Following a mishap in 2001 at Syngenta, the company developing the product, Bt10 maize has been grown in the USA without approval: the developers inadvertently provided this unapproved strain of GM maize seed to some U.S. farmers, while believing that they were selling seed from the deregulated GM maize Bt11. Upon being alerted by the U.S. authorities, the EU required all maize and maize gluten imports to be certifiably Bt10 free.
The only case of Bt10 actually being detected in a US shipment to the EU was in May 2005, and Bt10 was last found on the USA market in November 2005. Syngenta also has taken several measures to prevent further propagation of Bt10, and authorities in the US and the EU consider the problem to be solved. The European Member States consequently voted in favour of lifting the certificate requirement - however, national food inspectors will continue to test food and feed for Bt10 maize for the next six months.