Swiss biotechnology company Syngenta AG said yesterday it mistakenly sold to farmers an experimental corn seed genetically engineered to resist bugs that was never approved by US regulators. Hundreds of tons of the resulting corn crop were shipped to consumers and overseas between 2001 and 2004, but three US government agencies investigating said there was no health or environmental risk because of the seed’s similarity to another Syngenta product approved for sale and consumption by federal regulators.’'While there are no safety concerns, the regulatory agencies are conducting investigations to determine the circumstances surrounding and extent of any violations of relevant laws and regulations,” said Cynthia Bergman, an Environmental Protection Agency spokeswoman. ''The US government is also communicating with our major trading partners to ensure they understand there are no food safety or environmental concerns that could affect trade."The Department of Agriculture and the Food and Drug Administration are also investigating.