 1st June: The Japanese govenment announces all maize cargos from the US will be tested for Bt10 after a shipment was found to be contaminated with Bt10 on May 26th.

Wednesday, 8th June: Syngenta announces it will seek USDA official approval for Bt10 to reassure the Japanese government after further shipments are refused by Japanese authorities

Thursday, 9th June: The European Food Safety Agency (EFSA) issues a follow up statement that no safety evaluation of Bt10 can be conducted as there are not sufficient data from Syngenta. However, if  the information provided by Syngenta was correct, there may be no safety concerns about inadvertent contamination.

Friday, 10th June: 4,170 tons of imported feed corn from the US was tested as Bt10 positive at the Shibushi port, after its discovery in Nagoya Port and Tomakomai Port.

Wednesday, 15th June: The MAFF (Ministry of Agriculture, Forestry and Fisheries) proposed, as a provisional measure, allowing U.S. corn mixed with genetically modified Bt10 to be imported to Japan if the content of the unapproved corn variety is one pct or less.

Thursday, 23rd June: The MAFF released information on the third case of Bt10 contamination, which was discovered in Shibushi Port, Kagoshima Prefecture (on Kyusyu Island).

Thursday, 4th August: A MAFF press release states that there have been 7 shipments from the US tested as unapproved GMO Bt10 detected positive. So far 20,812 tons detected at the customs inspection (before importing them into Japan) in 6 different ports across Japan.

Monday, 22nd August: Japan's Agriculture Ministry said it discovered a ninth U.S. feed grain cargo tainted with Bt10 biotech corn, and has told the importer to destroy it or ship it back to the United States.

Thursday, 25th August: Ten shipments and 32,610 tons of tainted corn quarantined in Japan.

Tuesday, 16th January 2007: The European Commission lifted the extra controls on the US for Bt10 in imports of maize from the USA.