Excessive fipronil — an insecticide banned for use on farm animals because of its danger to human health — was found in batches of eggs | Andreas Rentz/Getty Images Brussels warns egg scandal could now involve seven countries Dutch farmers fear that fipronil fiasco could become even more damaging.

Brussels said today that eggs contaminated with the harmful chemical fipronil may have been sold in some seven countries, significantly escalating the geographical scope of the scandal.

Dutch authorities said in late July that they had shut poultry farms after finding high levels of fipronil — an insecticide banned for use on farm animals because of its danger to human health — in batches of eggs.

A Belgian company is under investigation for creating an illegal mite-killer containing fipronil. Belgium launched an investigation in June, but did not notify the European Commission until July. Germany, which receives Dutch egg shipments, launched its own investigation in July.

European Commission spokeswoman Anna-Kaisa Itkonen today said that the Netherlands, Belgium and Germany warned other countries through the European Union's food-safety alert system that they may have exported contaminated eggs to them.

The Netherlands warned Sweden that it had sent it eggs on August 4, while sending a similar warning to Switzerland on August 6. Germany, meanwhile warned on August 5 that it had distributed eggs to France and the U.K.

"It's up to the Swedish, Swiss and French authorities to check, because all these eggs are traceable," Itkonen said.

In the Netherlands, farmers have warned that the growing egg scandal could become even more damaging.

Reuters reported today that a spokesman for Dutch farmers' lobby LTO said that the fipronil scandal could force authorities to cull millions of chickens.